All EyeLink Publications
All 12,000+ peer-reviewed EyeLink research publications up until 2023 (with some early 2024s) 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!
2017 |
Stephan Koenig; Peter Nauroth; Sara Lucke; Harald Lachnit; Mario Gollwitzer; Metin Uengoer Fear acquisition and liking of out-group and in-group members: Learning bias or attention? Journal Article In: Biological Psychology, vol. 129, pp. 195–206, 2017. @article{Koenig2017, The present study explores the notion of an out-group fear learning bias that is characterized by facilitated fear acquisition toward harm-doing out-group members. Participants were conditioned with two in-group and two out-group faces as conditioned stimuli. During acquisition, one in-group and one out-group face was paired with an aversive shock whereas the other in-group and out-group face was presented without shock. Psychophysiological measures of fear conditioning (skin conductance and pupil size) and explicit and implicit liking exhibited increased differential responding to out-group faces compared to in-group faces. However, the results did not clearly indicate that harm-doing out-group members were more readily associated with fear than harm-doing in-group members. In contrast, the out-group face not paired with shock decreased conditioned fear and disliking at least to the same extent that the shock-associated out-group face increased these measures. Based on these results, we suggest an account of the out-group fear learning bias that relates to an attentional bias to process in-group information. |
Stephan Koenig; Metin Uengoer; Harald Lachnit Attentional bias for uncertain cues of shock in human fear conditioning: Evidence for Attentional Learning Theory Journal Article In: Frontiers in Human Neuroscience, vol. 11, pp. 266, 2017. @article{Koenig2017a, We conducted a human fear conditioning experiment in which three different color cues were followed by an aversive electric shock on 0, 50, and 100% of the trials, and thus induced low (L), partial (P), and high (H) shock expectancy, respectively. The cues differed with respect to the strength of their shock association (L H). During conditioning we measured pupil dilation and ocular fixations to index differences in the attentional processing of the cues. After conditioning, the shock-associated colors were introduced as irrelevant distracters during visual search for a shape target while shocks were no longer administered and we analyzed the cues' potential to capture and hold overt attention automatically. Our findings suggest that fear conditioning creates an automatic attention bias for the conditioned cues that depends on their correlation with the aversive outcome. This bias was exclusively linked to the strength of the cues' shock association for the early attentional processing of cues in the visual periphery, but additionally was influenced by the uncertainty of the shock prediction after participants fixated on the cues. These findings are in accord with attentional learning theories that formalize how associative learning shapes automatic attention. |
Ellen M. Kok; Avigael M. Aizenman; Melissa L. -H. Võ; Jeremy M. Wolfe Even if I showed you where you looked, remembering where you just looked is hard Journal Article In: Journal of Vision, vol. 17, no. 12, pp. 1–11, 2017. @article{Kok2017, People know surprisingly little about their own visual behavior, which can be problematic when learning or executing complex visual tasks such as search of medical images. We investigated whether providing observers with online information about their eye position during search would help them recall their own fixations immediately afterwards. Seventeen observers searched for various objects in "Where's Waldo" images for 3 s. On two-thirds of trials, observers made target present/absent responses. On the other third (critical trials), they were asked to click twelve locations in the scene where they thought they had just fixated. On half of the trials, a gaze-contingent window showed observers their current eye position as a 7.5 degrees diameter "spotlight." The spotlight "illuminated" everything fixated, while the rest of the display was still visible but dimmer. Performance was quantified as the overlap of circles centered on the actual fixations and centered on the reported fixations. Replicating prior work, this overlap was quite low (26%), far from ceiling (66%) and quite close to chance performance (21%). Performance was only slightly better in the spotlight condition (28% |
Ying-Yee Kong; Alexandra Jesse Low-frequency fine-structure cues allow for the online use of lexical stress during spoken-word recognition in spectrally degraded speech Journal Article In: The Journal of the Acoustical Society of America, vol. 141, no. 1, pp. 373–382, 2017. @article{Kong2017, English listeners use suprasegmental cues to lexical stress during spoken-word recognition. Prosodic cues are, however, less salient in spectrally degraded speech, as provided by cochlear implants. The present study examined how spectral degradation with and without low-frequency fine-structure information affects normal-hearing listeners' ability to benefit from suprasegmental cues to lexical stress in online spoken-word recognition. To simulate electric hearing, an eight-channel vocoder spectrally degraded the stimuli while preserving temporal envelope information. Additional lowpass-filtered speech was presented to the opposite ear to simulate bimodal hearing. Using a visual world paradigm, listeners' eye fixations to four printed words (target, competitor, two distractors) were tracked, while hearing a word. The target and competitor overlapped segmentally in their first two syllables but mismatched suprasegmentally in their first syllables, as the initial syllable received primary stress in one word and secondary stress in the other (e.g., "'admiral," "'admi'ration"). In the vocoder-only condition, listeners were unable to use lexical stress to recognize targets before segmental information disambiguated them from competitors. With additional lowpass-filtered speech, however, listeners efficiently processed prosodic information to speed up online word recognition. Low-frequency fine-structure cues in simulated bimodal hearing allowed listeners to benefit from suprasegmental cues to lexical stress during word recognition. |
Arnout W. Koornneef; Iris Mulders Can we ‘read' the eye-movement patterns of readers? Unraveling the relationship between reading profiles and processing strategies Journal Article In: Journal of Psycholinguistic Research, vol. 46, no. 1, pp. 39–56, 2017. @article{Koornneef2017, In an eye-tracking experiment we examined the risky reading hypothesis, in which long saccades and many regressions are considered to be indicative of a proactive reading style (Rayner et al. in Psychol Aging 21(3):448, 2006; Psychol Aging 24(3):755, 2009). We did so by presenting short texts-that confirmed or disconfirmed verb-based implicit causality expectations-to two types of readers: proactive readers (long saccades, many regressions) and conservative readers (short saccades, few regressions). Whereas proactive readers used implicit causality information to predict upcoming referents, and slowed down immediately when they encountered a pronoun that was inconsistent with these verb-based expectations, the conservative readers slowed down much later in the sentence. These findings were consistent with the predictions of the risky reading hypothesis and as such presented novel evidence for the general idea that the eye-movement profile of readers reveals valuable information about their processing strategy. |
Catarina C. Kordsachia; Izelle Labuschagne; Julie C. Stout Abnormal visual scanning of emotionally evocative natural scenes in Huntington's disease Journal Article In: Frontiers in Psychology, vol. 8, pp. 405, 2017. @article{Kordsachia2017, Abstract Huntington's disease (HD) is a neurodegenerative movement disorder associated with deficits in the processing of emotional stimuli, including alterations in the self-reported subjective experience of emotion when presented with pictures of emotional scenes. The aim of this study was to determine whether individuals with HD, compared to unaffected controls, display abnormal visual scanning of emotionally-evocative natural scenes. Using eye-tracking, we recorded eye-movements of 25 HD participants (advanced pre-symptomatic and early symptomatic) and 25 age-matched unaffected control participants during a picture viewing task. Participants viewed pictures of natural scenes associated with different emotions: anger, disgust, happiness, or neutral, and evaluated those pictures on a valence rating scale. Individuals with HD displayed abnormal visual scanning patterns, but did not differ from controls with respect to their valence ratings. Specifically, compared to controls, HD participants spent less time fixating on the pictures and made longer scan paths. This finding highlights the importance of taking visual scanning behavior into account when investigating emotion processing in HD. The visual scanning patterns displayed by HD participants could reflect a heightened, but possibly unfocussed, search for information, and might be linked to attentional deficits or to altered subjective emotional experiences in HD. Another possibility is that HD participants may have found it more difficult than controls to evaluate the emotional valence of the scenes, and the heightened search for information was employed as a compensatory strategy. |
Christoph W. Korn; Matthias Staib; Athina Tzovara; Giuseppe Castegnetti; Dominik R. Bach A pupil size response model to assess fear learning Journal Article In: Psychophysiology, vol. 54, no. 3, pp. 330–343, 2017. @article{Korn2017, During fear conditioning, pupil size responses dissociate between conditioned stimuli that are contingently paired (CS+) with an aversive unconditioned stimulus, and those that are unpaired (CS-). Current approaches to assess fear learning from pupil responses rely on ad hoc specifications. Here, we sought to develop a psychophysiological model (PsPM) in which pupil responses are characterized by response functions within the framework of a linear time-invariant system. This PsPM can be written as a general linear model, which is inverted to yield amplitude estimates of the eliciting process in the central nervous system. We first characterized fear-conditioned pupil size responses based on an experiment with auditory CS. PsPM-based parameter estimates distinguished CS+/CS- better than, or on par with, two commonly used methods (peak scoring, area under the curve). We validated this PsPM in four independent experiments with auditory, visual, and somatosensory CS, as well as short (3.5 s) and medium (6 s) CS/US intervals. Overall, the new PsPM provided equal or decisively better differentiation of CS+/CS- than the two alternative methods and was never decisively worse. We further compared pupil responses with concurrently measured skin conductance and heart period responses. Finally, we used our previously developed luminance-related pupil responses to infer the timing of the likely neural input into the pupillary system. Overall, we establish a new PsPM to assess fear conditioning based on pupil responses. The model has a potential to provide higher statistical sensitivity, can be applied to other conditioning paradigms in humans, and may be easily extended to nonhuman mammals. |
Matteo Lisi; Patrick Cavanagh Different spatial representations guide eye and hand movements Journal Article In: Journal of Vision, vol. 17, no. 2, pp. 1–12, 2017. @article{Lisi2017, Our visual system allows us to localize objects in the world and plan motor actions toward them. We have recently shown that the localization of moving objects differs between perception and saccadic eye movements (Lisi & Cavanagh, 2015), suggesting different localization mechanisms for perception and action. This finding, however, could reflect a unique feature of the saccade system rather than a general dissociation between perception and action. To disentangle these hypotheses, we compared object localization between saccades and hand movements. We flashed brief targets on top of double-drift stimuli (moving Gabors with the internal pattern drifting orthogonally to their displacement, inducing large distortions in perceived location and direction) and asked participants to point or make saccades to them. We found a surprising difference between the two types of movements: Although saccades targeted the physical location of the flashes, pointing movements were strongly biased toward the perceived location (about 63% of the perceptual illusion). The same bias was found when pointing movements were made in open-loop conditions (without vision of the hand). These results indicate that dissociations are present between different types of actions (not only between action and perception) and that visual processing for saccadic eye movements differs from that for other actions. Because the position bias in the double-drift stimulus depends on a persisting influence of past sensory signals, we suggest that spatial maps for saccades might reflect only recent, short-lived signals, and the spatial representations supporting conscious perception and hand movements integrate visual input over longer temporal intervals. |
Liu D. Liu; Christopher C. Pack The contribution of area MT to visual motion perception depends on training Journal Article In: Neuron, vol. 95, no. 2, pp. 436–446.e3, 2017. @article{Liu2017, Perceptual decisions require the transformation of raw sensory inputs into cortical representations suitable for stimulus discrimination. One of the best-known examples of this transformation involves the middle temporal area (MT) of the primate visual cortex. Area MT provides a robust representation of stimulus motion, and previous work has shown that it contributes causally to performance on motion discrimination tasks. Here we report that the strength of this contribution can be highly plastic: depending on the recent training history, pharmacological inactivation of MT can severely impair motion discrimination, or it can have little detectable influence. Further analysis of neural and behavioral data suggests that training moves the readout of motion information between MT and lower-level cortical areas. These results show that the contribution of individual brain regions to conscious perception can shift flexibly depending on sensory experience. |
Qingxiao Liu; Bo Tan; Jing Zhou; Zhong Zheng; Ling Li; Yanchun Yang Pathophysiology of refractory obsessive-compulsive disorder Journal Article In: Medicine, pp. 1–11, 2017. @article{Liu2017d, Based on both functional and structural studies of excessive activity, fronto-striatal-thalamic-cortical and cortico-striatal circuits have been hypothesized to underlie the pathophysiology of obsessive-compulsive disorder (OCD). However, the neurobiological underpinnings of OCD refractory to medication and therapy remain controversial. This study aimed to evaluate neuroanatomical abnormalities of the whole brain and to evaluate visual processing in patients with refractory OCD. This study was comprised of 2 experiments. The neuroanatomical abnormalities of the whole brain were evaluated using a visual search in combination with overactive performance monitoring (Experiment I), and visual processing was evaluated using event- related potentials recorded from subjects during performance of a visual search task. We also examined the amplitudes and latency of the error-related negativity (ERN) using a modified flanker task (Experiment II). Standard low-resolution electromagnetic tomography analysis was applied to determine the special areas. Patients with refractory OCD had a significantly greater number of saccades and prolonged latencies relative to the healthy controls. Scalp map topography confirmed that visual cognitive and executive dysfunction was localized to the fusiform gyrus. Furthermore, we found that during a modified flanker task, ERNs had a greater amplitude and a prolonged latency relative to those of the healthy controls. Further data analysis suggested that cognitive dysfunction and compulsive behavior in OCD patients were linked to abnormalities within the dorsolateral prefrontal cortex (DLPFC). We identified abnormal activities within the fusiform gyrus and DLPFC that likely play important roles in the pathophysiology of OCD. |
Yanping Liu; Ren Huang; Dingguo Gao; Erik D. Reichle Further tests of a dynamic-adjustment account of saccade targeting during the reading of Chinese Journal Article In: Cognitive Science, vol. 41, pp. 1264–1287, 2017. @article{Liu2017a, There are two accounts of how readers of unspaced writing systems (e.g., Chinese) know where to move their eyes: (a) saccades are directed toward default targets (e.g., centers of words that have been segmented in the parafovea); or (b) saccade lengths are adjusted dynamically, as a function of ongoing parafoveal processing. This article reports an eye-movement experiment supporting the latter hypothesis by demonstrating that the slope of the relationship between the saccade launch site on word "N" and the subsequent fixation landing site on word "N" + 1 is > 1, suggesting that saccades are lengthened from launch sites that afford more parafoveal processing. This conclusion is then evaluated and confirmed via simulations using implementations of both hypotheses (Liu, Reichle, & Li, 2016), with a discussion of these results for our understanding of saccadic targeting during reading and existing models of eye-movement control. |
Yanping Liu; Ren Huang; Yugang Li; Dingguo Gao The word frequency effect on saccade targeting during Chinese reading: Evidence from a survival analysis of saccade length Journal Article In: Frontiers in Psychology, vol. 8, pp. 116, 2017. @article{Liu2017b, Our study employs distributional analysis (i.e., survival analysis) to examine how the frequency of target words influences saccade lengths into and out of these target words in Chinese reading. The results of survival analysis indicate the survival curves in the high- and low-frequency conditions diverge for a short saccade length, with more than 80% of the lengths of incoming and outgoing saccades being larger than the divergence points. These results as well as simulations using the novel Dynamic-adjustment Model of saccadic targeting (Liu et al., 2016) are consistent with previous mean-based results and provide more precise information to support this novel model. The implications for saccade target selection during the reading of Chinese are discussed. |
Zhifang Liu; Yun Pan; Wen Tong; Nina Liu Effects of adults aging on word encoding in reading Chinese: Evidence from disappearing text Journal Article In: peerJ, pp. 1–22, 2017. @article{Liu2017e, The effect of aging on the process of word encoding for fixated words and words presented to the right of the fixation point during the reading of sentences in Chinese was investigated with two disappearing text experiments. The results of Experiment 1 showed that only the 40-ms onset disappearance of word n disrupted young adults' reading performance. However, for old readers, the disappearance of word n caused disruptions until the onset time was 120 ms. The results of Experiment 2 showed that the disappearance of word n+1 did not cause disruptions to young adults, but these conditions made old readers spend more time reading a sentence compared to the normal display condition. These results indicated a reliable aging effect on the process of word encoding when reading Chinese, and that the encoding process in the preview frame was more susceptible to normal aging compared to that in the fixation frame. We propose that sensory, cognitive, and specific factors related to the Chinese language are important contributors to these age-related differences. |
Zhong-Xu Liu; Kelly Shen; Rosanna K. Olsen; Jennifer D. Ryan Visual sampling predicts hippocampal activity Journal Article In: Journal of Neuroscience, vol. 37, no. 3, pp. 599–609, 2017. @article{Liu2017c, Eye movements serve to accumulate information from the visual world, contributing to the formation of coherent memory representations that support cognition and behavior. The hippocampus and the oculomotor network are well connected anatomically through an extensive set of polysynaptic pathways. However, the extent to which visual sampling behavior is related to functional responses in the hippocampus during encoding has not been studied directly in human neuroimaging. In the current study, participants engaged in a face processing task while brain responses were recorded with fMRI and eye movements were monitored simultaneously. The number of gaze fixations that a participant made on a given trial was correlated significantly with hippocampal activation such that more fixations were associated with stronger hippocampal activation. Similar results were also found in the fusiform face area, a face-selective perceptual processing region. Notably, the number of fixations was associated with stronger hippocampal activation when the presented faces were novel, but not when the faces were repeated. Increases in fixations during viewing of novel faces also led to larger repetition-related suppression in the hippocampus, indicating that this fixation–hippocampal relationship may reflect the ongoing development of lasting representations. Together, these results provide novel empirical support for the idea that visual exploration and hippocampal binding processes are inherently linked. |
