All EyeLink Eye Tracker Publications
All 14,000+ peer-reviewed EyeLink research publications up until 2025 (with some early 2026s) are listed below by year. You can search the publications library using keywords such as Visual Search, Smooth Pursuit, Parkinson’s, etc. You can also search for individual author names. Eye-tracking studies grouped by research area can be found on the solutions pages. If we missed any EyeLink eye-tracking papers, please email us!
2026 |
Ting Zhang; Shujia Zhang; Yi Jiang Automatic pupillary responses to pain perception in adults and children: The influence of race and autistic traits Journal Article In: Cognition, vol. 268, pp. 1–9, 2026. @article{Zhang2026d,The ability to understand and share others' emotional states (e.g., feeling of pain) plays a fundamental role in survival and prosocial behavior. The current study utilized pupillometry to assess automatic psychophysiological responses to others' painful facial expressions in both adults and children (N = 72). Results revealed that pupil size significantly increased when perceiving painful versus neutral expressions, independent of low-level visual features. Notably, both adults and children exhibited a racial in-group bias, with pupil dilation effects observed only for same-race painful faces. Furthermore, individuals' Autism Spectrum Quotient scores were negatively correlated with pupil dilation effects toward painful expressions of same-race faces. These findings suggest that pupillary responses might reflect automatic empathic arousal to others' pain and are modulated by racial group membership and autistic traits, providing a potential physiological indicator, at least at the group level, for probing affective resonance in children or individuals with socio-cognitive disorders (e.g., autism spectrum disorder). |
Sara LoTemplio; Jack Silcox; David L. Strayer; Brennan R. Payne Single‐trial relationships between the error‐related negativity, pe, error‐related pupillary dilation response, and post‐error behavior Journal Article In: Psychophysiology, vol. 63, no. 1, 2026. @article{LoTemplio2026,The amplitude of the error‐related negativity (ERN) is known to be correlated with attention to task and general cognitive control abilities. However, previous research has struggled to consistently link ERN amplitude with behavioral accuracy or reaction time in the task from which the ERN is being measured. This lack of relationship could be due to many factors that are difficult to control for, so explorations of other converging measures to understand error‐processing and subsequent behavior adjustment are warranted. The current study examines how two other physiological markers of error‐processing—the phasic pupillary dilation response (PDR) and the positivity following an error (Pe)—relate to post‐error behavior. Additionally, we also examine relationships between the three physiological indices of error‐processing. In the study, EEG and pupillometry were simultaneously recorded while participants completed 24 blocks (50 trials each) of an Ericksen Flanker task. For post‐error accuracy, we found that on a single‐trial level, the amplitude of all three physiological error‐processing indices for error trials predicted post‐error accuracy. At the subject level, only the PDR predicted average post‐error accuracy. For post‐error slowing, at the single‐trial level, only the Pe predicted post‐error slowing, whereas only the ERN predicted post‐error slowing at the subject level. We also found that both the ERN and Pe correlated with PDR amplitude. This is consistent with our hypothesis that the Pe and PDR may share underlying neural mechanisms, but qualified by the fact that the ERN, which is not hypothesized to have shared neural mechanisms, also predicted unique variance in pupillary amplitude. Collectively, these results suggest that the PDR and Pe might represent promising indicators of post‐error behavior adjustment and highlight the need to examine relationships at multiple levels of analysis. |
Madeline Jarvis; Adam Vasarhelyi; Joe Anderson; Caitlyn Mulley; Ottmar V. Lipp; Luke J. Ney js-mEye: An extension and plugin for the measurement of pupil size in the online platform jsPsych Journal Article In: Behavior Research Methods, vol. 58, no. 1, pp. 1–18, 2026. @article{Jarvis2026,The measurement of pupil size has become a topic of interest in psychology research over the past two decades due to its sensitivity to psychological processes such as arousal or cognitive load. However, pupil measurements have been limited by the necessity to conduct experiments in laboratory settings using high-quality and costly equipment. The current article describes the development and use of a jsPsych plugin and extension that incorporates an existing software that estimates pupil size using consumer-grade hardware, such as a webcam. We validated this new program (js-mEye) across two separate studies, which each manipulated screen luminance and color using a novel luminance task, as well as different levels of cognitive load using the N-back and the Stroop tasks. Changes in luminance and color produced significant changes in pupil size in the hypothesized direction. Changes in cognitive load induced in the N-back and Stroop tasks produced less clear findings; however, these findings were explained to some extent when participant engagement – indexed by task performance – was controlled for. Most importantly, all data were at least moderately correlated with data simultaneously recorded using an EyeLink 1000, suggesting that mEye was able to effectively substitute for a gold-standard eye-tracking device. This work presents an exciting future direction for pupillometry and, with further validation, may present a platform for measuring pupil size in online research studies, as well as in laboratory-based experiments that require minimal equipment. |
2025 |
Béla Weiss; Annamária Manga; Ádám Nárai; Adél Bihari; Judit Zsuga; Zoltán Vidnyánszky Reward boosts cognitive control during working memory maintenance Journal Article In: Scientific Reports, vol. 15, no. 1, 2025. @article{Weiss2025,Working memory (WM) involves short-term maintenance and manipulation of goal-relevant information, with cognitive control playing a crucial role in these processes due to WM's limited capacity. Pupillometry studies show distinct pupillary changes for WM stages, reflecting cognitive effort and load. Motivational incentives enhance WM performance by potentially improving encoding, maintenance, or retrieval, though the specific components influenced by reward remain unclear. This study specifically tested whether reward modulates cognitive control processes during WM maintenance using pupillometry. Participants performed a delayed-estimation orientation WM task with reward cues indicating reward levels at the beginning of trials. The results revealed that motivational incentives significantly improved WM performance and increased pupillary dilation during maintenance. These findings provide evidence for the modulation of WM maintenance by reward through enhanced top-down cognitive control processes. |
Vanessa C. Radtke; Wanja Wolff; Corinna S. Martarelli How effortful is boredom? Studying self-control demands through pupillometry Journal Article In: Collabra: Psychology, vol. 11, no. 1, pp. 1–24, 2025. @article{Radtke2025,Self-control is essential for managing actions, yet its exertion is perceived as effortful. Performing a task may require effort not only because of its inherent difficulty but also due to its potential for inducing boredom, as boredom has been shown to be self-control demanding itself. So far, the extent of self-control demands during boredom and its temporal dynamics remain elusive. We employed a multimethod approach to address this knowledge gap. Ninety-five participants took part in an easy and hard version of the Stroop task. During both tasks, they indicated several times their perceived task difficulty, boredom, boredom-related effort, difficulty-related effort, overall effort, and fatigue. We tested whether pupil size, as a physiological indicator of cognitive effort, was predicted more accurately by difficulty- and boredom-related effort together than by task-difficulty-related effort alone. The best model fit included boredom-, difficulty-related effort, and their interactions with task type (easy, hard Stroop). Tonic pupil size increased during the easy Stroop, while phasic pupil size decreased with greater boredom-related effort in both tasks. Greater difficulty-related effort was linked to increases in tonic and phasic pupil size in the easy, but not in the hard Stroop. Finally, boredom-related effort in the Stroop predicted performance in a subsequent flanker task. Our results provide preliminary support that enduring boredom may not only be perceived as effortful but also be reflected in psychophysiological changes. Moreover, it may influence subsequent behavior. This underscores the importance of considering boredom as a potential confound in self-control research and broader study designs. |
Oria Pitem; Yaniv Mama Predicting long-term memory via pupillometry Journal Article In: Scientific Reports, vol. 15, no. 1, 2025. @article{Pitem2025,Pupillometry research has established that pupil size reflects cognitive processes through autonomic nervous system activity, with high arousal triggering pupil dilation. Studies examining pupil size during encoding have yielded conflicting results regarding its relationship with subsequent memory performance, and few have investigated baseline pupil size. This study examined whether pupil diameter before and during stimulus presentation predicts memory performance. We hypothesized that successfully recalled words would be associated with larger pupils than forgotten words, based on the role of arousal and attention in memory formation. To test these hypotheses, we conducted two experiments in which we tracked ninety-five psychology students' eyes while they performed a long-term memory test. The results depict larger pupil size while studying later successfully retrieved words. Interestingly, this phenomenon also occurs before word presentation (during baseline), which supports the “readiness to remember” (R2R) framework. This implies that pupillary changes while preparing to encode information can indicate later memory performance. |
Claire O'Callaghan; Frank H. Hezemans; Naresh Subramaniam; Rong Ye; Kamen A. Tsvetanov; Alexander G. Murley; Negin Holland; Isabella F. Orlando; Ralf Regenthal; Roger A. Barker; Caroline H. Williams-Gray; Luca Passamonti; Trevor W. Robbins; James B. Rowe Pharmacological and pupillary evidence for the noradrenergic contribution to reinforcement learning in Parkinson's disease Journal Article In: Communications Biology, vol. 8, no. 1, pp. 1–15, 2025. @article{OCallaghan2025,Noradrenaline plays an integral role in learning by optimising behavioural strategies and facilitating choice execution. Testing the noradrenergic framework of learning in the context of human diseases offers a test bed for current normative neuroscience theories and may also indicate therapeutic potential. Parkinson's disease is often considered as a model of dopamine deficits, including dopamine's role in reinforcement learning. However, noradrenergic function is also severely impaired by Parkinson's disease, contributing to cognitive deficits. Using a single dose of the noradrenaline reuptake inhibitor atomoxetine in people with Parkinson's disease (in a randomised double-blind placebo-controlled crossover design), we show improvements in learning compared to placebo. Computational cognitive modelling confirmed a substantial shift in the decision noise parameter, indicative of more exploitative choices. This response pattern closely resembled that of age-matched controls and simulations of optimal response strategies. Pupillometry revealed increased baseline pupil diameter under atomoxetine, which correlated with behavioural improvements, and a heightened phasic pupillary response to feedback. Our findings confirm the noradrenergic contribution to reinforcement learning, and in doing so they challenge the simple interpretation of tonic-phasic locus coeruleus firing patterns based on pupillometry. Noradrenergic modulation is a potential treatment strategy for cognitive symptoms in Parkinson's disease and related disorders. |
Justin T. Fleming; Matthew B. Winn Seeing a talker's mouth reduces the effort of perceiving speech and repairing perceptual mistakes for listeners with cochlear implants Journal Article In: Ear and Hearing, vol. 46, no. 6, pp. 1502–1518, 2025. @article{Fleming2025,Objectives: Seeing a talker's mouth improves speech intelligibility, particularly for listeners who use cochlear implants (CIs). However, the impacts of visual cues on listening effort for listeners with CIs remain poorly understood, as previous studies have focused on listeners with typical hearing (TH) and featured stimuli that do not invoke effortful cognitive speech perception challenges. This study directly compared the effort of perceiving audiovisual speech between listeners who use CIs and those with TH. Visual cues were hypothesized to yield more relief from listening effort in a cognitively challenging speech perception condition that required listeners to mentally repair a missing word in the auditory stimulus. Eye gaze was simultaneously measured to examine whether the tendency to look toward a talker's mouth would increase during these moments of uncertainty about the speech stimulus. Design: Participants included listeners with CIs and an age-matched group of participants with typical age-adjusted hearing (N = 20 in both groups). The magnitude and time course of listening effort were evaluated using pupillometry. In half of the blocks, phonetic visual cues were severely degraded by selectively blurring the talker's mouth, which preserved stimulus luminance so visual conditions could be compared using pupillometry. Each block included a mixture of trials in which the sentence audio was intact, and trials in which a target word in the auditory stimulus was replaced by noise; the latter required participants to mentally reconstruct the target word upon repeating the sentence. Pupil and gaze data were analyzed using generalized additive mixed-effects models to identify the stretches of time during which effort or gaze strategy differed between conditions. Results: Visual release from effort was greater and lasted longer for listeners with CIs compared with those with TH. Within the CI group, visual cues reduced effort to a greater extent when a missing word needed to be repaired than when the speech was intact. Seeing the talker's mouth also improved speech intelligibility for listeners with CIs, including reducing the number of incoherent verbal responses when repair was required. The two hearing groups deployed different gaze strategies when perceiving audiovisual speech. CI listeners looked more at the mouth overall, even when it was blurred, while TH listeners tended to increase looks to the mouth in the moment following a missing word in the auditory stimulus. Conclusions: Integrating visual cues from a talker's mouth not only improves speech intelligibility but also reduces listening effort, particularly for listeners with CIs. For listeners with CIs (but not those with TH), these visual benefits are magnified when a missed word needs to be mentally corrected—a common occurrence during everyday speech perception for individuals with hearing loss. These results underscore the importance of including participants with hearing loss in listening effort studies and suggest caution in assuming results from TH listeners will generalize to those with hearing loss. They also highlight the potential clinical relevance of visual speech information, for counseling patients and families and potentially for the development of audiovisual strategies to reduce listening effort. |
Chloe Brittenham; Antoinette Sabatino DiCriscio; Vanessa Troiani; Yirui Hu; Jennifer B. Wagner Task-evoked pupil responses during free-viewing of hierarchical figures in relation to autistic traits in adults Journal Article In: Scientific Reports, vol. 15, no. 1, pp. 1–15, 2025. @article{Brittenham2025,Sensory processing differences, particularly within the visual domain, are common in neurodevelopmental conditions, including autism. Studies examining hierarchical processing of figures containing global (i.e., gist) and local (i.e., detail) elements are inconsistent but converge on a common theme in relation to autism: slowed global processing and a locally-oriented default. We examined behavioral and pupillary responses in adults with varying levels of autistic traits during a free-viewing hierarchical processing task. Results showed that participants were both more likely and faster to report global elements, but contrary to our hypothesis, differences in level of autistic traits were unrelated to spontaneous reporting of global vs. local elements. When examining phase-based analysis of pupillary responses, participants high on autistic traits showed more early and less later constriction within trials. Further, trajectory-based pupillary analysis revealed two trajectories, one characterized by constriction and the other dilation, and results showed that the dilation group disproportionately included low traits individuals. Findings suggest that although high and low traits groups showed similar behavioral responses, visual strategies used may differ, as indicated by pupillometry. This study advances our understanding of the relationship between autistic traits and visual processing, laying groundwork for further investigations into neurodivergent visual processing mechanisms. |
Tanvi Thakkar; Jarett Knoepker; Stephen R. Dennison; Joseph P. Roche; Ruth Y. Litovsky Spatial separation enhances speech intelligibility but increases listening effort with session-dependent variability in pupillometric measures Journal Article In: Frontiers in Neuroscience, vol. 19, pp. 1–13, 2025. @article{Thakkar2025,Introduction: The current understanding of the cognitive load of listening effort has been advanced by combining speech intelligibility and pupillometry measures. However, the reliability of pupil dilation metrics in complex listening scenarios like spatial release from masking (SRM) remains uncertain. This study investigated how spatial separation of sound sources impacts listening effort (via peak pupil dilation, PPD) and speech intelligibility. Methods: Speech intelligibility and listening effort were simultaneously measured under co-located and symmetric, spatially-separated conditions at varying signal-to-noise ratios (SNRs). Results: Results showed that although spatial separation improved speech intelligibility, it did not yield a corresponding reduction in listening effort. Instead, listening effort increased as SNR became more challenging. Furthermore, test–retest reliability was moderate-to-high for speech intelligibility but only moderate-to-low for PPD, with greater consistency observed at more challenging SNRs. These results suggest that obtaining stable PPD measures within an SRM paradigm may be difficult to achieve. Discussion: These findings indicate that obtaining stable PPD measures within an SRM paradigm can be challenging. Test session reliability is weak when combining SRM paradigms with measures of listening effort, which may reduce statistical power due to factors such as sample size, number of trials, and sessions tested. This is further limited by the relatively small and homogeneous sample of young, typical hearing adults. Future studies should include a larger and more diverse participant group to assess the generalizability of these results. |
Matthew A. Parrella; Isshori Gurung; Michael A. Grubb Luminance matching in cognitive pupillometry is not enough: The curious case of orientation Journal Article In: eNeuro, vol. 12, no. 11, pp. 1–10, 2025. @article{Parrella2025,Abrupt onsets reflexively shift covert spatial attention. Recent work demonstrated that trial-to-trial information about the probability of a peripheral onset modulated the magnitude of the attentional cueing effect (low probability > high probability). Although onsets were physically identical, pupil responses could have been modulated by information about the probability of the onset's appearance. Specifically, anticipatory constrictions may have preceded high-probability onsets. Here, we tested this hypothesis using centrally presented, luminance-matched onset-probability signals. For half the participants, vertical signaled high probability (0.8) of onset appearance, while horizontal signaled low probability (0.2). Contingencies were reversed for the other half. Participants fixated the onset-probability signal for 2,000 ms before the onset was briefly presented or omitted, in line with the signaled probability. To maintain engagement, participants completed a simple localization task. Preliminary evidence for an anticipatory reduction in the pupil area was obtained in Experiment 1. However, this effect disappeared in Experiment 2 with a larger replication sample. Exploratory analyses uncovered a violation of a fundamental methodological assumption: despite being task-irrelevant and perfectly luminance-matched, vertical onset-probability signals consistently generated smaller pupil areas, relative to horizontal signals in both Experiments 1 and 2. Interestingly, this “orientation effect” was stronger in the second half of the experimental session, and in a third experiment, we significantly reduced its magnitude by changing the locations of the task-relevant stimuli. In short, across three experiments (self-reported gender, 52 females, 26 males, 1 nonbinary), we show that even with perfect luminance matching, unforeseen changes in cognitive state can modulate pupillometric measurements. |
Yu-Jeh Liu; Mounya Elhilali Sound identity, salience, and perceived importance in complex auditory environments Journal Article In: The Journal of the Acoustical Society of America, vol. 158, no. 4, pp. 3489–3502, 2025. @article{Liu2025s,Human listeners effortlessly identify salient sounds in their environments, yet the relationship between sound class identity, auditory salience, and perceived importance in complex auditory scenes remains poorly understood. In this study, we investigate these connections with scores derived from subject responses using a scoring mechanism, combined with auditory salience and pupillometry data. By leveraging both psychophysical experiments as well as a large-scale annotated dataset, our findings reveal biased responses and higher importance rankings for specific sound classes, such as alarm sounds and speech, and highlight a consistent perceptual ordering of sounds based on their identity. Salience judgments and pupillary responses further support this distinction, showing that the level of heightened arousal follows the same sound class order. The results underscore the influence of semantic mappings on both bottom-up and top-down sensory processing, suggesting that sound identity plays a crucial role in shaping perceptual judgment and neural responses. Despite dataset limitations, our findings offer insights into auditory scene analysis and provide a novel framework for understanding how auditory perception prioritizes sounds based on both their inherent properties and learned semantic associations. |
