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 |
Nan Jia; Scott L. Brincat; Andrés F. Salazar-Gómez; Mikhail Panko; Frank H. Guenther; Earl K. Miller Decoding of intended saccade direction in an oculomotor brain-computer interface Journal Article In: Journal of Neural Engineering, vol. 14, no. 4, pp. 1–13, 2017. @article{Jia2017a, OBJECTIVE: To date, invasive brain-computer interface (BCI) research has largely focused on replacing lost limb functions using signals from of hand/arm areas of motor cortex. However, the oculomotor system may be better suited to BCI applications involving rapid serial selection from spatial targets, such as choosing from a set of possible words displayed on a computer screen in an augmentative and alternative communication (AAC) application. Here we aimed to demonstrate the feasibility of a BCI utilizing the oculomotor system. APPROACH: We developed a chronic intracortical BCI in monkeys to decode intended saccadic eye movement direction using activity from multiple frontal cortical areas. MAIN RESULTS: Intended saccade direction could be decoded in real time with high accuracy, particularly at contralateral locations. Accurate decoding was evident even at the beginning of the BCI session; no extensive BCI experience was necessary. High-frequency (80-500 Hz) local field potential magnitude provided the best performance, even over spiking activity, thus simplifying future BCI applications. Most of the information came from the frontal and supplementary eye fields, with relatively little contribution from dorsolateral prefrontal cortex. SIGNIFICANCE: Our results support the feasibility of high-accuracy intracortical oculomotor BCIs that require little or no practice to operate and may be ideally suited for 'point and click' computer operation as used in most current AAC systems. |
Yuncheng Jia; Gang Cheng; Dajun Zhang; Na Ta; Mu Xia; Fangyuan Ding Attachment avoidance is significantly related to attentional preference for infant faces: Evidence from eye movement data Journal Article In: Frontiers in Psychology, vol. 8, pp. 85, 2017. @article{Jia2017, Objective: To determine the influence of adult attachment orientations on infant preference. Methods: We adopted eye-tracking technology to monitor childless college women's eye movements when looking at pairs of faces, including one adult face (man or woman) and one infant face, with three different expressions (happy, sadness, and neutral). The participants (N = 150; 84% Han ethnicity) were aged 18–29 years (M = 19.22 |
Yu-Cin Jian Eye-movement patterns and reader characteristics of students with good and poor performance when reading scientific text with diagrams Journal Article In: Reading and Writing, vol. 30, no. 7, pp. 1447–1472, 2017. @article{Jian2017a, This study investigated the cognitive processes and reader characteristics of sixth graders who had good and poor performance when reading scientific text with diagrams. We first measured the reading ability and reading self-efficacy of sixth-grade participants, and then recorded their eye movements while they were reading an illustrated scientific text and scored their answers to content-related questions. Finally, the participants evaluated the difficulty of the article, the attractiveness of the content and diagram, and their learning performance. The participants were then classified into groups based on how many correct responses they gave to questions related to reading. The results showed that readers with good performance had better character recognition ability and reading self-efficacy, were more attracted to the diagrams, and had higher self-evaluated learning levels than the readers with poor performance did. Eye-movement data indicated that readers with good performance spent significantly more reading time on the whole article, the text section, and the diagram section than the readers with poor performance did. Interestingly, readers with good performance had significantly longer mean fixation duration on the diagrams than readers with poor performance did; further, readers with good performance made more saccades between the text and the diagrams. Additionally, sequential analysis of eye movements showed that readers with good performance preferred to observe the diagram rather than the text after reading the title, but this tendency was not present in readers with poor performance. In sum, using eye-tracking technology and several reading tests and questionnaires, we found that various cognitive aspects (reading strategy, diagram utilization) and affective aspects (reading self-efficacy, article likeness, diagram attraction, and self-evaluation of learning) affected sixth graders' reading performance in this study. |
Yu-Cin Jian; Hwa-Wei Ko Influences of text difficulty and reading ability on learning illustrated science texts for children: An eye movement study Journal Article In: Computers and Education, vol. 113, pp. 263–279, 2017. @article{Jian2017, In this study, eye movement recordings and comprehension tests were used to investigate children's cognitive processes and comprehension when reading illustrated science texts. Ten-year-old children (N = 42) who were beginning to read to learn, with high and low reading ability read two illustrated science texts in Chinese (one medium-difficult article, one difficult article), and then answered questions that measured comprehension of textual and pictorial information as well as text-and-picture integration. The high-ability group outperformed the low-ability group on all questions. Eye movement analyses showed that both group of students spent roughly the same amount of time reading both articles, but had different methods of reading them. The low-ability group was inclined to read what seemed easier to them and read the text more. The high-ability group attended more to the difficult article and made an effort to integrate the textual and pictorial information. During a first-pass reading of the difficult article, high- but not low-ability readers returned to the previous paragraph. The low-ability readers spent more time reading the less difficult article and not the difficult one that required teachers' attention. Suggestions for classroom instruction are proposed accordingly. |
Elizabeth K. Johnson; Henry W. Fields; F. Michael Beck; Allen R. Firestone; Stephen F. Rosenstiel In: American Journal of Orthodontics and Dentofacial Orthopedics, vol. 151, no. 2, pp. 297–310, 2017. @article{Johnson2017, Introduction: Previous eye-tracking research has demonstrated that laypersons view the range of dental attractiveness levels differently depending on facial attractiveness levels. How the borderline levels of dental attractiveness are viewed has not been evaluated in the context of facial attractiveness and compared with those with near-ideal esthetics or those in definite need of orthodontic treatment according to the Aesthetic Component of the Index of Orthodontic Treatment Need scale. Our objective was to determine the level of viewers' visual attention in its treatment need categories levels 3 to 7 for persons considered “attractive,” “average,” or “unattractive.” Methods: Facial images of persons at 3 facial attractiveness levels were combined with 5 levels of dental attractiveness (dentitions representing Aesthetic Component of the Index of Orthodontic Treatment Need levels 3-7) using imaging software to form 15 composite images. Each image was viewed twice by 66 lay participants using eye tracking. Both the fixation density (number of fixations per facial area) and the fixation duration (length of time for each facial area) were quantified for each image viewed. Repeated-measures analysis of variance was used to determine how fixation density and duration varied among the 6 facial interest areas (chin, ear, eye, mouth, nose, and other). Results: Viewers demonstrated excellent to good reliability among the 6 interest areas (intraviewer reliability, 0.70-0.96; interviewer reliability, 0.56-0.93). Between Aesthetic Component of the Index of Orthodontic Treatment Need levels 3 and 7, viewers of all facial attractiveness levels showed an increase in attention to the mouth. However, only with the attractive models were significant differences in fixation density and duration found between borderline levels with female viewers. Female viewers paid attention to different areas of the face than did male viewers. Conclusions: The importance of dental attractiveness is amplified in facially attractive female models compared with average and unattractive female models between near-ideal and borderline-severe dentally unattractive levels. |
Elizabeth L. Johnson; Callum D. Dewar; Anne Kristin Solbakk; Tor Endestad; Torstein R. Meling; Robert T. Knight Bidirectional frontoparietal oscillatory systems support working memory Journal Article In: Current Biology, vol. 27, no. 12, pp. 1829–1835, 2017. @article{Johnson2017a, The ability to represent and select information in working memory provides the neurobiological infrastructure for human cognition. For 80 years, dominant views of working memory have focused on the key role of prefrontal cortex (PFC) [1–8]. However, more recent work has implicated posterior cortical regions [9–12], suggesting that PFC engagement during working memory is dependent on the degree of executive demand. We provide evidence from neurological patients with discrete PFC damage that challenges the dominant models attributing working memory to PFC-dependent systems. We show that neural oscillations, which provide a mechanism for PFC to communicate with posterior cortical regions [13], independently subserve communications both to and from PFC—uncovering parallel oscillatory mechanisms for working memory. Fourteen PFC patients and 20 healthy, age-matched controls performed a working memory task where they encoded, maintained, and actively processed information about pairs of common shapes. In controls, the electroencephalogram (EEG) exhibited oscillatory activity in the low-theta range over PFC and directional connectivity from PFC to parieto-occipital regions commensurate with executive processing demands. Concurrent alpha-beta oscillations were observed over parieto-occipital regions, with directional connectivity from parieto-occipital regions to PFC, regardless of processing demands. Accuracy, PFC low-theta activity, and PFC → parieto-occipital connectivity were attenuated in patients, revealing a PFC-independent, alpha-beta system. The PFC patients still demonstrated task proficiency, which indicates that the posterior alpha-beta system provides sufficient resources for working memory. Taken together, our findings reveal neurologically dissociable PFC and parieto-occipital systems and suggest that parallel, bidirectional oscillatory systems form the basis of working memory. |
Kohitij Kar; Jacob Duijnhouwer; Bart Krekelberg Transcranial alternating current stimulation attenuates neuronal adaptation Journal Article In: Journal of Neuroscience, vol. 37, no. 9, pp. 2325–2335, 2017. @article{Kar2017, We previously showed that brief application of 2 mA (peak-to-peak) transcranial currents alternating at 10 Hz significantly reduces motion adaptation in humans. This is but one of many behavioral studies showing that weak currents applied to the scalp modulate neural processing. Transcranial stimulation has been shown to improve perception, learning, and a range of clinical symptoms. Few studies, however, have measured the neural consequences of transcranial current stimulation. We capitalized on the strong link between motion perception and neural activity in the middle temporal (MT) area of the macaque monkey to study the neural mechanisms that underlie the behavioral consequences of transcranial alternating current stimulation. First, we observed that 2 mA currents generated substantial intracranial fields, which were much stronger in the stimulated hemisphere (0.12 V/m) than on the opposite side of the brain (0.03 V/m). Second, we found that brief application of transcranial alternating current stimulation at 10 Hz reduced spike-frequency adaptation of MT neurons and led to a broadband increase in the power spectrum of local field potentials. Together, these findings provide a direct demonstration that weak electric fields applied to the scalp significantly affect neural processing in the primate brain and that this includes a hitherto unknown mechanism that attenuates sensory adaptation. |
Maryam Kavyani; Alireza Farsi; Behrouz Abdoli; Raymond M. Klein Using the locus-of-slack logic to determine whether inhibition of return in a cue-target paradigm is delaying early or late stages of processing Journal Article In: Canadian Journal of Experimental Psychology, vol. 71, no. 1, pp. 63–70, 2017. @article{Kavyani2017, Inhibition of return (IOR) is a phenomenon characterized by slower responses to targets at cued locations relative to those at uncued locations. Based on the results of previous research, it has been suggested that IOR affects a process at the input end of the processing continuum when it is generated while the reflexive oculomotor system is suppressed (cf. Satel, Hilchey, Wang, Story, & Klein, 2013). To test this theory, we employed a modified psychological refractory period paradigm designed to elicit input IOR with visual stimuli, allowing us to use the locus-of-slack logic to determine whether an early or late stage of processing was inhibited by IOR. On each trial a visual cue was presented, followed by an auditory target (T1) and visual target (T2) separated by a target–target onset asynchrony (TTOA) of varying lengths (200 ms, 400 ms, or 800 ms). Participants (31 young adults) were instructed to ignore the cue and respond to the targets as quickly and accurately as possible. Eye tracking was used to ensure that participants actively suppressed eye movements during trials. As predicted, the inhibitory effect of the cue was observed at the longest TTOA but not when TTOAs were short, supporting our hypothesis that, when generated while the reflexive oculomotor system is suppressed, IOR affects processing before response selection. |