Barbara C. Y. Lo; Jeffrey C. C. Liu Executive control in depressive rumination: Backward inhibition and non-inhibitory switching performance in a modified mixed antisaccade task Journal Article In: Frontiers in Psychology, vol. 8, pp. 136, 2017. @article{Lo2017, BACKGROUND AND OBJECTIVES: The present study examines backward inhibition (BI) and non-inhibitory switching performance among depressed and healthy participants in a modified mixed antisaccade task. Specifically, sad and neutral faces were incorporated in the design to examine executive control difficulties associated with brooding trait. METHODS: Thirty-nine participants took part in the study, including 19 depressed patients and 20 healthy control subjects. Participants completed a diagnostic interview and self-report questionnaires, including the Beck Depression Inventory and Ruminative Response Scale-Brooding Subscale. They were then instructed to complete prosaccade and antisaccade trials in the pure and mixed blocks whereby eye gazes were tracked to assess inhibition and switching efficiency. RESULTS: For the switching effects, a significant group x brooding x task type interaction was found as hypothesized when multilevel modeling analysis was employed. Switching deficits associated with brooding was found to be greatest when sad faces were presented to depressed group. No significant results in BI or error rates were observed. CONCLUSION: The patterns observed suggest that as opposed to BI, set shifting difficulty associated with brooding trait may be modulated by negative mood and cognition. In future research, emotional faces other than sad faces may be used to further explore if the observations could be generalized to other affective conditions. |
Florian Loffing; Stefanie Nickel; Norbert Hagemann Directionality in aesthetic judgments and performance evaluation: Sport judges and laypeople compared Journal Article In: Frontiers in Psychology, vol. 8, pp. 2109, 2017. @article{Loffing2017, Left-to-right readers are assumed to demonstrate a left-to-right bias in aesthetic preferences and performance evaluation. Here we tested the hypothesis that such bias occurs in left-to-right reading laypeople and gymnastic judges (n = 48 each) when asked to select the more beautiful image from a picture pair showing gymnastic or non-gymnastic actions (Experiment 1) and to evaluate videos of gymnasts' balance beam performances (Experiment 2). Overall, laypeople demonstrated a stronger left-to-right bias than judges. Unlike judges, laypeople rated images with left-to-right trajectory as more beautiful than content-wise identical images with right-to-left trajectory (Experiment 1). Also, laypeople tended to award slightly more points to videos showing left-to-right as opposed to right-to-left oriented actions (Experiment 2); however, in contrast to initial predictions the effect was weak and statistically unreliable. Collectively, judges, when considered as a group, seem less prone to directional bias than laypeople, thus tentatively suggesting that directionality may be an issue for unskilled but not for skilled judging. Possible mechanisms underlying the skill effect in Experiment 1 and the absence of clear bias in Experiment 2 are discussed alongside propositions for a broadening of perspectives in future research. |
Cai S. Longman; Aureliu Lavric; Stephen Monsell Self-paced preparation for a task switch eliminates attentional inertia but not the performance switch cost Journal Article In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 43, no. 6, pp. 862–873, 2017. @article{Longman2017, The performance overhead associated with changing tasks (the "switch cost") usually diminishes when the task is specified in advance but is rarely eliminated by preparation. A popular account of the "residual" (asymptotic) switch cost is that it reflects "task-set inertia": carry-over of task-set parameters from the preceding trial(s). New evidence for a component of "task-set inertia" comes from eye-tracking, where the location associated with the previously (but no longer) relevant task is fixated preferentially over other irrelevant locations, even when preparation intervals are generous. Might such limits in overcoming task-set inertia in general, and "attentional inertia" in particular, result from suboptimal scheduling of preparation when the time available is outside one's control? In the present study, the stimulus comprised 3 digits located at the points of an invisible triangle, preceded by a central verbal cue specifying which of 3 classification tasks to perform, each consistently applied to just 1 digit location. The digits were presented only when fixation moved away from the cue, thus giving the participant control over preparation time. In contrast to our previous research with experimenter-determined preparation intervals, we found no sign of attentional inertia for the long preparation intervals. Self-paced preparation reduced but did not eliminate the performance switch cost-leaving a clear residual component in both reaction time and error rates. That the scheduling of preparation accounts for some, but not all, components of the residual switch cost, challenges existing accounts of the switch cost, even those which distinguish between preparatory and poststimulus reconfiguration processes. |
Roman F. Loonis; Scott L. Brincat; Evan G. Antzoulatos; Earl K. Miller A meta-analysis suggests different neural correlates for implicit and explicit learning Journal Article In: Neuron, vol. 96, no. 2, pp. 521–534.e7, 2017. @article{Loonis2017, A meta-analysis of non-human primates performing three different tasks (Object-Match, Category-Match, and Category-Saccade associations) revealed signatures of explicit and implicit learning. Performance improved equally following correct and error trials in the Match (explicit) tasks, but it improved more after correct trials in the Saccade (implicit) task, a signature of explicit versus implicit learning. Likewise, error-related negativity, a marker for error processing, was greater in the Match (explicit) tasks. All tasks showed an increase in alpha/beta (10–30 Hz) synchrony after correct choices. However, only the implicit task showed an increase in theta (3–7 Hz) synchrony after correct choices that decreased with learning. In contrast, in the explicit tasks, alpha/beta synchrony increased with learning and decreased thereafter. Our results suggest that explicit versus implicit learning engages different neural mechanisms that rely on different patterns of oscillatory synchrony. Loonis et al. find that explicit and implicit learning use feedback about correct choices versus errors differently. Implicit learning relies more on theta synchrony (3–7 Hz) while explicit learning relies on alpha/beta synchrony (10–30 Hz). |
Matthew W. Lowder; Peter C. Gordon Print exposure modulates the effects of repetition priming during sentence reading Journal Article In: Psychonomic Bulletin & Review, vol. 24, no. 6, pp. 1935–1942, 2017. @article{Lowder2017, Individual readers vary greatly in the quality of their lexical representations, and consequently in how quickly and efficiently they can access orthographic and lexical knowledge. This variability may be explained, at least in part, by individual differences in exposure to printed language, because practice at reading promotes the development of stronger reading skills. In the present eyetracking experiment, we tested the hypothesis that the efficiency of word recognition during reading improves with increases in print exposure, by determining whether the magnitude of the repetition-priming effect is modulated by individual differences in scores on the author recognition test (ART). Lexical repetition of target words was manipulated across pairs of unrelated sentences that were presented on consecutive trials. The magnitude of the repetition effect was modulated by print exposure in early measures of processing, such that the magnitude of the effect was inversely related to scores on the ART. The results showed that low levels of print exposure, and thus lower-quality lexical representations, are associated with high levels of difficulty recognizing words, and thus with the greatest room to benefit from repetition. Furthermore, the interaction between scores on the ART and repetition suggests that print exposure is not simply an index of general reading speed, but rather that higher levels of print exposure are associated with an enhanced ability to access lexical knowledge and recognize words during reading. |
Jia E. Loy; Hannah Rohde; Martin Corley Effects of disfluency in online interpretation of deception Journal Article In: Cognitive Science, vol. 41, pp. 1434–1456, 2017. @article{Loy2017, A speaker's manner of delivery of an utterance can affect a listener's pragmatic interpretation of the message. Disfluencies (such as filled pauses) influence a listener's off-line assessment of whether the speaker is truthful or deceptive. Do listeners also form this assessment during the moment-by-moment processing of the linguistic message? Here we present two experiments that examined listeners' judgments of whether a speaker was indicating the true location of the prize in a game during fluent and disfluent utterances. Participants' eye and mouse movements were biased toward the location named by the speaker during fluent utterances, whereas the opposite bias was observed during disfluent utterances. This difference emerged rapidly after the onset of the critical noun. Participants were similarly sensitive to disfluencies at the start of the utterance (Experiment 1) and in the middle (Experiment 2). Our findings support recent research showing that listeners integrate pragmatic information alongside semantic content during the earliest moments of language processing. Unlike prior work which has focused on pragmatic effects in the interpretation of the literal message, here we highlight disfluency's role in guiding a listener to an alternative non-literal message. |
Jiachen Lu; Lili Tian; Jiafeng Zhang; Jing Wang; Chaoxiong Ye; Qiang Liu Strategic inhibition of distractors with visual working memory contents after involuntary attention capture Journal Article In: Scientific Reports, vol. 7, pp. 16314, 2017. @article{Lu2017, Previous research has suggested that visual working memory (VWM) contents had a guiding effect on selective attention, and once participants realized that the distractors shared the same information with VWM contents in the search task, they would strategically inhibit the potential distractors with VWM contents. However, previous behavioral studies could not reveal the way how distractors with VWM contents are inhibited strategically. By employing the eye-tracking technique and a dual-task paradigm, we manipulated the probability of memory items occurring as distractors to explore this issue. Consistent with previous behavioral studies, the results showed that the inhibitory effect occurred only in the high-probability condition, while the guiding effect emerged in the low-probability condition. More importantly, the eye-movement results indicated that in the high-probability condition, once few (even one) distractors with VWM contents were captured at first, all the remaining distractors with VWM contents would be rejected as a whole. However, in the low-probability condition, attention could be captured by the majority of distractors with VWM contents. These results suggested that the guiding effect of VWM contents on attention is involuntary in the early stage of visual search. After the completion of this involuntary stage, the guiding effect of task-irrelevant VWM contents on attention could be strategically controlled. |
Rachel G. Lucas-Thompson; Adina Dumitrache; Amy Quinn Sparks Appraisals of interparental conflict and change in attention to emotion after exposure to marital conflict Journal Article In: Journal of Child and Family Studies, vol. 26, no. 8, pp. 2175–2181, 2017. @article{LucasThompson2017, The goal of this study was to investigate whether exposure to marital conflict changes patterns of attention to anger and happiness, as well as whether those patterns vary based on appraisals of the history of interparental conflict in the home. Emerging adults viewed photo pairs with one emotionally-neutral photo and another photo depicting a happy/angry emotional interaction (while a high-speed camera tracked gaze), were randomly assigned to view a neutral or marital conflict recording, viewed neutral-emotional photo pairs again, and then reported their appraisals of their parents' conflict. Results indicated that feeling threatened by and to blame for parental conflict predicted avoidance of happy emotions at baseline. Although there were no significant changes in attention to emotion overall based on condition, self-blame for interparental conflict predicted greater increases in time spent looking at anger after watching marital conflict (but not after watching the neutral recording). These results indicate that differences in attention to emotion may be one mechanism linking parental conflict to anxiety that could be the focus of prevention/intervention efforts to reduce anxiety symptoms in those from high-conflict homes. |
Casimir J. H. Ludwig; David R. Evens Information foraging for perceptual decisions Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 43, no. 2, pp. 245–264, 2017. @article{Ludwig2017, We tested an information foraging framework to characterize the mechanisms that drive active (visual) sampling behavior in decision problems that involve multiple sources of information. Experiments 1 through 3 involved participants making an absolute judgment about the direction of motion of a single random dot motion pattern. In Experiment 4, participants made a relative comparison between 2 motion patterns that could only be sampled sequentially. Our results show that: (a) Information (about noisy motion information) grows to an asymptotic level that depends on the quality of the information source; (b) The limited growth is attributable to unequal weighting of the incoming sensory evidence, with early samples being weighted more heavily; (c) Little information is lost once a new source of information is being sampled; and (d) The point at which the observer switches from 1 source to another is governed by online monitoring of his or her degree of (un)certainty about the sampled source. These findings demonstrate that the sampling strategy in perceptual decision-making is under some direct control by ongoing cognitive processing. More specifically, participants are able to track a measure of (un)certainty and use this information to guide their sampling behavior. |
Shijian Luo; Yi Hu; Yuxiao Zhou Factors attracting Chinese Generation Y in the smartphone application marketplace Journal Article In: Frontiers of Computer Science, vol. 11, no. 2, pp. 290–306, 2017. @article{Luo2017, Smartphone applications (apps) are becoming increasingly popular all over the world, particularly in the Chinese Generation Y population; however, surprisingly, only a small number of studies on app factors valued by this important group have been conducted. Because the competition among app developers is increasing, app factors that attract users' attention are worth studying for sales promotion. This paper examines these factors through two separate studies. In the first study, i.e., Experiment 1, which consists of a survey, perceptual rating and verbal protocol methods are employed, and 90 randomly selected app websites are rated by 169 experienced smartphone users according to app attraction. Twelve of the most rated apps (six highest rated and six lowest rated) are selected for further investigation, and 11 influential factors that Generation Y members value are listed. A second study, i.e., Experiment 2, is conducted using the most and least rated app websites from Experiment 1, and eye tracking and verbal protocol methods are used. The eye movements of 45 participants are tracked while browsing these websites, providing evidence about what attracts these users' attention and the order in which the app components are viewed. The results of these two studies suggest that Chinese Generation Y is a content-centric group when they browse the smartphone app marketplace. Icon, screenshot, price, rating, and name are the dominant and indispensable factors that influence purchase intentions, among which icon and screenshot should be meticulously designed. Price is another key factor that drives Chinese Generation Y's attention. The recommended apps are the least dominant element. Design suggestions for app websites are also proposed. This research has important implications. |
Ehab W. Hermena; Simon P. Liversedge; Denis Drieghe In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 43, no. 3, pp. 451–471, 2017. @article{Hermena2017, The authors conducted 2 eye movement experiments in which they used the typographical and linguistic properties of Arabic to disentangle the influences of words' number of letters and spatial extent on measures of fixation duration and saccade targeting (Experiment 1), and to investigate the influence of initial bigram characteristics on saccade targeting during reading (Experiment 2). In the first experiment, through the use of a proportional font, which is more natural-looking in Arabic compared to monospaced fonts, the authors manipulated the number of letters (5 vs. 7) and the spatial extent (wide vs. narrow) of words embedded in frame sentences. The results obtained replicate and expand upon previous findings in other alphabetic languages that the number of letters influences fixation durations, whereas saccade targeting (as indicated by measures of fixation count and probability of skipping and refixation) is more influenced by the word's spatial extent. In the second experiment, the authors compared saccade targeting measures (saccade amplitude and initial fixation location) in 6- and 7-letter words beginning with initial bigrams that were of extremely high frequency ([character omitted] the), relatively high frequency ([character omitted] to/for the), or beginning with the letters of the word stem. The results showed negligible modulation of saccade targeting by initial bigram characteristics. The results also highlighted the importance of selecting the appropriate measures of initial fixation location (spatial vs. character-based measures) during reading text rendered using proportional fonts. |
Frouke Hermens The effects of social and symbolic cues on visual search: Cue shape trumps biological relevance Journal Article In: Psihologija, vol. 50, no. 2, pp. 117–140, 2017. @article{Hermens2017a, Arrow signs are often used in crowded environments such as airports to direct observers' attention to objects and areas of interest. Research with social and symbolic cues presented in isolation at fixation has suggested that social cues (such as eye gaze and pointing hands) are more effective in directing observers' attention than symbolic cues. The present work examines whether in visual search, social cues would therefore be more effective than arrows, by asking participants to locate target objects in crowded displays that were cued by eye-gaze, pointing hands or arrow cues. Results show an advantage for arrow cues, but only for arrow cues that stand out from the surroundings. The results confirm earlier suggestions that in extrafoveal vision cue shape trumps biological relevance. Eye movements suggest that these cueing effects rely predominantly on extrafoveal perception of the cues. |