Yuen Lai Chan; Xi Cheng; Chi Shing Tse Eye on ambiguity: Effects of valence and valence ambiguity on silent word reading and surprise memory recall using pupillometry Journal Article In: Psychonomic Bulletin & Review, vol. 32, no. 5, pp. 2158–2166, 2025. @article{Chan2025a,This study investigates the impact of valence and valence ambiguity on silent word reading and memory recall using pupillometry. While emotional stimuli are found to influence pupil dilation, there have been mixed findings for the effects of valence in the literature. This study aimed to examine this effect by controlling for extraneous lexical variables (e.g., word and character frequency) and considering valence ambiguity as a distinct factor in linear mixed effects modelling analyses. Native Cantonese-speaking university students (N = 94) engaged in a silent reading task of 90 two-character Chinese words, with their pupillary responses being recorded, followed by a surprise memory recall test. The words varied in valence (negative, neutral, positive) and valence ambiguity (high, low). Analyses revealed that valence ambiguity increased pupil dilation, providing support for the deeper and more elaborated processing associated with words with higher valence ambiguity. While there was no significant effect of valence on pupil dilation, the valence × valence ambiguity interaction showed that negative words with higher ambiguity elicited greater pupil dilation than those with lower ambiguity. Memory recall performance was enhanced by valence ambiguity, independent of word valence, indicating that words with higher valence ambiguity foster more elaborated memory encoding even when it is incidental. These findings further our understanding of pupil dilation in emotional processing during silent word reading and the role of valence ambiguity during memory encoding. |
Yahel Dror Ben-Baruch; Noga Cohen Look fear in the eyes: The influence of emotion regulation on spider size estimation—a pupillometry study Journal Article In: Psychophysiology, vol. 62, no. 10, pp. 1–16, 2025. @article{BenBaruch2025,The link between perceptual biases and fear has been extensively documented in recent years. For example, the size of spiders is overestimated among people with a high fear of them. While emotion regulation processes are known to reduce fear, it is yet unknown whether emotion regulation can also reduce fear-related perceptual biases. This study examined the behavioral and physiological influence of cognitive reappraisal, an adaptive emotion regulation strategy, on spider size estimation among women with a high fear of spiders. Forty women with a high fear of spiders completed a trial-by-trial task with three conditions: (1) reappraising a negative image (reappraise-negative), (2) passively viewing a negative image (watch-negative), and (3) passively viewing a neutral image (watch-neutral). Following each condition, participants estimated the size of either a spider or a butterfly depicted in a picture. Pupil size was tracked to assess arousal and regulation-related processes. Results showed that reappraisal was associated with greater pupil dilation, reflecting heightened cognitive effort. Following reappraisal, participants reported the animals as smaller. Pupil size during the reappraisal assignment did not mediate the effect of condition on size ratings, suggesting that cognitive effort during the regulation did not predict the perceptual bias. Together, the findings suggest that instructed reappraisal can reduce perceptual biases associated with fearful stimuli, and that pupil dilation can serve as a physiological marker of emotion regulation. We discuss the implications of the findings for the understanding of the links between emotion regulation and perceptual biases. |
Annika Agrawal; Antje Nuthmann Eyes wide open: Object-scene congruency and the pupillary response Journal Article In: Neuropsychologia, vol. 217, pp. 1–11, 2025. @article{Agrawal2025a,The pupil response has long been considered a robust marker of cognitive load. In the context of semantic processing, research has demonstrated that the pupil dilates in response to stimuli which violate contextual expectations (e.g. events presented out of chronological order). However, the scope of this relationship has yet to be fully elucidated. For example, incongruent object-scene relationships, while comprehensively explored by eye-tracking and electrophysiology research, have yet to be investigated via pupillometry. In this study, we measured pupil size in response to an object-scene congruency task. Participants were presented with a photorealistic background scene and instructed to fixate their gaze on a cued point within the scene. Upon recovery of pupil size to baseline, a congruent object (i.e. an object which fit into the overall meaning of the scene) or an incongruent object appeared at the cued fixation point for the remainder of each trial. We hypothesized that incongruent objects would result in greater mean pupil dilation from baseline than congruent objects, due to the increase in cognitive effort required for semantic processing of incongruent objects within a scene. Yet, in opposition to our hypothesis, the results of a time-course analysis revealed that pupil size was significantly greater for the congruent condition than the incongruent condition. The resulting implications for understanding pupil dilation as a physiological marker, both independently and in comparison to other markers, for high-level cognitive processes such as semantic integration are discussed. |
Swati Sharma; Mrinmoy Chakrabarty; Sonia Baloni Ray; Jainendra Shukla Machine learning-driven analysis of temporal pupil dynamics for interpretable ADHD diagnosis Journal Article In: Computers in Biology and Medicine, vol. 196, pp. 1–16, 2025. @article{Sharma2025b,Attention-deficit/hyperactivity disorder (ADHD) is a prevalent neurodevelopmental disorder characterized by inattention and hyperactivity. Current diagnostic methods rely on bias-prone subjective assessments, such as clinical interviews and behavior rating scales. Objective biomarkers remain elusive hindering standardized ADHD diagnosis. Pupillometry, measuring pupil responses linked to cognition and attention, offers a promising, objective alternative. However, prior work often overlooks clinically relevant features and lacks interpretability, limiting clinical adoption. We introduce an interpretable machine-learning framework leveraging temporal pupil dynamics to classify ADHD and control groups. The primary novelty of our work lies in identifying and statistically validating task-aligned features-specifically, novel dynamic pupil dilation and constriction rates extracted in block-wise temporal segments-which capture subtle attentional fluctuations overlooked by prior models. We analyzed published pupillometry data from 49 participants (21 controls, 28 ADHD, 17 assessed on and off medication) during a visuospatial working memory task. Candidate features were identified through statistical analyses using mixed analysis of variance. Classification models were trained to prioritize interpretability by utilizing statistically significant, literature-supported features. Model transparency was enhanced with heatmaps and feature-importance charts. The models demonstrated strong classification performance: using pupil features alone yielded 84.4% accuracy (area under the receiver operating characteristic (AUROC) 88.6%). Including task performance improved accuracy to 86.7% (AUROC 91.5%). Final integration of reaction time metrics achieved 88.9% accuracy (AUROC 90.8%), with 97.8% sensitivity and 82.2% specificity. By leveraging interpretable, dynamic pupil metrics, our approach advances objective, reproducible ADHD diagnosis and supports clinical deployment. |
Ziyue Hu; Dominic M. D. Tran; Reuben Rideaux Multimodal evidence challenges the effectiveness of probabilistic cueing for establishing sensory expectations Journal Article In: Imaging Neuroscience, vol. 3, pp. 1–19, 2025. @article{Hu2025b,Predictive coding theories posit a reduction in error-signaling neural activity when incoming sensory input matches existing expectations—a phenomenon termed expectation suppression. However, the empirical evidence for expectation suppression, as well as its underlying neural mechanism, is contentious. A further aspect of predictive coding that remains untested is how predictions are integrated across sensorimotor domains. To investigate these two questions, we employed a novel cross-domain probabilistic cueing paradigm, where participants were presented with both visual and motor cues within a single trial. These cues manipulated the orientation and temporal expectancy of target stimuli with 75% validity. Participants completed a reproduction task where they rotated a bar to match the orientation of the target stimulus while their neural and pupil responses were respectively measured via electroencephalography and eye tracking. Our results showed a consistent, feature-unspecific effect of motor expectancy across multiple measures, while evidence for visual expectancy was limited. However, neither motor nor visual expectancy modulated the fidelity of sensory representations. These results indicate that violations of temporal expectancy in the current study may reveal the brain's intrinsic sensitivity to temporal regularities in the natural settings, rather than feature-specific predictions. In contrast, the absence of visual expectancy effects in both neural and pupillometry results adds to a growing body of evidence questioning the effectiveness of probabilistic cueing paradigms for establishing expectations capable of altering sensory representations. Due to null findings in the visual and sensory representation analyses, we did not further investigate cross-domain prediction integration. |
Laura Doll; Sabine Heiland; Alexander Gutschalk A role of pupil-linked arousal, cingulo-insular cortex, and intralaminar thalamus for auditory near-threshold perception Journal Article In: Journal of Cognitive Neuroscience, vol. 37, no. 9, pp. 1391–1415, 2025. @article{Doll2025,The perception of near-threshold tones varies strongly across trials, likely because of fluctuations in sustained attention or arousal. We used parallel fMRI and pupillometry to study the role of attention networks for the detection of near-threshold tones in three phases: (1) passive listening, (2) active detection of salient tones, and (3) active detection of near-threshold tones. Results confirmed previous findings from magnetoencephalography that auditory cortex activity and pupil-dilation responses for near-threshold tones were only observed when task-relevant, stronger for hit trials, but also present for miss trials. We then sought which attention-related areas show a similar response pattern, and found it in insular cortex, anterior midcingulate cortex, and inferior precentral sulcus. Moreover, activity in the insula was already stronger for hit than miss trials in the prestimulus interval. Activity for hit trials was also observed in a number of subcortical nuclei, including thalamus, periaqueductal gray, locus coeruleus, and the colliculi. Like insula, activity in the intralaminar nuclei of the thalamus additionally showed activity for miss trials and stronger activity for hit trials in the baseline. Finally, BOLD activity correlated to spontaneous pupil fluctuations was evaluated and revealed biphasic activation and deactivation in a widespread cortical network, with a maximum 3 sec and minimum 7 sec after pupil dilation. The cortical networks included insula, anterior midcingulate cortex, retro-splenial, and sensory cortex. Overall, these data identify the cingulo-insular network and the intralaminar thalamic nuclei as potential sources of fluctuations in auditory cortex activity in the context of near-threshold tone detection. |
Giacomo Scanavini; Isabelle Martin; Ludvik Alkhoury; Ana Radanovic; Yakira Tepler; Abhishek Jaywant; N. Jeremy Hill; Tracy Butler; Keith W. Jamison; Amy Kuceyeski; Nicholas D. Schiff; Sudhin A. Shah Coupling of event-related potential and pupil dilation as a compensatory marker of executive attention in traumatic brain injury Journal Article In: Neurotrauma Reports, vol. 6, no. 1, pp. 706–719, 2025. @article{Scanavini2025,Traumatic brain injury (TBI) impairs attention and executive function, often through disrupted coordination between cognitive and autonomic systems. While electroencephalography (EEG) and pupillometry are widely used to assess neural and autonomic responses independently, little is known about how these systems interact in TBI. Understanding their coordination is essential to identify compensatory mechanisms that may support attention under conditions of neural inefficiency. In this study, we examined pupil dilation during the Attention Network Test in individuals with TBI (n = 25) and controls without brain injury (n = 45). TBI participants exhibited preserved accuracy but slower reaction times (RTs), suggesting increased cognitive effort. Paradoxically, this effort was not reflected in heightened pupil dilation. Instead, pupil responses were attenuated, suggesting impaired recruitment of the locus coeruleus-norepinephrine system and possible autonomic dysregulation. We further assessed the relationship between simultaneously recorded pupillary responses and visual evoked responses in a subset of those in whom both measures were available (n = 23, TBI; n = 35, controls). Crucially, while both pupil dilation and amplitude of the visual P3 event-related potential were reduced in TBI, these measures showed a positive correlation across participants with TBI; this was absent in controls. Our results suggest that TBI may induce a compensatory coupling between cortical and autonomic systems to sustain cognitive performance despite underlying dysfunction. Positive correlation between pupil dilation and event-related potential suggest a role for arousal dysregulation in subjects with TBI. Our findings provide new evidence for altered EEG-pupil dynamics in TBI and highlight the potential of combining cortical and autonomic measures as a multimodal biomarker for tracking recovery, stratifying injury severity, and guiding individualized rehabilitation strategies. |
Julie Kirwan; Deniz Başkent; Anita Wagner The time course of the pupillary response to auditory emotions in pseudospeech, music, and vocalizations Journal Article In: Trends in Hearing, vol. 29, pp. 1–14, 2025. @article{Kirwan2025,Emotions can be communicated through visual and dynamic characteristics such as smiles and gestures, but also through auditory channels such as laughter, music, and human speech. Pupil dilation has become a notable marker for visual emotion processing; however the pupil's sensitivity to emotional sounds, specifically speech, remains largely underexplored. This study investigated the processing of emotional pseudospeech, which are speech-like sentences devoid of semantic content. We measured participants' pupil dilations while they listened to pseudospeech, music, and human vocalizations, and subsequently performed an emotion recognition task. Our results showed that emotional pseudospeech can trigger increases of pupil dilation compared to neutral pseudospeech, supporting the use of pupillometry as a tool for indexing prosodic emotion processing in the absence of semantics. However, pupil responses to pseudospeech were smaller and slower than the responses evoked by human vocalizations. The pupillary response was not sensitive enough to distinguish between emotion categories in pseudospeech, but pupil dilations to music and vocalizations reflected some emotion-specific pupillary curves. The valence of the stimulus had a stronger overall influence on pupil size than arousal. These results highlight the potential for pupillometry in studying auditory emotion processing and provide a foundation for contextualizing pseudospeech alongside other affective auditory stimuli. |
David Clewett; Ringo Huang; Lila Davachi Locus coeruleus activation “resets” hippocampal event representations and separates adjacent memories Journal Article In: Neuron, vol. 113, no. 15, pp. 2521–2535.e1–e8, 2025. @article{Clewett2025,Memories reflect the ebb and flow of experiences, capturing distinct events from our lives. Using a combination of functional magnetic resonance imaging (fMRI), neuromelanin imaging, and pupillometry, we show that arousal and locus coeruleus (LC) activation segment continuous experiences into discrete memories. As sequences unfold, encountering a context shift or event boundary triggers pupil-linked arousal and LC processes that predict later memory separation. Boundaries, furthermore, promote temporal pattern separation within the left hippocampal dentate gyrus, which correlates with heightened LC responses to those same transition points. Unlike transient LC effects, indirect structural and functional markers of elevated background LC activation correlate with reduced arousal-related LC and pupil responses at boundaries, suggesting that hyperarousal disrupts event segmentation. Our findings support the idea that arousal mechanisms initiate a neural and memory “reset” in response to significant changes, fundamentally shaping the episodes that define episodic memory. |
Sabine Prantner; Alejandro Espino-Payá; M. Carmen Pastor; Cristina Giménez-García; Rafael Ballester-Arnal; Markus Junghoefer In: Psychophysiology, vol. 62, no. 7, pp. 1–21, 2025. @article{Prantner2025,Gender identity and sexual orientation form fundamental characteristics of an individual's sexual identity and relate to patterns of physiological and neural activity involved in processing erotic or explicit sexual stimuli. To investigate this, we used high-density magnetoencephalography (MEG) to measure brain responses of hetero- and homosexual women and men to opposite- and same-sex erotic images, as well as sexually explicit images. Additionally, we administered pupillometry and subjective measures of hedonic valence and emotional arousal. Erotic versus sexually explicit stimuli initially resulted in enhanced pupil dilation and stronger neural activity in the extended visual cortex, but at later times, reverse effects were found. Our results further showed that perceived affect varied by gender and sexual orientation, with significant group effects. Pupil measurements revealed differences in dilation depending on opposite- and same-sex erotic and sexually explicit images and participant groups. Similarly, effects of stimuli content were found for the neural activity. The findings suggest that preferred versus non-preferred stimuli are subjectively processed in a category-specific way, especially in hetero- and homosexual males as well as homosexual women compared to heterosexual women, and indicate a sensitivity to sexual images in affective-motivational and reward areas of the brain. To conclude, subjective, visual, and neural responses to sexually relevant stimuli seem partly dependent on gender and sexual orientation but predominanly indicate influences of stimulus content. |
Darías Holgado; Alice Cailleux; Paolo Ruggeri; Corinna Martarelli; Tristan A. Bekinschtein; Daniel Sanabria; Nicolas Place Individualized cognitive effort to failure does not affect subsequent strenuous physical performance Journal Article In: Medicine & Science in Sports & Exercise, vol. 57, no. 7, pp. 1603–1615, 2025. @article{Holgado2025,Introduction The relationship between cognitive tasks and physical performance has garnered significant attention, with evidence suggesting that cognitive effort before exercise may impair physical performance. However, recent findings challenge the robustness of this effect, necessitating a reassessment of the mechanisms linking cognitive load to physical performance. This study introduces a novel approach to address methodological limitations, emphasizing individualized cognitive task difficulty and duration. Using techniques such as temporal experience tracing and psychophysiological monitoring, we explore the dynamics between cognitive effort, subjective states, and physical performance. Methods In a preregistered, randomized, within-participant design experiment, 21 recreational athletes completed a running time to exhaustion test at 90% of their maximal aerobic speed after performing a cognitive task until failure or watching a self-selected documentary. Pupillometry and six subjective dimensions were measured with the temporal experience tracing during task performance. Results We found that 1) subjective changes during effortful tasks are not limited to a single experience, such as mental fatigue or boredom, but can be grouped into distinct patterns; 2) the individualized and demanding cognitive task, completed before exercise, did not impair subsequent physical performance; 3) pupil size reliably reflected cognitive load and is partially related to changes in subjective states, while fixation on the stimulus decreased over time, especially during high-demand periods. Conclusions These results do not support the effect of performing a highly demanding cognitive task on subsequent strenuous physical performance. Instead, they reveal the richness of the subjective experience linked to cognitive performance that goes beyond mere mental fatigue. Overall, we show a novel way to understand the interplay between cognitive and physical performance. |
Lola Beerendonk; Jorge F. Mejías; Stijn A. Nuiten; Jan Willem Gee; Jasper B. Zantvoord; Johannes J. Fahrenfort; Simon Gaal Adaptive arousal regulation: Pharmacologically shifting the peak of the Yerkes–Dodson curve by catecholaminergic enhancement of arousal Journal Article In: PNAS, vol. 122, no. 28, pp. 1–11, 2025. @article{Beerendonk2025,Performance typically peaks at moderate arousal levels, consistent with the Yerkes–Dodson law, as confirmed by recent human and mouse pupillometry studies. Arousal states are influenced by neuromodulators like catecholamines (noradrenaline and dopamine) and acetylcholine. To investigate their contributions to this law, we pharmacologically enhanced arousal while measuring human decision-making and spontaneous arousal fluctuations via pupil size. The catecholaminergic agent atomoxetine increased overall arousal and shifted the entire arousal–performance curve, suggesting a relative arousal mechanism where performance adapts to arousal fluctuations within arousal states. In contrast, the cholinergic agent donepezil did not measurably affect arousal or the curve. We modeled these findings in a neurobiologically plausible computational framework, showing how catecholaminergic modulation alters a disinhibitory neural circuit that encodes sensory evidence for decision-making. This work suggests that performance adapts flexibly to arousal fluctuations, ensuring optimal performance in each and every global arousal state. |