Devin H. Kehoe; Mazyar Fallah Rapid accumulation of inhibition accounts for saccades curved away from distractors Journal Article In: Journal of Neurophysiology, vol. 118, no. 2, pp. 832–844, 2017. @article{Kehoe2017, Saccades curved toward a distractor are accompanied by a burst of neuronal activation at the distractor locus in the intermediate layers of the superior colliculus (SCi) ~30 ms before the initiation of a saccade. Although saccades curve away from inactivated SCi loci, whether inhibition is restricted to a similar critical epoch for saccades curved away from a distractor remains unclear. We examined this possibility by modeling human saccade curvature as a function of the time between onset of a task irrelevant luminance- or color-modulated distractor and initiation of an impending saccade, referred to as saccade distractor onset asynchrony (SDOA). Our results demonstrated that 70 ms of luminance-modulated distractor processing or 90 ms of color-modulated distractor processing was required to modulate saccade trajectories. As these behavioral, feature-based differences were temporally consistent with the cortically mediated neurophysiological differences in visual onset latencies between luminance and color stimuli observed in the oculomotor and visual system, this method provides a noninvasive means to estimate the timing of peak activation in the oculomotor system. As such, we modeled SDOA functions separately for saccades curved toward and away from distractors and observed that a similar temporal process determined the magnitude of saccade curvatures in both contexts, suggesting that saccades deviate away from a distractor due to a rapid accumulation of inhibition in the critical epoch before saccade initiation. |
Carmen Keller; Alex Junghans In: Medical Decision Making, vol. 37, no. 8, pp. 942–954, 2017. @article{Keller2017, Background. Individuals with low numeracy have difficulties with understanding complex graphs. Combining the information-processing approach to numeracy with graph comprehension and information-reduction theories, we examined whether high numerates' better comprehension might be explained by their closer attention to task-relevant graphical elements, from which they would expect numerical information to understand the graph. Furthermore, we investigated whether participants could be trained in improving their attention to task-relevant information and graph comprehension. Design. In an eye-tracker experiment (N = 110) involving a sample from the general population, we presented participants with 2 hypothetical scenarios (stomach cancer, leukemia) showing survival curves for 2 treatments. In the training condition, participants received written instructions on how to read the graph. In the control condition, participants received another text. We tracked participants' eye movements while they answered 9 knowledge questions. The sum constituted graph comprehension. We analyzed visual attention to task-relevant graphical elements by using relative fixation durations and relative fixation counts. Results. The mediation analysis revealed a significant (P < 0.05) indirect effect of numeracy on graph comprehension through visual attention to task-relevant information, which did not differ between the 2 conditions. Training had a significant main effect on visual attention (P < 0.05) but not on graph comprehension (P < 0.07). Conclusions. Individuals with high numeracy have better graph comprehension due to their greater attention to task-relevant graphical elements than individuals with low numeracy. With appropriate instructions, both groups can be trained to improve their graph-processing efficiency. Future research should examine (e.g., motivational) mediators between visual attention and graph comprehension to develop appropriate instructions that also result in higher graph comprehension. |
Claire L. Kelly; Trevor J. Crawford; Emma Gowen; Kelly Richardson; Sandra I. Sünram-Lea A temporary deficiency in self-control: Can heightened motivation overcome this effect? Journal Article In: Psychophysiology, vol. 54, no. 5, pp. 773–779, 2017. @article{Kelly2017a, Self-control is important for everyday life and involves behavioral regulation. Self-control requires effort, and when completing two successive self-control tasks, there is typically a temporary drop in performance in the second task. High self-reported motivation and being made self-aware somewhat counteract this effect-with the result that performance in the second task is enhanced. The current study explored the relationship between self-awareness and motivation on sequential self-control task performance. Before employing self-control in an antisaccade task, participants initially applied self-control in an incongruent Stroop task or completed a control task. After the Stroop task, participants unscrambled sentences that primed self-awareness (each started with the word 'I') or unscrambled neutral sentences. Motivation was measured after the antisaccade task. Findings revealed that, after exerting self-control in the incongruent Stroop task, motivation predicted erroneous responses in the antisaccade task for those that unscrambled neutral sentences, and high motivation led to fewer errors. Those primed with self-awareness were somewhat more motivated overall, but motivation did not significantly predict antisaccade performance. Supporting the resource allocation account, if one was motivated-intrinsically or via the manipulation of self-awareness-resources were allocated to both tasks leading to the successful completion of two sequential self-control tasks. |
Krista R. Kelly; Reed M. Jost; Angie De La Cruz; Lori Dao; Cynthia L. Beauchamp; David R. Stager; Eileen E. Birch Slow reading in children with anisometropic amblyopia is associated with fixation instability and increased saccades Journal Article In: Journal of AAPOS, vol. 21, no. 6, pp. 447–451, 2017. @article{Kelly2017, Background: Previous studies show slow reading in strabismic amblyopia. We recently identified amblyopia, not strabismus, as the key factor in slow reading in children. No studies have focused on reading in amblyopic children without strabismus. We examined reading in anisometropic children and evaluated whether slow reading was associated with ocular motor dysfunction in children with amblyopia. Methods: Anisometropic children (7-12 years) with or without amblyopia were compared to age-similar normal controls. Children silently read a grade-appropriate paragraph during binocular viewing. Reading rate (words/min), number of forward and regressive saccades (per 100 words) and fixation duration were recorded with the ReadAlyzer. Binocular fixation instability was also evaluated (EyeLink 1000). Results: Amblyopic anisometropic children read more slowly (n = 25; mean with standard deviation, 149 ± 42 words/min) than nonamblyopic anisometropic children (n = 15; 196 ± 80 words/min; P = 0.024) and controls (n = 25; 191 ± 65 words/min; P = 0.020). Nonamblyopic anisometropic children read at a comparable rate to controls (P = 0.81). Slow reading in amblyopic anisometropic children was correlated with increased forward saccades (r = −0.84, P < 0.001), increased regressive saccades (r = −0.85, P < 0.001), and fellow eye instability during binocular viewing (r = −0.52 |
Donatas Jonikaitis; Anna Klapetek; Heiner Deubel Spatial attention during saccade decisions Journal Article In: Journal of Neurophysiology, vol. 118, no. 1, pp. 149–160, 2017. @article{Jonikaitis2017, Behavioral measures of decision making are usually limited to observations of decision outcomes. In the present study, we made use of the fact that oculomotor and sensory selection are closely linked to track oculomotor decision making before oculomotor responses are made. We asked participants to make a saccadic eye movement to one of two memorized target locations and observed that visual sensitivity increased at both the chosen and the non-chosen saccade target locations, with a clear bias towards the chosen target. The time course of changes in visual sensitivity was related to saccadic latency, with the competition between the chosen and non-chosen targets resolved faster before short latency saccades. On error trials, we observed an increased competition between the chosen and non-chosen targets. Moreover, oculomotor selection and visual sensitivity were influenced by top-down and bottom-up factors as well as by selection history and predicted the direction of saccades. Our findings demonstrate that saccade decisions have direct visual consequences and show that decision making can be traced in the human oculomotor system well before choices are made. Our results also indicate a strong association between decision making, saccade target selection and visual sensitivity. |
Timothy R. Jordan; Victoria A. McGowan; Stoyan Kurtev; Kevin B. Paterson In: Frontiers in Psychology, vol. 8, pp. 807, 2017. @article{Jordan2017, Printed words are complex visual stimuli containing a range of different spatial frequencies, and several studies have suggested that various spatial frequencies are effective for skilled adult reading. But while it is well known that the area of text from which information is acquired during reading extends to the left and right of each fixation, the effectiveness of spatial frequencies falling each side of fixation has yet to be determined. To investigate this issue, we used a spatial frequency adaptation of the gaze-contingent moving-window paradigm in which sentences were shown to skilled adult readers either entirely as normal or filtered to contain only low, medium, or high spatial frequencies except for a window of normal text around each point of fixation. Windows replaced filtered text either symmetrically 1 character to the left and right of each fixated character, or asymmetrically, 1 character to the left and 7 or 13 to the right, or 1 character to the right and 7 or 13 to the left. Reading times and eye-movement measures showed that reading performance for sentences presented entirely as normal generally changed very little with filtered displays when windows extended to the right but was often disrupted when windows extended to the left. However, asymmetrical windows affected performance on both sides of fixation. Indeed, increasing the leftward extent of windows from 7 to 13 characters produced decreases in both reading times and fixation durations, suggesting that reading was influenced by the spatial frequency content of leftward areas of text some considerable distance from fixation. Overall, the findings show that while a range of different spatial frequencies can be used by skilled adult readers, the effectiveness of spatial frequencies differs for text on each side of central vision, and may reflect different roles played by these two areas of text during reading. |
Barbara J. Juhasz; Rebecca L. Johnson; Jennifer Brewer An investigation into the processing of lexicalized English blend words: Evidence from lexical decisions and eye movements during reading Journal Article In: Journal of Psycholinguistic Research, vol. 46, no. 2, pp. 281–294, 2017. @article{Juhasz2017, New words enter the language through several word formation processes [see Simonini (Engl J 55:752-757, 1966)]. One such process, blending, occurs when two source words are combined to represent a new concept (e.g., SMOG, BRUNCH, BLOG, and INFOMERCIAL). While there have been examinations of the structure of blends [see Gries (Linguistics 42:639-667, 2004) and Lehrer (Am Speech 73:3-28, 1998)], relatively little attention has been given to how lexicalized blends are recognized and if this process differs from other types of words. In the present study, blend words were matched to non-blend control words on length, familiarity, and frequency. Two tasks were used to examine blend processing: lexical decision and sentence reading. The results demonstrated that blend words were processed differently than non-blend control words. However, the nature of the effect varied as a function of task demands. Blends were recognized slower than control words in the lexical decision task but received shorter fixation durations when embedded in sentences. |
Mordechai Z. Juni; Miguel P. Eckstein The wisdom of crowds for visual search Journal Article In: Proceedings of the National Academy of Sciences, vol. 114, no. 21, pp. E4306–E4315, 2017. @article{Juni2017, Decision-making accuracy typically increases through collective integration of people's judgments into group decisions, a phenomenon known as the wisdom of crowds. For simple perceptual laboratory tasks, classic signal detection theory specifies the upper limit for collective integration benefits obtained by weighted averaging of people's confidences, and simple majority voting can often approximate that limit. Life-critical perceptual decisions often involve searching large image data (e.g., medical, security, and aerial imagery), but the expected benefits and merits of using different pooling algorithms are unknown for such tasks. Here, we show that expected pooling benefits are significantly greater for visual search than for single-location perceptual tasks and the prediction given by classic signal detection theory. In addition, we show that simple majority voting obtains inferior accuracy benefits for visual search relative to averaging and weighted averaging of observers' confidences. Analysis of gaze behavior across observers suggests that the greater collective integration benefits for visual search arise from an interaction between the foveated properties of the human visual system (high foveal acuity and low peripheral acuity) and observers' nonexhaustive search patterns, and can be predicted by an extended signal detection theory framework with trial to trial sampling from a varying mixture of high and low target detectabilities across observers (SDT-MIX). These findings advance our theoretical understanding of how to predict and enhance the wisdom of crowds for real world search tasks and could apply more generally to any decision-making task for which the minority of group members with high expertise varies from decision to decision. |
Yoshinao Kajikawa; John F. Smiley; Charles E. Schroeder Primary generators of visually evoked field potentials recorded in the macaque auditory cortex Journal Article In: Journal of Neuroscience, vol. 37, no. 42, pp. 10139–10153, 2017. @article{Kajikawa2017, Prior studies have reported “local” field potential (LFP) responses to faces in the macaque auditory cortex and have suggested that such face-LFPs may be substrates of audiovisual integration. However, although field potentials (FPs) may reflect the synaptic currents of neurons near the recording electrode, due to the use of a distant reference electrode, they often reflect those of synaptic activity occurring in distant sites as well. Thus, FP recordings within a given brain region (e.g., auditory cortex) may be “contaminated” by activity generated elsewhere in the brain. To determine whether face responses are indeed generated within macaque auditory cortex, we recorded FPs and concomitant multiunit activity with linear array multielectrodes across auditory cortex in three macaques (one female), and applied current source density (CSD) analysis to the laminar FP profile. CSD analysis revealed no appreciable local generator contribution to the visual FP in auditory cortex, although we did note an increase in the amplitude of visual FP with cortical depth, suggesting that their generators are located below auditory cortex. In the underlying inferotemporal cortex, we found polarity inversions of the main visual FP components accompanied by robust CSD responses and large-amplitude multiunit activity. These results indicate that face-evoked FP responses in auditory cortex are not generated locally but are volume-conducted from other face-responsive regions. In broader terms, our results underscore the caution that, unless far-field contamination is removed, LFPs in general may reflect such “far-field” activity, in addition to, or in absence of, local synaptic responses. |