Frouke Hermens The influence of social stigmas on observers' eye movements Journal Article In: Journal of Articles in Support of the Null Hypothesis, vol. 14, no. 1, pp. 1–18, 2017. @article{Hermens2017, Some social stigmas are associated with clear visual cues (facial scars, tattoos). Eye tracking has shown that such social stigmas influence the eye movements of other people. Other social stigmas often go without clearly visible cues (e.g., a mental illness or a criminal record). The present study investigates whether providing information about such stigmas affects eye movements of observers. Participants were presented with video clips and advance information about one of the actors that was either stigmatizing (related to mental health or a criminal past) or non-stigmatizing. The results show that eye movements towards the target actor were not systematically affected by stigmatizing advance information and were not associated with explicit attitudes from questionnaires. Results therefore suggest that stigmas without clear visual cues do not draw attention to or away from the person involved. |
Frouke Hermens; Markus Bindemann; A. Mike Burton Responding to social and symbolic extrafoveal cues: Cue shape trumps biological relevance Journal Article In: Psychological Research, vol. 81, no. 1, pp. 24–42, 2017. @article{Hermens2017b, Social cues presented at visual fixation have been shown to strongly influence an observer's attention and response selection. Here we ask whether the same holds for cues (initially) presented away from fixation, as cues are commonly perceived in natural vision. In six experiments, we show that extrafoveally presented cues with a distinct outline, such as pointing hands, rotated heads, and arrow cues result in strong cueing of responses (either to the cue itself, or a cued object). In contrast, cues without a clear outline, such as gazing eyes and direction words exert much weaker effects on participants' responses to a target cue. We also show that distraction effects on response times are relatively weak, but that strong interference effects can be obtained by measuring mouse trajectories. Eye tracking suggests that gaze cues are slower to respond to because their direction cannot easily be perceived in extrafoveal vision. Together, these data suggest that the strength of an extrafoveal cue is determined by the shape of the cue outline, rather than its biological relevance (i.e., whether the cue is provided by another human being), and that this shape effect is due to how easily the direction of a cue can be perceived in extrafoveal vision. |
Carl J. J. Herrmann; Ralf Metzler; Ralf Engbert A self-avoiding walk with neural delays as a model of fixational eye movements Journal Article In: Scientific Reports, vol. 7, pp. 12958, 2017. @article{Herrmann2017, Fixational eye movements show scaling behaviour of the positional mean-squared displacement with a characteristic transition from persistence to antipersistence for increasing time-lag. These statistical patterns were found to be mainly shaped by microsaccades (fast, small-amplitude movements). However, our re-analysis of fixational eye-movement data provides evidence that the slow component (physiological drift) of the eyes exhibits scaling behaviour of the mean-squared displacement that varies across human participants. These results suggest that drift is a correlated movement that interacts with microsaccades. Moreover, on the long time scale, the mean-squared displacement of the drift shows oscillations, which is also present in the displacement auto-correlation function. This finding lends support to the presence of time-delayed feedback in the control of drift movements. Based on an earlier non-linear delayed feedback model of fixational eye movements, we propose and discuss different versions of a new model that combines a self-avoiding walk with time delay. As a result, we identify a model that reproduces oscillatory correlation functions, the transition from persistence to antipersistence, and microsaccades. |
Philipp N. Hesse; Frank Bremmer The SNARC effect in two dimensions: Evidence for a frontoparallel mental number plane Journal Article In: Vision Research, vol. 130, pp. 85–96, 2017. @article{Hesse2017a, The existence of an association between numbers and space is known for a long time. The most prominent demonstration of this relationship is the spatial numerical association of response codes (SNARC) effect, describing the fact that participants' reaction times are shorter with the left hand for small numbers and with the right hand for large numbers, when being asked to judge the parity of a number (Dehaene et al., J. Exp. Psychol., 122, 371–396, 1993). The SNARC effect is commonly seen as support for the concept of a mental number line, i.e. a mentally conceived line where small numbers are represented more on the left and large numbers are represented more on the right. The SNARC effect has been demonstrated for all three cardinal axes and recently a transverse SNARC plane has been reported (Chen et al., Exp. Brain Res., 233(5), 1519–1528, 2015). Here, by employing saccadic responses induced by auditory or visual stimuli, we measured the SNARC effect within the same subjects along the horizontal (HM) and vertical meridian (VM) and along the two interspersed diagonals. We found a SNARC effect along HM and VM, which allowed predicting the occurrence of a SNARC effect along the two diagonals by means of linear regression. Importantly, significant differences in SNARC strength were found between modalities. Our results suggest the existence of a frontoparallel mental number plane, where small numbers are represented left and down, while large numbers are represented right and up. Together with the recently described transverse mental number plane our findings provide further evidence for the existence of a three-dimensional mental number space. |
Philipp N. Hesse; Constanze Schmitt; Steffen Klingenhoefer; Frank Bremmer Preattentive processing of numerical visual information Journal Article In: Frontiers in Human Neuroscience, vol. 11, pp. 70, 2017. @article{Hesse2017, Humans can perceive and estimate approximate numerical information, even when accurate counting is impossible e.g. due to short presentation time. If the number of objects to be estimated is small, typically around one to four items, observers are able to give very fast and precise judgments with high confidence – an effect that is called subitizing. Due to its speed and effortless nature subitizing has usually been assumed to be preattentive, putting it into the same category as other low level visual features like color or orientation. More recently, however, a number of studies have suggested that subitizing might be dependent on attentional resources. In our current study we investigated the potentially preattentive nature of visual numerical perception in the subitizing range by means of EEG. We presented peripheral, task irrelevant sequences of stimuli consisting of a certain number of circular patches while participants were engaged in a demanding, non-numerical detection task at the fixation point drawing attention away from the number stimuli. Within a sequence of stimuli of a given number of patches (called ‘standards') we interspersed some stimuli of different numerosity (‘oddballs'). We compared the evoked responses to visually identical stimuli that had been presented in two different conditions, serving as standard in one condition and as oddball in the other. We found significant visual mismatch negativity (vMMN) responses over parieto-occipital electrodes. In addition to the ERP analysis, we performed a time-frequency analysis to investigate whether the vMMN was accompanied by additional oscillatory processes. We found a concurrent increase in evoked theta power of similar strength over both hemispheres. Our results provide clear evidence for a preattentive processing of numerical visual information in the subitizing range. |
Roy S. Hessels; Diederick C. Niehorster; Chantal Kemner; Ignace T. C. Hooge Noise-robust fixation detection in eye movement data: Identification by two-means clustering (I2MC) Journal Article In: Behavior Research Methods, vol. 49, no. 5, pp. 1802–1823, 2017. @article{Hessels2017, Eye-tracking research in infants and older children has gained a lot of momentum over the last decades. Although eye-tracking research in these participant groups has become easier with the advance of the remote eye-tracker, this often comes at the cost of poorer data quality than in research with well-trained adults (Hessels, Andersson, Hooge, Nystrom, & Kemner Infancy, 20, 601-633, 2015; Wass, Forssman, & Leppanen Infancy, 19, 427-460, 2014). Current fixation detection algorithms are not built for data from infants and young children. As a result, some researchers have even turned to hand correction of fixation detections (Saez de Urabain, Johnson, & Smith Behavior Research Methods, 47, 53-72, 2015). Here we introduce a fixation detection algorithm-identification by two-means clustering (I2MC)-built specifically for data across a wide range of noise levels and when periods of data loss may occur. We evaluated the I2MC algorithm against seven state-of-the-art event detection algorithms, and report that the I2MC algorithm's output is the most robust to high noise and data loss levels. The algorithm is automatic, works offline, and is suitable for eye-tracking data recorded with remote or tower-mounted eye-trackers using static stimuli. In addition to application of the I2MC algorithm in eye-tracking research with infants, school children, and certain patient groups, the I2MC algorithm also may be useful when the noise and data loss levels are markedly different between trials, participants, or time points (e.g., longitudinal research). |
Markus A. Hietanen; Nicholas S. C. Price; Shaun L. Cloherty; Kostas Hadjidimitrakis; Michael R. Ibbotson Long-term sensorimotor adaptation in the ocular following system of primates Journal Article In: PLoS ONE, vol. 12, no. 12, pp. e0189030, 2017. @article{Hietanen2017, The sudden movement of a wide-field image leads to a reflexive eye tracking response referred to as short-latency ocular following. If the image motion occurs soon after a saccade the initial speed of the ocular following is enhanced, a phenomenon known as post-saccadic enhancement. We show in macaque monkeys that repeated exposure to the same stimulus regime over a period of months leads to progressive increases in the initial speeds of ocular following. The improvement in tracking speed occurs for ocular following with and without a prior saccade. As a result of the improvement in ocular following speeds, the influence of post-saccadic enhancement wanes with increasing levels of training. The improvement in ocular following speed following repeated exposure to the same oculomotor task represents a novel form of sensori-motor learning in the context of a reflexive movement. |
Anne P. Hillstrom; Joice D. Segabinazi; Hayward J. Godwin; Simon P. Liversedge; Valerie Benson Cat and mouse search: The influence of scene and object analysis on eye movements when targets change locations during search Journal Article In: Philosophical Transactions of the Royal Society B: Biological Sciences, vol. 372, pp. 1–9, 2017. @article{Hillstrom2017, We explored the influence of early scene analysis and visible object characteristics on eye movements when searching for objects in photographs of scenes. On each trial, participants were shown sequentially either a scene preview or a uniform grey screen (250 ms), a visual mask, the name of the target and the scene, now including the target at a likely location. During the participant's first saccade during search, the target location was changed to: (i) a different likely location, (ii) an unlikely but possible location or (iii) a very implausible location. The results showed that the first saccade landed more often on the likely location in which the target re-appeared than on unlikely or implausible locations, and overall the first saccade landed nearer the first target location with a preview than without. Hence, rapid scene analysis influenced initial eye movement planning, but availability of the target rapidly modified that plan. After the target moved, it was found more quickly when it appeared in a likely location than when it appeared in an unlikely or implausible location. The findings show that both scene gist and object properties are extracted rapidly, and are used in conjunction to guide saccadic eye movements during visual search. |
Stephen J. Hinde; Tim J. Smith; Iain D. Gilchrist In search of oculomotor capture during film viewing: Implications for the balance of top-down and bottom-up control in the saccadic system Journal Article In: Vision Research, vol. 134, pp. 7–17, 2017. @article{Hinde2017, In the laboratory, the abrupt onset of a visual distractor can generate an involuntary orienting response: this robust oculomotor capture effect has been reported in a large number of studies (e.g. Ludwig & Gilchrist, 2002; Theeuwes, Kramer, Hahn, & Irwin, 1998) suggesting it may be a ubiquitous part of more natural visual behaviour. However the visual stimuli used in these experiments have tended to be static and had none of the complexity, and dynamism of more natural visual environments. In addition, the primary task in the laboratory (typically visual search) can be tedious for the participants with participant's losing interest and becoming stimulus driven and more easily distracted. Both of these factors may have led to an overestimation of the extent to which oculomotor capture occurs and the importance of this phenomena in everyday visual behaviour. To address this issue, in the current series of studies we presented abrupt and highly salient visual distractors away from fixation while participants watched a film. No evidence of oculomotor capture was found. However, the distractor does effect fixation duration: we find an increase in fixation duration analogous to the remote distractor effect (Walker, Deubel, Schneider, & Findlay, 1997). These results suggest that during dynamic scene perception, the oculomotor system may be under far more top-down control than traditional laboratory based-tasks have previously suggested. |
Florian Hintz; Antje S. Meyer; Falk Huettig Predictors of verb-mediated anticipatory eye movements in the visual world Journal Article In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 43, no. 9, pp. 1352–1374, 2017. @article{Hintz2017, Many studies have demonstrated that listeners use information extracted from verbs to guide anticipatory eye movements to objects in the visual context that satisfy the selection restrictions of the verb. An important question is what underlies such verb-mediated anticipatory eye gaze. Based on empirical and theoretical suggestions, we investigated the influence of 5 potential predictors of this behavior: functional associations and general associations between verb and target object, as well as the listeners' production fluency, receptive vocabulary knowledge, and nonverbal intelligence. In 3 eye-tracking experiments, participants looked at sets of 4 objects and listened to sentences where the final word was predictable or not predictable (e.g., "The man peels/draws an apple"). On predictable trials only the target object, but not the distractors, were functionally and associatively related to the verb. In Experiments 1 and 2, objects were presented before the verb was heard. In Experiment 3, participants were given a short preview of the display after the verb was heard. Functional associations and receptive vocabulary were found to be important predictors of verb-mediated anticipatory eye gaze independent of the amount of contextual visual input. General word associations did not and nonverbal intelligence was only a very weak predictor of anticipatory eye movements. Participants' production fluency correlated positively with the likelihood of anticipatory eye movements when participants were given the long but not the short visual display preview. These findings fit best with a pluralistic approach to predictive language processing in which multiple mechanisms, mediating factors, and situational context dynamically interact. |
Renske S. Hoedemaker; Jessica Ernst; Antje S. Meyer; Eva Belke Language production in a shared task: Cumulative Semantic Interference from self- and other-produced context words Journal Article In: Acta Psychologica, vol. 172, pp. 55–63, 2017. @article{Hoedemaker2017, This study assessed the effects of semantic context in the form of self-produced and other-produced words on subsequent language production. Pairs of participants performed a joint picture naming task, taking turns while naming a continuous series of pictures. In the single-speaker version of this paradigm, naming latencies have been found to increase for successive presentations of exemplars from the same category, a phenomenon known as Cumulative Semantic Interference (CSI). As expected, the joint-naming task showed a within-speaker CSI effect, such that naming latencies increased as a function of the number of category exemplars named previously by the participant (self-produced items). Crucially, we also observed an across-speaker CSI effect, such that naming latencies slowed as a function of the number of category members named by the participant's task partner (other-produced items). The magnitude of the across-speaker CSI effect did not vary as a function of whether or not the listening participant could see the pictures their partner was naming. The observation of across-speaker CSI suggests that the effect originates at the conceptual level of the language system, as proposed by Belke's (2013) Conceptual Accumulation account. Whereas self-produced and other-produced words both resulted in a CSI effect on naming latencies, post-experiment free recall rates were higher for self-produced than other-produced items. Together, these results suggest that both speaking and listening result in implicit learning at the conceptual level of the language system but that these effects are independent of explicit learning as indicated by item recall. |
Renske S. Hoedemaker; Peter C. Gordon The onset and time course of semantic priming during rapid recognition of visual words Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 43, no. 5, pp. 881–902, 2017. @article{Hoedemaker2017a, In 2 experiments, we assessed the effects of response latency and task-induced goals on the onset and time course of semantic priming during rapid processing of visual words as revealed by ocular response tasks. In Experiment 1 (ocular lexical decision task), participants performed a lexical decision task using eye movement responses on a sequence of 4 words. In Experiment 2, the same words were encoded for an episodic recognition memory task that did not require a metalinguistic judgment. For both tasks, survival analyses showed that the earliest observable effect (divergence point [DP]) of semantic priming on target-word reading times occurred at approximately 260 ms, and ex-Gaussian distribution fits revealed that the magnitude of the priming effect increased as a function of response time. Together, these distributional effects of semantic priming suggest that the influence of the prime increases when target processing is more effortful. This effect does not require that the task include a metalinguistic judgment; manipulation of the task goals across experiments affected the overall response speed but not the location of the DP or the overall distributional pattern of the priming effect. These results are more readily explained as the result of a retrospective, rather than a prospective, priming mechanism and are consistent with compound-cue models of semantic priming. |
Alexandra Hoffmann; Ulrich Ettinger; Gustavo A. Reyes del Paso; Stefan Duschek Executive function and cardiac autonomic regulation in depressive disorders Journal Article In: Brain and Cognition, vol. 118, pp. 108–117, 2017. @article{Hoffmann2017, Executive function impairments have been frequently observed in depressive disorders. Moreover, reduced heart rate variability (HRV) has repeatedly been described, especially in the high frequency band (i.e., respiratory sinus arrhythmia, RSA), suggesting lower vagal cardiac outflow. The study tested the hypothesis of involvement of low vagal tone in executive dysfunction in depression. In addition to RSA, HRV in the low frequency (LF) band was assessed. In 36 patients with depression and 36 healthy subjects, electrocardiography recordings were accomplished at rest and during performance of five executive function tasks (number-letter task, n-back task, continuous performance test, flanker task, and antisaccade task). Patients displayed increased error rates and longer reaction times in the task-switching condition of the number-letter task, in addition to increased error rates in the n-back task and the final of two blocks of the antisaccade task. In patients, both HRV parameters were lower during all experimental phases. RSA correlated negatively with reaction time during task-switching. This finding confirms reduced performance across different executive functions in depression and suggests that, in addition to RSA, LF HRV is also diminished. However, the hypothesis of involvement of low parasympathetic tone in executive dysfunction related to depression received only limited support. |