Miao Zhong; Yiwen Yu; Shiqi Tan; Xiangyong Yuan; Yi Jiang Pupil dynamics and causality perception: Insights from pupillometry Journal Article In: Psychophysiology, vol. 62, no. 6, pp. 1–11, 2025. @article{Zhong2025,Causality perception is fundamental to interpreting interactions between objects in the physical world. However, little is known about whether physiological responses, particularly pupil size, can implicitly track causality perception. This study employed pupillometry across three experiments to investigate the relationship between pupil dynamics and causality perception. The results revealed that spatiotemporally contiguous launching events (i.e., direct launching), perceived as a causal collision between two objects, induced greater pupil dilation after the collision than simple single-object motion (i.e., passing and pass-by events) or motion with a temporally inverted cause-effect order (i.e., temporal-inverted events), both of which lacked a causal structure. However, launching with a spatial gap (i.e., gap launching) also elicited pupil dilation comparable to direct launching, although gap launching was rated lower in perceived causality. Temporal-inverted events provoked early pupil dilation, corresponding to the sudden and spontaneous motion of the first object. Furthermore, for invariant visual stimuli that could be perceived as either causal launching or noncausal passing (i.e., ambiguous events), pupil size changes did not differentiate between subjective causal and noncausal judgments. These findings indicate that although pupil dilation was evident during causality perception, it was not uniquely or directly tied to causality perception but was influenced by multiple factors, particularly responses to spontaneous motion. This study deepens the understanding of the physiological mechanisms underlying causality perception while also emphasizing the limitation of using pupillometry to examine it. |
Gabriel Wainstein; Christopher J. Whyte; Kaylena A. Ehgoetz Martens; Eli J. Müller; Vicente Medel; Britt Anderson; Elisabeth Stöttinger; James Danckert; Brandon R. Munn; James M. Shine Evidence from pupillometry, fMRI, and RNN modelling shows that gain neuromodulation mediates task-relevant perceptual switches Journal Article In: eLife, vol. 13, pp. 1–26, 2025. @article{Wainstein2025,Perceptual updating has been hypothesised to rely on a network reset modulated by bursts of ascending neuromodulatory neurotransmitters, such as noradrenaline, abruptly altering the brain's susceptibility to changing sensory activity. To test this hypothesis at a large-scale, we analysed an ambiguous figures task using pupillometry and functional magnetic resonance imaging (fMRI). Behaviourally, qualitative shifts in the perceptual interpretation of an ambiguous image were associated with peaks in pupil diameter, an indirect readout of phasic bursts in neuromodulatory tone. We further hypothesised that stimulus ambiguity drives neuromodulatory tone, leading to heightened neural gain, hastening perceptual switches. To explore this hypothesis computationally, we trained a recurrent neural network (RNN) on an analogous perceptual categorisation task, allowing gain to change dynamically with classification uncertainty. As predicted, higher gain accelerated perceptual switching by transiently destabilising the network's dynamical regime in periods of maximal uncertainty. We leveraged a low-dimensional readout of the RNN dynamics to develop two novel macroscale predictions: perceptual switches should occur with peaks in low-dimensional brain state velocity and with a flattened egocentric energy landscape. Using fMRI, we confirmed these predictions, highlighting the role of the neuromodulatory system in the large-scale network reconfigurations mediating adaptive perceptual updates. |
Arianna N. LaCroix; Ileana Ratiu Saccades and blinks index cognitive demand during auditory noncanonical sentence comprehension Journal Article In: Journal of Cognitive Neuroscience, vol. 37, no. 6, pp. 1147–1172, 2025. @article{LaCroix2025,Noncanonical sentence structures pose comprehension challenges because they require increased cognitive demand. Prosody may partially alleviate this cognitive load. These findings largely stem from behavioral studies, yet physiological measures may reveal additional insights into how cognition is deployed to parse sentences. Pupillometry has been at the forefront of investigations into physiological measures of cognitive demand during auditory sentence comprehension. This study offers an alternative approach by examining whether eye-tracking measures, including blinks and saccades, index cognitive demand during auditory noncanonical sentence comprehension and whether these metrics are sensitive to reductions in cognitive load associated with typical prosodic cues. We further investigated how eye-tracking patterns differ across correct and incorrect responses, as a function of time, and how each related to behavioral measures of cognition. Canonical and noncanonical sentence comprehension was measured in 30 younger adults using an auditory sentence-picture matching task. We also assessed participants' attention and working memory. Blinking and saccades both differentiate noncanonical sentences from canonical sentences. Saccades further distinguish noncanonical structures from each other. Participants made more saccades on incorrect than correct trials. The number of saccades also related to working memory, regardless of syntax. However, neither eye-tracking metric was sensitive to the changes in cognitive demand that was behaviorally observed in response to typical prosodic cues. Overall, these findings suggest that eye-tracking indices, particularly saccades, reflect cognitive demand during auditory noncanonical sentence comprehension when visual information is present, offering greater insights into the strategies and neural resources participants use to parse auditory sentences. |
Lukas Suveg; Tanvi Thakkar; Emily Burg; Shelly P. Godar; Daniel Lee; Ruth Y. Litovsky The relationship between spatial release from masking and listening effort among cochlear implant users with single-sided deafness Journal Article In: Ear and Hearing, vol. 46, no. 3, pp. 624–639, 2025. @article{Suveg2025,Objectives: To examine speech intelligibility and listening effort in a group of patients with single-sided deafness (SSD) who received a cochlear implant (CI). There is limited knowledge on how effectively SSD-CI users can integrate electric and acoustic inputs to obtain spatial hearing benefits that are important for navigating everyday noisy environments. The present study examined speech intelligibility in quiet and noise simultaneously with measuring listening effort using pupillometry in individuals with SSD before, and 1 year after, CI activation. The study was designed to examine whether spatial separation between target and interfering speech leads to improved speech understanding (spatial release from masking [SRM]), and is associated with a decreased effort (spatial release from listening effort [SRE]) measured with pupil dilation (PPD). Design: Eight listeners with adult-onset SSD participated in two visits: (1) pre-CI and (2) post-CI (1 year after activation). Target speech consisted of Electrical and Electronics Engineers sentences and masker speech consisted of AzBio sentences. Outcomes were measured in three target-masker configurations with the target fixed at 0° azimuth: (1) quiet, (2) co-located target/maskers, and (3) spatially separated (±90° azimuth) target/maskers. Listening effort was quantified as change in peak proportional PPD on the task relative to baseline dilation. Participants were tested in three listening modes: acoustic-only, CI-only, and SSD-CI (both ears). At visit 1, the acoustic-only mode was tested in all three target-masker configurations. At visit 2, the acoustic-only and CI-only modes were tested in quiet, and the SSD-CI listening mode was tested in all three target-masker configurations. Results: Speech intelligibility scores in quiet were at the ceiling for the acoustic-only mode at both visits, and in the SSD-CI listening mode at visit 2. In quiet, at visit 2, speech intelligibility scores were significantly worse in the CI-only listening modes than in all other listening modes. Comparing SSD-CI listening at visit 2 with pre-CI acoustic-only listening at visit 1, speech intelligibility scores for co-located and spatially separated configurations showed a trend toward improvement (higher scores) that was not significant. However, speech intelligibility was significantly higher in the separated compared with the co-located configuration in acoustic-only and SSD-CI listening modes, indicating SRM. PPD evoked by speech presented in quiet was significantly higher with CI-only listening at visit 2 compared with acoustic-only listening at visit 1. However, there were no significant differences between co-located and spatially separated configurations on PPD, likely due to the variability among this small group of participants. There was a negative correlation between SRM and SRE, indicating that improved speech intelligibility with spatial separation of target and masker is associated with a greater decrease in listening effort on those conditions. Conclusions: The small group of patients with SSD-CI in the present study demonstrated improved speech intelligibility from spatial separation of target and masking speech, but PPD measures did not reveal the effects of spatial separation on listening effort. However, there was an association between the improvement in speech intelligibility (SRM) and the reduction in listening effort (SRE) from spatial separation of target and masking speech. |
Nabil Hasshim; Molly Carruthers; Ludovic Ferrand; Maria Augustinova; Benjamin A. Parris No pupillometric evidence for effortful proactive control in the proportion-congruent Stroop paradigm Journal Article In: Quarterly Journal of Experimental Psychology, vol. 78, no. 5, pp. 884–896, 2025. @article{Hasshim2025,Cognitive control is the ability to allocate attention away from stimuli that are irrelevant to achieving a goal, towards stimuli that are. When conflict is anticipated, attention is biased in a global, top-down manner called proactive control and this effortful type of cognitive control is engaged before stimulus onset. The list-wise congruency proportion (LWPC) effect, where the Stroop congruency effect is reduced when there are more incongruent than congruent trials compared to vice versa, has been viewed as one of the prime signatures of this type of cognitive control. However, there has been recent debate about the extent to which this effect should be attributed to proactive control instead of alternative explanations such as simpler associative learning or reactive control. Thus, by using pupillometry (i.e., an indicator of cognitive effort), the present study investigated the extent to which LWPC effects result from effortful proactive control. Experiment 1 employed a classic proportion congruency manipulation, while Experiment 2 replaced congruent trials with neutral trials to control for potential effects of associative learning. While in line with past findings, proportion congruency effects were obtained in response times of both experiments and pupillometry showed both proportion congruency and Stroop effects after stimulus onset, no differences in pupil sizes were found during the preparatory phase. Therefore, these results do not support the idea that the observed LWPC effects are due to participants engaging in effortful proactive control. |
Catherine N. Moran; David P. McGovern; Mike Melnychuk; Alan F. Smeaton; Paul M. Dockree Oscillations of the wandering mind: Neural evidence for distinct exploration/exploitation strategies in younger and older adults Journal Article In: Human Brain Mapping, vol. 46, no. 6, pp. 1–23, 2025. @article{Moran2025a,This study traced the neurophysiological signals of fluctuating attention and task-related processing to ascertain the mechanistic basis of transient strategic shifts between competing task focus and mind-wandering, as expressed by the ‘exploitation/exploration' framework, and explored how they are differentially affected with age. Thirty-four younger (16 female, mean age 22 years) and 34 healthy older (20 female, mean age 71 years) adults performed the Gradual Contrast Change Detection task; monitoring a continuously presented flickering annulus for intermittent gradual contrast reductions and responding to experience sampling probes to discriminate the nature of their thoughts at discrete moments. Electroencephalography and pupillometry were concurrently recorded during target- and probe-related intervals. Older adults tracked the downward stimulus trajectory with greater sensory integrity (reduced target SSVEP amplitude) and demonstrated earlier initiation of evidence accumulation (earlier onset CPP), attenuated variability in the attentional signal (posterior alpha) and more robust phasic pupillary responses to the target, suggesting steadier attentional engagement with age. Younger adults only exhibited intermittent sensory encoding, indexed by greater variability in the sensory (SSVEP) and attentional (alpha) signals before mind-wandering relative to focused states. Attentional variability was accompanied by disrupted behavioural performance and reduced task-related neural processing, independent of age group. Together, this elucidates distinct performance strategies employed by both groups. Older adults suspended mind-wandering and implemented an exploitative oscillation strategy to circumvent their reduced cognitive resources and allay potential behavioural costs. Conversely, younger adults exhibited greater exploration through mind-wandering, utilising their greater cognitive resources to flexibly alternate between competing goal-directed and mind-wandering strategies, with limited costs. |
Jing Shen; Elizabeth Heller Murray Breathy vocal quality, background noise, and hearing loss: How do these adverse conditions affect speech perception by older adults? Journal Article In: Ear and Hearing, vol. 46, no. 2, pp. 474–482, 2025. @article{Shen2025a,Objectives: Although breathy vocal quality and hearing loss are both prevalent age-related changes, their combined impact on speech communication is poorly understood. This study investigated whether breathy vocal quality affected speech perception and listening effort by older listeners. Furthermore, the study examined how this effect was modulated by the adverse listening environment of background noise and the listener's level of hearing loss. Design: Nineteen older adults participated in the study. Their hearing ranged from near-normal to mild-moderate sensorineural hearing loss. Participants heard speech material of low-context sentences, with stimuli resynthesized to simulate original, mild-moderately breathy, and severely breathy conditions. Speech intelligibility was measured using a speech recognition in noise paradigm, with pupillometry data collected simultaneously to measure listening effort. Results: Simulated severely breathy vocal quality was found to reduce intelligibility and increase listening effort. Breathiness and background noise level independently modulated listening effort. The impact of hearing loss was not observed in this dataset, which can be due to the use of individualized signal to noise ratios and a small sample size. Conclusion: Results from this study demonstrate the challenges of listening to speech with a breathy vocal quality. Theoretically, the findings highlight the importance of periodicity cues in speech perception in noise by older listeners. Breathy voice could be challenging to separate from the noise when the noise also lacks periodicity. Clinically, it suggests the need to address both listener- and talker-related factors in speech communication by older adults. |
Yuqing Cai; Stefan Van der Stigchel; Julia Ganama; Marnix Naber; Christoph Strauch Uncovering distinct drivers of covert attention in complex environments with pupillometry Journal Article In: Psychophysiology, vol. 62, no. 3, pp. 1–15, 2025. @article{Cai2025b,Spatial visual attention prioritizes specific locations while disregarding others. The location of spatial attention can be deployed without overt movements (covertly). Spatial dynamics of covert attention are exceptionally difficult to measure due to the hidden nature of covert attention. One way to implicitly index covert attention is via the pupillary light response (PLR), as the strength of PLR is modulated by where attention is allocated. However, this method has so far necessitated simplistic stimuli and targeted only one driver of covert attention per experiment. Here we report a novel pupillometric method that allows tracking multiple effects on covert attention with highly complex stimuli. Participants watched movie clips while either passively viewing or top-down shifting covert attention to targets on the left, right, or both sides of the visual field. Using a recent toolbox (Open-DPSM), we evaluated whether luminance changes in regions presumably receiving more attention contribute more strongly to the pupillary responses—and thereby reveal covert attention. Three established effects of covert attention on pupil responses were found: (1) a bottom-up effect suggesting more attention drawn to more dynamic regions, (2) a top-down effect suggesting more attention towards the instructed direction, and (3) an overall tendency to attend to the left side (i.e. pseudoneglect). Beyond the successful validation of our method, these drivers of covert attention did not modulate each other's effects, indicating independent contributions of bottom-up, top-down, and pseudoneglect to covert attention in stimuli as dynamic as the present. We further explain how to use Open-DPSM to track covert attention in a brief tutorial. |
Dana Bsharat-Maalouf; Jens Schmidtke; Tamar Degani; Hanin Karawani Through the pupils' lens: Multilingual effort in first and second language listening Journal Article In: Ear and Hearing, vol. 46, no. 2, pp. 494–511, 2025. @article{BsharatMaalouf2025b,Objectives: The present study aimed to examine the involvement of listening effort among multilinguals in their first (L1) and second (L2) languages in quiet and noisy listening conditions and investigate how the presence of a constraining context within sentences influences listening effort. Design: A group of 46 young adult Arabic (L1)-Hebrew (L2) multilinguals participated in a listening task. This task aimed to assess participants' perceptual performance and the effort they exert (as measured through pupillometry) while listening to single words and sentences presented in their L1 and L2, in quiet and noisy environments (signal to noise ratio = 0 dB). Results: Listening in quiet was easier than in noise, supported by both perceptual and pupillometry results. Perceptually, multilinguals performed similarly and reached ceiling levels in both languages in quiet. However, under noisy conditions, perceptual accuracy was significantly lower in L2, especially when processing sentences. Critically, pupil dilation was larger and more prolonged when listening to L2 than L1 stimuli. This difference was observed even in the quiet condition. Contextual support resulted in better perceptual performance of high-predictability sentences compared with low-predictability sentences, but only in L1 under noisy conditions. In L2, pupillometry showed increased effort when listening to high-predictability sentences compared with low-predictability sentences, but this increased effort did not lead to better understanding. In fact, in noise, speech perception was lower in high-predictability L2 sentences compared with low-predictability ones. Conclusions: The findings underscore the importance of examining listening effort in multilingual speech processing and suggest that increased effort may be present in multilingual's L2 within clinical and educational settings. |
Paola Binda; Chiara Terzo; Marco Turi; David C. Burr Pupillometric signature of implicit learning of statistical regularities Journal Article In: Current Biology, vol. 35, no. 6, pp. 1431–1435, 2025. @article{Binda2025,Animals learn about the statistical regularities of their environment by a process of implicit learning, a powerful mechanism that may operate by mere exposure.1 Implicit learning supports processes such as speech acquisition but also learning about the spatial and temporal structure of the world more generally, which is essential for effective interaction.2 Here, we used a frequency-tagging technique to demonstrate a pupillometric signature of the learning of the temporal structure (pairing of numerosities) of sequential arrays. Although the numerosity pairings were unnoticed by all participants, the pupil responded clearly to their repetition frequency (1 Hz). Pupillometry allowed us to track the learning as it unfolded (the response became significant after less than 3 min of passive viewing), without ever directing attention to the temporal structure of the stimuli. Diverting attention away from the numerosity feature did not prevent learning, but it did affect the dynamics of the response acquisition. A clear pupillometric response was also elicited by pairing dyads of digits. In all our stimuli, the local features were randomized, implying that learning successfully generalized across stimuli that were locally different and only acquired a temporal structure once their global statistics (overall shape or numerosity) were extracted. |
Roos A. Doekemeijer; Quinn Cabooter; Intan K. Wardhani; Frederick Verbruggen; C. Nico Boehler From pupil to performance: Exploring the role of tonic norepinephrine levels in response inhibition using pretrial pupil measures Journal Article In: Psychophysiology, vol. 62, no. 2, pp. 1–13, 2025. @article{Doekemeijer2025,Response inhibition is key to flexible behavior. Importantly, performance in any task, including response inhibition tasks, fluctuates on a moment-to-moment basis. Using pupillometry, we investigated the relationship between these behavioral fluctuations in response inhibition and naturally occurring fluctuations of norepinephrine (NE) levels in the brain before a given trial has even started. This was motivated by earlier pharmacological work suggesting a pivotal role of NE in response inhibition, in particular. We specifically used two pupillometry proxies for pretrial (tonic) NE levels, the absolute pretrial pupil size and its derivative, and investigated whether and to which degree they were related to response-inhibition performance in a stop-signal task. Specifically, we investigated the relationship to stopping success, and the speed of the go response (GoRT) and that of the stop response (SSRT). In two experiments, we showed that larger pretrial pupil measures predicted (1) lower stopping success, (2) faster GoRTs (particularly so when the go response needed to be executed in a stop context), and some evidence for (3) faster SSRTs. Taken together, our findings show a clear pattern that pretrial pupil measures predict behavioral fluctuations in response inhibition, which suggests that tonic levels of NE are involved in the regulation of these behavioral fluctuations. Yet, our work furthermore indicates that this involvement is not stopping-specific, given its effect on both the go and the stop response. |
Masataka Yano; Keiyu Niikuni; Ruri Shimura; Natsumi Funasaki; Masatoshi Koizumi Producing non-basic word orders in (in)felicitous contexts: Evidence from pupillometry and functional near-infrared spectroscopy (fNIRS) Journal Article In: Language, Cognition and Neuroscience, vol. 40, no. 1, pp. 1–22, 2025. @article{Yano2025,The present study examined why speakers of languages with flexible word orders are more likely to use syntactically complex non-basic word orders when they provide discourse-given information earlier in sentences. This may be because they are more efficient for speakers to produce (the Speaker Economy Hypothesis). Alternatively, speakers may produce them to help listeners understand sentences more efficiently (the Listener Economy Hypothesis), given that previous studies showed that the processing of non-basic word orders was facilitated when the felicitous context was provided (i.e. a displaced object refers to discourse-given information). We addressed this issue by conducting a picture-description experiment, in which participants uttered sentences with syntactically basic Subject-Object-Verb (SOV) or non-basic Object-Subject-Verb (OSV) in felicitous or infelicitous contexts while cognitive load was tracked using pupillometry and functional near-infrared spectroscopy. The results showed that the felicitous context facilitated the filler-gap dependency formation of OSVs in production, supporting the Speaker Economy Hypothesis. |