Sakari Kallio; Mika Koivisto; Johanna K. Kaakinen Synaesthesia-type associations and perceptual changes induced by hypnotic suggestion Journal Article In: Scientific Reports, vol. 7, pp. 17310, 2017. @article{Kallio2017, Are synaesthetic experiences congenital and so hard-wired, or can a functional analogue be created? We induced an equivalent of form-colour synaesthesia using hypnotic suggestions in which symbols in an array (circles, crosses, squares) were suggested always to have a certain colour. In a Stroop type-naming task, three of the four highly hypnotizable participants showed a strong synaesthesia-type association between symbol and colour. This was verified both by their subjective reports and objective eye-movement behaviour. Two resembled a projector- and one an associator-type synaesthete. Participant interviews revealed that subjective experiences differed somewhat from typical (congenital) synaesthesia. Control participants who mimicked the task using cognitive strategies showed a very different response pattern. Overall, the results show that the targeted, preconsciously triggered associations and perceptual changes seen in association with congenital synaesthesia can rapidly be induced by hypnosis. They suggest that each participant's subjective experience of the task should be carefully evaluated, especially when studying hypnotic hallucinations. Studying such experiences can increase understanding of perception, automaticity, and awareness and open unique opportunities in cognitive neuroscience and consciousness research. |
Zampeta Kalogeropoulou; Akshay V. Jagadeesh; Sven Ohl; Martin Rolfs Setting and changing feature priorities in visual short-term memory Journal Article In: Psychonomic Bulletin & Review, vol. 24, no. 2, pp. 453–458, 2017. @article{Kalogeropoulou2017a, Many everyday tasks require prioritizing some vi-sual features over competing ones, both during the selection from the rich sensory input and while maintaining information in visual short-term memory (VSTM). Here, we show that observers can change priorities in VSTM when, initially, they attended to a different feature. Observers reported from mem-ory the orientation of one of two spatially interspersed groups of black and white gratings. Using colored pre-cues (presented before stimulus onset) and retro-cues (presented after stimulus offset) predicting the to-be-reported group, we manipulated observers' feature priorities independently during stimulus encoding and maintenance, respectively. Valid pre-cues reli-ably increased observers' performance (reduced guessing, in-creased report precision) as compared to neutral ones; invalid pre-cues had the opposite effect. Valid retro-cues also consis-tently improved performance (by reducing random guesses), even if the unexpected group suddenly became relevant (in-valid-valid condition). Thus, feature-based attention can re-shape priorities in VSTM protecting information that would otherwise be forgotten. |
Zampeta Kalogeropoulou; Martin Rolfs Saccadic eye movements do not disrupt the deployment of feature-based attention Journal Article In: Journal of Vision, vol. 17, no. 8, pp. 1–15, 2017. @article{Kalogeropoulou2017, The tight link of saccades to covert spatial attention has been firmly established, yet their relation to other forms of visual selection remains poorly understood. Here we studied the temporal dynamics of feature-based attention (FBA) during fixation and across saccades. Participants reported the orientation (on a continuous scale) of one of two sets of spatially interspersed Gabors (black or white). We tested performance at different intervals between the onset of a colored cue (black or white, indicating which stimulus was the most probable target; red: neutral condition) and the stimulus. FBA built up after cue onset: Benefits (errors for valid vs. neutral cues), costs (invalid vs. neutral), and the overall cueing effect (valid vs. invalid) increased with the cue– stimulus interval. Critically, we also tested visual performance at different intervals after a saccade, when FBA had been fully deployed before saccade initiation. Cueing effects were evident immediately after the saccade and were predicted most accurately and most precisely by fully deployed FBA, indicating that FBA was continuous throughout saccades. Finally, a decomposition of orientation reports into target reports and random guesses confirmed continuity of report precision and guess rates across the saccade.We discuss the role of FBA in perceptual continuity across saccades. |
Kei Kanari; Kiyomi Sakamoto; Hirohiko Kaneko Effect of visual attention on the properties of optokinetic nystagmus Journal Article In: PLoS ONE, vol. 12, no. 4, pp. e0175453, 2017. @article{Kanari2017, It has been demonstrated that optokinetic nystagmus (OKN) gain increases through attention to peripheral motion when the central visual field is occluded. However, how the properties of OKN change when two areas containing motion in different directions are presented in the peripheral visual field is still unclear. In this study, we investigated whether OKN corresponding to the attended motion in the periphery occurred while the observer was maintaining fixation at the center. We presented two areas with different directions of motion arranged on the left and right, top and bottom, or center and surrounding (concentric) areas in the display. Observers counted targets appearing on the attended area in the stimulus to maintain their attention on it. The results indicate that attention enhances the gain and frequency of OKN corresponding to the attended motion even in the case of stimuli having several areas with different directions of motion. |
Min Suk Kang; Sori Kim; Kyoung-Min Lee Peripheral target identification performance modulates eye movements Journal Article In: Vision Research, vol. 133, pp. 81–86, 2017. @article{Kang2017a, We often shift our eyes to an interesting stimulus, but it is important to inhibit that eye movement in some environments (e.g., a no-look pass in basketball). Here, we investigated participants' ability to inhibit eye movements when they had to process a peripheral target with a requirement to maintain strict fixation. An array of eight letters composed of four characters was briefly presented and a directional cue was centrally presented to indicate the target location. The stimulus onset asynchrony (SOA) between the cue and the stimulus array was chosen from six values, consisting of pre-cue conditions (−400 and −200 ms), a simultaneous cue condition (0 ms), and post-cue conditions (200, 400, and 800 ms). We found the following: 1) participants shifted their eyes toward the cued location even though the stimulus array was absent at the onset of eye movements, but the eye movement amplitude was smaller than the actual location of the target; 2) eye movements occurred approximately 150 ms after the onset of stimulus array in the pre-cue conditions and 250 ms after cue onset in the simultaneous and post-cue conditions; and 3) eye movement onsets were delayed and their amplitudes were smaller in correct trials than incorrect trials. These results indicate that the inhibitory process controlling eye movements also compete for cognitive resources like other cognitive processes. |
Yul H. R. Kang; Frederike H. Petzschner; Daniel M. Wolpert; Michael N. Shadlen Piercing of consciousness as a threshold-crossing operation Journal Article In: Current Biology, vol. 27, no. 15, pp. 1–11, 2017. @article{Kang2017, Many decisions arise through an accumulation of evidence to a terminating threshold. The process, termed bounded evidence accumulation (or drift diffusion), provides a unified account of decision speed and accuracy, and it is supported by neurophysiology in human and animal models. In many situations, a decision maker may not communicate a decision immediately and yet feel that at some point she had made up her mind. We hypothesized that this occurs when an accumulation of evidence reaches a termination threshold, registered, subjectively, as an “aha” moment. We asked human participants to make perceptual decisions about the net direction of dynamic random dot motion. The difficulty and viewing duration were controlled by the experimenter. After indicating their choice, participants adjusted the setting of a clock to the moment they felt they had reached a decision. The subjective decision times (tSDs) were faster on trials with stronger (easier) motion, and they were well fit by a bounded drift-diffusion model. The fits to the tSDs alone furnished parameters that fully predicted the choices (accuracy) of four of the five participants. The quality of the prediction provides compelling evidence that these subjective reports correspond to the terminating process of a decision rather than a post hoc inference or arbitrary report. Thus, conscious awareness of having reached a decision appears to arise when the brain's representation of accumulated evidence reaches a threshold or bound. We propose that such a mechanism might play a more widespread role in the “piercing of consciousness” by non-conscious thought processes. |
Julia A. Wolfson; Dan J. Graham; Sara N. Bleich Attention to physical activity–equivalent calorie information on nutrition facts labels: An eye-tracking investigation Journal Article In: Journal of Nutrition Education and Behavior, vol. 49, no. 1, pp. 35–42.e1, 2017. @article{Wolfson2017, Objective Investigate attention to Nutrition Facts Labels (NFLs) with numeric only vs both numeric and activity-equivalent calorie information, and attitudes toward activity-equivalent calories. Design An eye-tracking camera monitored participants' viewing of NFLs for 64 packaged foods with either standard NFLs or modified NFLs. Participants self-reported demographic information and diet-related attitudes and behaviors. Setting Participants came to the Behavioral Medicine Lab at Colorado State University in spring, 2015. Participants The researchers randomized 234 participants to view NFLs with numeric calorie information only (n = 108) or numeric and activity-equivalent calorie information (n = 126). Main Outcome Measure(s) Attention to and attitudes about activity-equivalent calorie information. Analysis Differences by experimental condition and weight loss intention (overall and within experimental condition) were assessed using t tests and Pearson's chi-square tests of independence. Results Overall, participants viewed numeric calorie information on 20% of NFLs for 249 ms. Participants in the modified NFL condition viewed activity-equivalent information on 17% of NFLs for 231 ms. Most participants indicated that activity-equivalent calorie information would help them decide whether to eat a food (69%) and that they preferred both numeric and activity-equivalent calorie information on NFLs (70%). Conclusions and Implications Participants used activity-equivalent calorie information on NFLs and found this information helpful for making food decisions. |
Mu Xia; Xueliu Li; Haiqing Zhong; Hong Li Fixation patterns of chinese participants while identifying facial expressions on Chinese faces Journal Article In: Frontiers in Psychology, vol. 8, pp. 581, 2017. @article{Xia2017, Two experiments in this study were designed to explore a model of Chinese fixation with four types of native facial expressions—happy, peaceful, sad, and angry. In both experiments, Participants performed an emotion recognition task while their behaviors and eye movements were recorded. Experiment 1(24 Participants, 12 men) demonstrated that both eye fixations and durations were lower for the upper part of the face than for the lower part of the face for all four types of facial expression. Experiment 2(20 Participants, 6men) repeated this finding and excluded the disturbance of fixation point. These results indicate that Chinese participants demonstrated a superiority effect for the lower part of face while interpreting facial expressions, possibly due to the influence of eastern etiquette culture. |
Aiping Xiong; Robert W. Proctor; Weining Yang; Ninghui Li Is domain highlighting actually helpful in identifying phishing web pages? Journal Article In: Human Factors, vol. 59, no. 4, pp. 640–660, 2017. @article{Xiong2017, OBJECTIVE: To evaluate the effectiveness of domain highlighting in helping users identify whether Web pages are legitimate or spurious. BACKGROUND: As a component of the URL, a domain name can be overlooked. Consequently, browsers highlight the domain name to help users identify which Web site they are visiting. Nevertheless, few studies have assessed the effectiveness of domain highlighting, and the only formal study confounded highlighting with instructions to look at the address bar. METHOD: We conducted two phishing detection experiments. Experiment 1 was run online: Participants judged the legitimacy of Web pages in two phases. In Phase 1, participants were to judge the legitimacy based on any information on the Web page, whereas in Phase 2, they were to focus on the address bar. Whether the domain was highlighted was also varied. Experiment 2 was conducted similarly but with participants in a laboratory setting, which allowed tracking of fixations. RESULTS: Participants differentiated the legitimate and fraudulent Web pages better than chance. There was some benefit of attending to the address bar, but domain highlighting did not provide effective protection against phishing attacks. Analysis of eye-gaze fixation measures was in agreement with the task performance, but heat-map results revealed that participants' visual attention was attracted by the highlighted domains. CONCLUSION: Failure to detect many fraudulent Web pages even when the domain was highlighted implies that users lacked knowledge of Web page security cues or how to use those cues. APPLICATION: Potential applications include development of phishing prevention training incorporating domain highlighting with other methods to help users identify phishing Web pages. |