Jessica Hanley; David E. Warren; Natalie Glass; Daniel Tranel; Matthew Karam; Joseph Buckwalter Visual interpretation of plain radiographs in orthopaedics using eye-tracking technology Journal Article In: The Iowa Orthopaedic Journal, vol. 37, pp. 225–231, 2017. @article{Hanley2017, BACKGROUND: Despite the importance of radiographic interpretation in orthopaedics, there not a clear understanding of the specific visual strategies used while analyzing a plain film. Eyetracking technology allows for the objective study of eye movements while performing a dynamic task, such as reading X-rays. Our study looks to elucidate objective differences in image interpretation between novice and experienced orthopaedic trainees using this novel technology. METHODS: Novice and experienced orthopaedic trainees (N=23) were asked to interpret AP pelvis films, searching for unilateral acetabular fractures while eye-movements were assessed for pattern of gaze, fixation on regions of interest, and time of fixation at regions of interest. Participants were asked to label radiographs as "fractured" or "not fractured." If "fractured", the participant was asked to determine the fracture pattern. A control condition employed Ekman faces and participants judged gender and facial emotion. Data were analyzed for variation in eye movements between participants, accuracy of responses, and response time. RESULTS: Accuracy: There was no significant difference by level of training for accurately identifing fracture images (p=0.3255). There was a significant association between higher level of training and correctly identifying non-fractured images (p=0.0155); greater training was also associated with more success in identifying the correct Judet-Letournel classification (p=0.0029). Response Time: Greater training was associated with faster response times (p=0.0009 for fracture images and 0.0012 for non-fractured images). Fixation Duration: There was no correlation of average fixation duration with experience (p=0.9632). Regions of Interest (ROIs): More experience was associated with an average of two fewer fixated ROIs (p=0.0047). Number of Fixations: Increased experience was associated with fewer fixations overall (p=0.0007). CONCLUSIONS: Experience has a significant impact on both accuracy and efficiency in interpreting plain films. Greater training is associated with a shift toward a more efficient and thorough assessment of plain radiographs. Eyetracking is a useful descriptive tool in the setting of plain film interpretation. CLINICAL RELEVANCE: We propose further assessment of eye movements in larger populations of orthopaedic surgeons, including staff orthopaedists. Describing the differences between novice and expert interpretation may provide insight into ways to accelerate the learning process in young orthopaedists. |
Juan Haro; Marc Guasch; Blanca Vallès; Pilar Ferré Is pupillary response a reliable index of word recognition? Evidence from a delayed lexical decision task Journal Article In: Behavior Research Methods, vol. 49, no. 5, pp. 1930–1938, 2017. @article{Haro2017, Previous word recognition studies have shown that the pupillary response is sensitive to a word's frequency. However, such a pupillary effect may be due to the process of executing a response, instead of being an index of word processing. With the aim of exploring this possibility, we recorded the pupillary responses in two experiments involving a lexical decision task (LDT). In the first experiment, participants completed a standard LDT, whereas in the second they performed a delayed LDT. The delay in the response allowed us to compare pupil dilations with and without the response execution component. The results showed that pupillary response was modulated by word frequency in both the standard and the delayed LDT. This finding supports the reliability of using pupillometry for word recognition research. Importantly, our results also suggest that tasks that do not require a response during pupil recording lead to clearer and stronger effects. |
Anthony M. Harris; Roger W. Remington Contextual cueing improves attentional guidance, even when guidance is supposedly optimal Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 43, no. 5, pp. 926–940, 2017. @article{Harris2017, Visual search through previously encountered contexts typically produces reduced reaction times compared with search through novel contexts. This contextual cueing benefit is well established, but there is debate regarding its underlying mechanisms. Eye-tracking studies have consistently shown reduced number of fixations with repetition, supporting improvements in attentional guidance as the source of contextual cueing. However, contextual cueing benefits have been shown in conditions in which attentional guidance should already be optimal—namely, when attention is captured to the target location by an abrupt onset, or under pop-out conditions. These results have been used to argue for a response-related account of contextual cueing. Here, we combine eye tracking with response time to examine the mechanisms behind contextual cueing in spatially cued and pop-out conditions. Three experiments find consistent response time benefits with repetition, which appear to be driven almost entirely by a reduction in number of fixations, supporting improved attentional guidance as the mechanism behind contextual cueing. No differences were observed in the time between fixating the target and responding—our proxy for response related processes. Furthermore, the correlation between contextual cueing magnitude and the reduction in number of fixations on repeated contexts approaches 1. These results argue strongly that attentional guidance is facilitated by familiar search contexts, even when guidance is near-optimal. |
Siobhán Harty; Peter R. Murphy; Ian H. Robertson; Redmond G. O'Connell Parsing the neural signatures of reduced error detection in older age Journal Article In: NeuroImage, vol. 161, pp. 43–55, 2017. @article{Harty2017, Recent work has demonstrated that explicit error detection relies on a neural evidence accumulation process that can be traced in the human electroencephalogram (EEG). Here, we sought to establish the impact of natural aging on this process by recording EEG from young (18–35 years) and older adults (65–88 years) during the performance of a Go/No-Go paradigm in which participants were required to overtly signal their errors. Despite performing the task with equivalent accuracy, older adults reported substantially fewer errors, and the timing of their reports were both slower and more variable. These behavioral differences were linked to three key neurophysiological changes reflecting distinct parameters of the error detection decision process: a reduction in medial frontal delta/theta (2–7 Hz) activity, indicating diminished top-down input to the decision process; a slower rate of evidence accumulation as indexed by the rate of rise of a centro-parietal signal, known as the error positivity; and a higher motor execution threshold as indexed by lateralized beta-band (16–30 Hz) activity. Our data provide novel insight into how the natural aging process affects the neural underpinnings of error detection. |
Hannah Harvey; Hayward J. Godwin; Gemma Fitzsimmons; Simon P. Liversedge; Robin Walker Oculomotor and linguistic processing effects in reading dynamic horizontally scrolling text Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 43, no. 3, pp. 518–536, 2017. @article{Harvey2017, Two experiments are reported investigating oculomotor behavior and linguistic processing when reading dynamic horizontally scrolling text (compared to reading normal static text). Three factors known to modulate processing time in normal reading were investigated: Word length and word frequency were examined in Experiment 1, and target word predictability in Experiment 2. An analysis of global oculomotor behavior across the 2 experiments showed that participants made fewer and longer fixations when reading scrolling text, with shorter progressive and regressive saccades between these fixations. Comparisons of the linguistic manipulations showed evidence of a dissociation between word-level and sentence-level processing. Word-level processing (Experiment 1) was preserved for the dynamic scrolling text condition with no difference in length and frequency effects between scrolling and static text formats. However, sentence-level integration (Experiment 2) was reduced for scrolling compared to static text in that we obtained no early facilitation effect for predictable words under scrolling text conditions. (PsycINFO Database Record |
Sogand Hasanzadeh; Behzad Esmaeili; Michael D. Dodd In: Journal of Management in Engineering, vol. 33, no. 5, pp. 1–17, 2017. @article{Hasanzadeh2017a, Although several studies have highlighted the importance of attention in reducing the number of injuries in the construction industry, few have attempted to empirically measure the attention of construction workers. One technique that can be used to measure worker attention is eye tracking, which is widely accepted as the most direct and continuous measure of attention because where one looks is highly correlated with where one is focusing his or her attention. Thus, with the fundamental objective of measuring the impacts of safety knowledge (specifically, training, work experience, and injury exposure) on construction workers' attentional allocation, this study demonstrates the application of eye tracking to the realm of construction safety practices. To achieve this objective, a laboratory experiment was designed in which participants identified safety hazards presented in 35 construction site images ordered randomly, each of which showed multiple hazards varying in safety risk. During the experiment, the eye movements of 27 construction workers were recorded using a head-mounted EyeLink II system. The impact of worker safety knowledge in terms of training, work experience, and injury exposure (independent variables) on eye-tracking metrics (dependent variables) was then assessed by implementing numerous permutation simulations. The results show that tacit safety knowledge acquired from work experience and injury exposure can significantly improve construction workers' hazard detection and visual search strategies. The results also demonstrate that (1) there is minimal difference, with or without the Occupational Safety and Health Administration 10-h certificate, in workers' search strategies and attentional patterns while exposed to or seeing hazardous situations; (2) relative to less experienced workers (<5 years), more experienced workers (>10 years) need less processing time and deploy more frequent short fixations on hazardous areas to maintain situational awareness of the environment; and (3) injury exposure significantly impacts a worker's visual search strategy and attentional allocation. In sum, practical safety knowledge and judgment on a jobsite requires the interaction of both tacit and explicit knowledge gained through work experience, injury exposure, and interactive safety training. This study significantly contributes to the literature by demonstrating the potential application of eye-tracking technology in studying the attentional allocation of construction workers. Regarding practice, the results of the study show that eye tracking can be used to improve worker training and preparedness, which will yield safer working conditions, detect at-risk workers, and improve the effectiveness of safety-training programs. |
Sogand Hasanzadeh; Behzad Esmaeili; Michael D. Dodd Impact of construction workers' hazard identification skills on their visual attention Journal Article In: Journal of Construction Engineering and Management, vol. 143, no. 10, pp. 1–16, 2017. @article{Hasanzadeh2017, Eye-movement metrics have been shown to correlate with attention and, therefore, represent a means of identifying and analyzing an individual's cognitive processes. Human errors–such as failure to identify a hazard–are often attributed to a worker's lack of attention. Piecemeal attempts have been made to investigate the potential of harnessing eye movements as predictors of human error (e.g., failure to identify a hazard) in the construction industry, although more attempts have investigated human error via subjective measurements. To address this knowledge gap, the present study harnessed eye-tracking technology to evaluate the impacts of workers' hazard-identification skills on their attentional distributions and visual search strategies. To achieve this objective, an experiment was designed in which the eye movements of 31 construction workers were tracked while they searched for hazards in 35 randomly ordered construction scenario images. Workers were then divided into three groups on the basis of their hazard identification performance. Three fixation-related metrics–fixation count, dwell-time percentage, and run count–were analyzed during the eye-tracking experiment for each group (low, medium, and high hazard-identification skills) across various types of hazards. Then, multivariate ANOVA (MANOVA) was used to evaluate the impact of workers' hazard-identification skills on their visual attention. To further investigate the effect of hazard identification skills on the dependent variables (eye movement metrics), two distinct processes followed: separate ANOVAs on each of the dependent variables, and a discriminant function analysis. The analyses indicated that hazard identification skills significantly impact workers' visual search strategies: workers with higher hazard-identification skills had lower dwell-time percentages on ladder-related hazards; higher fixation counts on fall-to-lower-level hazards; and higher fixation counts and run counts on fall-protection systems, struck-by, housekeeping, and all hazardous areas combined. Among the eye-movement metrics studied, fixation count had the largest standardized coefficient in all canonical discriminant functions, which implies that this eye-movement metric uniquely discriminates workers with high hazard-identification skills and at-risk workers. Because discriminant function analysis is similar to regression, discriminant function (linear combinations of eye-movement metrics) can be used to predict workers' hazard-identification capabilities. In conclusion, this study provides a proof of concept that certain eye- movement metrics are predictive indicators of human error due to attentional failure. These outcomes stemmed from a laboratory setting, and, foreseeably, safety managers in the future will be able to use these findings to identify at-risk construction workers, pinpoint required safety training, measure training effectiveness, and eventually improve future personal protective equipment to measure construction workers' situation awareness in real time. |
S. A. Hassani; Mariann Oemisch; M. Balcarras; Stephanie Westendorff; S. Ardid; M. A. Meer; P. Tiesinga; T. Womelsdorf In: Scientific Reports, vol. 7, pp. 40606, 2017. @article{Hassani2017, Noradrenaline is believed to support cognitive flexibility through the alpha 2A noradrenergic receptor (a2A-NAR) acting in prefrontal cortex. Enhanced flexibility has been inferred from improved working memory with the a2A-NA agonist Guanfacine. But it has been unclear whether Guanfacine improves specific attention and learning mechanisms beyond working memory, and whether the drug effects can be formalized computationally to allow single subject predictions. We tested and confirmed these suggestions in a case study with a healthy nonhuman primate performing a feature-based reversal learning task evaluating performance using Bayesian and Reinforcement learning models. In an initial dose-testing phase we found a Guanfacine dose that increased performance accuracy, decreased distractibility and improved learning. In a second experimental phase using only that dose we examined the faster feature-based reversal learning with Guanfacine with single-subject computational modeling. Parameter estimation suggested that improved learning is not accounted for by varying a single reinforcement learning mechanism, but by changing the set of parameter values to higher learning rates and stronger suppression of non-chosen over chosen feature information. These findings provide an important starting point for developing nonhuman primate models to discern the synaptic mechanisms of attention and learning functions within the context of a computational neuropsychiatry framework. |
Taylor R. Hayes; John M. Henderson Scan patterns during real-world scene viewing predict individual differences in cognitive capacity Journal Article In: Journal of Vision, vol. 17, no. 5, pp. 1–17, 2017. @article{Hayes2017, From the earliest recordings of eye movements during active scene viewing to the present day, researchers have commonly reported individual differences in eye movement scan patterns under constant stimulus and task demands. These findings suggest viewer individual differences may be important for understanding gaze control during scene viewing. However, the relationship between scan patterns and viewer individual differences during scene viewing remains poorly understood because scan patterns are difficult to analyze. The present study uses a powerful technique called Successor Representation Scanpath Analysis (Hayes, Petrov, & Sederberg, 2011, 2015) to quantify the strength of the association between individual differences in scan patterns during real-world scene viewing and individual differences in viewer intelligence, working memory capacity, and speed of processing. The results of this analysis revealed individual differences in scan patterns that explained more than 40% of the variance in viewer intelligence and working memory capacity measures, and more than a third of the variance in speed of processing measures. The theoretical implications of our findings for models of gaze control and avenues for future individual differences research are discussed. |
Dana A. Hayward; Willa Voorhies; Jenna L. Morris; Francesca Capozzi; Jelena Ristic Staring reality in the face: A comparison of social attention across laboratory and real world measures suggests little common ground Journal Article In: Canadian Journal of Experimental Psychology, vol. 71, no. 3, pp. 212–225, 2017. @article{Hayward2017, The ability to attend to someone else's gaze is thought to represent 1 of the essential building blocks of the human sociocognitive system. This behavior, termed social attention, has traditionally been assessed using laboratory procedures in which participants' response time and/or accuracy performance indexes attentional function. Recently, a parallel body of emerging research has started to examine social attention during real life social interactions using naturalistic and observational methodologies. The main goal of the present work was to begin connecting these two lines of inquiry. To do so, here we operationalized, indexed, and measured the engagement and shifting components of social attention using covert and overt measures. These measures were obtained during an unconstrained real-world social interaction and during a typical laboratory social cuing task. Our results indicated reliable and overall similar indices of social attention engagement and shifting within each task. However, these measures did not relate across the 2 tasks. We discuss these results as potentially reflecting the differences in social attention mechanisms, the specificity of the cuing task's measurement, as well as possible general dissimilarities with respect to context, task goals, and/or social presence. |