Jens Schmidtke; Dana Bsharat-Maalouf; Tamar Degani; Hanin Karawani How lexical frequency, language dominance and noise affect listening effort–insights from pupillometry insights from pupillometry Journal Article In: Language, Cognition and Neuroscience, vol. 40, no. 2, pp. 195–208, 2025. @article{Schmidtke2025a,Acoustic, listener, and stimulus-related factors modulate speech-in-noise processes. This study examined how noise, listening experience, manipulated at two levels, native [L1] vs. second language [L2], and lexical frequency impact listening effort. Forty-seven participants, tested in their L1 Hebrew and L2 English, completed a word recognition test in quiet and noisy conditions while pupil size was recorded to assess listening effort. Results showed that listening in L2 was overall more effortful than in L1, with frequency effects modulated by language and noise. In L1, pupil responses to high and low frequency words were similar in both conditions. In L2, low frequency words elicited a larger pupil response, indicating greater effort, but this effect vanished in noise. A time-course analysis of the pupil response suggests that L1–L2 processing differences occur during lexical selection, indicating that L2 listeners may struggle to match acoustic-phonetic signals to long-term memory representations. |
Reuben Rideaux; Phuong Dang; Luke Jackel-David; Zak Buhmann; Dragan Rangelov; Jason B. Mattingley Violated predictions enhance the representational fidelity of visual features in perception Journal Article In: Journal of Vision, vol. 25, no. 4, pp. 1–11, 2025. @article{Rideaux2025,Predictive coding theories argue that recent experience establishes expectations that generate prediction errors whenviolated. In humans, brain imaging studies have revealed unique signatures of violated predictions in sensory cortex, but the perceptual consequences of these effects remain unknown. We had observers perform a dual-report task on the orientation of a briefly presented target grating within predictable or random sequences, while we recorded pupil size as an index of surprise. Observers first made a speeded response to categorize the orientation of the target grating (clockwise or counterclockwise from vertical), then reproduced its orientation without time pressure by rotating a bar. This allowed us to separately assess response speed and precision for the same stimuli. Critically, on half the trials, the target orientation deviated from the spatiotemporal structure established by the preceding gratings. Observers responded faster and moreaccurately to unexpected gratings, and pupillometry provided physiological evidence of observers' surprise in response to these events. In a second experiment, we cued the spatial location and timing of the grating and found the same pattern of results, demonstrating that unexpected orientation information is sufficient to produce faster and more precise responses, even when the location and timing of the relevant stimuli are fully expected. These findings indicate that unexpected events are prioritized by the visual system both in terms of processing speed and representational fidelity. |
Hannah N. Rembrandt; Ellyn A. Riley Evidence of physiological changes associated with single-session pre-frontal tDCS: A pilot study Journal Article In: Frontiers in Human Neuroscience, vol. 19, pp. 1–17, 2025. @article{Rembrandt2025,Objective: Transcranial direct current stimulation (tDCS), a non-invasive, painless method of applying direct current electrical stimulation to specific areas of the brain, is an effective method for enhancing attention and post-stroke fatigue, as shown by behavioral improvements in post-stroke populations. While behavioral evidence supports this method, there is a paucity of physiological data corroboration of this improvement. The current study is designed to investigate if a single session of tDCS will improve attention and fatigue as shown by relevant physiological methods in persons with post-stroke aphasia. Methods: Ten participants (5 male; mean age: 62.8) engaged in two identically structured data collection sessions with at least a 3-day wash-out period between them. Sessions started with a sustained attention task with simultaneous electroencephalography (EEG) and pupillometry data collection, followed by an attention training program with simultaneous active or sham tDCS. Following tDCS, participants repeated the sustained attention task with simultaneous EEG and pupillometry data collection. Participants received active tDCS during one session, and sham tDCS during the other, with the order randomized. Results: No differences between conditions were found for either behavioral results from the sustained attention task (i.e., reaction time of correct responses; n = 9 p = 0.39) or EEG measured attention state data for any of the four attention states: no attention (n = 10 |
Mohamed Rahme; Vijay Parsa; Mojgan Farahani; Paula Folkeard; Susan Scollie; Ingrid Suzanne Johnsrudea Evaluating the validity of gazepoint GP3 HD in assessing listening effort: A pupillometry study Journal Article In: American Journal of Audiology, vol. 34, no. 3, pp. 742–753, 2025. @article{Rahme2025,Purpose: Individuals with hearing loss typically experience greater listening effort, which is the additional recruitment of cognitive/mental resources such as attention and memory to understand speech and can be aversive and tiring. Reducing effort is an important goal of the hearing health care industry. Pupillo-metry is an objective and increasingly popular measure of listening effort, but gold standard measures of pupil size are expensive and unwieldy. The purpose of this study was to compare a low-cost and portable pupillometry device (Gazepoint GP3 HD) to a more traditional gold standard pupillometry tool (Eye-Link 1000) for indexing listening effort via pupil size. Method: Twenty normal-hearing young adults (age range: 18–23 years) were recruited in this study. Participants' pupil size was measured using the Gazepoint and EyeLink pupillometry devices while listening to Hearing in Noise Test sen-tences in stationary speech–shaped noise at signal-to-noise ratios (SNRs) ranging from −8to +8 dB. Results: Participants' word report accuracy increased from approximately 12% to 100% when the SNRs increased from −8 to +8 dB. Peak pupil diameter decreased for both devices and was smaller with the Gazepoint device. Data quality was comparable for the two devices. Conclusion: Gazepoint appeared to be an effective pupillometry device that records pupil dilation across a wide range of SNRs, without interfering with the auditory task. |
Kristina I. Pultsina; Galina L. Kozunova; Boris V. Chernyshev; Andrey O. Prokofyev; Vera D. Tretyakova; Artem Y. Novikov; Anna M. Rytikova; Tatiana A. Stroganova Neural adaptation to expected uncertainty in neurotypical adults and high-functioning adults with autism spectrum disorder Journal Article In: Cognitive, Affective, & Behavioral Neuroscience, pp. 1–22, 2025. @article{Pultsina2025,The ability to adjust brain resources to manage expected uncertainty is hypothesized to be impaired in autism spectrum disorder (ASD), although the evidence remains limited. To investigate this, we studied 29 neurotypical (NT) and 29 high-functioning adults with ASD performing a probabilistic two-alternative value-based task while undergoing magnetoencephalography (MEG) and pupillometry. The task comprised five sequential blocks with stable reward probabilities (70%:30%), but varying stimulus pairs and reward values, enabling assessment of behavioral and neural adaptation to expected uncertainty. We analyzed a hit rate of advantageous choices, response times, and computational measures of prior belief strength and precision. To examine cortical activation during decision-making, we used MEG source reconstruction to quantify α-β oscillation suppression in decision-relevant cortical regions within the predecision time window. Linear mixed models assessed trial-by-trial effects. Behaviorally, ASD participants exhibited lower overall belief precision but intact probabilistic rule generalization, showing gradual performance improvement and strengthening of prior beliefs across blocks. However, unlike NT individuals, they did not show progressive downscaling of neural activation during decision-making or reduction in neural response to feedback signals as performance improved. Furthermore, on a trial-by-trial basis, increased belief precision in ASD was not associated with reduced cortical activation, a pattern observed in NT individuals. These findings suggest an atypically rigid and enhanced allocation of neural resources to advantageous decisions in individuals with ASD, although they, as NT individuals, rationally judge such decisions as optimal. This pattern may reflect an aversive response to the irreducible uncertainty inherent in probabilistic decision-making. |
Erdem Pulcu; Michael Browning Humans adapt rationally to approximate estimates of uncertainty Technical Report 2025. @techreport{Pulcu2025,Efficient learning requires estimation of, and adaptation to, different forms of uncertainty. If uncertainty is caused by randomness in outcomes (noise), observed events should have less influence on beliefs, whereas if uncertainty is caused by a change in the process being estimated (volatility) the influence of events should increase. Previously, we showed that humans respond appropriately to changes in volatility irrespective of outcome valence (Pulcu and Browning, 2017), but there is less evidence of a rational response to noise. Here, we test adaptation to variable levels of volatility and noise in human participants, using choice behaviour and pupillometry as a measure of the central arousal system. We find that participants adapt as expected to changes in volatility, but not to changes in noise. Using a Bayesian observer model, we demonstrate that participants are, in fact, adapting to estimated noise, but that their estimates are imprecise, leading them to misattri- bute it as volatility and thus to respond inappropriately. |
Luise Pfalz; Carl Müller; Karl Kopiske Can pupillometry reveal perturbation detection in sensorimotor adaptation during grasping? Journal Article In: Journal of neurophysiology, vol. 134, no. 5, pp. 1804–1817, 2025. @article{Pfalz2025,Humans adjust their motor actions to correct for errors both with and without being aware of doing so. Little is known, however, about what makes errors detectable for the actor, and how researchers can know when errors are detected. Here, we investigated pupillometry as an unobtrusive, no-report marker of perturbation detection. We also replicate and extend prior work showing that motor adjustments may mask the very errors they correct for. Participants (n = 48) grasped objects while a visuo-haptic size mismatch was applied either sinusoidally (with a continuously changing perturbation) or abruptly (with a constant perturbation that could more easily be adapted to). When mismatches started abruptly and thereafter stayed the same, participants adapted well but also showed decreasing discrimination performance and decreasing confidence in their responses. This was not the case for sinusoidally introduced perturbations. As hypothesized, parameters that characterize phasic and tonic pupil responses were predicted by stimulus parameters and differed depending on participants' grasping and behavioral responses. In particular, tonic responses were smaller for stronger perturbations but larger in trials with correct and confident responses, whereas phasic responses were correlated positively with perturbation magnitude and response correctness, but negatively with response confidence. However, predicting response characteristics from pupil-dilation features using support-vector machine classifiers was not successful. This shows that although pupillometry may yet prove to be a useful no-report marker of perturbation and error detection, there are some challenges for trial-by-trial prediction.NEW & NOTEWORTHY Actors detecting the need to adjust motor actions can make adjustments more efficiently. We show that pupil dilation during perturbed actions reflected perturbation properties and participants' responses, but trial-wise prediction of responses using pupil-dilation parameters was close to chance. Error signals, in addition to perturbation magnitude, play a specific central role in humans' detection of and meta-cognition about motor perturbations. This is a step toward potentially using pupillometry as a no-report marker of perturbation detection. |
Jadyn S. Park; Kruthi Gollapudi; Jin Ke; Matthias Nau; Ioannis Pappas; Yuan Chang Leong Emotional arousal enhances narrative memories through functional integration of large-scale brain networks Journal Article In: Nature Human Behaviour, pp. 1–24, 2025. @article{Park2025a,Emotional events tend to be vividly remembered. While growing evidence suggests that emotions have their basis in brain-wide network interactions, it is unclear whether and how these whole-brain dynamics contribute to memory encoding. Here we combined functional MRI, graph theory, text analyses and pupillometry in a naturalistic context where participants recalled complex narratives in their own words. Across three independent datasets, emotionally arousing moments during narrative perception were associated with an integrated brain state characterized by increased cohesion across functional modules, which in turn predicted the fidelity of subsequent recall. Network integration mediated the influence of emotional arousal on recall fidelity, with consistent within- and between-network interactions supporting the mediation across datasets. Together, these results suggest that emotional arousal enhances memory encoding via strengthening functional integration across brain networks. Our findings advance a cross-level understanding of emotional memories that bridges large-scale brain network dynamics, affective states and ongoing cognition. |
Alex Mepham; Sarah Knight; Ronan McGarrigle; Lyndon Rakusen; Sven Mattys Pupillometry reveals the role of signal-to-noise ratio in adaption to linguistic interference over time Journal Article In: Journal of Speech, Language, and Hearing Research, vol. 68, no. 5, pp. 2291–2317, 2025. @article{Mepham2025,Purpose: Studies of speech-in-speech listening show that intelligible maskers are more detrimental to target perception than unintelligible maskers, an effect we refer to as linguistic interference. Research also shows that performance improves over time through adaptation. The extent to which the speed of adap-tation differs for intelligible and unintelligible maskers and whether this pattern is reflected in changes in listening effort are open questions. Method: In this preregistered study, native English listeners transcribed English sentences against an intelligible masker (time-forward English talkers) versus an unintelligible masker (time-reversed English talkers). Over 50 trials, transcription accuracy and task-evoked pupil response (TEPR) were recorded, along with self-reported effort and fatigue ratings. In Experiment 1, we used an adaptive procedure to ensure a starting performance of ~50% correct in both conditions. In Experiment 2, we used a fixed signal-to-noise ratio (SNR = −1.5 dB) for both conditions. Results: Both experiments showed performance patterns consistent with lin-guistic interference. The speed of adaptation depended on the SNR. When the SNR was higher for the intelligible masker condition as a result of the 50% starting performance across conditions (Experiment 1), adaptation was faster for that condition; TEPRs were not affected by trial number or condition. When the SNR was fixed (Experiment 2), adaptation was similar in both conditions, but TEPRs decreased faster in the unintelligible than intelligible masker condi-tion. Self-reported ratings of effort and fatigue were not affected by masker conditions in either experiment. Conclusions: Learning to segregate target speech from maskers depends on both the intelligibility of the maskers and the SNR. We discuss ways in which auditory stream formation is automatic or requires cognitive resources. |
Xinhe Liu; Zhiting Zhang; Ji Dai Evaluating pupillometry as a tool for assessing facial and emotional processing in nonhuman primates Journal Article In: Applied Sciences, vol. 15, no. 6, pp. 1–14, 2025. @article{Liu2025r,Non-human primates (NHPs) are extensively utilized to investigate the neural mechanisms underlying face processing; however, measuring their brain activity necessitates a diverse array of technologies. Pupillometry emerges as a convenient, cost-effective, and non-invasive alternative for indirectly assessing brain activity. To evaluate the efficacy of pupillometry in assessing facial and emotional processing in NHPs, this study designed a face fixation task for experimental monkeys (Rhesus macaque) and recorded variations in their pupil size in response to face images with differing characteristics, such as species, emotional expression, viewing angles, and orientation (upright vs. inverted). All face images were balanced with luminance and spatial frequency. A sophisticated eye-tracking system (Eye-link 1000 plus) was employed to observe the pupils and track the viewing trajectories of monkeys as they examined images of faces. Our findings reveal that monkeys exhibited larger pupil sizes in response to carnivore faces (versus human faces |
Sharif I. Kronemer; Victoria E. Gobo; Catherine R. Walsh; Joshua B. Teves; Diana C. Burk; Somayeh Shahsavarani; Javier Gonzalez; Castillo Peter Cross‑species real‑time detection of trends in pupil size fluctuation Journal Article In: Behavior Research Methods, vol. 57, no. 1, pp. 1–14, 2025. @article{Kronemer2025,Pupillometry is a popular method because pupil size is easily measured and sensitive to central neural activity linked to behavior, cognition, emotion, and perception. Currently, there is no method for online monitoring phases of pupil size fluctuation. We introduce rtPupilPhase—an open-source software that automatically detects trends in pupil size in real time. This tool enables novel applications of real-time pupillometry for achieving numerous research and translational goals. We validated the performance of rtPupilPhase on human, rodent, and monkey pupil data, and we propose future implementations of real-time pupillometry. |
Aleksandra Koprowska; Dorothea Wendt; Maja Serman; Torsten Dau; Jeremy Marozeau The effect of auditory training on listening effort in hearing-aid users: Insights from a pupillometry study Journal Article In: International Journal of Audiology, vol. 64, no. 1, pp. 59–69, 2025. @article{Koprowska2025,Objective: The study investigated how auditory training affects effort exerted by hearing-impaired listeners in speech-in-noise task. Design: Pupillometry was used to characterise listening effort during a hearing in noise test (HINT) before and after phoneme-in-noise identification training. Half of the study participants completed the training, while the other half formed an active control group. Study sample: Twenty 63-to-79 years old experienced hearing-aid users. Results: Higher peak pupil dilations (PPDs) were obtained at the end of the study compared to the beginning in both groups of the participants. The analysis of pupil dilation in an extended time window revealed, however, that the magnitude of pupillary response increased more in the training than in the control group. The effect of training on effort was observed in pupil responses even when no improvement in HINT was found. Conclusion: The results demonstrate that using a listening effort metric adds additional insights into the effectiveness of auditory training compared to the situation when only speech-in-noise performance is considered. Trends observed in pupil responses suggested increased effort—both after the training and the placebo intervention—most likely reflecting the effect of the individual's motivation. |
Andy Jeesu Kim; Kristine Nguyen; Ying Tian; Mara Mather Eye movement evidence for locus coeruleus-noradrenaline system contributions to age differences in attention Journal Article In: Psychology and Aging, vol. 40, no. 8, pp. 929–944, 2025. @article{Kim2025a,Neuroimaging studies have shown that aging alters the brain mechanisms underlying attentional control, even when behavioral performance is equivalent between younger and older adults. Instead of attributing these changes to compensatory mechanisms, we investigated whether age-related neuromodulatory changes in the locus coeruleus-noradrenaline (LC-NA) system are underlying these effects. To test whether aging leads to LC-NA system hyperactivity, we combined two methodological approaches: an oculomotor visual search task to assess eye movements and the threat of unpredictable electric shock paradigm to induce sustained arousal. Using pupillometry, we found that arousal reduced evoked pupil responses in both age groups, demonstrating the expected pattern of lower phasic noradrenergic activity under arousal. Young adults made significantly more first fixations to the physically salient distractor under threat of shock compared to baseline conditions, unlike in older adults with no effect. This modulation of attentional priority was only observable immediately following shock delivery and dissipated over time. Additionally, we found moderate evidence supporting the null hypothesis that arousal does not modulate the speed of attention processing in either age group. These results suggest that arousal selectively modulates attentional priority maps in the early visual cortex but does not influence broader interactions across higher order attentional networks. While first fixation measures revealed age-related differences consistent with the hypothesis of LC-NA system hyperactivity in aging, pupillometry and processing speed measures showed age-equivalent effects. Together, these findings highlight the potential for age-related changes in the LC-NA system to modulate mechanisms of attentional control and demonstrate the utility of eye movement measures as a promising tool to track changes across the adult lifespan. |