Kitty Z. Xu; Brian A. Anderson; Erik E. Emeric; Anthony W. Sali; Veit Stuphorn; Steven Yantis; Susan M. Courtney Neural basis of cognitive control over movement inhibition: Human fMRI and primate electrophysiology evidence Journal Article In: Neuron, vol. 96, no. 6, pp. 1447–1458.e6, 2017. @article{Xu2017, Executive control involves the ability to flexibly inhibit or change an action when it is contextually inappropriate. Using the complimentary techniques of human fMRI and monkey electrophysiology in a context-dependent stop signal task, we found a functional double dissociation between the right ventrolateral prefrontal cortex (rVLPFC) and the bi-lateral frontal eye field (FEF). Different regions of rVLPFC were associated with context-based signal meaning versus intention to inhibit a response, while FEF activity corresponded to success or failure of the response inhibition regardless of the stimulus response mapping or the context. These results were validated by electrophysiological recordings in rVLPFC and FEF from one monkey. Inhibition of a planned behavior is therefore likely not governed by a single brain system as had been previously proposed, but instead depends on two distinct neural processes involving different sub-regions of the rVLPFC and their interactions with other motor-related brain regions. Xu et al. present a rare combination of complementary evidence from human fMRI and primate neurophysiology, demonstrating that response inhibition is not directly accomplished by the rVLPFC, but instead requires multiple, distinct rVLPFC networks involving attention and contextual stimulus interpretation. |
Maya Yablonski; Uri Polat; Yoram S. Bonneh; Michal Ben-Shachar Microsaccades are sensitive to word structure: A novel approach to study language processing Journal Article In: Scientific Reports, vol. 7, pp. 3999, 2017. @article{Yablonski2017, Microsaccades are miniature eye movements that occur involuntarily during fixation. They are typically inhibited following stimulus onset and are released from inhibition about 300 ms post-stimulus. Microsaccade-inhibition is modulated by low level features of visual stimuli, but it is currently unknown whether they are sensitive to higher level, abstract linguistic properties. To address this question, we measured the timing of microsaccades while subjects were presented with written Hebrew words and pronounceable nonwords (pseudowords). We manipulated the underlying structure of pseudowords such that half of them contained real roots while the other half contained invented roots. Importantly, orthographic similarity to real words was equated between the two conditions. Microsaccade onset was significantly slower following real-root compared to invented-root stimuli. Similar results were obtained when considering post-stimulus delay of eye blinks. Moreover, microsaccade-delay was positively and significantly correlated with measures of real-word similarity. These findings demonstrate, for the first time, sensitivity of microsaccades to linguistic structure. Because microsaccades are involuntary and can be measured in the absence of overt response, our results provide initial evidence that they can be used as a novel physiological measure in the study of language processes in healthy and clinical populations. |
Toshiyuki Yamada; Manabu Arai; Yuki Hirose Unforced revision in processing relative clause association ambiguity in Japanese: Evidence against revision as last resort Journal Article In: Journal of Psycholinguistic Research, vol. 46, no. 3, pp. 661–714, 2017. @article{Yamada2017, The current study tackles a long standing question of whether comprehenders perform structural revision when it is not forced by grammar or not. Using an eye-tracking reading paradigm, we addressed this issue by making use of global structural ambiguity in Japanese. Our results show that comprehenders initially associate a relative clause with the first potential head noun and that they revise this analysis when the second noun is lexico-semantically possible as the relative clause head, but do not when it is impossible. The results are incompatible with the Revision as Last Resort hypothesis. Instead, they support the parsing with unforced revision that is immediately sensitive to lexical properties. We argue that our results cannot be accounted for by serial modular processing models but that they can be explained by ranked-parallel interactive processing models. Furthermore, we propose that head-finality is a key factor involved in the availability of unforced revision. |
Ying Yan; Xiaofei Wang; Ludan Shi; Haoxue Liu Influence of light zones on drivers' visual fixation characteristics and traffic safety in extra-long tunnels Journal Article In: Traffic Injury Prevention, vol. 18, no. 1, pp. 102–110, 2017. @article{Yan2017, OBJECTIVE: Special light zone is a new illumination technique that promises to improve the visual environment and improve traffic safety in extra-long tunnels. The purpose of this study is to identify how light zones affect the dynamic visual characteristics and information perception of drivers as they pass through extra-long tunnels on highways. METHODS: Thirty-two subjects were recruited for this study, and fixation data were recorded using eye movement tracking devices. A back-propagation artificial neural network was employed to predict and analyze the influence of special light zones on the variations in the fixation duration and pupil area of drivers. The analytic coordinates of focus points at different light zones were clustered to obtain different visual fixation regions using dynamic cluster theory. RESULTS: The findings of this study indicated that the special light zones had different influences on fixation duration and pupil area compared to other sections. Drivers gradually changed their fixation points from a scattered pattern to a narrow and zonal distribution that mainly focused on the main visual area at the center, the road just ahead, and the right side of the main visual area while approaching the special light zones. The results also showed that the variation in illumination and landscape in light zones was more important than driving experience to yield changes in visual cognition and driving behavior. CONCLUSIONS: It can be concluded that the special light zones can help relieve drivers' vision fatigue to some extent and further develop certain visual stimulus that can enhance drivers' attention. The study would provide a scientific basis for safety measurement implementation in extra-long tunnels. |
Panpan Yao; Baoguo Chen Cross-linguistic differences affect late Chinese-English learners on-line processing of English tense and aspect Journal Article In: International Journal of Bilingualism, vol. 21, no. 3, pp. 268–290, 2017. @article{Yao2017, Aims: The present study aimed to explore how varied cross-linguistic differences affect late Chinese-English learners' on-line processing of tense and aspect in English. Methodology: We used the self-paced reading task (Experiment 1) and the eye-tracking technique (Experiment 2) to test the above question. Data and analysis: Reading times in Experiment 1 and first-fixation duration, and gaze time in Experiment 2 in four interested positions were analysed in R by ANOVAs and t-tests. Findings: Both high-and low-proficiency participants showed their sensitivity to the violation of progressive, which is nearly congruent between English and Chinese. Only high-proficiency participants were sensitive to the violation of past tense, which is similar but not congruent between Chinese and English. With regard to present third person singular, which is incongruent between Chinese and English, high-proficiency participants also showed their sensitivity to its violation; however, this sensitivity is only detected by the eye-tracking method (Experiment 2). These results suggested that cross-linguistic differences affect late second language learners' on-line processing of English tense and aspect. Originality: To the best of our knowledge, this study is the first one exploring varied cross-linguistic differences' influence on late Chinese-English learners' on-line processing of tense and aspect in English. Significance: Our results provide new evidence to support the Performance Deficit Account. |
Jacob L. Yates; Il Memming Park; Leor N. Katz; Jonathan W. Pillow; Alexander C. Huk Functional dissection of signal and noise in MT and LIP during decision-making Journal Article In: Nature Neuroscience, vol. 20, no. 9, pp. 1285–1292, 2017. @article{Yates2017, During perceptual decision-making, responses in the middle temporal (MT) and lateral intraparietal (LIP) areas appear to map onto theoretically defined quantities, with MT representing instantaneous motion evidence and LIP reflecting the accumulated evidence. However, several aspects of the transformation between the two areas have not been empirically tested. We therefore performed multistage systems identification analyses of the simultaneous activity of MT and LIP during individual decisions. We found that monkeys based their choices on evidence presented in early epochs of the motion stimulus and that substantial early weighting of motion was present in MT responses. LIP responses recapitulated MT early weighting and contained a choice-dependent buildup that was distinguishable from motion integration. Furthermore, trial-by-trial variability in LIP did not depend on MT activity. These results identify important deviations from idealizations of MT and LIP and motivate inquiry into sensorimotor computations that may intervene between MT and LIP. |
Menahem Yeari; Marja Oudega; Paul W. Broek The effect of highlighting on processing and memory of central and peripheral text information: evidence from eye movements Journal Article In: Journal of Research in Reading, vol. 40, no. 4, pp. 365–383, 2017. @article{Yeari2017, The present study investigated the effect of text highlighting on online processing and memory of central and peripheral information. We compared processing time (using eye-tracking methodology) and recall of central and peripheral information for three types of highlighting: (a) highlighting of central information, (b) highlighting of pe-ripheral information and (c) no highlighting. Results indicate that highlighting central information decreased the amount of rereading of peripheral information, whereas highlighting peripheral information increased the amount of rereading of peripheral information. Processing and recall of central information did not differ across highlighting conditions but were higher than the processing and recall of peripheral information (i.e., centrality effects). These findings suggest that highlighting influ-ences processing of text but that this influence occurs after initial processing, interacts with centrality and is strongest for text information that is relatively peripheral to the overall coherence and meaning of the text. Proficient readers apparently selectively process and store central information regardless of what is highlighted in the text. |
Miao-Hsuan Yen; Ying-Tien Wu In: Computers in Human Behavior, vol. 75, pp. 14–24, 2017. @article{Yen2017, With an online reading context, this study aimed to investigate whether university students' informal reasoning ability and disposition (indicated by counterargument construction) could reduce or even reverse “myside bias” in reading relevant webpages regarding a controversial issue. Also, the association of students' online reading patterns with their progress in counterargument construction and changes in attitude extremity was examined in this study. The participants were sixty-four university students. They were asked to read eight relevant webpages freely (eye movement recorded) and to express their personal opinions about building nuclear power plants. These webpages were edited from various aspects regarding this controversial issue, with half of them presenting supporting and opposing information respectively. Before and after reading the webpages, the participants' counterargument construction performance and attitude extremity toward the controversial issue were assessed. This study revealed that participants who could construct successful counterarguments in the pre-test tended to pay more attention to other-side than to myside webpages. For their counterparts, it was found that those who spent more time viewing other-side webpages either progressed in counterargument construction or neutralized their attitude in the post-test. With different methodology, this study also provides convergent evidences that myside bias was associated with attitude polarization. |
Wei Yi; Shiyi Lu; Guojie Ma Frequency, contingency and online processing of multiword sequences: An eye-tracking study Journal Article In: Second Language Research, vol. 33, no. 4, pp. 519–549, 2017. @article{Yi2017, Frequency and contingency are two primary statistical factors that drive the acquisition and processing of language. This study explores the role of phrasal frequency and contingency (the co- occurrence probability/statistical association of the constituent words in multiword sequences) during online processing of multiword sequences. Meanwhile, it also examines language users' sensitivity to the two types of statistical information. Using the eye-tracking paradigm, native and advanced nonnative speakers of Chinese were instructed to read 80 disyllabic two-word Chinese adverbial sequences embedded in sentence contexts. Eye movements of the participants were recorded using both early and late measures. Mixed-effects modeling revealed that both phrasal frequency and contingency influenced the processing of the adverbial sequences; however, they were likely to function in different time windows. In addition, both native and nonnative speakers were sensitive to the phrasal frequency and contingency of the sequences, though their degrees of such sensitivity differed. Our findings suggest that adult language learners retain the statistical learning ability in second language acquisition and they may share a general statistical learning mechanism with native speakers when processing multiword sequences. |