Matthew Heath; Erin M. Shellington; Sam Titheridge; Dawn P. Gill; Robert J. Petrella In: Journal of Alzheimer's Disease, vol. 56, no. 1, pp. 167–183, 2017. @article{Heath2017, Exercise programs involving aerobic and resistance training (i.e., multiple-modality) have shown promise in improving cognition and executive control in older adults at risk, or experiencing, cognitive decline. It is, however, unclear whether cognitive training within a multiple-modality program elicits an additive benefit to executive/cognitive processes. This is an important question to resolve in order to identify optimal training programs that delay, or ameliorate, executive deficits in persons at risk for further cognitive decline. In the present study, individuals with a self-reported cognitive complaint (SCC) participated in a 24-week multiple-modality (i.e., the M2 group) exercise intervention program. In addition, a separate group of individuals with a SCC completed the same aerobic and resistance training as the M2 group but also completed a cognitive-based stepping task (i.e., multiple-modality, mind-motor intervention: M4 group). Notably, pre- and post-intervention executive control was examined via the antisaccade task (i.e., eye movement mirror-symmetrical to a target). Antisaccades are an ideal tool for the study of individuals with subtle executive deficits because of its hands- and language-free nature and because the task's neural mechanisms are linked to neuropathology in cognitive decline (i.e., prefrontal cortex). Results showed that M2 and M4 group antisaccade reaction times reliably decreased from pre- to post-intervention and the magnitude of the decrease was consistent across groups. Thus, multi-modality exercise training improved executive performance in persons with a SCC independent of mind-motor training. Accordingly, we propose that multiple-modality training provides a sufficient intervention to improve executive control in persons with a SCC. |
Jessica Heeman; Stefan Van der Stigchel; Jan Theeuwes The influence of distractors on express saccades Journal Article In: Journal of Vision, vol. 17, no. 1, pp. 1–17, 2017. @article{Heeman2017, It is well known that regular target-driven saccades are affected by the presence of close and remote distractors. Distractors close to the target affect the saccade landing position (known as the global effect), while remote distractors prolong saccade latencies to the target (known as the remote-distractor effect). Little is known about whether a different population of saccades known as express saccades (saccades with very short latencies between 80 and 130 ms) is similarly affected by close and remote distractors, as these saccades are considered to be the result of advanced preparation of an oculomotor program toward the target. We designed a task in which we were able to generate a large number of express saccades, as evidenced by a separate and very early peak in the saccade-latency distribution—a distribution that was different from that of regular saccades. Our results show that irrelevant and unexpected visual input had a large effect on express saccades. We found a global and a remote-distractor effect which were similar to those seen in regular saccades. Even though our findings confirm the existence of very-short-latency saccades in humans, it is questionable whether they represent a different population of saccades, as they were equally affected by the presence of distractors as are regular saccades. |
Christoph Helmchen; Jan Birger Kirchhoff; Martin Göttlich; Andreas Sprenger Postural ataxia in cerebellar downbeat nystagmus: Its relation to visual, proprioceptive and vestibular signals and cerebellar atrophy Journal Article In: PLoS ONE, vol. 12, no. 1, pp. e0168808, 2017. @article{Helmchen2017, Background: The cerebellum integrates proprioceptive, vestibular and visual signals for postural control. Cerebellar patients with downbeat nystagmus (DBN) complain of unsteadiness of stance and gait as well as blurred vision and oscillopsia. Objectives: The aim of this study was to elucidate the differential role of visual input, gaze eccentricity, vestibular and proprioceptive input on the postural stability in a large cohort of cerebellar patients with DBN, in comparison to healthy age-matched control subjects. Methods: Oculomotor (nystagmus, smooth pursuit eye movements) and postural (postural sway speed) parameters were recorded and related to each other and volumetric changes of the cerebellum (voxel-based morphometry, SPM). Results: Twenty-seven patients showed larger postural instability in all experimental conditions. Postural sway increased with nystagmus in the eyes closed condition but not with the eyes open. Romberg's ratio remained stable and was not different from healthy controls. Postural sway did not change with gaze position or graviceptive input. It increased with attenuated proprioceptive input and on tandem stance in both groups but Romberg's ratio also did not differ. Cerebellar atrophy (vermal lobule VI, VIII) correlated with the severity of impaired smooth pursuit eye movements of DBN patients. Conclusions: Postural ataxia of cerebellar patients with DBN cannot be explained by impaired visual feedback. Despite oscillopsia visual feedback control on cerebellar postural control seems to be preserved as postural sway was strongest on visual deprivation. The increase in postural ataxia is neither related to modulations of single components characterizing nystagmus nor to deprivation of single sensory (visual, proprioceptive) inputs usually stabilizing stance. Re-weighting of multisensory signals and/or inappropriate cerebellar motor commands might account for this postural ataxia. |
Jens R. Helmert; Claudia Symmank; Sebastian Pannasch; Harald Rohm Have an eye on the buckled cucumber: An eye tracking study on visually suboptimal foods Journal Article In: Food Quality and Preference, vol. 60, pp. 40–47, 2017. @article{Helmert2017, Waste is an ever growing problem in the food supply chain, starting in the production up to the consumers' households. A precondition for a consumer to purchase a product is to recognize it as an option in the first place. Therefore, in the present study, we investigated eye movement behavior on impeccable and visually suboptimal food items in a purchase or discard decision task. Additionally, in some trials price badges of the suboptimal food items were designed specifically in order to attract attention. Design changes included messages regarding price and taste, respectively, either presented in red or green. The results show that the design changes indeed attracted attention towards suboptimal food items in terms of time to first fixation, and also prolonged total fixation duration. However, only color yielded differences between the design variations, with red resulting in longer total fixation durations. Additionally, we inspected choice behavior towards visually suboptimal food items. As can be expected, purchase decisions declined for the suboptimal as compared to the impeccable items. However, when presented with differently designed price badges, a positive trend to purchase the suboptimal items was obtained. Our results show that price badge designs impact attention, cognitive processing, and finally also purchase decisions. Therefore, supplying visually suboptimal food in stores should be embedded into efforts to attract attention towards these products, as selling visually suboptimal food might positively impact waste balance in the food domain. |
Andrea Helo; Sandrien Ommen; Sebastian Pannasch; Lucile Danteny-Dordoigne; Pia Rämä Influence of semantic consistency and perceptual features on visual attention during scene viewing in toddlers Journal Article In: Infant Behavior and Development, vol. 49, pp. 248–266, 2017. @article{Helo2017, Conceptual representations of everyday scenes are built in interaction with visual environment and these representations guide our visual attention. Perceptual features and object-scene semantic consistency have been found to attract our attention during scene exploration. The present study examined how visual attention in 24-month-old toddlers is attracted by semantic violations and how perceptual features (i. e. saliency, centre distance, clutter and object size) and linguistic properties (i. e. object label frequency and label length) affect gaze distribution. We compared eye movements of 24-month-old toddlers and adults while exploring everyday scenes which either contained an inconsistent (e.g., soap on a breakfast table) or consistent (e.g., soap in a bathroom) object. Perceptual features such as saliency, centre distance and clutter of the scene affected looking times in the toddler group during the whole viewing time whereas looking times in adults were affected only by centre distance during the early viewing time. Adults looked longer to inconsistent than consistent objects either if the objects had a high or a low saliency. In contrast, toddlers presented semantic consistency effect only when objects were highly salient. Additionally, toddlers with lower vocabulary skills looked longer to inconsistent objects while toddlers with higher vocabulary skills look equally long to both consistent and inconsistent objects. Our results indicate that 24-month-old children use scene context to guide visual attention when exploring the visual environment. However, perceptual features have a stronger influence in eye movement guidance in toddlers than in adults. Our results also indicate that language skills influence cognitive but not perceptual guidance of eye movements during scene perception in toddlers. |
John M. Henderson; Taylor R. Hayes Meaning-based guidance of attention in scenes as revealed by meaning maps Journal Article In: Nature Human Behaviour, vol. 1, no. 10, pp. 743–747, 2017. @article{Henderson2017, Real-world scenes comprise a blooming, buzzing confusion of information. To manage this complexity, visual attention is guided to important scene regions in real time1–7. What factors guide attention within scenes? A leading theoretical position suggests that visual salience based on semantically uninterpreted image features plays the critical causal role in attentional guidance, with knowledge and meaning playing a secondary or modulatory role8–11. Here we propose instead that meaning plays the dominant role in guiding human attention through scenes. To test this proposal, we developed ‘meaning maps' that represent the semantic richness of scene regions in a format that can be directly compared to image salience. We then contrasted the degree to which the spatial distributions of meaning and salience predict viewers' overt attention within scenes. The results showed that both meaning and salience predicted the distribution of attention, but that when the relationship between meaning and salience was controlled, only meaning accounted for unique variance in attention. This pattern of results was apparent from the very earliest time-point in scene viewing. We conclude that meaning is the driving force guiding attention through real-world scenes. |
Piril Hepsomali; Julie A. Hadwin; Simon P. Liversedge; Matthew Garner Pupillometric and saccadic measures of affective and executive processing in anxiety Journal Article In: Biological Psychology, vol. 127, pp. 173–179, 2017. @article{Hepsomali2017, Anxious individuals report hyper-arousal and sensitivity to environmental stimuli, difficulties concentrating, performing tasks efficiently and inhibiting unwanted thoughts and distraction. We used pupillometry and eye-movement measures to compare high vs. low anxious individuals hyper-reactivity to emotional stimuli (facial expressions) and subsequent attentional biases in a memory-guided pro- and antisaccade task during conditions of low and high cognitive load (short vs. long delay). High anxious individuals produced larger and slower pupillary responses to face stimuli, and more erroneous eye-movements, particularly following long delay. Low anxious individuals' pupillary responses were sensitive to task demand (reduced during short delay), whereas high anxious individuals' were not. These findings provide evidence in anxiety of enhanced, sustained and inflexible patterns of pupil responding during affective stimulus processing and cognitive load that precede deficits in task performance. |
James P. Herman; Richard J. Krauzlis Color-change detection activity in the primate superior colliculus Journal Article In: eNeuro, vol. 4, no. 2, pp. 1–16, 2017. @article{Herman2017, The primate superior colliculus (SC) is a midbrain structure that participates in the control of spatial attention. Previous studies examining the role of the SC in attention have mostly used luminance-based visual features (e.g., motion, contrast) as the stimuli and saccadic eye movements as the behavioral response, both of which are known to modulate the activity of SC neurons. To explore the limits of the SC's involvement in the control of spatial attention, we recorded SC neuronal activity during a task using color, a visual feature dimension not traditionally associated with the SC, and required monkeys to detect threshold-level changes in the saturation of a cued stimulus by releasing a joystick during maintained fixation. Using this color-based spatial attention task, we found substantial cue-related modulation in all categories of visually responsive neurons in the intermediate layers of the SC. Notably, near-threshold changes in color saturation, both increases and decreases, evoked phasic bursts of activity with magnitudes as large as those evoked by stimulus onset. This change-detection activity had two distinctive features: activity for hits was larger than for misses, and the timing of change-detection activity accounted for 67% of joystick release latency, even though it preceded the release by at least 200 ms. We conclude that during attention tasks, SC activity denotes the behavioral relevance of the stimulus regardless of feature dimension and that phasic event-related SC activity is suitable to guide the selection of manual responses as well as saccadic eye movements. |
Erno J. Hermans; Jonathan W. Kanen; Arielle Tambini; Guillén Fernández; Lila Davachi; Elizabeth A. Phelps In: Cerebral Cortex, vol. 27, no. 5, pp. 3028–3041, 2017. @article{Hermans2017, After encoding, memories undergo a process of consolidation that determines long-term retention. For conditioned fear, animal models postulate that consolidation involves reactivations of neuronal assemblies supporting fear learning during postlearning " offline " periods. However, no human studies to date have investigated such processes, particularly in relation to long-term expression of fear. We tested 24 participants using functional MRI on 2 consecutive days in a fear conditioning paradigm involving 1 habituation block, 2 acquisition blocks, and 2 extinction blocks on day 1, and 2 re-extinction blocks on day 2. Conditioning blocks were preceded and followed by 4.5-min rest blocks. Strength of spontaneous recovery of fear on day 2 served as a measure of long-term expression of fear. Amygdala connectivity primarily with hippocampus increased progressively during postacquisition and postextinction rest on day 1. Intraregional multi-voxel correlation structures within amygdala and hippocampus sampled during a block of differential fear conditioning furthermore persisted after fear learning. Critically, both these main findings were stronger in participants who exhibited spontaneous recovery 24 h later. Our findings indicate that neural circuits activated during fear conditioning exhibit persistent postlearning activity that may be functionally relevant in promoting consolidation of the fear memory. |
Tandra Ghose; Yannik T. H. Schelske; Takeshi Suzuki; Andreas Dengel Low-level pixelated representations suffice for aesthetically pleasing contrast adjustment in photographs Journal Article In: Psihologija, vol. 50, no. 3, pp. 239–270, 2017. @article{Ghose2017, Today's web-based automatic image enhancement algorithms decide to apply an enhancement operation by searching for “similar” images in an online database of images and then applying the same level of enhancement as the image in the database. Two key bottlenecks in these systems are the storage cost for images and the cost of the search. Based on the principles of computational aesthetics, we consider storing task-relevant aesthetic summaries, a set of features which are sufficient to predict the level at which an image enhancement operation should be performed, instead of the entire image. The empirical question, then, is to ensure that the reduced representation indeed maintains enough information so that the resulting operation is perceived to be aesthetically pleasing to humans. We focus on the contrast adjustment operation, an important image enhancement primitive. We empirically study the efficacy of storing a pixelated summary of the 16 most representative colors of an image and performing contrast adjustments on this representation. We tested two variants of the pixelated image: a “mid-level pixelized version” that retained spatial relationships and allowed for region segmentation and grouping as in the original image and a “low-level pixelized-random version” which only retained the colors by randomly shuffling the 50 x 50 pixels. In an empirical study on 25 human subjects, we demonstrate that the preferred contrast for the low-level pixelized-random image is comparable to the original image even though it retains very few bits and no semantic information, thereby making it ideal for image matching and retrieval for automated contrast editing. In addition, we use an eye tracking study to show that users focus only on a small central portion of the low-level image, thus improving the performance of image search over commonly used computer vision algorithms to determine interesting key points. |
Steven M. Gillespie; Pia Rotshtein; Anthony R. Beech; Ian J. Mitchell Boldness psychopathic traits predict reduced gaze toward fearful eyes in men with a history of violence Journal Article In: Biological Psychology, vol. 128, pp. 29–38, 2017. @article{Gillespie2017, Research with developmental and adult samples has shown a relationship of psychopathic traits with reduced eye gaze. However, these relationships remained to be investigated among forensic samples. Here we examined the eye movements of male violent offenders during an emotion recognition task. Violent offenders performed similar to non-offending controls, and their eye movements varied with the emotion and intensity of the facial expression. In the violent offender group Boldness psychopathic traits, but not Meanness or Disinhibition, were associated with reduced dwell time and fixation counts, and slower first fixation latencies, on the eyes compared with the mouth. These results are the first to show a relationship of psychopathic traits with reduced attention to the eyes in a forensic sample, and suggest that Boldness is associated with difficulties in orienting attention toward emotionally salient aspects of the face. |
Mackenzie G. Glaholt; Grace Sim Gaze-contingent center-surround fusion of infrared images to facilitate visual search for human targets Journal Article In: Journal of Imaging Science and Technology, vol. 61, no. 1, pp. 230–235, 2017. @article{Glaholt2017, We investigated gaze-contingent fusion of infrared imagery during visual search. Eye movements were monitored while subjects searched for and identified human targets in images captured simultaneously in the short-wave (SWIR) and long-wave (LWIR) infrared bands. Based on the subject's gaze position, the search displaywas updated such that imagery from one sensorwas continuously presented to the subject's central visual field (“center”) and another sensor was presented to the subject's non-central visual field (“surround”). Analysis ofperformance data indicated that, compared to the other combinations, the scheme featuring SWIR imagery in the center region and LWIR imagery in the surround region constituted an optimal combination of the SWIR and LWIR information: it inherited the superior target detection performance of LWIR imagery and the superior target identification performance of SWIR imagery. This demonstrates a novel method for efficiently combining imagery from two infrared sources as an alternative to conventional image fusion. |
Hayward J. Godwin; Tamaryn Menneer; Simon P. Liversedge; Kyle R. Cave; Nick S. Holliman; Nick Donnelly Adding depth to overlapping displays can improve visual search performance Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 43, no. 8, pp. 1532–1549, 2017. @article{Godwin2017, Standard models of visual search have focused upon asking participants to search for a single target in displays where the objects do not overlap one another, and where the objects are presented on a single depth plane. This stands in contrast to many everyday visual searches wherein variations in overlap and depth are the norm, rather than the exception. Here, we addressed whether presenting overlapping objects on different depths planes to one another can improve search performance. Across 4 different experiments using different stimulus types (opaque polygons, transparent polygons, opaque real-world objects, and transparent X-ray images), we found that depth was primarily beneficial when the displays were transparent, and this benefit arose in terms of an increase in response accuracy. Although the benefit to search performance only appeared in some cases, across all stimulus types, we found evidence of marked shifts in eye-movement behavior. Our results have important implications for current models and theories of visual search, which have not yet provided detailed accounts of the effects that overlap and depth have on guidance and object identification processes. Moreover, our results show that the presence of depth information could aid real-world searches of complex, overlapping displays. |