Magdalena Gruner; Andreas Widmann; Stefan Wöhner; Erich Schröger; Jörg D. Jescheniak Semantic context effects in picture and sound naming: Evidence from event-related potentials and pupillometric data Journal Article In: Journal of cognitive neuroscience, vol. 37, no. 2, pp. 443–463, 2025. @article{Gruner2025,When a picture is repeatedly named in the context of semantically related pictures (homogeneous context), responses are slower than when the picture is repeatedly named in the context of unrelated pictures (heterogeneous context). This semantic interference effect in blocked-cyclic naming plays an important role in devising theories of word production. Wöhner, Mädebach, and Jescheniak [Wöhner, S., Mädebach, A., & Jescheniak, J. D. Naming pictures and sounds: Stimulus type affects semantic context effects. Journal of Experimental Psychology: Human Perception and Performance, 47, 716-730, 2021] have shown that the effect is substantially larger when participants name environmental sounds than when they name pictures. We investigated possible reasons for this difference, using EEG and pupillometry. The behavioral data replicated Wöhner and colleagues. ERPs were more positive in the homogeneous compared with the heterogeneous context over central electrode locations between 140-180 msec and 250-350 msec for picture naming and between 250 and 350 msec for sound naming, presumably reflecting semantic interference during semantic and lexical processing. The later component was of similar size for pictures and sounds. ERPs were more negative in the homogeneous compared with the heterogeneous context over frontal electrode locations between 400 and 600 msec only for sounds. The pupillometric data showed a stronger pupil dilation in the homogeneous compared with the heterogeneous context only for sounds. The amplitudes of the late ERP negativity and pupil dilation predicted naming latencies for sounds in the homogeneous context. The latency of the effects indicates that the difference in semantic interference between picture and sound naming arises at later, presumably postlexical processing stages closer to articulation. We suggest that the processing of the auditory stimuli interferes with phonological response preparation and self-monitoring, leading to enhanced semantic interference. |
Pablo R. Grassi; Lena Hoeppe; Emre Baytimur; Andreas Bartels Restoring sight in choice blindness: Pupillometry and behavioral evidence of covert detection Journal Article In: Frontiers in Psychology, vol. 16, pp. 1–17, 2025. @article{Grassi2025,Intriguing results from “choice blindness” (CB) experiments have shown that when people make choices, but are presented with a false outcome, many seem not to notice the mismatch and even provide reasons for choices they never made. They appear to be “blind” about their intentions. Yet, this effect goes against decision-making accounts and experience, in which we regularly notice outcomes that do not match our choices (e.g., when ordering food). Here, we ask whether participants really fail to detect the manipulation, or whether CB can be accounted for by covert detection, in that participants detect changes, but do not report them. To test this, we measured pupil dilation during the experiments to quantify objective responses in addition to reports by participants. In both experiments, we consistently observed that participants failed to report detected mismatches. Moreover, we observed increased pupil dilation during all manipulated trials, irrespective of whether they were reported or not. Thus, we provide conclusive evidence of covert detection in CB. In addition, we show that CB is strongly modulated by the idiosyncrasies of the experimental design. Our results cast doubt on the general validity of CB, and with that on key conclusions of previous studies. Instead, our results suggest no failure of detection, but instead higher-level, cognitively or socially driven hesitance of reporting. Our evidence leads us to a cautious discussion of CB and provides an account that no longer violates our intuitions about human intentionality and rationality, in that participants are less introspectively blind than originally portrayed. |
Steven P. Gianakas; Matthew B. Winn Advance contextual clues alleviate listening effort during sentence repair in listeners with hearing aids Journal Article In: Journal of Speech, Language, and Hearing Research, vol. 68, no. 4, pp. 2144–2156, 2025. @article{Gianakas2025,Purpose: When words are misperceived, listeners can rely on later context to repair an auditory perception, at the cost of increased effort. The current study examines whether the effort to repair a missing word in a sentence is alleviated when the listener has some advance knowledge of what to expect in the sentence. Method: Sixteen adults with hearing aids and 17 with typical hearing heard sentences with a missing word that was followed by context sufficient to infer what the word was. They repeated the sentences with the missing words repaired. Sentences were preceded by visual text on the screen showing either “XXXX” (unprimed) or a priming word previewing the word that would be masked in the auditory signal. Along with intelligibility measures, pupillometry was used as an index of listening effort over the course of each trial to measure how priming influenced the effort needed to mentally repair a missing word. Results: When listeners were primed for the word that would need to be repaired in an upcoming sentence, listening effort was reduced, as indicated by pupil size returning more quickly toward baseline after the sentence was heard. Priming reduced the lingering cost of mental repair in both listener groups. For the group with hearing loss, priming also reduced the prevalence of errors on target words and words other than the target word in the sentence, suggesting that priming preserves the cognitive resources needed to process the whole sentence. Conclusion: These results suggest that listeners with typical hearing and with hearing loss can benefit from priming (advance cueing) during speech recognition, to accurately repair speech and to process the speech less effortfully. |
Joshua O. Eayrs; Haya Serena Tobing; S. Tabitha Steendam; Nicoleta Prutean; Wim Notebaert; Jan R. Wiersema; Ruth M. Krebs; C. Nico Boehler Reward and efficacy modulate the rate of anticipatory pupil dilation Journal Article In: Psychophysiology, vol. 62, no. 1, pp. 1–12, 2025. @article{Eayrs2025,Pupil size is a well-established marker of cognitive effort, with greater efforts leading to larger pupils. This is particularly true for pupil size during task performance, whereas findings on anticipatory effort triggered by a cue stimulus are less consistent. For example, a recent report by Frömer et al. found that in a cued-Stroop task, behavioral performance and electrophysiological markers of preparatory effort allocation were modulated by cued reward and ‘efficacy' (the degree to which rewards depended on good performance), but pupil size did not show a comparable pattern. Here, we conceptually replicated this study, employing an alternative approach to the pupillometry analyses. In line with previous findings, we found no modulation of absolute pupil size in the cue-to-target interval. Instead, we observed a significant difference in the rate of pupil dilation in anticipation of the target: pupils dilated more rapidly for high-reward trials in which rewards depended on good performance. This was followed by a significant difference in absolute pupil size within the first hundreds of milliseconds following Stroop stimulus onset, likely reflecting a lagging effect of anticipatory effort allocation. Finally, the slope of pupil dilation was significantly correlated with behavioral response times, and this association was strongest for the high-reward, high-efficacy trials, further supporting that the rate of anticipatory pupil dilation reflects anticipatory effort. We conclude that pupil size is modulated by anticipatory effort, but in a highly temporally-specific manner, which is best reflected by the rate of dilation in the moments just prior to stimulus onset. |
Christophe Delay; Jan W. Brascamp; Jessica Fattal; Matthew Lehet; Beier Yao; Katharine N. Thakkar Associations between blunted pupillary constriction and dilation in individuals with schizophrenia: Evidence of a common mechanism? Journal Article In: Schizophrenia Bulletin Open, vol. 6, no. 1, pp. 1–12, 2025. @article{Delay2025,Background and Hypothesis: Unpacking the pathophysiological mechanisms of schizophrenia is necessary for advancing prediction, prevention, and treatment efforts. Mechanisms can be identified using easy-to-use and scalable clinical biomarkers, which reflect illness processes. Pupillometry is one such biomarker. Blunted dilation related to cognitive demand has been interpreted as a metric of diminished effort in schizophrenia, while blunted constriction to light has been interpreted as a metric of altered autonomic balance in schizophrenia. However, these 2 sets of findings may also reflect a common mechanism of schizophrenia. Therefore, this study aimed to explore the association between blunted cognitive dilation and blunted constriction to light to provide a parsimonious mechanism of autonomic and effort disturbances experienced by individuals with schizophrenia. Study Design: We assessed light-induced constriction and cognitive dilation during a double-step task in individuals with schizophrenia (n=84) and demographically matched healthy controls (HC |
Michael C. B. David; Emma Jane Mallas; Lucia M. Li; Magdalena A. Kolanko; Ramin Nilforooshan; Man Lai Tsoi; Hanim Karakoc; Karen Hoang; Johanna Brandt; Charikleia Triantafyllou; Dragos C. Gruia; Darije Custovic; Peter J. Lally; Karl A. Zimmerman; David Sharp; Care Research Institute; Technology Group UK Dementia Research; Paresh A. Malhotra; Gregory Scott1; David J. Sharp Pupil-linked arousal, cortical activity, and cognition in Alzheimer's disease Journal Article In: Brain Communications, vol. 7, no. 4, pp. 1–17, 2025. @article{David2025,Arousal dysfunction contributes to impairments seen in Alzheimer's disease. However, the nature and degree of this dysfunction have not been studied in detail. We investigated changes in tonic and phasic arousal using simultaneous pupillometry-EEG, relating these changes to locus coeruleus integrity, a key arousal nucleus. Forty Alzheimer's disease participants and 30 controls underwent neuropsychological testing using the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog), MRI designed to show contrast in the locus coeruleus as a measure of integrity and simultaneous pupillometry-EEG during 5 min of eyes-open resting-state. Pupillometry-EEG was then also applied during an oddball task which included a passive session and sessions in which responses to target stimuli were required, to test the effect of salience. Alzheimer's disease had lower locus coeruleus integrity (b = -0.26 |
Yi Hsuan Chang; Rachel Yep; Chin An Wang In: Psychophysiology, vol. 62, no. 1, pp. 1–22, 2025. @article{Chang2025e,Pupil size is a non-invasive index for autonomic arousal mediated by the locus coeruleus–norepinephrine (LC-NE) system. While pupil size and its derivative (velocity) are increasingly used as indicators of arousal, limited research has investigated the relationships between pupil size and other well-known autonomic responses. Here, we simultaneously recorded pupillometry, heart rate, skin conductance, pulse wave amplitude, and respiration signals during an emotional face–word Stroop task, in which task-evoked (phasic) pupil dilation correlates with LC-NE responsivity. We hypothesized that emotional conflict and valence would affect pupil and other autonomic responses, and trial-by-trial correlations between pupil and other autonomic responses would be observed during both tonic and phasic epochs. Larger pupil dilations, higher pupil size derivative, and lower heart rates were observed in the incongruent condition compared to the congruent condition. Additionally, following incongruent trials, the congruency effect was reduced, and arousal levels indexed by previous-trial pupil dilation were correlated with subsequent reaction times. Furthermore, linear mixed models revealed that larger pupil dilations correlated with higher heart rates, higher skin conductance responses, higher respiration amplitudes, and lower pulse wave amplitudes on a trial-by-trial basis. Similar effects were seen between positive and negative valence conditions. Moreover, tonic pupil size before stimulus presentation significantly correlated with all other tonic autonomic responses, whereas tonic pupil size derivative correlated with heart rates and skin conductance responses. These results demonstrate a trial-by-trial relationship between pupil dynamics and other autonomic responses, highlighting pupil size as an effective real-time index for autonomic arousal during emotional conflict and valence processing. |
Dana Bsharat-Maalouf; Tamar Degani; Hanin Karawani How variability in language experience modulates multilingual listening effort Journal Article In: Bilingualism: Language and Cognition, pp. 1–15, 2025. @article{BsharatMaalouf2025,Multilinguals face greater challenges than monolinguals in speech perception tasks, such as processing noisy sentences. Factors related to multilinguals' language experience, such as age of acquisition, proficiency, exposure and usage, influence their perceptual performance. However, how language experience variability modulates multilinguals' listening effort remains unclear. We analyzed data from 92 multilinguals who completed a listening task with words and sentences, presented in quiet and noise across participants' spoken languages (Arabic, Hebrew and English). Listening effort was assessed using pupillometry. The results indicated higher accuracy and reduced effort in quiet than in noise, with greater language experience predicting better accuracy and reduced effort. These effects varied by stimulus and listening condition. For single words, greater language experience most strongly reduced effort in noise; for sentences, it had a more pronounced effect in quiet, especially for high-predictability sentences. These findings emphasize the importance of considering language experience variability when evaluating multilingual effort. |
Marc Barnard; Scott Kunkel; Rémi Lamarque; Adam J. Chong Listening effort across non-native and regional accents: A pupillometry study Journal Article In: Language and Speech, pp. 1–30, 2025. @article{Barnard2025,Previous work has shown that L2-accented speech incurs a processing cost even when accurately understood. It remains unknown, however, whether an online processing cost is found when listeners process speech produced in L1 accents that are not their own. In this study, we examine this question by using comparative pupil dilation as a measure of cognitive load. Participants from the South of England heard sentences produced in four different accents: Southern British English (the listeners' own familiar accent), American English (a standard L1 accent widely used in media), Glaswegian English (a less-familiar regional L1 accent), and Mandarin Chinese-accented English (an L2 English accent). Results show that Chinese-accented speech elicited significantly larger pupil dilation responses compared with Southern British English. Speech from less-familiar L1 accents elicited pupil dilation responses of different shapes and trajectories, suggesting differences in processing of these accents. Furthermore, participants showed larger mean pupil dilation when they heard relatively less-familiar L1 American-accented speech than when hearing Glaswegian English. Interestingly, this effect was found despite participants self-reporting that they were less familiar with the Glaswegian accent and found it more effortful to comprehend compared with American English. These results suggest that accurately perceived and highly intelligible L1 accents such as American English also incur a cognitive cost in processing, but to a smaller extent compared with L2-accented speech. We discuss the implications of our findings for the relationship between exposure, subjective effortfulness measures, and pupil dilation responses. |
Khaled H. A. Abdel-Latif; Thomas Koelewijn; Deniz Başkent; Hartmut Meister Assessment of speech processing and listening effort associated with speech-on-speech masking using the visual world paradigm and pupillometry Journal Article In: Trends in hearing, vol. 29, pp. 1–13, 2025. @article{AbdelLatif2025,Speech-on-speech masking is a common and challenging situation in everyday verbal communication. The ability to segregate competing auditory streams is a necessary requirement for focusing attention on the target speech. The Visual World Paradigm (VWP) provides insight into speech processing by capturing gaze fixations on visually presented icons that reflect the speech signal. This study aimed to propose a new VWP to examine the time course of speech segregation when competing sentences are presented and to collect pupil size data as a measure of listening effort. Twelve young normal-hearing participants were presented with competing matrix sentences (structure "name-verb-numeral-adjective-object") diotically via headphones at four target-to-masker ratios (TMRs), corresponding to intermediate to near perfect speech recognition. The VWP visually presented the number and object words from both the target and masker sentences. Participants were instructed to gaze at the corresponding words of the target sentence without providing verbal responses. The gaze fixations consistently reflected the different TMRs for both number and object words. The slopes of the fixation curves were steeper, and the proportion of target fixations increased with higher TMRs, suggesting more efficient segregation under more favorable conditions. Temporal analysis of pupil data using Bayesian paired sample t-tests showed a corresponding reduction in pupil dilation with increasing TMR, indicating reduced listening effort. The results support the conclusion that the proposed VWP and the captured eye movements and pupil dilation are suitable for objective assessment of sentence-based speech-on-speech segregation and the corresponding listening effort. |
2024 |
Jourdan J. Pouliot; Richard T. Ward; Caitlin M. Traiser; Payton Chiasson; Faith E. Gilbert; Andreas Keil Neurophysiological and autonomic dynamics of threat processing during sustained social fear generalization Journal Article In: Journal of Cognitive Neuroscience, vol. 37, no. 2, pp. 482–497, 2024. @article{Pouliot2024,Survival in rapidly changing environments requires that organisms learn to predict noxious outcomes based on situational cues. One key facet of successful threat prediction is generalization from a specific predictive cue to similar cues, ensuring that a cue-outcome contingency is applied beyond the original learning environment. Generalization has also been observed in laboratory studies of human aversive conditioning: Most behavioral and physiological processes generalize responses from a stimulus paired with threat, (the CS+), to unpaired stimuli, with response magnitudes varying as a function of stimulus similarity. In contrast, work focusing on sensory responses in visual cortex has found a sharpening pattern, in which responses to stimuli closely resembling the CS+ are maximally suppressed, potentially reflecting lateral inhibitory interactions with the CS+ representation. Originally demonstrated with simple visual cues, changes in visuocortical tuning have also been observed in threat generalization learning across facial identity cues. It is however unclear to what extent these visuocortical changes represent transient or sustained effects and if generalization learning requires prior conditioning to the CS+. The present study addressed these questions using EEG and pupillometry in a paradigm involving several hundreds of trials of aversive generalization learning along a gradient of facial identities. Visuocortical ssVEP sharpening occurred after dozens of trials of generalization learning without prior differential conditioning, but diminished as learning progressed further. By contrast, generalization of EEG alpha power suppression, pupil dilation, and self-reported valence and arousal ratings was seen throughout the experimental session. Findings are consistent with models of threat processing emphasizing the role of changing visucocortical and attention dynamics in the formation, curation, and shaping of fear memories as observers continue learning about stimulus-outcome contingencies. |
Fangshu Yao; Xiaoyue Chang; Bin Zhou; Wen Zhou Olfaction modulates cortical arousal independent of perceived odor intensity and pleasantness Journal Article In: NeuroImage, vol. 299, pp. 1–11, 2024. @article{Yao2024a,Throughout history, various odors have been harnessed to invigorate or relax the mind. The mechanisms underlying odors' diverse arousal effects remain poorly understood. We conducted five experiments (184 participants) to investigate this issue, using pupillometry, electroencephalography, and the attentional blink paradigm, which exemplifies the limit in attentional capacity. Results demonstrated that exposure to citral, compared to vanillin, enlarged pupil size, reduced resting-state alpha oscillations and alpha network efficiency, augmented beta-gamma oscillations, and enhanced the coordination between parietal alpha and frontal beta-gamma activities. In parallel, it attenuated the attentional blink effect. These effects were observed despite citral and vanillin being comparable in perceived odor intensity, pleasantness, and nasal pungency, and were unlikely driven by semantic biases. Our findings reveal that odors differentially alter the small-worldness of brain network architecture, and thereby brain state and arousal. Furthermore, they establish arousal as a unique dimension in olfactory space, distinct from intensity and pleasantness. |
Mario A. Svirsky; Jonathan D. Neukam; Nicole Hope Capach; Nicole M. Amichetti; Annette Lavender; Arthur Wingfield Communication under sharply degraded auditory input and the “2-sentence” problem Journal Article In: Ear & Hearing, vol. 45, no. 4, pp. 1045–1058, 2024. @article{Svirsky2024,Objectives: Despite performing well in standard clinical assessments of speech perception, many cochlear implant (CI) users report experiencing significant difficulties when listening in real-world environments. We hypothesize that this disconnect may be related, in part, to the limited ecological validity of tests that are currently used clinically and in research laboratories. The challenges that arise from degraded auditory information provided by a CI, combined with the listener's finite cognitive resources, may lead to difficulties when processing speech material that is more demanding than the single words or single sentences that are used in clinical tests. Design: Here, we investigate whether speech identification performance and processing effort (indexed by pupil dilation measures) are affected when CI users or normal-hearing control subjects are asked to repeat two sentences presented sequentially instead of just one sentence. Results: Response accuracy was minimally affected in normal-hearing listeners, but CI users showed a wide range of outcomes, from no change to decrements of up to 45 percentage points. The amount of decrement was not predictable from the CI users' performance in standard clinical tests. Pupillometry measures tracked closely with task difficulty in both the CI group and the normal-hearing group, even though the latter had speech perception scores near ceiling levels for all conditions. Conclusions: Speech identification performance is significantly degraded in many (but not all) CI users in response to input that is only slightly more challenging than standard clinical tests; specifically, when two sentences are presented sequentially before requesting a response, instead of presenting just a single sentence at a time. This potential “2-sentence problem” represents one of the simplest possible scenarios that go beyond presentation of the single words or sentences used in most clinical tests of speech perception, and it raises the possibility that even good performers in single-sentence tests may be seriously impaired by other ecologically relevant manipulations. The present findings also raise the possibility that a clinical version of a 2-sentence test may provide actionable information for counseling and rehabilitating CI users, and for people who interact with them closely. |