Takumi Yokosaka; Scinob Kuroki; Junji Watanabe; Shin'ya Nishida Linkage between free exploratory movements and subjective tactile ratings Journal Article In: IEEE Transactions on Haptics, vol. 10, no. 2, pp. 217–225, 2017. @article{Yokosaka2017, We actively move our hands and eyes when exploring the external world and gaining information about object's attributes. Previous studies showing that how we touch might be related to how we felt led us to consider whether we could decode observers' subjective tactile experiences only by analyzing their exploratory movements without explicitly asking how they perceived. However, in those studies, explicit judgment tasks were performed about specific tactile attributes that were prearranged by experimenters. Here, we systematically investigated whether exploratory movements can explain tactile ratings even when participants do not need to judge any tactile attributes. While measuring both hand and eye movements, we asked participants to touch materials freely without judging any specific tactile attributes (free-touch task) or to evaluate one of four tactile attributes (roughness, hardness, slipperiness, and temperature). We found that tactile ratings in the judgment tasks correlated with exploratory movements even in the free-touch task and that eye movements as well as hand movements correlated with tactile ratings. These results might open up the possibility of decoding tactile experiences by exploratory movements. |
Gongchen Yu; Mingpo Yang; Peng Yu; Michael C. Dorris Time compression of visual perception around microsaccades Journal Article In: Journal of Neurophysiology, vol. 118, no. 1, pp. 416–424, 2017. @article{Yu2017a, Even during fixation, our eyes are in constant motion. For example, microsaccades are small (typically<1°) eye movements that occur 1~3 times/second. Despite their tiny and transient nature, our percept of visual space is compressed prior to microsaccades (Hafed 2013). As visual space and time are interconnected at both the 46 physical and physiological levels, we asked whether microsaccades also affect the temporal aspects of visual perception. Here we demonstrate that the perceived interval between transient visual stimuli was compressed if accompanied by microsaccades. This temporal compression extended approximately ±200 ms from microsaccade occurrence, and depending on their particular pattern, multiple microsaccades further enhanced or counteracted this temporal compression. The compression of time surrounding microsaccades resembles that associated with more voluntary macrosaccades (Morrone et al. 2005). Our results suggest common neural processes underlying both saccade and microsaccade misperceptions, mediated, likely, through extra-retinal mechanisms. |
Hongbo Yu; Yunyan Duan; Xiaolin Zhou Guilt in the eyes: Eye movement and physiological evidence for guilt-induced social avoidance Journal Article In: Journal of Experimental Social Psychology, vol. 71, no. March, pp. 128–137, 2017. @article{Yu2017, Guilt is widely acknowledged as an exemplary social emotion that is unpleasant but has positive interpersonal consequences. Previous empirical research focuses largely on documenting the behavioral consequences of guilt; less is known about the psychophysiology of experiencing guilt. Here we designed an interactive paradigm and asked participants to play multiple rounds of a dot-estimation task with two partners. Failure in the task, either due to the participant or due to the partner, would cause electric shocks to the partner. In Experiment 1, we asked the participant to watch video clips depicting the partner's facial expressions while the partner was receiving pain stimulation. Eye movement recording showed that the participant fixated less on the partner's eyes but more on the nose region in the participant-caused pain (high guilt) condition than in the partner-caused pain (low guilt) condition, an indication of social avoidance. In Experiment 2, we asked the participant to either fixate on the eye (Eye Group) or the nose region (Nose group) of the partner and recorded their skin conductance during the viewing. We found that the Eye Group exhibited higher skin conductance response in the high guilt condition than in the low guilt condition and such a difference was absent for the Nose Group, indicating that the forced eye contact with the victim enhanced the emotional arousal of guilt. The life-like interactive paradigm is thus able to demonstrate the mutual dependence between eye contact and social emotions: eye contact both elicits and is regulated by emotional content in social interaction. |
Lili Yu; Qiaoming Zhang; Caspian Priest; Erik D. Reichle; Heather Sheridan Character-complexity effects in Chinese reading and visual search: A comparison and theoretical implications Journal Article In: Quarterly Journal of Experimental Psychology, vol. 71, no. 1, pp. 140–151, 2017. @article{Yu2017b, Three eye-movement experiments were conducted to examine how the complexity of characters in Chinese words (i.e., number of strokes per character) influences their processing and eye-movement behaviour. In Experiment 1, English speakers with no significant knowledge of Chinese searched for specific low-, medium-, and high-complexity target characters in a multi-page narrative containing characters of varying complexity (3–16 strokes). Fixation durations and skipping rates were influenced by the visual complexity of both the target characters and the characters being searched even though participants had no knowledge of Chinese. In Experiment 2, native Chinese speakers performed the same character-search task, and a similar pattern of results was observed. Finally, in Experiment 3, a second sample of native Chinese speakers read the same text used in Experiments 1 and 2, with text characters again exhibiting complexity effects. These results collectively suggest that character-complexity effects on eye movements may not be due to lexical processing per se but may instead reflect whatever visual processing is required to know whether or not a character corresponds to an episodically represented target. The theoretical implications of this for our understanding of normal reading are discussed. |
Shulin Yue; Zhenlan Jin; Chenggui Fan; Qian Zhang; Ling Li Interference between smooth pursuit and color working memory Journal Article In: Journal of Eye Movement Research, vol. 10, no. 3, pp. 1–10, 2017. @article{Yue2017, Spatial working memory (WM) and spatial attention are closely related, but the relationship between non-spatial WM and spatial attention still remains unclear. The present study aimed to investigate the interaction between color WM and smooth pursuit eye movements. A modified delayed-match-to-sample paradigm (DMS) was applied with 2 or 4 items presented in each visual field. Subjects memorized the colors of items in the cued visual field and smoothly moved eyes towards or away from memorized items during retention interval despite that the colored items were no longer visible. The WM performance decreased with higher load in general. More importantly, the WM performance was better when subjects pursued towards rather than away from the cued visual field. Meanwhile, the pursuit gain decreased with higher load and demonstrated a higher result when pursuing away from the cued visual field. These results indicated that spatial attention, guiding attention to the memorized items, benefits color WM. Therefore, we propose that a competition for attention resources exists between color WM and smooth pursuit eye movements. |
Steffi Zander; Stefanie Wetzel; Tim Kühl; Sven Bertel Underlying processes of an inverted personalization effect in multimedia learning - An eye-tracking study Journal Article In: Frontiers in Psychology, vol. 8, pp. 2202, 2017. @article{Zander2017, One of the frequently examined design principles in multimedia learning is the personalization principle. Based on empirical evidence this principle states that using personalised messages in multimedia learning is more beneficial than using formal language (e.g. using ‘you' instead of ‘the'). Although there is evidence that these slight changes in regard to the language style affect learning, motivation and the perceived cognitive load, it remains unclear, (1) whether the positive effects of personalised language can be transferred to all kinds of content of learning materials (e.g. specific potentially aversive health issues) and (2) which are the underlying processes (e.g. attention allocation) of the personalization effect. German university students (N= 37) learned symptoms and causes of cerebral haemorrhages either with a formal or a personalised version of the learning material. Analysis revealed comparable results to the few existing previous studies, indicating an inverted personalization effect for potentially aversive learning material. This effect was specifically revealed in regard to decreased average fixation duration and the number of fixations exclusively on the images in the personalised compared to the formal version. This result can be seen as indicators for an inverted effect of personalization on the level of visual attention. |
Thomas Zawisza; Ray Garza Using an eye tracking device to assess vulnerabilities to burglary Journal Article In: Journal of Police and Criminal Psychology, vol. 32, no. 3, pp. 203–213, 2017. @article{Zawisza2017, This research examines the extent to which visual cues influence a person's decision to burglarize. Participants in this study (n = 65) viewed ten houses through an eye tracking device and were asked whether or not they thought each house was vulnerable to burglary. The eye tracking device recorded where a person looked and for how long they looked (in milliseconds). Our findings showed that windows and doors were two of the most important visual stimuli. Results from our follow-up questionnaire revealed that stimuli such as fencing, beware of pet signs, cars in driveways, and alarm systems are also considered. There are a number of implications for future research and policy. |
Hang Zeng; Ralph Weidner; Gereon R. Fink; Qi Chen Neural correlates underlying the attentional spotlight in human parietal cortex independent of task difficulty Journal Article In: Human Brain Mapping, vol. 38, no. 10, pp. 4996–5018, 2017. @article{Zeng2017, Changes in the size of the attentional focus and task difficulty often co-vary. Nevertheless, the neural processes underlying the attentional spotlight process and task difficulty are likely to differ from each other. To differentiate between the two, we parametrically varied the size of the attentional focus in a novel behavioral paradigm while keeping visual processing difficulty either constant or not. A behavioral control experiment proved that the present behavioral paradigm could indeed effectively manipulate the size of the attentional focus per se, rather than affecting purely perceptual processes or surface processing. Imaging results showed that neural activity in a dorsal frontoparietal network, including right superior parietal cortex (SPL), was positively correlated with the size of the attentional spotlight, irrespective of whether task difficulty was constant or varied across different sizes of attentional focus. In contrast, neural activity in the ventral frontoparietal network, including the right inferior parietal cortex (IPL), was positively correlated with increasing task difficulty. Data suggest that sub-regions in parietal cortex are differentially involved in the attentional spotlight process and task difficulty: while SPL was involved in the attentional spotlight process independent of task difficulty, IPL was involved in the effect of task difficulty independent of the attentional spotlight process. |
Alexandre Zénon Time-domain analysis for extracting fast-paced pupil responses Journal Article In: Scientific Reports, vol. 7, pp. 41484, 2017. @article{Zenon2017, The eye pupil reacts to cognitive processes, but its analysis is challenging when luminance varies or when stimulation is fast-paced. Current approaches relying on deconvolution techniques do not account for the strong low-frequency spontaneous changes in pupil size or the large interindividual variability in the shape of the responses. Here a system identification framework is proposed in which the pupil responses to different parameters are extracted by means of an autoregressive model with exogenous inputs. In an example application of this technique, pupil size was shown to respond to the luminance and arousal scores of affective pictures presented in rapid succession. This result was significant in each subject (N = 5), but the pupil response varied between individuals both in amplitude and latency, highlighting the need for determining impulse responses subjectwise. The same method was also used to account for pupil size variations caused by respiration, illustrating the possibility to model the relation between pupil size and other continuous signals. In conclusion, this new framework for the analysis of pupil size data allows us to dissociate the response of the eye pupil from intermingled sources of influence and can be used to study the relation between pupil size and other physiological signals. |
Paul Zerr; Surya Gayet; Kees Mulder; Yaïr Pinto; Ilja Sligte; Stefan Van der Stigchel Remapping high-capacity, pre-attentive, fragile sensory memory Journal Article In: Scientific Reports, vol. 7, pp. 15940, 2017. @article{Zerr2017, Humans typically make several saccades per second. This provides a challenge for the visual system as locations are largely coded in retinotopic (eye-centered) coordinates. Spatial remapping, the updating of retinotopic location coordinates of items in visuospatial memory, is typically assumed to be limited to robust, capacity-limited and attention-demanding working memory (WM). Are pre-attentive, maskable, sensory memory representations (e.g. fragile memory, FM) also remapped? We directly compared trans-saccadic WM (tWM) and trans-saccadic FM (tFM) in a retro-cue change-detection paradigm. Participants memorized oriented rectangles, made a saccade and reported whether they saw a change in a subsequent display. On some trials a retro-cue indicated the to-be-tested item prior to probe onset. This allowed sensory memory items to be included in the memory capacity estimate. The observed retro-cue benefit demonstrates a tFM capacity considerably above tWM. This provides evidence that some, if not all sensory memory was remapped to spatiotopic (world-centered, task-relevant) coordinates. In a second experiment, we show backward masks to be effective in retinotopic as well as spatiotopic coordinates, demonstrating that FM was indeed remapped to world-centered coordinates. Together this provides conclusive evidence that trans-saccadic spatial remapping is not limited to higher-level WM processes but also occurs for sensory memory representations. |