Hayward J. Godwin; Erik D. Reichle; Tamaryn Menneer Modeling lag-2 revisits to understand trade-offs in mixed control of fixation termination during visual search Journal Article In: Cognitive Science, vol. 41, no. 4, pp. 996–1019, 2017. @article{Godwin2017a, An important question about eye-movement behavior is when the decision is made to terminate a fixation and program the following saccade. Different approaches have found converging evidence in favor of a mixed-control account, in which there is some overlap between processing information at fixation and planning the following saccade. We examined one interesting instance of mixed control in visual search: lag-2 revisits, during which observers fixate a stimulus, move to a different stimulus, and then revisit the first stimulus on the next fixation. Results show that the probability of lag-2 revisits occurring increased with the number of target-similar stimuli, and revisits were preceded by a brief fixation on the intervening distractor stimulus. We developed the Efficient Visual Sampling (EVS) computational model to simulate our findings (fixation durations and fixation locations) and to provide insight into mixed control of fixations and the perceptual, cognitive, and motor processes that produce lag-2 revisits. |
Lisa C. Goelz; Fabian J. David; John A. Sweeney; David E. Vaillancourt; Howard Poizner; Leonard Verhagen Metman; Daniel M. Corcos The effects of unilateral versus bilateral subthalamic nucleus deep brain stimulation on prosaccades and antisaccades in Parkinson's disease Journal Article In: Experimental Brain Research, vol. 235, no. 2, pp. 615–626, 2017. @article{Goelz2017, Unilateral deep brain stimulation (DBS) of the subthalamic nucleus (STN) in patients with Parkinson's disease improves skeletomotor function assessed clinically, and bilateral STN DBS improves motor function to a significantly greater extent. It is unknown whether unilateral STN DBS improves oculomotor function and whether bilateral STN DBS improves it to a greater extent. Further, it has also been shown that bilateral, but not unilateral, STN DBS is associated with some impaired cognitive-motor functions. The current study compared the effect of unilateral and bilateral STN DBS on sensorimotor and cognitive aspects of oculomotor control. Patients performed prosaccade and antisaccade tasks during no stimulation, unilateral stimulation, and bilateral stimulation. There were three sets of findings. First, for the prosaccade task, unilateral STN DBS had no effect on prosaccade latency and it reduced prosaccade gain; bilateral STN DBS reduced prosaccade latency and increased prosaccade gain. Second, for the antisaccade task, neither unilateral nor bilateral stimulation had an effect on antisaccade latency, unilateral STN DBS increased antisaccade gain, and bilateral STN DBS increased antisaccade gain to a greater extent. Third, bilateral STN DBS induced an increase in prosaccade errors in the antisaccade task. These findings suggest that while bilateral STN DBS benefits spatiotemporal aspects of oculomotor control, it may not be as beneficial for more complex cognitive aspects of oculomotor control. Our findings are discussed considering the strategic role the STN plays in modulating information in the basal ganglia oculomotor circuit. |
Tal Golan; Ido Davidesco; Meir Meshulam; David M. Groppe; Pierre Mégevand; Erin M. Yeagle; Matthew S. Goldfinger; Michal Harel; Lucia Melloni; Charles E. Schroeder; Leon Y. Deouell; Ashesh D. Mehta; Rafael Malach Increasing suppression of saccade-related transients along the human visual hierarchy Journal Article In: eLife, vol. 6, pp. 1–15, 2017. @article{Golan2017, A key hallmark of visual perceptual awareness is robustness to instabilities arising from unnoticeable eye and eyelid movements. In previous human intracranial (iEEG) work (Golan et al., 2016) we found that excitatory broadband high-frequency activity transients, driven by eye blinks, are suppressed in higher-level but not early visual cortex. Here, we utilized the broad anatomical coverage of iEEG recordings in 12 eye-tracked neurosurgical patients to test whether a similar stabilizing mechanism operates following small saccades. We compared saccades (1.3°-3.7°) initiated during inspection of large individual visual objects with similarly-sized external stimulus displacements. Early visual cortex sites responded with positive transients to both conditions. In contrast, in both dorsal and ventral higher-level sites the response to saccades (but not to external displacements) was suppressed. These findings indicate that early visual cortex is highly unstable compared to higher-level visual regions which apparently constitute the main target of stabilizing extra-retinal oculomotor influences. |
Florión Goller; Donghoon Lee; Ulrich Ansorge; Soonja Choi Effects of language background on gaze behavior: A crosslinguistic comparison between Korean and German speakers Journal Article In: Advances in Cognitive Psychology, vol. 13, no. 4, pp. 267–279, 2017. @article{Goller2017, Languages differ in how they categorize spatial relations: While German differentiates between containment (in) and support (auf) with distinct spatial words-(a) den Kuli IN die Kappe stecken ("put pen in cap"); (b) die Kappe AUF den Kuli stecken ("put cap on pen")-Korean uses a single spatial word (kkita) collapsing (a) and (b) into one semantic category, particularly when the spatial enclosure is tight-fit. Korean uses a different word (i.e., netha) for loose-fits (e.g., apple in bowl). We tested whether these differences influence the attention of the speaker. In a crosslinguistic study, we compared native German speakers with native Korean speakers. Participants rated the similarity of two successive video clips of several scenes where two objects were joined or nested (either in a tight or loose manner). The rating data show that Korean speakers base their rating of similarity more on tight-versus loose-fit, whereas German speakers base their rating more on containment versus support (in vs. auf). Throughout the experiment, we also measured the participants' eye movements. Korean speakers looked equally long at the moving Figure object and at the stationary Ground object, whereas German speakers were more biased to look at the Ground object. Additionally, Korean speakers also looked more at the region where the two objects touched than did German speakers. We discuss our data in the light of crosslinguistic semantics and the extent of their influence on spatial cognition and perception. |
Evan M. Gordon; Timothy O. Laumann; Adrian W. Gilmore; Dillan J. Newbold; Deanna J. Greene; Jeffrey J. Berg; Mario Ortega; Catherine Hoyt-Drazen; Caterina Gratton; Haoxin Sun; Jacqueline M. Hampton; Rebecca S. Coalson; Annie L. Nguyen; Kathleen B. McDermott; Joshua S. Shimony; Abraham Z. Snyder; Bradley L. Schlaggar; Steven E. Petersen; Steven M. Nelson; Nico U. F. Dosenbach Precision functional mapping of individual human brains Journal Article In: Neuron, vol. 95, no. 4, pp. 791–807.e7, 2017. @article{Gordon2017, Human functional MRI (fMRI) research primarily focuses on analyzing data averaged across groups, which limits the detail, specificity, and clinical utility of fMRI resting-state functional connectivity (RSFC) and task-activation maps. To push our understanding of functional brain organization to the level of individual humans, we assembled a novel MRI dataset containing 5 hr of RSFC data, 6 hr of task fMRI, multiple structural MRIs, and neuropsychological tests from each of ten adults. Using these data, we generated ten high-fidelity, individual-specific functional connectomes. This individual-connectome approach revealed several new types of spatial and organizational variability in brain networks, including unique network features and topologies that corresponded with structural and task-derived brain features. We are releasing this highly sampled, individual-focused dataset as a resource for neuroscientists, and we propose precision individual connectomics as a model for future work examining the organization of healthy and diseased individual human brains. |
Ernesto Guerra; Pia Knoeferle In: Journal of Memory and Language, vol. 92, pp. 43–56, 2017. @article{Guerra2017, Recent experimental evidence suggests that spatial distance between two depicted objects in a non-referential visual context (i.e., when neither spatial distance nor the objects were mentioned) can rapidly and incrementally modulate the processing of semantic similarity between and-coordinated subject noun phrases in a sentence. The present research examines in three eye-tracking reading experiments whether these spatial distance effects extend to another abstract domain (social relations). More importantly, we assessed how precisely cognitive mechanisms link spatial information to sentence interpretation. To this end we varied between experiments the (order of the) constituents conveying information about social relations. We examined to what extent object distance effects on sentence interpretation depend upon a one-to-one mapping (relating objects to nouns). The eye-tracking record showed that spatial distance effects extended to abstract language other than semantic similarity and that these effects occurred as soon as the readers encountered linguistic information about social relations - independent of whether that information was conveyed by the (coordinated) nouns or by other constituents. Finally, the direction of the spatial distance effects seemed to depend on the activation level of the spatial distance representations, as determined by the constituent order. We discuss the contribution of these results to accounts of situated sentence comprehension. |
Maria J. S. Guerreiro; Pascal W. M. Van Gerven Disregarding hearing loss leads to overestimation of age-related cognitive decline Journal Article In: Neurobiology of Aging, vol. 56, pp. 180–189, 2017. @article{Guerreiro2017, Aging is associated with cognitive and sensory decline. While several studies have indicated greater cognitive decline among older adults with hearing loss, the extent to which age-related differences in cognitive processing may have been overestimated due to group differences in sensory processing has remained unclear. We addressed this question by comparing younger adults, older adults with good hearing, and older adults with poor hearing in several cognitive domains: working memory, selective attention, processing speed, inhibitory control, and abstract reasoning. Furthermore, we examined whether sensory-related cognitive decline depends on cognitive demands and on the sensory modality used for assessment. Our results revealed that age-related cognitive deficits in most cognitive domains varied as a function of hearing loss, being more pronounced in older adults with poor hearing. Furthermore, sensory-related cognitive decline was observed across different levels of cognitive demands and independent of the sensory modality used for cognitive assessment, suggesting a generalized effect of age-related hearing loss on cognitive functioning. As most cognitive aging studies have not taken sensory acuity into account, age-related cognitive decline may have been overestimated. |
Diego A. Gutnisky; Charles B. Beaman; Sergio E. Lew; Valentin Dragoi Spontaneous fluctuations in visual cortical responses influence population coding accuracy Journal Article In: Cerebral Cortex, vol. 27, no. 2, pp. 1409–1427, 2017. @article{Gutnisky2017, Information processing in the cerebral cortex depends not only on the nature of incoming stimuli, but also on the state of neuronal networks at the time of stimulation. That is, the same stimulus will be processed differently depending on the neuronal context in which it is received. A major factor that could influence neuronal context is the background, or ongoing neuronal activity before stimulation. In visual cortex, ongoing activity is known to play a critical role in the development of local circuits, yet whether it influences the coding of visual features in adult cortex is unclear. Here, we investigate whether and how the information encoded by individual neurons and populations in primary visual cortex (V1) depends on the ongoing activity before stimulus presentation. We report that when individual neurons are in a "low" prestimulus state, they have a higher capacity to discriminate stimulus features, such as orientation, despite their reduction in evoked responses. By measuring the distribution of prestimulus activity across a population of neurons, we found that network discrimination accuracy is improved in the low prestimulus state. Thus, the distribution of ongoing activity states across the network creates an "internal context" that dynamically filters incoming stimuli to modulate the accuracy of sensory coding. The modulation of stimulus coding by ongoing activity state is consistent with recurrent network models in which ongoing activity dynamically controls the balanced background excitation and inhibition to individual neurons. |
Diego A. Gutnisky; Charles Beaman; Sergio E. Lew; Valentin Dragoi Cortical response states for enhanced sensory discrimination Journal Article In: eLife, vol. 6, pp. 1–23, 2017. @article{Gutnisky2017a, Brain activity during wakefulness is characterized by rapid fluctuations in neuronal responses. Whether these fluctuations play any role in modulating the accuracy of behavioral responses is poorly understood. Here, we investigated whether and how trial changes in the population response impact sensory coding in monkey V1 and perceptual performance. Although the responses of individual neurons varied widely across trials, many cells tended to covary with the local population. When population activity was in a 'low' state, neurons had lower evoked responses and correlated variability, yet higher probability to predict perceptual accuracy. The impact of firing rate fluctuations on network and perceptual accuracy was strongest 200-ms before stimulus presentation, and it greatly diminished when the number of cells used to measure the state of the population was decreased. These findings indicate that enhanced perceptual discrimination occurs when population activity is in a 'silent' response mode in which neurons increase information extraction. |
Tjerk P. Gutteling; D. J. L. G. Schutter; W. Pieter Medendorp Alpha-band transcranial alternating current stimulation modulates precision, but not gain during whole-body spatial updating Journal Article In: Neuropsychologia, vol. 106, pp. 52–59, 2017. @article{Gutteling2017, Spatial updating is essential to maintain an accurate representation of our visual environment when we move. A neural mechanism that contributes to this ability is called remapping: the transfer of visual information from neural populations that code a location before the motion to those that encode it after the motion. While there is ample evidence for neural remapping in conjunction with eye movements, only recent findings suggest a role of this mechanism for whole-body motion updating, based on the observation that alpha band (10 Hz) activity is selectively reorganized during remapping. This study tested whether alpha oscillations directly contribute to whole-body motion updating using transcranial alternating current stimulation (tACS). In a double blind sham controlled design, healthy volunteers received 10 Hz tACS at an intensity of 1 mA over either the left or right posterior hemisphere during a whole-body motion updating task. Updating performance was assessed psychometrically and indices of gain and precision were obtained. No tACS-related effects on updating gain were found, irrespective of whether the remapping was across or within the hemispheres. In contrast, updating precision was enhanced when a target representation had to be internally remapped to the stimulated hemisphere, but not in other remapping conditions. Our observations suggest that alpha band oscillations do not directly affect the transfer of target representations during remapping, but increase the fidelity of the updated representation by attenuating interference of afferent information. |
Nathalie Guyader; Alan Chauvin; Muriel Boucart; Carole Peyrin Do low spatial frequencies explain the extremely fast saccades towards human faces? Journal Article In: Vision Research, vol. 133, pp. 100–111, 2017. @article{Guyader2017, The visual perception of human faces by man is fast and efficient compared to that of other categories of objects. Using a saccadic choice task, recent studies showed that participants were able to initiate fast reliable saccades in just 100–110 ms toward an image of a human face, when this was presented alongside another image without a face. This extremely fast saccadic reaction time is barely predicted using classical models of visual perception. Thus, the present research investigates whether this result might be explained by the low spatial frequency content of images. Using the same paradigm, with two images simultaneously presented to the left or right visual fields, participants were asked to make a saccade towards a target image. The target was defined as an image belonging to one category: human face, animal or vehicle. The other image corresponded to the distractor and belongs to the other categories. We compared performance to saccade toward one category of target. The two images were displayed either in color, gray-level, low-pass filtered or high-pass filtered. As previous studies, we found that the shortest SRT was observed for saccades towards faces rather than towards animals or vehicles. Analysis of saccadic reaction time distributions showed that, in 130–140 ms, participants were able to make more correct than incorrect saccades towards faces for unfiltered (color and gray-level) and low-pass filtered images whereas they needed more time for high-pass filtered images. In contrast, the minimum time participants needed to correctly saccade towards animals and vehicles was longer for low-pass and high-pass filtered than for unfiltered images. The analysis of the image statistics in the Fourier domain revealed that the amplitude spectrum of faces was mainly contained in the low spatial frequencies. Consistent with a coarse-to-fine processing of visual information, our results suggest that extremely fast saccades towards faces could be initiated by low spatial frequencies. |
Selam W. Habtegiorgis; Katharina Rifai; Markus Lappe; Siegfried Wahl Adaptation to skew distortions of natural scenes and retinal specificity of its aftereffects Journal Article In: Frontiers in Psychology, vol. 8, pp. 1158, 2017. @article{Habtegiorgis2017, Image skew is one of the prominent distortions that exist in optical elements, such as in spectacle lenses. The present study evaluates adaptation to image skew in dynamic natural images. Moreover, the cortical levels involved in skew coding were probed using retinal specificity of skew ad=ptation aftereffects. Left and right skewed natural image sequences were shown to observers as adapting stimuli. The point of subjective equality (PSE), i.e., the skew amplitude in simple geometrical patterns that is perceived to be unskewed, was used to quantify the aftereffect of each adapting skew direction. The PSE, in a two-alternative forced choice paradigm, shifted toward the adapting skew direction. Moreover, significant adaptation aftereffects were obtained not only at adapted, but also at non-adapted retinal locations during fixation. Skew adaptation information was transferred partially to non-adapted retinal locations. Thus, adaptation to skewed natural scenes induces coordinated plasticity in lower and higher cortical areas of the visual pathway. |