Yanliang Sun; Lixue Wang; Wenhao Yu; Xue Yang; Jiaru Song; Shouxin Li Mechanisms of visual working memory processing task-irrelevant information retrieved from visual long-term memory Journal Article In: Cognition, vol. 250, pp. 1–10, 2024. @article{Sun2024d,Visual working memory (VWM) can selectively filter task-irrelevant information from incoming visual stimuli. However, whether a similar filtering process applies to task-irrelevant information retrieved from visual long-term memory (VLTM) remains elusive. We assume a “resource-limited retrieval mechanism” in VWM in charge of the retrieval of irrelevant VLTM information. To make a comprehensive understanding of this mechanism, we conducted three experiments using both a VLTM learning task and a VWM task combined with pupillometry. The presence of a significant pupil light response (PLR) served as empirical evidence that VLTM information can indeed make its way into VWM. Notably, task-relevant VLTM information induced a sustained PLR, contrasting with the transient PLR observed for task-irrelevant VLTM information. Importantly, the transience of the PLR occurred under conditions of low VWM load, but this effect was absent under conditions of high load. Collectively, these results show that task-irrelevant VLTM information can enter VWM and then fade away only under conditions of low VWM load. This dynamic underscores the resource-limited retrieval mechanism within VWM, exerting control over the entry of VLTM information. |
S. Tabitha Steendam; Nicoleta Prutean; Fleur Clybouw; Joshua O. Eayrs; Nanne Kukkonen; Wim Notebaert; Ruth M. Krebs; Jan R. Wiersema; C. Nico Boehler Compensating for the mobile menace with extra effort: A pupillometry investigation of the mere presence effect of smartphones Journal Article In: Biological Psychology, vol. 193, pp. 1–11, 2024. @article{Steendam2024,Previous research suggests that the mere presence of a smartphone can detrimentally affect performance. However, other studies failed to observe such detrimental effects. A limitation of existing studies is that no indexes of (potentially compensating) effort were included. Further, time-on-task effects have been unexplored. Here, we address these limitations by investigating the mere-presence effect of a smartphone on performance in two continuous-performance experiments (Experiment 1 using an n-back and a number judgement task at two difficulty levels, and Experiment 2 using a pure, challenging n-back task), measuring pupil size to assess invested effort, and taking into account time-on-task effects. Finally, contrary to previous studies that predominantly used between-subject designs, we utilized within-subject designs in both experiments. Contrary to expectations, Experiment 1 largely yielded no significant effects of smartphone presence on performance. Nonetheless, the presence of a smartphone triggered larger tonic pupil size in the more difficult task, and a more rapid decrease over time. Experiment 2 similarly failed to demonstrate smartphone effects on performance, but replicated the finding of larger tonic pupil size in the presence of a smartphone. In addition, tonic pupil size showed a slower decrease over time when a smartphone was present. In Experiment 2, we could furthermore look at phasic pupil size, which decreased over time in the absence of a phone but not in its presence. These findings suggest a complex relationship between smartphone presence, effort, and time-on-task, which does not necessarily express itself behaviorally, highlighting in particular the need to also explore potential contributions of (compensatory) effort. |
Connor Spiech; Anne Danielsen; Bruno Laeng; Tor Endestad Oscillatory attention in groove Journal Article In: Cortex, vol. 174, pp. 137–148, 2024. @article{Spiech2024,Attention is not constant but rather fluctuates over time and these attentional fluctuations may prioritize the processing of certain events over others. In music listening, the pleasurable urge to move to music (termed ‘groove' by music psychologists) offers a particularly convenient case study of oscillatory attention because it engenders synchronous and oscillatory movements which also vary predictably with stimulus complexity. In this study, we simultaneously recorded pupillometry and scalp electroencephalography (EEG) from participants while they listened to drumbeats of varying complexity that they rated in terms of groove afterwards. Using the intertrial phase coherence of the beat frequency, we found that while subjects were listening, their pupil activity became entrained to the beat of the drumbeats and this entrained attention persisted in the EEG even as subjects imagined the drumbeats continuing through subsequent silent periods. This entrainment in both the pupillometry and EEG worsened with increasing rhythmic complexity, indicating poorer sensory precision as the beat became more obscured. Additionally, sustained pupil dilations revealed the expected, inverted U-shaped relationship between rhythmic complexity and groove ratings. Taken together, this work bridges oscillatory attention to rhythmic complexity in relation to musical groove. |
Blanca T. M. Spee; Jozsef Arato; Jan Mikuni; Ulrich S. Tran; Matthew Pelowski; Helmut Leder In: Frontiers in Psychology, vol. 15, pp. 1–15, 2024. @article{Spee2024,Introduction: Gestalt perception refers to the cognitive ability to perceive various elements as a unified whole. In our study, we delve deeper into the phenomenon of Gestalt recognition in visual cubist art, a transformative process culminating in what is often described as an Aha moment. This Aha moment signifies a sudden understanding of what is seen, merging seemingly disparate elements into a coherent meaningful picture. The onset of this Aha moment can vary, either appearing almost instantaneously, which is in line with theories of hedonic fluency, or manifesting after a period of time, supporting the concept of delayed but more in-depth meaningful insight. Methods: We employed pupillometry to measure cognitive and affective shifts during art interaction, analyzing both maximum pupil dilation and average dilation across the trial. The study consisted of two parts: in the first, 84 participants identified faces in cubist paintings under various conditions, with Aha moments and pupil dilation measured. In part 2, the same 84 participants assessed the artworks through ratings in a no-task free-viewing condition. Results: Results of part 1 indicate a distinctive pattern of pupil dilation, with maximum dilation occurring at both trial onset and end. Longer response times were observed for high-fluent, face-present stimuli, aligning with a delayed but accurate Aha-moment through recognition. Additionally, the time of maximum pupil dilation, rather than average dilation, exhibited significant associations, being later for high-fluent, face-present stimuli and correct detections. In part 2, average, not the time of maximum pupil dilation emerged as the significant factor. Face-stimuli and highly accessible art evoked stronger dilations, also reflecting high clearness and negative valence ratings. Discussion: The study underscores a complex relationship between the timing of recognition and the Aha moment, suggesting nuanced differences in emotional and cognitive responses during art viewing. Pupil dilation measures offer insight into these processes especially for moments of recognition, though their application in evaluating emotional responses through artwork ratings warrants further exploration. |
Jack W. Silcox; Karen Bennett; Allyson Copeland; Sarah Hargus Ferguson; Brennan R. Payne The costs (and benefits?) of effortful listening for older adults: Insights from simultaneous electrophysiology, pupillometry, and memory Journal Article In: Journal of Cognitive Neuroscience, vol. 36, no. 6, pp. 997–1020, 2024. @article{Silcox2024,Although the impact of acoustic challenge on speech processing and memory increases as a person ages, older adults may engage in strategies that help them compensate for these demands. In the current preregistered study, older adults (n = 48) listened to sentences—presented in quiet or in noise—that were high constraint with either expected or unexpected endings or were low constraint with unexpected endings. Pupillometry and EEG were simultaneously recorded, and subsequent sentence recognition and word recall were measured. Like young adults in prior work, we found that noise led to increases in pupil size, delayed and reduced ERP responses, and decreased recall for unexpected words. However, in contrast to prior work in young adults where a larger pupillary response predicted a recovery of the N400 at the cost of poorer memory performance in noise, older adults did not show an associated recovery of the N400 despite decreased memory performance. Instead, we found that in quiet, increases in pupil size were associated with delays in N400 onset latencies and increased recognition memory performance. In conclusion, we found that transient variation in pupil-linked arousal predicted trade-offs between real-time lexical processing and memory that emerged at lower levels of task demand in aging. Moreover, with increased acoustic challenge, older adults still exhibited costs associated with transient increases in arousal without the corresponding benefits. |
Eser Sendesen; Meral Didem Türkyılmaz In: Auris Nasus Larynx, vol. 51, no. 4, pp. 659–665, 2024. @article{Sendesen2024b,Objective: In previous studies, the results regarding the presence of listening effort or fatigue in tinnitus patients were inconsistent. The reason for this inconsistency could be that extended high frequencies, which can cause listening handicap, were not within normal limits. Therefore, this study aimed to evaluate the listening skills in tinnitus patients by matching the normal hearing thresholds at all frequencies, including the extended high frequency. Methods: Eighteen chronic tinnitus patients and thirty matched healthy controls having normal pure-tone average with symmetrical hearing thresholds was included. Subjects were evaluated with 0.125–20 kHz pure-tone audiometry, Montreal cognitive assessment test (MoCA), Tinnitus Handicap Inventory (THI), Matrix Test, Pupillometry. Results: Pupil dilatation in the 'coding' phase of the sentence presented in tinnitus patients was less than in the control group (p < 0.05). There was no difference between the groups for Matrix test scores (p > 0.05) Also, there was no statistically significant correlation between THI and Pupillometry components nor between MoCA (p > 0.05). Conclusion: Even though tinnitus patients had normal hearing in the range of 0.125–20 kHz, their autonomic nervous system responses during listening differed from healthy subjects. This difference was interpreted for potential listening fatigue in tinnitus patients. |
Eser Sendesen; Didem Turkyilmaz Listening handicap in tinnitus patients by controlling extended high frequencies - Effort or fatigue? Journal Article In: Auris Nasus Larynx, vol. 51, no. 1, pp. 198–205, 2024. @article{Sendesen2024,Objective: In previous studies, the results regarding the presence of listening effort or fatigue in tinnitus patients were inconsistent. The reason for this inconsistency could be that extended high frequencies, which can cause listening handicap, were not considered. Therefore, this study aimed to evaluate the listening skills in tinnitus patients by matching the hearing thresholds at all frequencies, including the extended high frequency. Methods: Eighteen chronic tinnitus patients and thirty matched healthy controls having normal pure-tone average with symmetrical hearing thresholds was included. Subjects were evaluated with 0.125-20 kHz pure-tone audiometry, Montreal cognitive assessment test (MoCA), Tinnitus Handicap Inventory (THI), Matrix Test, Pupillometry. Results: Pupil dilatation in the 'coding' phase of the sentence presented in tinnitus patients was less than in the control group (p<0.05). There was no difference between the groups for Matrix test scores (p> 0.05) Also, there was no statistically significant correlation between THI and Pupillometry components nor between MoCA (p>0.05). Conclusion: The results were interpreted for potential listening fatigue in tinnitus patients. Considering the possible listening handicap in tinnitus patients, reducing the listening difficulties especially in noisy environments, can be added to the goals of tinnitus therapy protocols. |
Eser Sendesen; Didem Turkyilmaz Investigation of the behavior of tinnitus patients under varying listening conditions with simultaneous electroencephalography and pupillometry Journal Article In: Brain and Behavior, vol. 14, no. 6, pp. 1–11, 2024. @article{Sendesen2024a,Objective: This study aims to control all hearing thresholds, including extended high frequencies (EHFs), presents stimuli of varying difficulty levels, and measures electroencephalography (EEG) and pupillometry responses to determine whether listening difficulty in tinnitus patients is effort or fatigue-related. Methods: Twenty-one chronic tinnitus patients and 26 matched healthy controls having normal pure-tone averages with symmetrical hearing thresholds were included. Subjects were evaluated with 0.125−20 kHz pure-tone audiometry, Montreal Cognitive Assessment Test (MoCA), Tinnitus Handicap Inventory (THI), EEG, and pupillometry. Results: Pupil dilatation and EEG alpha power during the “encoding” phase of the presented sentence in tinnitus patients were less in all listening conditions (p <.05). Also, there was no statistically significant relationship between EEG and pupillometry components for all listening conditions and THI or MoCA (p >.05). Conclusion: EEG and pupillometry results under various listening conditions indicate potential listening effort in tinnitus patients even if all frequencies, including EHFs, are controlled. Also, we suggest that pupillometry should be interpreted with caution in autonomic nervous system-related conditions such as tinnitus. |
Anna Render; Hedwig Eisenbarth; Matt Oxner; Petra Jansen Arousal, interindividual differences and temporal binding a psychophysiological study Journal Article In: Psychological Research, vol. 88, no. 5, pp. 1653–1677, 2024. @article{Render2024,The sense of agency varies as a function of arousal in negative emotional contexts. As yet, it is unknown whether the same is true for positive affect, and how inter-individual characteristics might predict these effects. Temporal binding, an implicit measure of the sense of agency, was measured in 59 participants before and after watching either an emotionally neutral film clip or a positive film clip with high or low arousal. Analyses included participants' individual differences in subjective affective ratings, physiological arousal (pupillometry, skin conductance, heart rate), striatal dopamine levels via eye blink rates, and psychopathy. Linear mixed models showed that sexual arousal decreased temporal binding whereas calm pleasure had no facilitation effect on binding. Striatal dopamine levels were positively linked whereas subjective and physiological arousal may be negatively associated with binding towards actions. Psychopathic traits reduced the effect of high arousal on binding towards actions. These results provide evidence that individual differences influence the extent to which the temporal binding is affected by high arousing states with positive valence. |
Jasmine Pan; Xuelin Sun; Edison Park; Marine Kaufmann; Michaela Klimova; Joseph T. McGuire; Sam Ling The effects of emotional arousal on pupil size depend on luminance Journal Article In: Scientific reports, vol. 14, no. 1, pp. 1–18, 2024. @article{Pan2024,Pupillometry is widely used to measure arousal states. The primary functional role of the pupil, however, is to respond to the luminance of visual inputs. We previously demonstrated that cognitive effort-related arousal interacted multiplicatively with luminance, with the strongest pupillary effects of arousal occurring at low-to-mid luminances (< 37 cd/m2), implying a narrow range of conditions ideal for assessing cognitive arousal-driven pupillary differences. Does this generalize to other forms of arousal? To answer this, we assessed luminance-driven pupillary response functions while manipulating emotional arousal, using well-established visual and auditory stimulus sets. At the group level, emotional arousal interacted with the pupillary light response differently from cognitive arousal: the effects occurred primarily at much lower luminances (< 20 cd/m2). Analyses at the individual-participant level revealed qualitatively distinct patterns of modulation, with a sizable number of individuals displaying no arousal response to the visual or auditory stimuli, regardless of luminance. Together, our results suggest that effects of arousal on pupil size are not monolithic: different forms of arousal exert different patterns of effects. More practically, our findings suggest that lower luminances create better conditions for measuring pupil-linked arousal, and when selecting ambient luminance levels, consideration of the arousal manipulation and individual differences is critical. |
Sean R. O'Bryan; Mindi M. Price; Jessica L. Alquist; Tyler Davis; Miranda Scolari Changes in pupil size track self-control failure Journal Article In: Experimental Brain Research, vol. 242, no. 4, pp. 829–841, 2024. @article{OBryan2024a,People are more likely to perform poorly on a self-control task following a previous task requiring self-control (ego-depletion), but the mechanism for this effect remains unclear. We used pupillometry to test the role of attentional effort in ego-depletion. We hypothesized that an elevated pupil diameter (PD)—a common physiological measure of effort—during an initial task requiring self-control should be negatively associated with performance on a subsequent control task. To test this hypothesis, participants were first assigned to either a high- or low-demand attention task (manipulation; a standard ego-depletion paradigm), after which all participants completed the same Stroop task. We then separately extracted both sustained (low-frequency) and phasic (high-frequency) changes in PD from both tasks to evaluate possible associations with lapses of cognitive control on the Stroop task. We first show that in the initial task, sustained PD was larger among participants who were assigned to the demanding attention condition. Furthermore, ego-depletion effects were serially mediated by PD: an elevated PD response emerged rapidly among the experimental group during the manipulation, persisted as an elevated baseline response during the Stroop task, and predicted worse accuracy on incongruent trials, revealing a potential indirect pathway to ego-depletion via sustained attention. Secondary analyses revealed another, independent and direct pathway via high levels of transient attentional control: participants who exhibited large phasic responses during the manipulation tended to perform worse on the subsequent Stroop task. We conclude by exploring the neuroscientific implications of these results within the context of current theories of self-control. |
Leonie Nowack; Hermann J. Müller; Markus Conci Changes in attentional breadth scale with the demands of Kanizsa-figure object completion–evidence from pupillometry Journal Article In: Attention, Perception, & Psychophysics, vol. 86, no. 2, pp. 439–456, 2024. @article{Nowack2024,The present study investigated whether the integration of separate parts into a whole-object representation varies with the amount of available attentional resources. To this end, two experiments were performed, which required observers to maintain central fixation while searching in peripheral vision for a target among various distractor configurations. The target could either be a “grouped” whole-object Kanizsa figure, or an “ungrouped” configuration of identical figural parts, but which do not support object completion processes to the same extent. In the experiments, accuracies and changes in pupil size were assessed, with the latter reflecting a marker of the covert allocation of attention in the periphery. Experiment 1 revealed a performance benefit for grouped (relative to ungrouped) targets, which increased with decreasing distance from fixation. By contrast, search for ungrouped targets was comparably poor in accuracy without revealing any eccentricity-dependent variation. Moreover, measures of pupillary dilation mirrored this eccentricity-dependent advantage in localizing grouped targets. Next, in Experiment 2, an additional attention-demanding foveal task was introduced in order to further reduce the availability of attentional resources for the peripheral detection task. This additional task hampered performance overall, alongside with corresponding pupil size changes. However, there was still a substantial benefit for grouped over ungrouped targets in both the behavioral and the pupillometric data. This shows that perceptual grouping scales with the allocation of attention even when only residual attentional resources are available to trigger the representation of a complete (target) object, thus illustrating that object completion operates in the “near absence” of attention. |
Hannah Mechtenberg; Cristal Giorio; Emily B. Myers Pupil dilation reflects perceptual priorities during a receptive speech task Journal Article In: Ear & Hearing, vol. 45, no. 2, pp. 425–440, 2024. @article{Mechtenberg2024,Objectives: The listening demand incurred by speech perception fluctuates in normal conversation. At the acoustic-phonetic level, natural variation in pronunciation acts as speedbumps to accurate lexical selection. Any given utterance may be more or less phonetically ambiguous - a problem that must be resolved by the listener to choose the correct word. This becomes especially apparent when considering two common speech registers - clear and casual - that have characteristically different levels of phonetic ambiguity. Clear speech prioritizes intelligibility through hyperarticulation which results in less ambiguity at the phonetic level, while casual speech tends to have a more collapsed acoustic space. We hypothesized that listeners would invest greater cognitive resources while listening to casual speech to resolve the increased amount of phonetic ambiguity, as compared with clear speech. To this end, we used pupillometry as an online measure of listening effort during perception of clear and casual continuous speech in two background conditions: quiet and noise. Design: Forty-eight participants performed a probe detection task while listening to spoken, nonsensical sentences (masked and unmasked) while recording pupil size. Pupil size was modeled using growth curve analysis to capture the dynamics of the pupil response as the sentence unfolded. Results: Pupil size during listening was sensitive to the presence of noise and speech register (clear/casual). Unsurprisingly, listeners had overall larger pupil dilations during speech perception in noise, replicating earlier work. The pupil dilation pattern for clear and casual sentences was considerably more complex. Pupil dilation during clear speech trials was slightly larger than for casual speech, across quiet and noisy backgrounds. Conclusions: We suggest that listener motivation could explain the larger pupil dilations to clearly spoken speech. We propose that, bounded by the context of this task, listeners devoted more resources to perceiving the speech signal with the greatest acoustic/phonetic fidelity. Further, we unexpectedly found systematic differences in pupil dilation preceding the onset of the spoken sentences. Together, these data demonstrate that the pupillary system is not merely reactive but also adaptive - sensitive to both task structure and listener motivation to maximize accurate perception in a limited resource system. |