David Zeugin; Norhan Arfa; Michael Notter; Micah M. Murray; Silvio Ionta Implicit self-other discrimination affects the interplay between multisensory affordances of mental representations of faces Journal Article In: Behavioural Brain Research, vol. 333, pp. 282–285, 2017. @article{Zeugin2017, Face recognition is an apparently straightforward but, in fact, complex ability, encompassing the activation of at least visual and somatosensory representations. Understanding how identity shapes the interplay between these face-related affordances could clarify the mechanisms of self-other discrimination. To this aim, we exploited the so-called “face inversion effect” (FIE), a specific bias in the mental rotation of face images (of other people): with respect to inanimate objects, face images require longer time to be mentally rotated from the upside-down. Via the FIE, which suggests the activation of somatosensory mechanisms, we assessed identity-related changes in the interplay between visual and somatosensory affordances between self- and other-face representations. Methodologically, to avoid the potential interference of the somatosensory feedback associated with musculoskeletal movements, we introduced the tracking of gaze direction to record participants' response. Response times from twenty healthy participants showed the larger FIE for self- than other-faces, suggesting that the impact of somatosensory affordances on mental representation of faces varies according to identity. The present study lays the foundations of a quantifiable method to implicitly assess self-other discrimination, with possible translational benefits for early diagnosis of face processing disturbances (e.g. prosopagnosia), and for neurophysiological studies on self-other discrimination in ethological settings. |
Yang Zhou; Lixin Liang; Yujun Pan; Ning Qian; Mingsha Zhang Sites of overt and covert attention define simultaneous spatial reference centers for visuomotor response Journal Article In: Scientific Reports, vol. 7, pp. 46556, 2017. @article{Zhou2017c, The site of overt attention (fixation point) defines a spatial reference center that affects visuomotor response as indicated by the stimulus-response-compatibility (SRC) effect: When subjects press, e.g., a left key to report stimuli, their reaction time is shorter when stimuli appear to the left than to the right of the fixation. Covert attention to a peripheral site appears to define a similar reference center but previous studies did not control for confounding spatiotemporal factors or investigate the relationship between overt-and covert-attention-defined centers. Using an eye tracker to monitor fixation, we found an SRC effect relative to the site of covert attention induced by a flashed cue dot, and a concurrent reduction, but not elimination, of the overt-attention SRC effect. The two SRC effects jointly determined the overall motor reaction time. Since trials with different cue locations were randomlZhou, Y., Liang, L., Pan, Y., Qian, N., & Zhang, M. (2017). Sites of overt and covert attention define simultaneous spatial reference centers for visuomotor response. Scientific Reports, 7, 1–12. https://doi.org/10.1038/srep46556y interleaved, the integration of the two reference centers must be updated online. When the cue was invalid and diminished covert attention, the covert-attention SRC effect disappeared and the overt-attention SRC effect retained full strength, excluding non-attention-based interpretations. We conclude that both covert-and overt-attention sites define visual reference centers that simultaneously contribute to motor response. |
Yang Zhou; Gongchen Yu; Xuefei Yu; Si Wu; Mingsha Zhang Asymmetric representations of upper and lower visual fields in egocentric and allocentric references Journal Article In: Journal of Vision, vol. 17, no. 1, pp. 1–11, 2017. @article{Zhou2017b, Two spatial reference systems, i.e., the observer- centered (egocentric) and object-centered (allocentric) references, are most commonly used to locate the position of the external objects in space. Although we sense the world as a unified entity, visual processing is asymmetric between upper and lower visual fields (VFs). For example, the goal-directed reaching responses are more efficient in the lower VF. Such asymmetry suggests that the visual space might be composed of different realms regarding perception and action. Since the peripersonal realm includes the space that one can reach, mostly in the lower VF, it is highly likely that the peripersonal realm might mainly be represented in the egocentric reference for visuomotor operation. In contrast, the extrapersonal realm takes place away from the observer and is mostly observed in the upper VF, which is presumably represented in the allocentric reference for orientation in topographically defined space. This theory, however, has not been thoroughly tested experimentally. In the present study, we assessed the contributions of the egocentric and allocentric reference systems on visual discrimination in the upper and lower VFs through measuring the manual reaction times (RTs) of human subjects. We found that: (a) the influence of a target's egocentric location on visual discrimination was stronger in the lower VF; and (b) the influence of a target's allocentric location on visual discrimination was stronger in the upper VF. These results support the hypothesis that the upper and lower VFs are primarily represented in the allocentric and egocentric references, respectively. |
Ying Zhou; Bing Li; Gang Wang; Mingsha Zhang; Yujun Pan Leftward deviation and asymmetric speed of egocentric judgment between left and right visual fields Journal Article In: Frontiers in Neuroscience, vol. 11, pp. 364, 2017. @article{Zhou2017, The egocentric reference frame is essential for body orientation and spatial localization of external objects. Recent neuroimaging and lesion studies have revealed that the right hemisphere of humans may play a more dominant role in processing egocentric information than the left hemisphere. However, previous studies of egocentric discrimination mainly focused on assessing the accuracy of egocentric judgment, leaving its timing unexplored. In addition, most previous studies never monitored the subjects' eye position during the experiments, so the influence of eye position on egocentric judgment could not be excluded. In the present study, we systematically assessed the processing of egocentric information in healthy human subjects by measuring the location of their visual subjective straight ahead (SSA) and their manual reaction time (RT) during fixation (monitored by eye tracker). In an egocentric discrimination task, subjects were required to judge the position of a visual cue relative to the subjective mid-sagittal plane and respond as quickly as possible. We found that the SSA of all subjects deviated to the left side of the body mid-sagittal plane. In addition, all subjects but one showed the longest RT at the location closest to the SSA; and in population, the RTs in the left visual field (VF) were longer than that in the right VF. These results might be due to the right hemisphere's dominant role in processing egocentric information, and its more prominent representation of the ipsilateral VF than that of the left hemisphere. |
Eckart Zimmermann; Ralph Weidner; Gereon R. Fink Spatiotopic updating of visual feature information Journal Article In: Journal of Vision, vol. 17, no. 12, pp. 6, 2017. @article{Zimmermann2017, Saccades shift the retina with high-speed motion. In order to compensate for the sudden displacement, the visuomotor system needs to combine saccade-related information and visual metrics. Many neurons in oculomotor but also in visual areas shift their receptive field shortly before the execution of a saccade (Duhamel, Colby, & Goldberg, 1992; Nakamura & Colby, 2002). These shifts supposedly enable the binding of information from before and after the saccade. It is a matter of current debate whether these shifts are merely location based (i.e., involve remapping of abstract spatial coordinates) or also comprise information about visual features. We have recently presented fMRI evidence for a feature-based remapping mechanism in visual areas V3, V4, and VO (Zimmermann, Weidner, Abdollahi, & Fink, 2016). In particular, we found fMRI adaptation in cortical regions representing a stimulus' retinotopic as well as its spatiotopic position. Here, we asked whether spatiotopic adaptation exists independently from retinotopic adaptation and which type of information is behaviorally more relevant after saccade execution. We first adapted at the saccade target location only and found a spatiotopic tilt aftereffect. Then, we simultaneously adapted both the fixation and the saccade target location but with opposite tilt orientations. As a result, adaptation from the fixation location was carried retinotopically to the saccade target position. The opposite tilt orientation at the retinotopic location altered the effects induced by spatiotopic adaptation. More precisely, it cancelled out spatiotopic adaptation at the saccade target location. We conclude that retinotopic and spatiotopic visual adaptation are independent effects. |
Xuemeng Zhang; Shuaiyu Chen; Hong Chen; Yan Gu; Wenjian Xu General and food-specific inhibitory control as moderators of the effects of the impulsive systems on food choices Journal Article In: Frontiers in Psychology, vol. 8, pp. 802, 2017. @article{Zhang2017, The present study aimed to extend the application of the reflective-impulsive model to restrained eating and explore the effect of automatic attention (impulsive system) on food choices. Furthermore, we examined the moderating effects of general inhibitory control (G-IC) and food-specific inhibitory control (F-IC) on successful and unsuccessful restrained eaters (US-REs). Automatic attention was measured using ``the EyeLink 1000,'' which tracked eye movements during the process of making food choices, and G-IC and F-IC were measured using the Stop-Signal Task. The results showed that food choices were related to automatic attention and that G-IC and F-IC moderated the predictive relationship between automatic attention and food choices. Furthermore, among successful restrained eaters (S-REs), automatic attention to high caloric foods did not predict food choices, regardless of whether G-IC or F-IC was high or low. Whereas food choice was positively correlated with automatic attention among US-REs with poor F-IC, this pattern was not observed in those with poor G-IC. In conclusion, the S-REs had more effective self-management skills and their food choices were affected less by automatic attention and inhibitory control. Unsuccessful restrained eating was associated with poor F-IC (not G-IC) and greater automatic attention to high caloric foods. Thus, clinical interventions should focus on enhancing F-IC, not G-IC, and on reducing automatic attention to high caloric foods. |
Yan Zhang; Xiaoying Wang; Juan Wang; Lili Zhang; Yu Xiang Patterns of eye movements when observers judge female facial attractiveness Journal Article In: Frontiers in Psychology, vol. 8, pp. 1909, 2017. @article{Zhang2017a, The purpose of the present study is to explore the fixation patterns for the explicit judgments of attractiveness judgments and infer which features are used for attractiveness. Facial attractiveness is of high importance for human interaction and social behavior. Behavioral studies on the perceptual cues for female facial attractiveness suggested three potentially important features: averageness, symmetry, and sexual dimorphy. However, none of these studies explained which regions of stimulus images influence observers' judgments. Therefore, the present research recorded the eye movements of 24 male observers and 19 female observers as they rated a set of 30 photographs of female facial attractiveness. Results demonstrated the following: (1) Fixation is longer and more frequent on the noses of female faces than on their eyes and mouths (no difference exists between the eyes and the mouth); (2) The average pupil diameter at the nose region is bigger than that at the eyes and mouth (no difference exists between the eyes and the mouth); (3) the number of fixations of male participants was significantly more than female participants. (4) Observers first fixate on the eyes and mouth (no difference exists between the eyes and the mouth) before fixating on the nose area. In general, participants attend predominantly to the nose to form attractiveness judgments. The results of this study add a new dimension to the existing literature on judgment of facial attractiveness. The major contribution of the present study is the finding that the area of the nose is vital in the judgment of facial attractiveness. This finding establish a contribution of partial processing on female facial attractiveness judgments during eye-tracking. |
Youming Zhang; Martti Juhola On biometrics with eye movements Journal Article In: IEEE Journal of Biomedical and Health Informatics, vol. 21, no. 5, pp. 1360–1366, 2017. @article{Zhang2017b, Eye movements are a relatively novel data source for biometric identification. When video cameras applied to eye tracking become smaller and more efficient, this data source could offer interesting opportunities for the development of eye movement biometrics. In the present article, we study primarily biometric identification as seen as a classification task of multiple classes, and secondarily biometric verification considered as binary classification. Our research is based on the saccadic eye movement signal measurements from 109 young subjects. In order to test the data measured, we use a procedure of biometric identification according to the one-versus-one (subject) principle. In a development from our previous research, which also involved biometric verification based on saccadic eye movements, we now apply another eye movement tracker device with a higher sampling frequency of 250 Hz. The results obtained are good, with correct identification rates at 80-90% at their best. |
Huixia Zhou; Sonja Rossi; Juan Li; Huanhuan Liu; Ran Chen; Baoguo Chen Effects of working memory capacity in processing wh-extractions: Eye-movement evidence from Chinese–English bilinguals Journal Article In: Journal of Research in Reading, vol. 40, no. 4, pp. 420–438, 2017. @article{Zhou2017a, By using the eye-tracking method, the present study explores whether working memory capacity assessed via the second language (L2) reading span (L2WMC) as well as the operational span task (OSPAN) affects the processing of subject-extraction and object-extraction in Chinese–English bilinguals. Results showed that L2WMC has no effects on the grammatical judgement accuracies, the first fixation duration, gaze duration, go-past times and total fixation duration of the critical regions in wh-extractions. In contrast, OSPAN influences the first fixation duration and go-past times of the critical regions in wh-extractions. Specifically, in region 1, (e.g., Who do you think loved the comedian [region 1] with [region 2] all his heart [subject-extraction]? versus Who do you think the comedian loved [region 1] with [region 2] all his heart? [object-extraction] ), participants with high OSPAN were much slower than those with low OSPAN in their first fixation duration in reading subject-extractions, whereas there were no differences between participants with different OSPANs in reading object-extractions. In region 2, participants with high OSPAN were much faster than those with low OSPAN in their go-past times of object-extractions. These results indicated that individual differences in OSPAN rather than in L2WMC more strongly affect processing of wh-extractions. Thus, OSPAN results to be more suitable to explore the influences of working memory while processing L2 sentences with complex syntax, at least for intermediate proficient bilinguals. Results of the study also provide further support for the Capacity Theory of Comprehension. |