Gerald Hahn; Adrian Ponce-Alvarez; Cyril Monier; Giacomo Benvenuti; Arvind Kumar; Frédéric Chavane; Gustavo Deco; Yves Frégnac Spontaneous cortical activity is transiently poised close to criticality Journal Article In: PLoS Computational Biology, vol. 13, no. 5, pp. e1005543, 2017. @article{Hahn2017, Brain activity displays a large repertoire of dynamics across the sleep-wake cycle and even during anesthesia. It was suggested that criticality could serve as a unifying principle underlying the diversity of dynamics. This view has been supported by the observation of spontaneous bursts of cortical activity with scale-invariant sizes and durations, known as neuronal avalanches, in recordings of mesoscopic cortical signals. However, the existence of neuronal avalanches in spiking activity has been equivocal with studies reporting both its presence and absence. Here, we show that signs of criticality in spiking activity can change between synchronized and desynchronized cortical states. We analyzed the spontaneous activity in the primary visual cortex of the anesthetized cat and the awake monkey, and found that neuronal avalanches and thermodynamic indicators of criticality strongly depend on collective synchrony among neurons, LFP fluctuations, and behavioral state. We found that synchronized states are associated to criticality, large dynamical repertoire and prolonged epochs of eye closure, while desynchronized states are associated to sub-criticality, reduced dynamical repertoire, and eyes open conditions. Our results show that criticality in cortical dynamics is not stationary, but fluctuates during anesthesia and between different vigilance states. |
Clotilde Hainline; John-Ross Rizzo; Todd E. Hudson; Weiwei Dai; Joel Birkemeier; Jenelle Raynowska; Rachel C. Nolan; Lisena Hasanaj; Ivan Selesnick; Teresa C. Frohman; Elliot M. Frohman; Steven L. Galetta; Laura J. Balcer; Janet C. Rucker Capturing saccades in multiple sclerosis with a digitized test of rapid number naming Journal Article In: Journal of Neurology, vol. 264, no. 5, pp. 989–998, 2017. @article{Hainline2017, The King-Devick (K-D) test of rapid number naming is a visual performance measure that captures saccadic eye movements. Patients with multiple sclerosis (MS) have slowed K-D test times associated with neurologic disability and reduced quality of life. We assessed eye movements during the K-D test to identify characteristics associated with slowed times. Participants performed a computerized K-D test with video-oculography. The 25-Item National Eye Institute Visual Functioning Questionnaire (NEI-VFQ-25) and its 10-Item Neuro-Ophthalmic Supplement measured vision-specific quality of life (VSQOL). Among 25 participants with MS (age 37 ± 10 years, range 20-59) and 42 controls (age 33 ± 9 years, range 19-54), MS was associated with significantly longer (worse) K-D times (58.2 ± 19.8 vs. 43.8 ± 8.6 s |
Dorothea Hämmerer; Alexandra Hopkins; Matthew J. Betts; Anne Maaß; Raymond J. Dolan; Emrah Düzel In: Neurobiology of Aging, vol. 58, pp. 129–139, 2017. @article{Haemmerer2017, A better memory for negative emotional events is often attributed to a conjoint impact of increased arousal and noradrenergic modulation (NA). A decline in NA during aging is well documented but its impact on memory function during aging is unclear. Using pupil diameter (PD) as a proxy for NA, we examined age differences in memory for negative events in younger (18–30 years) and older (62–83 years) adults based on a segregation of early arousal to negative events, and later retrieval-related PD responses. In keeping with the hypothesis of reduced age-related NA influences, older adults showed attenuated induced PD responses to negative emotional events. The findings highlight a likely contribution of NA to negative emotional memory, mediated via arousal that may be compromised with aging. |
Paul Hands; Jenny C. A. Read True stereoscopic 3D cannot be simulated by shifting 2D content off the screen plane Journal Article In: Displays, vol. 48, pp. 35–40, 2017. @article{Hands2017, Generating stereoscopic 3D (S3D) content is expensive, so industry producers sometimes attempt to save money by including brief sections of 2D content displayed with a uniform disparity, i.e. the 2D image is geometrically shifted behind the screen plane. This manipulation is believed to produce an illusion of depth which, while not as powerful as true S3D, is nevertheless more compelling than simple 2D. Our study examined whether this belief is correct. 30 s clips from a nature documentary were shown in the original S3D, in ordinary 2D and in shifted versions of S3D and 2D. Participants were asked to determine the impression of depth on a 7 point Likert scale. There was a clear and highly significant difference between the S3D depth perception (mean 6.03) and the shifted 2D depth perception (mean 4.13) (P = 0.002, ANOVA). There was no difference between ordinary 2D presented on the screen plane, and the shifted 2D. We conclude that the shifted 2D method not only fails to mimic the depth effect of true S3D, it in fact has no benefit over ordinary 2D in terms of the depth illusion created. This could impact viewing habits of people who notice the difference in depth quality. |
Martin Gorges; Melanie N. Maier; Johannes Rosskopf; Olga Vintonyak; Elmar H. Pinkhardt; Albert C. Ludolph; Hans Peter Müller; Jan Kassubek In: Journal of Neurology, vol. 264, no. 9, pp. 1919–1928, 2017. @article{Gorges2017, Characteristic alterations of eye movement control are a common feature of neurodegenerative parkinsonism, including Parkinson's disease (PD), progressive supranuclear palsy (PSP), and multiple system atrophy (MSA). Regional microstructural alterations as assessed by diffusion tensor imaging (DTI) have been reported in PD, PSP, and MSA. Therefore, we investigated the specific association between eye movement disturbances and microstructural impairment in these diseases. Video-oculographic recordings of smooth pursuit and visually guided reactive saccades as well as fractional anisotropy (FA) maps computed from whole-brain DTI data were analyzed for 36 PD, 30 PSP, 18 MSA patients, and 23 matched healthy control subjects. In PSP, peak eye velocity was pathologically slowed compared to controls (p < 0.001) and correlated significantly with microstructural impairment in the midbrain (p < 0.001, corrected). Smooth pursuit eye movements were substantially disturbed in MSA mainly by characteristic 'catch-up' saccades resulting in significantly reduced pursuit gain (p < 0.001, corrected), and the shape of saccadized pursuit in MSA was significantly correlated with FA reductions in the middle cerebral peduncle (p < 0.001, FDR corrected). The prevalence of saccadic intrusions as a measure for inhibitory control was significantly increased in PD compared with controls (p < 0.001), but was uncorrelated with FA in cortical and subcortical white matter. Eye movement disturbances in PSP and MSA-but not in PD-are associated with diagnosis-specific regional microstructural alterations in the white matter. The non-invasive quantified oculomotor function analysis can give clues to the underlying structural connectivity network pathology and underpins its role as a technical marker in PSP and MSA. |
Frédéric Gosselin; Simon Faghel-Soubeyrand Stationary objects flashed periodically appear to move during smooth pursuit eye movement Journal Article In: Perception, vol. 46, no. 7, pp. 874–881, 2017. @article{Gosselin2017, We discovered that a white disc flashed twice at the same location appears to move during smooth pursuit eye tracking in the direction opposite to that of the eye movement. We called this novel phenomenon movement-induced apparent motion (MIAM). Using the method of constant stimuli, we measured the required displacement of the second appearance of the disc in the pursuit direction to null the effect during the closed-loop stage of smooth pursuit eye tracking. We observed a strong linear relationship between the points of subjective stationarity and the inter-stimuli intervals for four smooth pursuit eye movement speeds. The slopes and y-intercepts of these linear fits were well predicted by the hypothesis according to which subjects saw illusory motion from the first to the second retinal projections of the flashed disc during smooth pursuit eye movement, with no extra-retinal signal compensation. |
Harold H. Greene; James M. Brown Where did I come from? Where am I going? Functional differences in visual search fixation duration Journal Article In: Journal of Eye Movement Research, vol. 10, no. 1, pp. 1–13, 2017. @article{Greene2017, Real time simulation of visual search behavior can occur only if the control of fixation du- rations is sufficiently understood. Visual search studies have typically confounded pre- and post-saccadic influences on fixation duration. In the present study, pre- and post-saccadic influences on fixation durations were compared by considering saccade direction. Novel use of a gaze-contingent moving obstructer paradigm also addressed relative contributions of both influences to total fixation duration. As a function of saccade direction, pre-saccadic fixation durations exhibited a different pattern from post-saccadic fixation durations. Post- saccadic fixations were also more strongly influenced by peripheral obstruction than pre- saccadic fixation durations. This suggests that post-saccadic influences may contribute more to fixation durations than pre-saccadic influences. Together, the results demonstrate that it is insufficient to model the control of visual search fixation durations without consideration of pre- and post-saccadic influences. |
John A. Greenwood; Martin Szinte; Bilge Sayim; Patrick Cavanagh Variations in crowding, saccadic precision, and spatial localization reveal the shared topology of spatial vision Journal Article In: Proceedings of the National Academy of Sciences, vol. 114, no. 17, pp. E3573–E3582, 2017. @article{Greenwood2017, Visual sensitivity varies across the visual field in several characteristic ways. For example, sensitivity declines sharply in peripheral (vs. foveal) vision and is typically worse in the upper (vs. lower) visual field. These variations can affect processes ranging from acuity and crowding (the deleterious effect of clutter on object recognition) to the precision of saccadic eye movements. Here we examine whether these variations can be attributed to a common source within the visual system. We first compared the size of crowding zones with the precision of saccades using an oriented clock target and two adjacent flanker elements. We report that both saccade precision and crowded-target reports vary idiosyncratically across the visual field with a strong correlation across tasks for all participants. Nevertheless, both group-level and trial-by-trial analyses reveal dissociations that exclude a common representation for the two processes. We therefore compared crowding with two measures of spatial localization: Landolt-C gap resolution and three-dot bisection. Here we observe similar idiosyncratic variations with strong interparticipant correlations across tasks despite considerably finer precision. Hierarchical regression analyses further show that variations in spatial precision account for much of the variation in crowding, including the correlation between crowding and saccades. Altogether, we demonstrate that crowding, spatial localization, and saccadic precision show clear dissociations, indicative of independent spatial representations, whilst nonetheless sharing idiosyncratic variations in spatial topology. We propose that these topological idiosyncrasies are established early in the visual system and inherited throughout later stages to affect a range of higher-level representations. |
Svenja Gremmler; Markus Lappe Saccadic suppression during voluntary versus reactive saccades Journal Article In: Journal of Vision, vol. 17, no. 8, pp. 1–10, 2017. @article{Gremmler2017, Saccades are fast eye movements that reorient gaze. They can be performed voluntarily-for example, when viewing a scene-but they can also be triggered in reaction to suddenly appearing targets. The generation of these voluntary and reactive saccades have been shown to involve partially different cortical pathways. However, saccades of either type confront the visual system with a major challenge from massive image motion on the retina. Despite the fact that the whole scene is swept across the retina, a saccade usually does not elicit a percept of motion. This saccadic omission has been linked to a transient decrease of visual sensitivity during the eye movement, a phenomenon called saccadic suppression. A passive origin of saccadic suppression based on temporal masking has been proposed as well as an active central process that inhibits visual processing during the saccade. The latter one would need to include an extraretinal signal, which is generated already during saccade preparation. Since saccade generation differs for voluntary and reactive saccades, timing and nature of this extraretinal signal as well as its impact on visual sensitivity might also differ. We measured detection thresholds for luminance stimuli that were flashed during voluntary and reactive saccades and during fixation. Detection thresholds were higher during voluntary than during reactive saccades such that suppression appeared stronger during voluntary saccades. Stronger suppression in voluntary saccades could arise from a stronger extraretinal signal that activates suppression or could indicate that a suppression underlying process itself partially differs between voluntary and reactive saccades. |
Joseph C. Griffis; Abdurahman S. Elkhetali; Wesley K. Burge; Richard H. Chen; Anthony D. Bowman; Jerzy P. Szaflarski; Kristina M. Visscher Retinotopic patterns of functional connectivity between V1 and large-scale brain networks during resting fixation Journal Article In: NeuroImage, vol. 146, pp. 1071–1083, 2017. @article{Griffis2017, Psychophysical and neurobiological evidence suggests that central and peripheral vision are specialized for different functions. This specialization of function might be expected to lead to differences in the large-scale functional interactions of early cortical areas that represent central and peripheral visual space. Here, we characterize differences in whole-brain functional connectivity among sectors in primary visual cortex (V1) corresponding to central, near-peripheral, and far-peripheral vision during resting fixation. Importantly, our analyses reveal that eccentricity sectors in V1 have different functional connectivity with non-visual areas associated with large-scale brain networks. Regions associated with the fronto-parietal control network are most strongly connected with central sectors of V1, regions associated with the cingulo-opercular control network are most strongly connected with near-peripheral sectors of V1, and regions associated with the default mode and auditory networks are most strongly connected with far-peripheral sectors of V1. Additional analyses suggest that similar patterns are present during eyes-closed rest. These results suggest that different types of visual information may be prioritized by large-scale brain networks with distinct functional profiles, and provide insights into how the small-scale functional specialization within early visual regions such as V1 relates to the large-scale organization of functionally distinct whole-brain networks. |
Elise Grison; Valérie Gyselinck; Jean Marie Burkhardt; Jan M. Wiener Route planning with transportation network maps: An eye-tracking study Journal Article In: Psychological Research, vol. 81, no. 5, pp. 1020–1034, 2017. @article{Grison2017, Planning routes using transportation network maps is a common task that has received little attention in the literature. Here, we present a novel eye-tracking paradigm to investigate psychological processes and mechanisms involved in such a route planning. In the experiment, participants were first presented with an origin and destination pair before we presented them with fictitious public transportation maps. Their task was to find the connecting route that required the minimum number of transfers. Based on participants' gaze behaviour, each trial was split into two phases: (1) the search for origin and destination phase, i.e., the initial phase of the trial until participants gazed at both origin and destination at least once and (2) the route planning and selection phase. Comparisons of other eye-tracking measures between these phases and the time to complete them, which depended on the complexity of the planning task, suggest that these two phases are indeed distinct and supported by different cognitive processes. For example, participants spent more time attending the centre of the map during the initial search phase, before directing their attention to connecting stations, where transitions between lines were possible. Our results provide novel insights into the psychological processes involved in route planning from maps. The findings are discussed in relation to the current theories of route planning. |
Axel Grzymisch; Cathleen Grimsen; Udo A. Ernst Contour integration in dynamic scenes: Impaired detection performance in extended presentations Journal Article In: Frontiers in Psychology, vol. 8, pp. 1501, 2017. @article{Grzymisch2017, Since scenes in nature are highly dynamic, perception requires an on-going and robust 5 integration of local information into global representations. In vision, contour integration (CI) 6 is one of these tasks, and it is performed by our brain in a seemingly effortless manner. 7 Following the rule of good continuation, oriented line segments are linked into contour percepts, 8 thus supporting important visual computations such as the detection of object boundaries. 9 This process has been studied almost exclusively using static stimuli, raising the question of 10 whether the observed robustness and “pop-out” quality of CI carries over to dynamic scenes. 11 We investigate contour detection in dynamic stimuli where targets appear at random times by 12 Gabor elements aligning themselves to form contours. In briefly presented displays (230ms), 13 a situation comparable to classical paradigms in CI, performance is about 87%. Surprisingly, 14 we find that detection performance decreases to 67% in extended presentations (about 1.9- 15 3.8s) for the same target stimuli. In order to observe the same reduction with briefly presented 16 stimuli, presentation time has to be drastically decreased to intervals as short as 50ms. Cueing a 17 specific contour position or shape helps in partially compensating this deterioration, and only in 18 extended presentations combining a location and a shape cue was more efficient than providing 19 a single cue. Our findings challenge the notion of CI as a mainly stimulus-driven process leading 20 to pop-out percepts, indicating that top-down processes play a much larger role in supporting 21 fundamental integration processes in dynamic scenes than previously thought. |
Marc Guasch; Pilar Ferré; Juan Haro Pupil dilation is sensitive to the cognate status of words: Further evidence for non-selectivity in bilingual lexical access Journal Article In: Bilingualism: Language and Cognition, vol. 20, no. 1, pp. 49–54, 2017. @article{Guasch2017, The cognate facilitation effect (i.e., a processing advantage for cognates compared to non-cognates) is an evidence of language non-selectivity in bilingual lexical access. Several studies using behavioral or electrophysiological measures have demonstrated that this effect is modulated by the degree of formal overlap between translations. However, it has never been tested with a psychophysiological measure such as pupillometry. In the present study we replicate the cognate facilitation effect by examining reaction times and pupil responses. Our results endorse pupillometry as a promising tool for bilingual research, and confirm the modulation of the cognate effect by the degree of formal similarity. |
Marc Galanter; Zoran Josipovic; Helen Dermatis; Jochen Weber; Mary Alice Millard An initial fMRI study on neural correlates of prayer in members of Alcoholics Anonymous Journal Article In: American Journal of Drug and Alcohol Abuse, vol. 43, no. 1, pp. 44–54, 2017. @article{Galanter2017, Background: Many individuals with alcohol-use disorders who had experienced alcohol craving before joining Alcoholics Anonymous (AA) report little or no craving after becoming long-term members. Their use of AA prayers may contribute to this. Neural mechanisms underlying this process have not been delineated. Objective: To define experiential and neural correlates of diminished alcohol craving followingAA prayers amongmembers with long-termabstinence. Methods: Twenty AAmembers with long-term abstinence participated. Self-report measures and functional magnetic resonance imaging of differential neural response to alcohol-craving-inducing images were obtained in three conditions: after reading of AA prayers, after reading irrelevant news, and with passive viewing. Random-effects robust regressions were computed for the main effect (prayer > passive + news) and for estimating the correlations between themain effect and the self-report measures. Results: Compared to the other two conditions, the prayer condition was characterized by: less self-reported craving; increased activation in left-anterior middle frontal gyrus, left superior parietal lobule, bilateral precuneus, and bilateral posterior middle temporal gyrus. Craving following prayer was inversely correlated with activation in brain areas associated with self-referential processing and the default mode network, and with characteristics reflecting AA program involvement. Conclusion:AA members' prayer was asso- ciated with a relative reduction in self-reported craving and with concomitant engagement of neural mechanisms that reflect control of attention and emotion. These findings suggest neural processes underlying the apparent effectiveness of AA prayer. |