Drew J. McLaughlin; Jackson S. Colvett; Julie M. Bugg; Kristin J. Van Engen Sequence effects and speech processing: cognitive load for speaker-switching within and across accents Journal Article In: Psychonomic Bulletin & Review, vol. 31, no. 1, pp. 1–11, 2024. @article{McLaughlin2024,Prior work in speech processing indicates that listening tasks with multiple speakers (as opposed to a single speaker) result in slower and less accurate processing. Notably, the trial-to-trial cognitive demands of switching between speakers or switching between accents have yet to be examined. We used pupillometry, a physiological index of cognitive load, to examine the demands of processing first (L1) and second (L2) language-accented speech when listening to sentences produced by the same speaker consecutively (no switch), a novel speaker of the same accent (within-accent switch), and a novel speaker with a different accent (across-accent switch). Inspired by research on sequential adjustments in cognitive control, we aimed to identify the cognitive demands of accommodating a novel speaker and accent by examining the trial-to-trial changes in pupil dilation during speech processing. Our results indicate that switching between speakers was more cognitively demanding than listening to the same speaker consecutively. Additionally, switching to a novel speaker with a different accent was more cognitively demanding than switching between speakers of the same accent. However, there was an asymmetry for across-accent switches, such that switching from an L1 to an L2 accent was more demanding than vice versa. Findings from the present study align with work examining multi-talker processing costs, and provide novel evidence that listeners dynamically adjust cognitive processing to accommodate speaker and accent variability. We discuss these novel findings in the context of an active control model and auditory streaming framework of speech processing. |
Priscila López-Beltrán; Paola E. Dussias Heritage speakers' processing of the Spanish subjunctive: A pupillometric study Priscila Journal Article In: Linguistic Approaches to Bilingualism, vol. 14, no. 6, pp. 809–855, 2024. @article{LopezBeltran2024,We investigated linguistic knowledge of subjunctive mood in heritage speakers of Spanish who live in a long-standing English-Spanish bilingual community in Albuquerque, New Mexico. Three experiments examine the constraints on subjunctive selection. Experiment 1 and Experiment 2 employed pupillometry to investigate heritage speakers' online sensitivity to the presence of the subjunctive with non-variable governors (Lexical conditioning) and with negated governors (Structural conditioning). Experiment 3 employed an elicited production task to examine production of subjunctive in the same contexts. The findings of the heritage group were compared to those of a group ofSpanish-dominant Mexican bilinguals. Results showed that in comprehension and production, heritage speakers were as sensitive as the Spanish-dominant bilinguals to the lexical and structural factors that condition mood selection. In comprehension, the two groups experienced an increased pupillary dilation in conditions where the indicative was used but the subjunctive was expected. In addition, high- frequency governors and irregular subordinate verbs boosted participants' sensitivity to the presence of the subjunctive. In production, there were no significant differences between heritage speakers and Spanish-dominant bilinguals when producing the subjunctive with non-variable and negated governors. |
Ye Liu; Bridget W. Mahony; Xiaochun Wang; Pierre M. Daye; Wei Wang; Patrick Cavanagh; Pierre Pouget; Ian Max Andolina Assessing perceptual chromatic equiluminance using a reflexive pupillary response Journal Article In: Scientific Reports, vol. 14, no. 1, pp. 1–12, 2024. @article{Liu2024i,Equiluminant stimuli help assess the integrity of colour perception and the relationship of colour to other visual features. As a result of individual variation, it is necessary to calibrate experimental visual stimuli to suit each individual's unique equiluminant ratio. Most traditional methods rely on training observers to report their subjective equiluminance point. Such paradigms cannot easily be implemented on pre-verbal or non-verbal observers. Here, we present a novel Pupil Frequency-Tagging Method (PFTM) for detecting a participant's unique equiluminance point without verbal instruction and with minimal training. PFTM analyses reflexive pupil oscillations induced by slow (< 2 Hz) temporal alternations between coloured stimuli. Two equiluminant stimuli will induce a similar pupil dilation response regardless of colour; therefore, an observer's equiluminant point can be identified as the luminance ratio between two colours for which the oscillatory amplitude of the pupil at the tagged frequency is minimal. We compared pupillometry-based equiluminance ratios to those obtained with two established techniques in humans: minimum flicker and minimum motion. In addition, we estimated the equiluminance point in non-human primates, demonstrating that this new technique can be successfully employed in non-verbal subjects. |
Frauke Kraus; Bernhard Ross; Björn Herrmann; Jonas Obleser Neurophysiology of effortful listening: Decoupling motivational modulation from task demands Journal Article In: The Journal of Neuroscience, vol. 44, no. 44, pp. 1–15, 2024. @article{Kraus2024,In demanding listening situations, a listener's motivational state may affect their cognitive investment. Here, we aim to delineate how domain-specific sensory processing, domain-general neural alpha power, and pupil size as a proxy for cognitive investment encode influences of motivational state under demanding listening. Participants performed an auditory gap-detection task while pupil size and the magnetoencephalogram (MEG) were simultaneously recorded. Task demand and a listener's motivational state were orthogonally manipulated through changes in gap duration and monetary-reward prospect, respectively. Whereas task difficulty impaired performance, reward prospect enhanced it. Pupil size reliably indicated the modulatory impact of an individual's motivational state. At the neural level, the motivational state did not affect auditory sensory processing directly but impacted attentional post-processing of an auditory event as reflected in the late evoked-response field and alpha power change. Both pre-gap pupil dilation and higher parietal alpha power predicted better performance at the single-trial level. The current data support a framework wherein the motivational state acts as an attentional top-down neural means of post-processing the auditory input in challenging listening situations. Significance Statement How does an individual's motivational state affect cognitive investment during effortful listening? In this simultaneous pupillometry and MEG study, participants performed an auditory gap-detection task while their motivational state was manipulated through varying prospect of a monetary reward. The pupil size directly mirrored this motivational modulation of the listening demand. The individual's motivational state also enhanced top-down attentional post-processing of the auditory event but did neither change auditory sensory processing nor pre-gap parietal alpha power. These data suggest that a listener's motivational state acts as a late attentional top-down effect on auditory neural processes in challenging listening situations. ### Competing Interest Statement The authors have declared no competing interest. |
Damian Koevoet; Marnix Naber; Stefan Stigchel The intensity of internal and external attention assessed with pupillometry Journal Article In: Journal of Cognition, vol. 7, pp. 1–10, 2024. @article{Koevoet2024,Not only is visual attention shifted to objects in the external world, attention can also be directed to objects in memory. We have recently shown that pupil size indexes how strongly items are attended externally, which was reflected in more precise encoding into visual working memory. Using a retro-cuing paradigm, we here replicated this finding by showing that stronger pupil constrictions during encoding were reflective of the depth of encoding. Importantly, we extend this previous work by showing that pupil size also revealed the intensity of internal attention toward content stored in visual working memory. Specifically, pupil dilation during the prioritization of one among multiple internally stored representations predicted the precision of the prioritized item. Furthermore, the dynamics of the pupillary responses revealed that the intensity of internal and external attention independently determined the precision of internalized visual representations. Our results show that both internal and external attention are not all-or-none processes, but should rather be thought of as continuous resources that can be deployed at varying intensities. The employed pupillometric approach allows to unravel the intricate interplay between internal and external attention and their effects on visual working memory. |
Samet Kılıç; Eser Sendesen; Filiz Aslan; Nurhan Erbil; Özgür Aydın; Didem Türkyılmaz Investigating sensitivity to auditory cognition in listening effort assessments: A simultaneous EEG and pupillometry study Journal Article In: Brain and Behavior, vol. 14, no. 11, pp. 1–12, 2024. @article{Kilic2024,Background: It is still not fully explained what kind of cognitive sources the methods used in the assessment of listening effort are more sensitive to and how these measurement results are related to each other. The aim of the study is to ascertain which neural resources crucial for listening effort are most sensitive to objective measurement methods using differently degraded speech stimuli. Methods: A total of 49 individuals between the ages of 19 and 34 with normal hearing participated in the study. In the first stage, simultaneous pupillometry, electroencephalogram (EEG), and single-task paradigm reaction time (RT) measurements were made during the challenging listening and repetition task with noise-vocoded speech. Two speech reception thresholds (SRT) (50% and 80%) for two vocoding conditions (16 and 6 channels) were collected, resulting in 4 conditions. In the second stage, the Rey Auditory Verbal Learning Test (RAVLT) and the test of attention in listening (TAIL) were applied. Stepwise linear regression analyses were conducted to examine the predictors of listening effort measurements. Results: A significant difference was found between 6 and 16 channel stimuli in both pupil dilation change and EEG alpha band power change. In the hardest listening condition, whereas RAVLT scores are significant predictors of pupil dilation change, TAIL scores are significant predictors of EEG alpha power. As the stimulus difficulty decreased, the factors that predicted both EEG and pupillometry results decreased. In the single-task paradigm, a significant regression model could not be obtained at all four difficulty levels. Conclusion: As a result of the study, it was found that the pupil dilation change was more sensitive to auditory memory skills and the EEG alpha power change was more sensitive to auditory attention skills. To our knowledge, this study is the first to investigate the sensitivity of different listening effort measurement methods to auditory cognitive skills. |
M. A. Johns; R. C. Calloway; I. M. D. Karunathilake; L. P. Decruy; S. Anderson; J. Z. Simon; S. E. Kuchinsky Attention mobilization as a modulator of listening effort: Evidence from pupillometry Journal Article In: Trends in Hearing, vol. 28, pp. 1–20, 2024. @article{Johns2024,Listening to speech in noise can require substantial mental effort, even among younger normal-hearing adults. The task-evoked pupil response (TEPR) has been shown to track the increased effort exerted to recognize words or sentences in increasing noise. However, few studies have examined the trajectory of listening effort across longer, more natural, stretches of speech, or the extent to which expectations about upcoming listening difficulty modulate the TEPR. Seventeen younger normal-hearing adults listened to 60-s-long audiobook passages, repeated three times in a row, at two different signal-to-noise ratios (SNRs) while pupil size was recorded. There was a significant interaction between SNR, repetition, and baseline pupil size on sustained listening effort. At lower baseline pupil sizes, potentially reflecting lower attention mobilization, TEPRs were more sustained in the harder SNR condition, particularly when attention mobilization remained low by the third presentation. At intermediate baseline pupil sizes, differences between conditions were largely absent, suggesting these listeners had optimally mobilized their attention for both SNRs. Lastly, at higher baseline pupil sizes, potentially reflecting overmobilization of attention, the effect of SNR was initially reversed for the second and third presentations: participants initially appeared to disengage in the harder SNR condition, resulting in reduced TEPRs that recovered in the second half of the story. Together, these findings suggest that the unfolding of listening effort over time depends critically on the extent to which individuals have successfully mobilized their attention in anticipation of difficult listening conditions. |
Ronen Hershman; David L. Share; Elisabeth M. Weiss; Avishai Henik; Adi Shechter Insights from eye blinks into the cognitive processes involved in visual word recognition Journal Article In: Journal of Cognition, vol. 7, no. 1, pp. 1–9, 2024. @article{Hershman2024,Behavioral differences in speed and accuracy between reading familiar and unfamiliar words are well-established in the empirical literature. However, these standard measures of skill proficiency are limited in their ability to capture the moment-to-moment processing involved in visual word recognition. In the present study, the effect of word familiarity was initially investigated using an eye blink rate among adults and children. The probability of eye blinking was higher for familiar (real) words than for unfamiliar (pseudo)words. This counterintuitive pattern of results suggests that the processing of unfamiliar (pseudo)words is more demanding and perhaps less rewarding than the processing of familiar (real) words, as previously observed in both behavioral and pupillometry data. Our findings suggest that the measurement of eye blinks might shed new light on the cognitive processes involved in visual word recognition and other domains of human cognition. |
Björn Herrmann; Jennifer D. Ryan Pupil size and eye movements differently index effort in both younger and older adults Journal Article In: Journal of Cognitive Neuroscience, vol. 36, no. 7, pp. 1325–1340, 2024. @article{Herrmann2024,The assessment of mental effort is increasingly relevant in neurocognitive and life span domains. Pupillometry, the measure of the pupil size, is often used to assess effort but has disadvantages. Analysis of eye movements may provide an alternative, but research has been limited to easy and difficult task demands in younger adults. An effort measure must be sensitive to the whole effort profile, including “giving up” effort investment, and capture effort in different age groups. The current study comprised three experiments in which younger (n = 66) and older (n = 44) adults listened to speech masked by background babble at different signal-to-noise ratios associated with easy, difficult, and impossible speech comprehension. We expected individuals to invest little effort for easy and impossible speech (giving up) but to exert effort for difficult speech. Indeed, pupil size was largest for difficult but lower for easy and impossible speech. In contrast, gaze dispersion decreased with increasing speech masking in both age groups. Critically, gaze dispersion during difficult speech returned to levels similar to easy speech after sentence offset, when acoustic stimulation was similar across conditions, whereas gaze dispersion during impossible speech continued to be reduced. These findings show that a reduction in eye movements is not a byproduct of acoustic factors, but instead suggest that neurocognitive processes, different from arousal-related systems regulating the pupil size, drive reduced eye movements during high task demands. The current data thus show that effort in one sensory domain (audition) differentially impacts distinct functional properties in another sensory domain (vision). |
Laura S. Geurts; Sam Ling; Janneke F. M. Jehee Pupil-linked arousal modulates precision of stimulus representation in cortex Journal Article In: The Journal of Neuroscience, vol. 44, no. 42, pp. 1–11, 2024. @article{Geurts2024,Neural responses are naturally variable from one moment to the next, even when the stimulus is held constant. What factors might underlie this variability in neural population activity? We hypothesized that spontaneous fluctuations in cortical stimulus representations are created by changes in arousal state. We tested the hypothesis using a combination of fMRI, probabilistic decoding methods, and pupillometry. Human participants (20 female, 12 male) were presented with gratings of random orientation. Shortly after viewing the grating, participants reported its orientation and gave their level of confidence in this judgment. Using a probabilistic fMRI decoding technique, we quantified the precision of the stimulus representation in the visual cortex on a trial-by-trial basis. Pupil size was recorded and analyzed to index the observer's arousal state. We found that the precision of the cortical stimulus representation, reported confidence, and variability in the behavioral orientation judgments varied from trial to trial. Interestingly, these trial-by-trial changes in cortical and behavioral precision and confidence were linked to pupil size and its temporal rate of change. Specifically, when the cortical stimulus representation was more precise, the pupil dilated more strongly prior to stimulus onset and remained larger during stimulus presentation. Similarly, stronger pupil dilation during stimulus presentation was associated with higher levels of subjective confidence, a secondary measure of sensory precision, as well as improved behavioral performance. Taken together, our findings support the hypothesis that spontaneous fluctuations in arousal state modulate the fidelity of the stimulus representation in the human visual cortex, with clear consequences for behavior. |
Natsumi Funasaki; Masataka Yano Role of prosody and word order in identifying focus: Evidence from pupillometry Journal Article In: Language, Cognition and Neuroscience, vol. 40, no. 2, pp. 23–40, 2024. @article{Funasaki2024,This study investigated the role of prosody and word order in identifying the focus of sentences in Japanese. Native Japanese speakers listened to sentences with different types of word order (subject–object–verb (SOV) vs. object–subject–verb (OSV)), prosody (whether the first noun phrase is stressed or not) and preceding contexts (object- vs. subject-wh questions), while processing costs were measured using pupillometry. Although syntactically non-basic OSV was more difficult to process than basic SOV, this processing difficulty was considerably reduced when the supportive context (the subject-wh question) required S to be focused. The time–course analysis of pupillometry revealed that the Japanese speakers immediately used prosodic cues to determine the focus of sentences, but the effect of word order cues for focus was delayed until the sentence-final verb was encountered. This study advances our understanding of the temporal dynamics of focus processing and the interplay between syntactic and information structures in sentence comprehension. |
Julia Fietz; Dorothee Pöhlchen; BeCOME Working Group; Tanja M. Brückl; Anna-Katharine Brem; Frank Padberg; Michael Czisch; Philipp G. Sämann; Victor I. Spoormaker In: Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, vol. 9, no. 6, pp. 580–587, 2024. @article{Fietz2024,Background: Neurocognitive functioning is a relevant transdiagnostic dimension in psychiatry. As pupil size dynamics track cognitive load during a working memory task, we aimed to explore if this parameter allows identification of psychophysiological subtypes in healthy participants and patients with affective and anxiety disorders. Methods: Our sample consisted of 226 participants who completed the n-back task during simultaneous functional magnetic resonance imaging and pupillometry measurements. We used latent class growth modeling to identify clusters based on pupil size in response to cognitive load. In a second step, these clusters were compared on affective and anxiety symptom levels, performance in neurocognitive tests, and functional magnetic resonance imaging activity. Results: The clustering analysis resulted in two distinct pupil response profiles: one with a stepwise increasing pupil size with increasing cognitive load (reactive group) and one with a constant pupil size across conditions (nonreactive group). A larger increase in pupil size was significantly associated with better performance in neurocognitive tests in executive functioning and sustained attention. Statistical maps of parametric modulation of pupil size during the n-back task showed the frontoparietal network in the positive contrast and the default mode network in the negative contrast. The pupil response profile of the reactive group was associated with more thalamic activity, likely reflecting better arousal upregulation and less deactivation of the limbic system. Conclusions: Pupil measurements have the potential to serve as a highly sensitive psychophysiological readout for detection of neurocognitive deficits in the core domain of executive functioning, adding to the development of valid transdiagnostic constructs in psychiatry. |