Alix Kowalski; Yi Ting Huang Predicting and priming thematic roles: Flexible use of verbal and nonverbal cues during relative clause comprehension Journal Article In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 43, no. 9, pp. 1341–1351, 2017. @article{Kowalski2017, Relative-clause sentences (RCs) have been a key test case for psycholinguistic models of comprehension. While object-relative clauses (e.g., ORCs: "The bear that 'the horse' . . .") are distinguished from subject-relative clauses (SRCs) after the second noun phrase (NP2; e.g., SRCs: "The bear that 'pushed' . . ."), role assignments are often delayed until the embedded verb (e.g., ". . . 'pushed' ate the sandwich"). This contrasts with overwhelming evidence of incremental role assignment in other garden-path sentences. The current study investigates how contextual factors modulate reliance on verbal and nonverbal cues. Using a visual-world paradigm, participants saw preceding discourse contexts that highlighted relevant roles within events (e.g., pusher, pushee). Nevertheless, role assignment for ORCs remained delayed until the embedded verb (Experiment 1). However, role assignment for ORCs occurred before the embedded verb when additional linguistic input was provided by an adverb (Experiment 2). Finally, when the likelihood of encountering RCs increased within the experimental context, role immediate assignment for ORCs was observed after NP2 (Experiment 3). Together, these findings suggest that real-time role assignment often prefers verbal cues, but can also flexibly adapt to the statistical properties of the local context. |
Ivan Koychev; Dan Joyce; E. Barkus; Ulrich Ettinger; Anne Schmechtig; Colin T. Dourish; G. R. Dawson; Kevin J. Craig; J. F. William Deakin In: Cognitive Neuropsychiatry, vol. 22, no. 3, pp. 213–232, 2017. @article{Koychev2017, Introduction: Body dysmorphic disorder (BDD) is characterised by repetitive behaviours and/or mental acts occurring in response to preoccupations with perceived flaws in physical appearance. Based on an eye-tracking paradigm, this study aimed to examine how individuals with BDD processed their own face. Methods: Participants were 21 BDD patients, 19 obsessive– compulsive disorder patients and 21 healthy controls (HC), who were age-, sex-, and IQ-matched. Stimuli were photographs of participants' own faces as well as those from the Pictures of Facial Affect battery. Outcome measures were affect recognition accuracy as well as spatial and temporal scanpath parameters. Results: The BDD group exhibited significantly decreased recognition accuracy for their own face relative to the HC group, and this was most pronounced for those who had a key concern centred on their face. Individual qualitative scanpath analysis revealed restricted and extensive scanning behaviours in BDD participants with a facial preoccupation. Persons with severe BDD also exhibited more marked scanpath deficits. Conclusions: Future research should be directed at extending the current work by incorporating neuroimaging techniques, and investigations of eye-tracking focused on affected body parts in BDD. These could yield fruitful therapeutic applications via incorporation with existing treatment approaches. |
Matthew R. Krause; Theodoros P. Zanos; Bennett A. Csorba; Praveen K. Pilly; Jaehoon Choe; Matthew E. Phillips; Abhishek Datta; Christopher C. Pack Transcranial direct current stimulation facilitates associative learning and alters functional connectivity in the primate brain Journal Article In: Current Biology, vol. 27, no. 20, pp. 3086–3096, 2017. @article{Krause2017, There has been growing interest in transcranial direct current stimulation (tDCS), a non-invasive technique purported to modulate neural activity via weak, externally applied electric fields. Although some promising preliminary data have been reported for applications ranging from stroke rehabilitation to cognitive enhancement, little is known about how tDCS affects the human brain, and some studies have concluded that it may have no effect at all. Here, we describe a macaque model of tDCS that allows us to simultaneously examine the effects of tDCS on brain activity and behavior. We find that applying tDCS to right prefrontal cortex improves monkeys' performance on an associative learning task. While firing rates do not change within the targeted area, tDCS does induce large low-frequency oscillations in the underlying tissue. These oscillations alter functional connectivity, both locally and between distant brain areas, and these long-range changes correlate with tDCS's effects on behavior. Together, these results are consistent with the idea that tDCS leads to widespread changes in brain activity and suggest that it may be a valuable method for cheaply and non-invasively altering functional connectivity in humans. Krause et al. test transcranial direct current stimulation (tDCS) in a realistic non-human primate model. Stimulation of prefrontal cortex (PFC) improved animals' associative learning while altering coherence between PFC and sensory areas. Their data suggest that tDCS may act by altering long-range connectivity between PFC and other brain areas. |
Mariska E. Kret; Carsten K. W. De Dreu Pupil-mimicry conditions trust in partners: Moderation by oxytocin and group membership Journal Article In: Proceedings of the Royal Society B: Biological Sciences, vol. 284, pp. 1–10, 2017. @article{Kret2017, Across species, oxytocin, an evolutionarily ancient neuropeptide, facilitates social communication by attuning individuals to conspecifics' social signals, fostering trust and bonding. The eyes have an important signalling function; and humans use their salient and communicative eyes to intentionally and unintentionally send social signals to others, by contracting the muscles around their eyes and pupils. In our earlier research, we observed that interaction partners with dilating pupils are trusted more than partners with constricting pupils. But over and beyond this effect, we found that the pupil sizes of partners synchronize and that when pupils synchronously dilate, trust is further boosted. Critically, this linkage between mimicry and trust was bound to interactions between ingroup members. The current study investigates whether these findings are modulated by oxytocin and sex of participant and partner. Using incentivized trust games with partners from ingroup and outgroup whose pupils dilated, remained static or constricted, this study replicates our earlier findings. It further reveals that (i) male participants withhold trust from partners with constricting pupils and extend trust to partners with dilating pupils, especially when given oxytocin rather than placebo; (ii) female participants trust partners with dilating pupils most, but this effect is blunted under oxytocin; (iii) under oxytocin rather than placebo, pupil dilation mimicry is weaker and pupil constriction mimicry stronger; and (iv) the link between pupil constriction mimicry and distrust observed under placebo disappears under oxytocin. We suggest that pupil-contingent trust is parochial and evolved in social species in and because of group life. |
Mariska E. Kret; Jeroen J. Stekelenburg; Beatrice Gelder; Karin Roelofs From face to hand: Attentional bias towards expressive hands in social anxiety Journal Article In: Biological Psychology, vol. 122, pp. 42–50, 2017. @article{Kret2017a, The eye-region conveys important emotional information that we spontaneously attend to. Socially submissive individuals avoid other's gaze which is regarded as avoidance of others' emotional face expressions. But this interpretation ignores the fact that there are other sources of emotional information besides the face. Here we investigate whether gaze-aversion is associated with increased attention to emotional signals from the hands. We used eye-tracking to compare eye-fixations of pre-selected high and low socially anxious students when labeling bodily expressions (Experiment 1) with (non)-matching facial expressions (Experiment 2) and passively viewed (Experiment 3). High compared to low socially anxious individuals attended more to hand-regions. Our findings demonstrate that socially anxious individuals do attend to emotions, albeit to different signals than the eyes and the face. Our findings call for a closer investigation of alternative viewing patterns explaining gaze-avoidance and underscore that other signals besides the eyes and face must be considered to reach conclusions about social anxiety. |
Magali Kreutzfeldt; Denise N. Stephan; Klaus Willmes; Iring Koch Modality-specific preparatory influences on the flexibility of cognitive control in task switching Journal Article In: Journal of Cognitive Psychology, vol. 29, no. 5, pp. 607–617, 2017. @article{Kreutzfeldt2017, In the current study, we addressed modality-specificity of the flexibility of cognitive control. We compared performance in single-task and mixed-tasks blocks between blocked auditory and visual stimuli assessing alternation costs (single vs. mixed). Mixed blocks comprised task switches only. The tasks consisted of numerical parity, magnitude, and distance judgments about numbers between one and nine without five. A cue indicated the relevant task. The cue–stimulus interval was varied (short vs. long interval) to examine preparation effects. The results indicated higher response times (RTs) and error rates (ERs) in mixed- vs. single-tasks blocks. The alternation costs in ERs were larger for auditory compared to visual stimulus presentation. Moreover, the reduction of RT alternation costs based on increased preparation time was more pronounced for the auditory modality compared to the visual modality. These results suggest a modality-specific influence on processes involved in maintaining and updating task sets in working memory. |
Philipp Kreyenmeier; Jolande Fooken; Miriam Spering Context effects on smooth pursuit and manual interception of a disappearing target Journal Article In: Journal of Neurophysiology, vol. 118, no. 1, pp. 404–415, 2017. @article{Kreyenmeier2017, In our natural environment, we interact with moving objects that are surrounded by richly textured, dynamic visual contexts. Yet most laboratory studies on vision and movement show visual objects in front of uniform gray backgrounds. Context effects on eye movements have been widely studied, but it is less well known how visual contexts affect hand movements. Here we ask whether eye and hand movements integrate motion signals from target and context similarly or differently, and whether context effects on eye and hand change over time. We developed a track-intercept task requiring participants to track the initial launch of a moving object (" ball ") with smooth pursuit eye movements. The ball disappeared after a brief presentation, and participants had to intercept it in a designated " hit zone. " In two experiments (n ϭ 18 human observers each), the ball was shown in front of a uniform or a textured background that either was stationary or moved along with the target. Eye and hand movement latencies and speeds were similarly affected by the visual context, but eye and hand interception (eye position at time of interception, and hand interception timing error) did not differ significantly between context conditions. Eye and hand interception timing errors were strongly correlated on a trial-by-trial basis across all context conditions, highlighting the close relation between these responses in manual interception tasks. Our results indicate that visual contexts similarly affect eye and hand movements but that these effects may be short-lasting, affecting movement trajectories more than movement end points. |
Onkar Krishna; Kiyoharu Aizawa; Andrea Helo; Rama Pia Gaze distribution analysis and saliency prediction across age groups Journal Article In: PLoS ONE, vol. 13, no. 2, pp. e0193149, 2017. @article{Krishna2017, Knowledge of the human visual system helps to develop better computational models of visual attention. State-of-the-art models have been developed to mimic the visual attention system of young adults that, however, largely ignore the variations that occur with age. In this paper, we investigated how visual scene processing changes with age and we propose an age-adapted framework that helps to develop a computational model that can predict saliency across different age groups. Our analysis uncovers how the explorativeness of an observer varies with age, how well saliency maps of an age group agree with fixation points of observers from the same or different age groups, and how age influences the center bias tendency. We analyzed the eye movement behavior of 82 observers belonging to four age groups while they explored visual scenes. Explorative- ness was quantified in terms of the entropy of a saliency map, and area under the curve (AUC) metrics was used to quantify the agreement analysis and the center bias tendency. Analysis results were used to develop age adapted saliency models. Our results suggest that the proposed age-adapted saliency model outperforms existing saliency models in predicting the regions of interest across age groups. |