Christine M. Gamble; Joo-Hyun Song Dynamic modulation of illusory and physical target size on separate and coordinated eye and hand movements Journal Article In: Journal of Vision, vol. 17, no. 3, pp. 1–23, 2017. @article{Gamble2017, In everyday behavior, two of the most common visually guided actions-eye and hand movements-can be performed independently, but are often synergistically coupled. In this study, we examine whether the same visual representation is used for different stages of saccades and pointing, namely movement preparation and execution, and whether this usage is consistent between independent and naturalistic coordinated eye and hand movements. To address these questions, we used the Ponzo illusion to dissociate the perceived and physical sizes of visual targets and measured the effects on movement preparation and execution for independent and coordinated saccades and pointing. During independent movements, we demonstrated that both physically and perceptually larger targets produced faster preparation for both effectors. Furthermore, participants who showed a greater influence of the illusion on saccade preparation also showed a greater influence on pointing preparation, suggesting that a shared mechanism involved in preparation across effectors is influenced by illusions. However, only physical but not perceptual target sizes influenced saccade and pointing execution. When pointing was coordinated with saccades, we observed different dynamics: pointing no longer showed modulation from illusory size, while saccades showed illusion modulation for both preparation and execution. Interestingly, in independent and coordinated movements, the illusion modulated saccade preparation more than pointing preparation, with this effect more pronounced during coordination. These results suggest a shared mechanism, dominated by the eyes, may underlie visually guided action preparation across effectors. Furthermore, the influence of illusions on action may operate within such a mechanism, leading to dynamic interactions between action modalities based on task demands. |
Matthew A. Gannon; Stephanie M. Long; Nathan A. Parks Homeostatic plasticity in human extrastriate cortex following a simulated peripheral scotoma Journal Article In: Experimental Brain Research, vol. 235, no. 11, pp. 3391–3401, 2017. @article{Gannon2017, Neuroimaging and patient work over the past decade have indicated that, following retinal deafferenta- tion, the human visual cortex undergoes a large-scale and enduring reorganization of its topography such that the clas- sical retinotopic organization of deafferented visual cortex remaps to represent non-classical regions of visual space. Such long-term visual reorganization is proposed to occur through changes in the functional balance of deafferented visual circuits that engage more lasting changes through activity-dependent neuroplasticity. Here, we investigated the short-term changes in functional balance (short-term plastic- ity; homeostatic plasticity) that occur within deafferented human visual cortices. We recorded electroencephalogram (EEG) while observers were conditioned for 6 s with a simu- lated retinal scotoma (artificial scotoma) positioned 8.0° in the periphery. Visual evoked potentials (VEPs) evoked by the onset of sinusoidal visual probes that varied in their tilt were used to examine changes in cortical excitability within and around cortical representations of the simulated sco- toma. Psychophysical orientation functions obtained from discrimination of visual probe tilt were used to examine alterations in the stimulus selectivity within the scotoma representations. Consistent with a mechanism of homeo- static disinhibition, an early extrastriate component of the VEP (the early phase P1) exhibited increased amplitude fol- lowing the condition with a simulated scotoma relative to a stimulus-matched control condition. This increased visual cortical response was associated with a reduction in the slope of the psychophysical orientation function, suggesting a broader tuning of neural populations within scotoma repre- sentations. Together, these findings support a mechanism of disinhibition in promoting visual plasticity and topographi- cal reorganization. |
Lesya Y. Ganushchak; Agnieszka E. Konopka; Yiya Chen Accessibility of referent information influences sentence planning: An eye-tracking study Journal Article In: Frontiers in Psychology, vol. 8, pp. 250, 2017. @article{Ganushchak2017, This study investigated the time-course of online sentence formulation (i.e., incrementality in sentence planning) as a function of the preceding discourse context. In two eye-tracking experiments, participants described pictures of transitive events (e.g., a frog catching a fly). The accessibility of the agent (Experiment 1) and patient (Experiment 2) was manipulated in the discourse preceding each picture. In the Literal condition, participants heard a story where the agent or patient was mentioned explicitly (fly, frog). In the Associative condition, the agent or patient was not mentioned but was primed by the story (via semantically or associatively related words such as insect, small, black, wings). In the No Mention condition, the stories did not explicitly mention or prime either character. The target response was expected to have the same structure and content in all conditions (SVO sentences: The frog catches the fly). The results showed that participants generally looked first at the agent, before speech onset, regardless of condition, and then at the patient around and after speech onset. Analyses of eye movements in time window associated with linguistic planning showed that formulation was sensitive mainly to whether the agent was literally mentioned in the context or not and to lesser extent to conceptual accessibility (Experiment 1). Furthermore, accessibility of the patient (be it literal mention of its name or only availability of the concept) showed no effect on the time-course of utterance planning (Experiment 2). Together, these results suggest that linguistic planning before speech onset was influenced only by the accessibility of the first character name in the sentence, providing further evidence for highly incremental planning in sentence production. |
Ying Gao; Bernhard A. Sabel Microsaccade dysfunction and adaptation in hemianopia after stroke Journal Article In: Restorative Neurology and Neuroscience, vol. 35, no. 4, pp. 365–376, 2017. @article{Gao2017, Background: Besides the reduction of visual field size, hemianopic patients may also experience other poorly understood symptoms such as blurred vision, diplopia, or reduced visual acuity, which may be related to microsaccade function. Objective: To determine (i) if microsaccades are altered in hemianopia; (ii) how altered microsaccade features correlate with visual performances; and (iii) how their direction relates to visual field defect topography. Methods: In this case-control study, microsaccades ofhemianopic stroke patients (n = 14) were assessed with high-resolution eye-tracking technique, compared with those of healthy controls (n = 14), and correlated with visual performances, visual field defect parameters and lesion age. Results: Patients' microsaccades had (i) larger amplitude (P= 0.027), (ii) longer duration (P= 0.042), and (iii) impaired binocular microsaccade conjugacy (horizontal: P= 0.002; vertical: P= 0.035). Older lesions were associated with poorer binocular conjugacy (horizontal: r(14) = 0.67 |
David Garcia-Burgos; Junpeng Lao; Simone Munsch; Roberto Caldara Visual attention to food cues is differentially modulated by gustatory-hedonic and post-ingestive attributes Journal Article In: Food Research International, vol. 97, pp. 199–208, 2017. @article{GarciaBurgos2017, Although attentional biases towards food cues may play a critical role in food choices and eating behaviours, it remains largely unexplored which specific food attribute governs visual attentional deployment. The allocation of visual attention might be modulated by anticipatory postingestive consequences, from taste sensations derived from eating itself, or both. Therefore, in order to obtain a comprehensive understanding of the attentional mechanisms involved in the processing of food-related cues, we recorded the eye movements to five categories of well-standardised pictures: neutral non-food, high-calorie, good taste, distaste and dangerous food. In particular, forty-four healthy adults of both sexes were assessed with an antisaccade paradigm (which requires the generation of a voluntary saccade and the suppression of a reflex one) and a free viewing paradigm (which implies the free visual exploration of two images). The results showed that observers directed their initial fixations more often and faster on items with high survival relevance such as nutrient and possible dangers; although an increase in antisaccade error rates was only detected for high-calorie items. We also found longer prosaccade fixation duration and initial fixation duration bias score related to maintained attention towards high-calorie, good taste and danger categories; while shorter reaction times to correct an incorrect prosaccade related to less difficulties in inhibiting distasteful images. Altogether, these findings suggest that visual attention is differentially modulated by both the accepted and rejected food attributes, but also that normal-weight, non-eating disordered individuals exhibit enhanced approach to food's postingestive effects and avoidance of distasteful items (such as bitter vegetables or pungent products). |
Ray Garza; Roberto R. Heredia; Anna B. Cieślicka An eye tracking examination of men's attractiveness by conceptive risk women Journal Article In: Evolutionary Psychology, vol. 15, no. 1, pp. 1–11, 2017. @article{Garza2017, Previous research has indicated that women prefer men who exhibit an android physical appearance where fat distribution is deposited on the upper body (i.e., shoulders and arms) and abdomen. This ideal physical shape has been associated with perceived dominance, health, and immunocompetence. Although research has investigated attractability of men with these ideal characteristics, research on how women visually perceive these characteristics is limited. The current study investigated visual perception and attraction toward men in Hispanic women of Mexican American descent. Women exposed to a front-posed image, where the waist-to-chest ratio (WCR) and hair distribution were manipulated, rated men's body image associated with upper body strength (low WCR 0.7) as more attractive. Additionally, conceptive risk did not play a strong role in attractiveness and visual attention. Hair distribution did not contribute to increased ratings of attraction but did contribute to visual attraction when measuring total time where men with both facial and body hair were viewed longer. These findings suggest that physical characteristics in men exhibiting upper body strength and dominance are strong predictors of visual attraction. |
Nicholas Gaspelin; Carly J. Leonard; Steven J. Luck Suppression of overt attentional capture by salient-but-irrelevant color singletons Journal Article In: Attention, Perception, and Psychophysics, vol. 79, no. 1, pp. 45–62, 2017. @article{Gaspelin2017, For more than 2 decades, researchers have debated the nature ofcognitive control in the guidance ofvisual atten- tion. Stimulus-driven theories claim that salient stimuli auto- matically capture attention, whereas goal-driven theories pro- pose that an individual's attentional control settings determine whether salient stimuli capture attention. In the current study, we tested a hybrid account called the signal suppression hy- pothesis, which claims that all stimuli automatically generate a salience signal but that this signal can be actively suppressed by top-down attentional mechanisms. Previous behavioral and electrophysiological research has shown that participants can suppress covert shifts ofattention to salient-but-irrelevant col- or singletons. In this study, we used eye-tracking methods to determine whether participants can also suppress overt shifts ofattention to irrelevant singletons. We found that under con- ditions that promote active suppression of the irrelevant sin- gletons, overt attention was less likely to be directed toward the salient distractors than toward nonsalient distractors. This result provides direct evidence that people can suppress salient-but-irrelevant singletons below baseline levels. |
Nigel Gebodh; M. Isabel Vanegas; Simon P. Kelly Effects of stimulus size and contrast on the initial primary visual cortical response in humans Journal Article In: Brain Topography, vol. 30, no. 4, pp. 450–460, 2017. @article{Gebodh2017, Decades of intracranial electrophysiological investigation into the primary visual cortex (V1) have produced many fundamental insights into the computations carried out in low-level visual circuits of the brain. Some of the most important work has been simply concerned with the precise measurement of neural response variations as a function of elementary stimulus attributes such as contrast and size. Surprisingly, such simple but fundamental characterization of V1 responses has not been carried out in human electrophysiology. Here we report such a detailed characterization for the initial “C1” component of the scalp-recorded visual evoked potential (VEP). The C1 is known to be dominantly generated by initial afferent activation in V1, but is difficult to record reliably due to interindividual anatomical variability. We used pattern-pulse multifocal VEP mapping to identify a stimulus position that activates the left lower calcarine bank in each individual, and afterwards measured robust negative C1s over posterior midline scalp to gratings presented sequentially at that location. We found clear and systematic increases in C1 peak amplitude and decreases in peak latency with increasing size as well as with increasing contrast. With a sample of 15 subjects and ~180 trials per condition, reliable C1 amplitudes of −0.46 µV were evoked at as low a contrast as 3.13% and as large as −4.82 µV at 100% contrast, using stimuli of 3.33° diameter. A practical implication is that by placing sufficiently-sized stimuli to target favorable calcarine cortical loci, robust V1 responses can be measured at contrasts close to perceptual thresholds, which could greatly facilitate principled studies of early visual perception and attention. |
Alexander Geiger; Eva Niessen; Gary Bente; Kai Vogeley Eyes versus hands: How perceived stimuli influence motor actions Journal Article In: PLoS ONE, vol. 12, no. 7, pp. e0180780, 2017. @article{Geiger2017, Many studies showed that biological (e.g., gaze-shifts or hand movements) and non-biological stimuli (e.g., arrows or moving points) redirect attention. Biological stimuli seem to be more suitable than non-biological to perform this task. However, the question remains if biological stimuli do have different influences on redirecting attention and if this property is dependent on how we react to those stimuli. In two separate experiments, participants interact either with a biological or a non-biological stimulus (experiment 1), or with two biological stimuli (gaze-shifts, hand movements)(experiment 2) to which they responded with two different actions (saccade, button press), either in a congruent or incongruent manner. Results from experiment 1 suggest that interacting with the biological stimulus lead to faster responses, compared to the non-biological stimulus, independent of the response type. Results from experiment 2 show longer reaction times when the depicted stimulus was not matching the response type (e.g., reacting with hand movements to a moving object or gaze-shift) compared to a matching condition, while especially the gaze-following condition (reacting with a gaze shift to a perceived gaze shift) led to the fastest responses. These results suggest that redirecting attention is not only dependent on the perceived stimulus but also on the way how those stimuli are responded to. |
Joy J. Geng; N. E. Di Quattro; Jonathan Helm Distractor probability changes the shape of the attentional template Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 43, no. 12, pp. 1993–2007, 2017. @article{Geng2017, Theories of attention commonly refer to the “attentional template” as the collection of features in working memory that represent the target of visual search. Many models of attention assume that the template contains a veridical representation of target features, but recent studies have shown that the target representation is “shifted” away from distractor features in order to optimize their distinctiveness and facilitate visual search. Here, we manipulated the probability of target-similar distractors during a visual search task in 2 groups, and separately measured the contents of the attentional template. We hypothesized that having a high probability of target-similar distractors would increase pressure to shift and/or sharpen the target representation in order to increase the distinctiveness of targets from distractors. We found that the high-similarity group experienced less distractor interference during visual search, but only for highly target-similar distractors. Additionally, while both groups shifted the target representation away from the actual target color, the high-similarity group also had a sharper representation of the target color. We conclude that the contents of the attentional template in working memory can be flexibly adjusted with multiple mechanisms to increase target-to-distractor distinctiveness and optimize attentional selection. |
Edden M. Gerber; Tal Golan; Robert T. Knight; Leon Y. Deouell Cortical representation of persistent visual stimuli Journal Article In: NeuroImage, vol. 161, pp. 67–79, 2017. @article{Gerber2017, Research into visual neural activity has focused almost exclusively on onset- or change-driven responses and little is known about how information is encoded in the brain during sustained periods of visual perception. We used intracranial recordings in humans to determine the degree to which the presence of a visual stimulus is persistently encoded by neural activity. The correspondence between stimulus duration and neural response duration was strongest in early visual cortex and gradually diminished along the visual hierarchy, such that is was weakest in inferior-temporal category-selective regions. A similar posterior-anterior gradient was found within inferior temporal face-selective regions, with posterior but not anterior sites showing persistent face-selective activity. The results suggest that regions that appear uniform in terms of their category selectivity are dissociated by how they temporally represent a stimulus in support of ongoing visual perception, and delineate a large-scale organizing principle of the ventral visual stream. |
Tobias Gerstenberg; Matthew F. Peterson; Noah D. Goodman; David A. Lagnado; Joshua B. Tenenbaum Eye-tracking causality Journal Article In: Psychological Science, vol. 28, no. 12, pp. 1731–1744, 2017. @article{Gerstenberg2017, How do people make causal judgments? What role, if any, does counterfactual simulation play? Counterfactual theories of causal judgments predict that people compare what actually happened with what would have happened if the candidate cause had been absent. Process theories predict that people focus only on what actually happened, to assess the mechanism linking candidate cause and outcome. We tracked participants' eye movements while they judged whether one billiard ball caused another one to go through a gate or prevented it from going through. Both participants' looking patterns and their judgments demonstrated that counterfactual simulation played a critical role. Participants simulated where the target ball would have gone if the candidate cause had been removed from the scene. The more certain participants were that the outcome would have been different, the stronger the causal judgments. These results provide the first direct evidence for spontaneous counterfactual simulation in an important domain of high-level cognition. |