Hadeel Ershaid; Mikel Lizarazu; D. J. Drew McLaughlin; Martin Cooke; Olympia Simantiraki; Maria Koutsogiannaki; Marie Lallier Contributions of listening effort and intelligibility to cortical tracking of speech in adverse listening conditions Journal Article In: Cortex, vol. 172, pp. 54–71, 2024. @article{Ershaid2024,Cortical tracking of speech is vital for speech segmentation and is linked to speech intelligibility. However, there is no clear consensus as to whether reduced intelligibility leads to a decrease or an increase in cortical speech tracking, warranting further investigation of the factors influencing this relationship. One such factor is listening effort, defined as the cognitive resources necessary for speech comprehension, and reported to have a strong negative correlation with speech intelligibility. Yet, no studies have examined the relationship between speech intelligibility, listening effort, and cortical tracking of speech. The aim of the present study was thus to examine these factors in quiet and distinct adverse listening conditions. Forty-nine normal hearing adults listened to sentences produced casually, presented in quiet and two adverse listening conditions: cafeteria noise and re- verberant speech. Electrophysiological responses were registered with electroencephalogram, and listening effort was estimated subjectively using self-reported scores and objectively using pupillometry. Results indicated varying impacts of adverse conditions on intelligibility, listening effort, and cortical tracking of speech, depending on the preservation of the speech temporal envelope. The more distorted envelope in the reverberant condition led to higher listening effort, as reflected in higher subjective scores, increased pupil diameter, and stronger cortical tracking of speech in the delta band. These findings suggest that using measures of listening effort in addition to those of intelligibility is useful for interpreting cortical tracking of speech results. Moreover, reading and phonological skills of participants were positively correlated with listening effort in the cafeteria condition, suggesting a special role of expert language skills in processing speech in this noisy condition. Implications for future research and theories linking atypical cortical tracking of speech and reading disorders are further discussed. |
Laura Doll; Andrew R. Dykstra; Alexander Gutschalk Perceptual awareness of near-threshold tones scales gradually with auditory cortex activity and pupil dilation Journal Article In: iScience, vol. 27, no. 8, pp. 1–20, 2024. @article{Doll2024,Negative-going responses in sensory cortex co-vary with perceptual awareness of sensory stimuli. Given that this awareness negativity has also been observed for undetected stimuli, some have challenged its role for perception. To address this question, we combined magnetoencephalography, electroencephalography, and pupillometry to study how sustained attention and response criterion affect the auditory awareness negativity. Participants first detected distractor sounds and denied hearing task-irrelevant near-threshold tones, which evoked neither awareness negativity nor pupil dilation. These same tones evoked both responses when task-relevant, stronger for hit but also present for miss trials. Participants then rated their perception on a six-point scale to test whether response criterion explains the presence of these responses for miss trials. Decreasing perception ratings were associated with gradually reduced evoked responses, consistent with signal detection theory. These results support the concept of an awareness negativity that is modulated by attention but does not require a non-linear threshold mechanism. |
Hsin-Hua Chin; Ying-Hsuan Tai; Rachel Yep; Yi-Hsuan Chang; Chun-Hsien Hsu; Chin-An Wang Investigating causal effects of pupil size on visual discrimination and visually evoked potentials in an optotype discrimination task Journal Article In: Frontiers in Neuroscience, vol. 18, pp. 1–10, 2024. @article{Chin2024,Pupil size primarily changes to regulate the amount of light entering the retina, optimizing the balance between visual acuity and sensitivity for effective visual processing. However, research directly examining the relationship between pupil size and visual processing has been limited. While a few studies have recorded pupil size and EEG signals to investigate the role of pupil size in visual processing, these studies have predominantly focused on the domain of visual sensitivity. Causal effects of pupil size on visual acuity, therefore, remain poorly understood. By manipulating peripheral background luminance levels and target stimulus contrast while simultaneously recording pupillometry and EEG signals, we examined how absolute pupil size affects visual discrimination and visually evoked potentials (VEP) in a task using optotype mimicking the Snellen eye chart, the most common assessment of visual acuity. Our findings indicate that both higher background luminance levels and higher target contrast were associated with improved target discrimination and faster correct reaction times. Moreover, while higher contrast visual stimuli evoked larger VEPs, the effects of pupil size on VEPs were not significant. Additionally, we did not observe inter-individual correlations between absolute pupil size and discrimination performance or VEP amplitude. Together, our results demonstrate that absolute pupil size, regulated by global luminance level, played a functional role in enhancing visual discrimination performance in an optotype discrimination task. The differential VEP effects of pupil size compared to those of stimulus contrast further suggested distinct neural mechanisms involved in facilitating visual acuity under small pupils. |
Yuqing Cai; Christoph Strauch; Stefan Van der Stigchel; Marnix Naber Open-DPSM: An open-source toolkit for modeling pupil size changes to dynamic visual inputs Journal Article In: Behavior Research Methods, vol. 56, no. 6, pp. 5605–5621, 2024. @article{Cai2024,Pupil size change is a widely adopted, sensitive indicator for sensory and cognitive processes. However, the interpretation of these changes is complicated by the influence of multiple low-level effects, such as brightness or contrast changes, posing challenges to applying pupillometry outside of extremely controlled settings. Building on and extending previous models, we here introduce Open Dynamic Pupil Size Modeling (Open-DPSM), an open-source toolkit to model pupil size changes to dynamically changing visual inputs using a convolution approach. Open-DPSM incorporates three key steps: (1) Modeling pupillary responses to both luminance and contrast changes; (2) Weighing of the distinct contributions of visual events across the visual field on pupil size change; and (3) Incorporating gaze-contingent visual event extraction and modeling. These steps improve the prediction of pupil size changes beyond the here-evaluated benchmarks. Open-DPSM provides Python functions, as well as a graphical user interface (GUI), enabling the extension of its applications to versatile scenarios and adaptations to individualized needs. By obtaining a predicted pupil trace using video and eye-tracking data, users can mitigate the effects of low-level features by subtracting the predicted trace or assess the efficacy of the low-level feature manipulations a priori by comparing estimated traces across conditions. |
Andy Brendler; Max Schneider; Immanuel G. Elbau; Rui Sun; Taechawidd Nantawisarakul; Dorothee Pöhlchen; Tanja Brückl; A. K. Brem; E. B. Binder; A. Erhardt; J. Fietz; N. C. Grandi; Y. Kim; S. Ilić-Ćoćić; L. Leuchs; S. Lucae; T. Namendorf; J. Pape; L. Schilbach; I. Mücke-Heim; J. Ziebula; Michael Czisch; Philipp G. Sämann; Michael D. Lee; Victor I. Spoormaker In: Scientific Reports, vol. 14, no. 344, pp. 1–11, 2024. @article{Brendler2024,Major depressive disorder (MDD) is a devastating and heterogenous disorder for which there are no approved biomarkers in clinical practice. We recently identified anticipatory hypo-arousal indexed by pupil responses as a candidate mechanism subserving depression symptomatology. Here, we conducted a replication and extension study of these findings. We analyzed a replication sample of 40 unmedicated patients with a diagnosis of depression and 30 healthy control participants, who performed a reward anticipation task while pupil responses were measured. Using a Bayesian modelling approach taking measurement uncertainty into account, we could show that the negative correlation between pupil dilation and symptom load during reward anticipation is replicable within MDD patients, albeit with a lower effect size. Furthermore, with the combined sample of 136 participants (81 unmedicated depressed and 55 healthy control participants), we further showed that reduced pupil dilation in anticipation of reward is inversely associated with anhedonia items of the Beck Depression Inventory in particular. Moreover, using simultaneous fMRI, particularly the right anterior insula as part of the salience network was negatively correlated with depressive symptom load in general and anhedonia items specifically. The present study supports the utility of pupillometry in assessing noradrenergically mediated hypo-arousal during reward anticipation in MDD, a physiological process that appears to subserve anhedonia. |
Elvio Blini; Roberto Arrighi; Giovanni Anobile Pupillary manifolds: Uncovering the latent geometrical structures behind phasic changes in pupil size Journal Article In: Scientific reports, vol. 14, no. 1, pp. 1–10, 2024. @article{Blini2024a,The size of the pupils reflects directly the balance of different branches of the autonomic nervous system. This measure is inexpensive, non-invasive, and has provided invaluable insights on a wide range of mental processes, from attention to emotion and executive functions. Two outstanding limitations of current pupillometry research are the lack of consensus in the analytical approaches, which vary wildly across research groups and disciplines, and the fact that, unlike other neuroimaging techniques, pupillometry lacks the dimensionality to shed light on the different sources of the observed effects. In other words, pupillometry provides an integrated readout of several distinct networks, but it is unclear whether each has a specific fingerprint, stemming from its function or physiological substrate. Here we show that phasic changes in pupil size are inherently low-dimensional, with modes that are highly consistent across behavioral tasks of very different nature, suggesting that these changes occur along pupillary manifolds that are highly constrained by the underlying physiological structures rather than functions. These results provide not only a unified approach to analyze pupillary data, but also the opportunity for physiology and psychology to refer to the same processes by tracing the sources of the reported changes in pupil size in the underlying biology. |
Isabel Bleimeister; Inbar Avni; Michael Granovetter; Gal Meiri; Michal Ilan; Analya Michaelovski; Idan Menashe; Marlene Behrmann; Ilan Dinstein Idiosyncratic pupil regulation in autistic children Journal Article In: Autism Research, vol. 17, pp. 2503–2513, 2024. @article{Bleimeister2024,Recent neuroimaging and eye tracking studies have suggested that children with autism spectrum disorder (ASD) may exhibit more variable and idiosyncratic brain responses and eye movements than typically developing (TD) children. Here we extended this research for the first time to pupillometry recordings. We successfully completed pupillometry recordings with 103 children (66 with ASD), 4.5-years-old on average, who viewed three 90 second movies, twice. We extracted their pupillary time-course for each movie, capturing their stimulus evoked pupillary responses. We then computed the correlation between the time-course of each child and those of all others in their group. This yielded an average inter-subject correlation value per child, representing how similar their pupillary responses were to all others in their group. ASD participants exhibited significantly weaker inter-subject correlations than TD participants, reliably across all three movies. Differences across groups were largest in responses to a naturalistic movie containing footage of a social interaction between two TD children. This measure enabled classification of ASD and TD children with a sensitivity of 0.82 and specificity of 0.73 when trained and tested on independent datasets. Using the largest ASD pupillometry dataset to date, we demonstrate the utility of a new technique for measuring the idiosyncrasy of pupil regulation, which can be completed even by young children with co-occurring intellectual disability. These findings reveal that a considerable subgroup of ASD children have significantly more unstable, idiosyncratic pupil regulation than TD children, indicative of more variable, weakly regulated, underlying neural activity. |
Omer Ben Barak-Dror; Barak Hadad; Hani Barhum; David Haggiag; Michal Tepper; Israel Gannot; Yuval Nir Touchless short-wave infrared imaging for dynamic rapid pupillometry and gaze estimation in closed eyes Journal Article In: Communications Medicine, vol. 4, no. 1, pp. 1–12, 2024. @article{BenBarakDror2024,Background: Assessments of gaze direction (eye movements), pupil size, and the pupillary light reflex (PLR) are critical for neurological examination and neuroscience research and constitute a powerful tool in diverse clinical settings ranging from critical care through endocrinology and drug addiction to cardiology and psychiatry. However, current bedside pupillometry is typically intermittent, qualitative, manual, and limited to open-eye cases, restricting its use in sleep medicine, anesthesia, and intensive care. Methods: We combined short-wave infrared (SWIR, ~0.9-1.7μm) imaging with image processing algorithms to perform rapid (~30 ms) pupillometry and eye tracking behind closed eyelids. Forty-three healthy volunteers participated in two experiments with PLR evoked by visible light stimuli or directing eye movements towards screen targets. Imaging was performed simultaneously on one eye closed, and the other open eye serving as ground truth. Data analysis was performed with a custom approach quantifying changes in brightness around the pupil area or with a deep learning U-NET-based procedure. Results: Here we show that analysis of SWIR imaging data can successfully measure stimulus-evoked PLR in closed-eye conditions, revealing PLR events in single trials and significant PLRs in nearly all individual subjects, as well as estimating gaze direction. The neural net-based analysis could successfully use closed-eye SWIR data to recreate estimates of open-eye images and assess pupil size. Conclusions: Continuous touchless monitoring of rapid dynamics in pupil size and gaze direction through closed eyes paves the way for developing devices with wide-ranging applications, fulfilling long-standing goals in clinical and research fields. |
Janika Becker; Marvin Viertler; Christoph W. Korn; Helen Blank The pupil dilation response as an indicator of visual cue uncertainty and auditory outcome surprise Journal Article In: European Journal of Neuroscience, vol. 59, no. 10, pp. 2686–2701, 2024. @article{Becker2024a,In everyday perception, we combine incoming sensory information with prior expectations. Expectations can be induced by cues that indicate the probability of following sensory events. The information provided by cues may differ and hence lead to different levels of uncertainty about which event will follow. In this experiment, we employed pupillometry to investigate whether the pupil dilation response to visual cues varies depending on the level of cue-associated uncertainty about a following auditory outcome. Also, we tested whether the pupil dilation response reflects the amount of surprise about the subsequently presented auditory stimulus. In each trial, participants were presented with a visual cue (face image) which was followed by an auditory outcome (spoken vowel). After the face cue, participants had to indicate by keypress which of three auditory vowels they expected to hear next. We manipulated the cue-associated uncertainty by varying the probabilistic cue-outcome contingencies: One face was most likely followed by one specific vowel (low cue uncertainty), another face was equally likely followed by either of two vowels (intermediate cue uncertainty) and the third face was followed by all three vowels (high cue uncertainty). Our results suggest that pupil dilation in response to task-relevant cues depends on the associated uncertainty, but only for large differences in the cue-associated uncertainty. Additionally, in response to the auditory outcomes, the pupil dilation scaled negatively with the cue-dependent probabilities, likely signalling the amount of surprise. |
Janika Becker; Christoph W. Korn; Helen Blank Pupil diameter as an indicator of sound pair familiarity after statistically structured auditory sequence Journal Article In: Scientific Reports, vol. 14, no. 1, pp. 1–14, 2024. @article{Becker2024,Inspired by recent findings in the visual domain, we investigated whether the stimulus-evoked pupil dilation reflects temporal statistical regularities in sequences of auditory stimuli. We conducted two preregistered pupillometry experiments (experiment 1 |
Shira Baror; Thomas J. Baumgarten; Biyu J. He Neural mechanisms determining the duration of task-free, self-paced visual perception Journal Article In: Journal of Cognitive Neuroscience, vol. 36, no. 5, pp. 756–775, 2024. @article{Baror2024,Humans spend hours each day spontaneously engaging with visual content, free from specific tasks and at their own pace. Currently, the brain mechanisms determining the duration of self-paced perceptual behavior remain largely unknown. Here, participants viewed naturalistic images under task-free settings and self-paced each image's viewing duration while undergoing EEG and pupillometry recordings. Across two independent data sets, we observed large inter-and intra-individual variability in viewing duration. However, beyond an image's presentation order and category, specific image content had no consistent effects on spontaneous viewing duration across participants. Overall, longer viewing durations were associated with sustained enhanced posterior positivity and anterior negativity in the ERPs. Individual-specific variations in the spontaneous viewing duration were consistently correlated with evoked EEG activity amplitudes and pupil size changes. By contrast, presentation order was selectively correlated with baseline alpha power and baseline pupil size. Critically, spontaneous viewing duration was strongly predicted by the temporal stability in neural activity patterns starting as early as 350 msec after image onset, suggesting that early neural stability is a key predictor for sustained perceptual engagement. Interestingly, neither bottom–up nor top–down predictions about image category influenced spontaneous viewing duration. Overall, these results suggest that individual-specific factors can influence perceptual processing at a surprisingly early time point and influence the multifaceted ebb and flow of spontaneous human perceptual behavior in naturalistic settings. |
Evgeniia I. Alshanskaia; Galina V. Portnova; Krystsina Liaukovich; Olga V. Martynova Pupillometry and autonomic nervous system responses to cognitive load and false feedback: An unsupervised machine learning approach Journal Article In: Frontiers in Neuroscience, vol. 18, pp. 1–18, 2024. @article{Alshanskaia2024,Objectives: Pupil dilation is controlled both by sympathetic and parasympathetic nervous system branches. We hypothesized that the dynamic of pupil size changes under cognitive load with additional false feedback can predict individual behavior along with heart rate variability (HRV) patterns and eye movements reflecting specific adaptability to cognitive stress. To test this, we employed an unsupervised machine learning approach to recognize groups of individuals distinguished by pupil dilation dynamics and then compared their autonomic nervous system (ANS) responses along with time, performance, and self-esteem indicators in cognitive tasks. Methods: Cohort of 70 participants were exposed to tasks with increasing cognitive load and deception, with measurements of pupillary dynamics, HRV, eye movements, and cognitive performance and behavioral data. Utilizing machine learning k-means clustering algorithm, pupillometry data were segmented to distinct responses to increasing cognitive load and deceit. Further analysis compared clusters, focusing on how physiological (HRV, eye movements) and cognitive metrics (time, mistakes, self-esteem) varied across two clusters of different pupillary response patterns, investigating the relationship between pupil dynamics and autonomic reactions. Results: Cluster analysis of pupillometry data identified two distinct groups with statistically significant varying physiological and behavioral responses. Cluster 0 showed elevated HRV, alongside larger initial pupil sizes. Cluster 1 participants presented lower HRV but demonstrated increased and pronounced oculomotor activity. Behavioral differences included reporting more errors and lower self-esteem in Cluster 0, and faster response times with more precise reactions to deception demonstrated by Cluster 1. Lifestyle variations such as smoking habits and differences in Epworth Sleepiness Scale scores were significant between the clusters. Conclusion: The differentiation in pupillary dynamics and related metrics between the clusters underlines the complex interplay between autonomic regulation, cognitive load, and behavioral responses to cognitive load and deceptive feedback. These findings underscore the potential of pupillometry combined with machine learning in identifying individual differences in stress resilience and cognitive performance. Our research on pupillary dynamics and ANS patterns can lead to the development of remote diagnostic tools for real-time cognitive stress monitoring and performance optimization, applicable in clinical, educational, and occupational settings. |
Miriam Acquafredda; Paola Binda Pupillometry indexes ocular dominance plasticity Journal Article In: Vision Research, vol. 222, pp. 1–8, 2024. @article{Acquafredda2024,Short-term monocular deprivation in normally sighted adult humans produces a transient shift of ocular dominance, boosting the deprived eye. This effect has been documented with both perceptual tests and through physiological recordings, but no previous study simultaneously measured physiological responses and the perceptual effects of deprivation. Here we propose an integrated experimental paradigm that combines binocular rivalry with pupillometry, to introduce an objective physiological index of ocular dominance plasticity, acquired concurrently with perceptual testing. Ten participants reported the perceptual dynamics of binocular rivalry, while we measured pupil diameter. Stimuli were a white and a black disk, each presented monocularly. Rivalry dynamics and pupil-size traces were compared before and after 2 h of monocular deprivation, achieved by applying a translucent patch over the dominant eye. Consistent with prior research, we observed that monocular deprivation boosts the deprived-eye signal and consequently increases ocular dominance. In line with previous studies, we also observed subtle but systematic modulations of pupil size that tracked alternations between exclusive dominance phases of the black or white disk. Following monocular deprivation, the amplitude of these pupil-size modulations increased, which is consistent with the post-deprivation boost of the deprived eye and the increase of ocular dominance. This provides evidence that deprivation impacts the effective strength of monocular visual stimuli, coherently affecting perceptual reports and the automatic and unconscious regulation of pupil diameter. Our results show that a combined paradigm of binocular rivalry and pupillometry gives new insights into the physiological mechanisms underlying deprivation effects. |