Emmanuelle Kristensen; Anne Guerin-Dugué; Bertrand Rivet Regularization and a general linear model for event-related potential estimation Journal Article In: Behavior Research Methods, vol. 49, no. 6, pp. 2255–2274, 2017. @article{Kristensen2017, The usual event-related potential (ERP) estimation is the average across epochs time-locked on stimuli of interest. These stimuli are repeated several times to improve the signal-to-noise ratio (SNR) and only one evoked potential is estimated inside the temporal window of interest. Consequently, the average estimation does not take into account other neural responses within the same epoch that are due to short inter stimuli intervals. These adjacent neural responses may overlap and distort the evoked potential of interest. This overlapping process is a significant issue for the eye fixation-related potential (EFRP) technique in which the epochs are time-locked on the ocular fixations. The inter fixation intervals are not experimentally controlled and can be shorter than the neural response's latency. To begin, the Tikhonov regularization, applied to the classical average estimation, was introduced to improve the SNR for a given number of trials. The generalized cross validation was chosen to obtain the optimal value of the ridge parameter. Then, to deal with the issue of overlapping, the general linear model (GLM), was used to extract all neural responses inside an epoch. Finally, the regularization was also applied to it. The models (the classical average and the GLM with and without regularization) were compared on both simulated data and real datasets from a visual scene exploration in co-registration with an eye-tracker, and from a P300 Speller experiment. The regularization was found to improve the estimation by average for a given number of trials. The GLM was more robust and efficient, its efficiency actually reinforced by the regularization. |
Emmanuelle Kristensen; Bertrand Rivet; Anne Guérin-Dugué Estimation of overlapped Eye Fixation Related Potentials: The General Linear Model, a more flexible framework than the ADJAR algorithm Journal Article In: Journal of Eye Movement Research, vol. 10, no. 1, pp. 1–27, 2017. @article{Kristensen2017a, The Eye Fixation Related Potential (EFRP) estimation is the average of EEG signals across epochs at ocular fixation onset. Its main limitation is the overlapping issue. Inter Fixation Intervals (IFI) - typically around 300 ms in the case of unrestricted eye movement- depend on participants' oculomotor patterns, and can be shorter than the latency of the components of the evoked potential. If the duration of an epoch is longer than the IFI value, more than one fixation can occur, and some overlapping between adjacent neural responses ensues. The classical average does not take into account either the presence of several fixations during an epoch or overlapping. The Adjacent Response algorithm (ADJAR), which is popular for event-related potential estimation, was compared to the General Linear Model (GLM) on a real dataset from a conjoint EEG and eye-tracking experiment to address the overlapping issue. The results showed that the ADJAR algorithm was based on assumptions that were too restrictive for EFRP estimation. The General Linear Model appeared to be more robust and efficient. Different configurations of this model were compared to estimate the potential elicited at image onset, as well as EFRP at the beginning of exploration. These configurations took into account the overlap between the event-related potential at stimulus presentation and the following EFRP, and the distinction between the potential elicited by the first fixation onset and subsequent ones. The choice of the General Linear Model configuration was a tradeoff between assumptions about expected behavior and the quality of the EFRP estimation: the number of different potentials estimated by a given model must be controlled to avoid erroneous estimations with large variances. |
Edmundo Kronmüller; Ira Noveck; Natalia Rivera; Francisco Jaume-Guazzini; Dale Barr The positive side of a negative reference: The delay between linguistic processing and common ground Journal Article In: Royal Society Open Science, vol. 4, no. 2, pp. 1–14, 2017. @article{Kronmueller2017, Interlocutors converge on names to refer to entities. For example, a speaker might refer to a novel looking object as the jellyfish and, once identified, the listener will too. The hypothesized mechanism behind such referential precedents is a subject of debate. The common ground view claims that listeners register the object as well as the identity of the speaker who coined the label. The linguistic view claims that, once established, precedents are treated by listeners like any other linguistic unit, i.e. without needing to keep track of the speaker. To test predictions from each account, we used visual-world eyetracking, which allows observations in real time, during a standard referential communication task. Participants had to select objects based on instructions from two speakers. In the critical condition, listeners sought an object with a negative reference such as not the jellyfish. We aimed to determine the extent to which listeners rely on the linguistic input, common ground or both. We found that initial interpretations were based on linguistic processing only and that common ground considerations do emerge but only after 1000 ms. Our findings support the idea that-at least temporally-linguistic processing can be isolated from common ground. |
Thomas C. Kübler; Colleen Rothe; Ulrich Schiefer; Wolfgang Rosenstiel; Enkelejda Kasneci SubsMatch 2.0: Scanpath comparison and classification based on subsequence frequencies Journal Article In: Behavior Research Methods, vol. 49, no. 3, pp. 1048–1064, 2017. @article{Kuebler2017, Our eye movements are driven by a continuous trade-off between the need for detailed examination of objects of interest and the necessity to keep an overview of our surrounding. In consequence, behavioral patterns that are characteristic for our actions and their planning are typically manifested in the way we move our eyes to interact with our environment. Identifying such patterns from individual eye movement measurements is however highly challenging. In this work, we tackle the challenge of quantifying the influence of experimental factors on eye movement sequences. We introduce an algorithm for extracting sequence-sensitive features from eye movements and for the classification of eye movements based on the frequencies of small subsequences. Our approach is evaluated against the state-of-the art on a novel and a very rich collection of eye movements data derived from four experimental settings, from static viewing tasks to highly dynamic outdoor settings. Our results show that the proposed method is able to classify eye movement sequences over a variety of experimental designs. The choice of parameters is discussed in detail with special focus on highlighting different aspects of general scanpath shape. Algorithms and evaluation data are available at: http://www.ti.uni-tuebingen.de/scanpathcomparison.html . |
Anna B. Kuhns; Pascasie L. Dombert; Paola Mengotti; Gereon R. Fink; Simone Vossel Spatial attention, motor intention, and Bayesian cue predictability in the human brain Journal Article In: Journal of Neuroscience, vol. 37, no. 21, pp. 5334–5344, 2017. @article{Kuhns2017, Predictions about upcoming events influence how we perceive and respond to our environment. There is increasing evidence that predictions may be generated based upon previous observations following Bayesian principles, but little is known about the underlying corticalmechanismsandtheir specificity for different cognitive subsystems.Thepresent studyaimedat identifyingcommonanddistinct neural signatures of predictive processing in the spatial attentional and motor intentional system. Twenty-three female and male healthy human volunteers performed two probabilistic cueing tasks with either spatial or motor cues while lying in the fMRI scanner. In these tasks, the percentage of cue validity changed unpredictably over time. Trialwise estimates of cue predictability were derived from a Bayesian observer model of behavioral responses. These estimates were included as parametric regressors for analyzing the BOLD time series. Parametric effects of cue predictability in valid and invalid trials were considered to reflect belief updating by precision-weighted prediction errors. The brain areas exhibiting predictability-dependent effects dissociated between the spatial attention and motor inten- tion task, with the right temporoparietal cortex being involved during spatial attention and the left angular gyrus and anterior cingulate cortex during motor intention. Connectivity analyses revealed that all three areas showed predictability-dependent coupling with the right hippocampus. These results suggest that precision-weighted prediction errors of stimulus locations and motor responses are encoded in distinct brain regions, but that crosstalk with the hippocampusmaybe necessary to integrate new trialwise outcomes in both cognitive systems. |
Thibaut Le Naour; Jean-Pierre Bresciani A skeleton-based approach to analyze and visualize oculomotor behavior when viewing znimated characters Journal Article In: Journal of Eye Movement Research, vol. 10, no. 5, pp. 1–19, 2017. @article{LeNaour2017, Knowing what people look at and understanding how they analyze the dynamic gestures of their peers is an exciting challenge. In this context, we propose a new approach to quan- tifying and visualizing the oculomotor behavior of viewers watching the movements of animated characters in dynamic sequences. Using this approach, we were able to illustrate, on a 'heat mesh', the gaze distribution of one or several viewers, i.e., the time spent on each part of the body, and to visualize viewers' timelines, which are linked to the heat mesh. Our approach notably provides an 'intuitive' overview combining the spatial and temporal characteristics of the gaze pattern, thereby constituting an efficient tool for quickly comparing the oculomotor behaviors of different viewers. The functionalities of our system are illustrated through two use case experiments with 2D and 3D animated media sources, respectively. |
Matthew L. Leavitt; Florian Pieper; Adam J. Sachs; Julio C. Martinez-Trujillo Correlated variability modifies working memory fidelity in primate prefrontal neuronal ensembles Journal Article In: Proceedings of the National Academy of Sciences, vol. 114, no. 12, pp. E2494–E2503, 2017. @article{Leavitt2017a, Neurons in the primate lateral prefrontal cortex (LPFC) encode working memory (WM) representations via sustained firing, a phenomenon hypothesized to arise from recurrent dynamics within ensembles of interconnected neurons. Here, we tested this hypothesis by using microelectrode arrays to examine spike count correlations (rsc) in LPFC neuronal ensembles during a spatial WM task. We found a pattern of pairwise rsc during WM maintenance indicative of stronger coupling between similarly tuned neurons and increased inhibition between dissimilarly tuned neurons. We then used a linear decoder to quantify the effects of the high-dimensional rsc structure on information coding in the neuronal ensembles. We found that the rsc structure could facilitate or impair coding, depending on the size of the ensemble and tuning properties of its constituent neurons. A simple optimization procedure demonstrated that near-maximum decoding performance could be achieved using a relatively small number of neurons. These WM- optimized subensembles were more signal correlation (rsignal)- diverse and anatomically dispersed than predicted by the statistics of the full recorded population of neurons, and they often con- tained neurons that were poorly WM-selective, yet enhanced cod- ing fidelity by shaping the ensemble's rsc structure. We observed a pattern of rsc between LPFC neurons indicative of recurrent dynamics as a mechanism for WM-related activity and that the rsc structure can increase the fidelity ofWM representations. Thus, WM coding in LPFC neuronal ensembles arises from a complex synergy between single neuron coding properties and multidimensional, ensemble-level phenomena. |
Jeongmi Lee; Joy J. Geng Idiosyncratic patterns of representational similarity in prefrontal cortex predict attentional performance Journal Article In: Journal of Neuroscience, vol. 37, no. 5, pp. 1257–1268, 2017. @article{Lee2017a, The efficiency of finding an object in a crowded environment depends largely on the similarity of nontargets to the search target. Models of attention theorize that the similarity is determined by representations stored within an "attentional template" held in working memory. However, the degree to which the contents of the attentional template are individually unique and where those idiosyncratic representations are encoded in the brain are unknown. We investigated this problem using representational similarity analysis of human fMRI data to measure the common and idiosyncratic representations of famous face morphs during an identity categorization task; data from the categorization task were then used to predict performance on a separate identity search task. We hypothesized that the idiosyncratic categorical representations of the continuous face morphs would predict their distractability when searching for each target identity. The results identified that patterns of activation in the lateral prefrontal cortex (LPFC) as well as in face-selective areas in the ventral temporal cortex were highly correlated with the patterns of behavioral categorization of face morphs and search performance that were common across subjects. However, the individually unique components of the categorization behavior were reliably decoded only in right LPFC. Moreover, the neural pattern in right LPFC successfully predicted idiosyncratic variability in search performance, such that reaction times were longer when distractors had a higher probability of being categorized as the target identity. These results suggest that the prefrontal cortex encodes individually unique components of categorical representations that are also present in attentional tem-plates for target search. |
Jeyeon Lee; Hoseok Choi; Seho Lee; Baek Hwan Cho; Kyoung-ha Ahn; In Young Kim; Kyoung-Min Lee; Dong-Pyo Jang Decoding saccadic directions using epidural ECoG in non-human primates Journal Article In: Journal of Korean Medical Science, vol. 32, no. 8, pp. 1243–1250, 2017. @article{Lee2017, A brain-computer interface (BCI) can be used to restore some communication as an alternative interface for patients suffering from locked-in syndrome. However, most BCI systems are based on SSVEP, P300, or motor imagery, and a diversity of BCI protocols would be needed for various types of patients. In this paper, we trained the choice saccade (CS) task in 2 non-human primate monkeys and recorded the brain signal using an epidural electrocorticogram (eECoG) to predict eye movement direction. We successfully predicted the direction of the upcoming eye movement using a support vector machine (SVM) with the brain signals after the directional cue onset and before the saccade execution. The mean accuracies were 80% for 2 directions and 43% for 4 directions. We also quantified the spatial-spectro-temporal contribution ratio using SVM recursive feature elimination (RFE). The channels over the frontal eye field (FEF), supplementary eye field (SEF), and superior parietal lobule (SPL) area were dominantly used for classification. The α-band in the spectral domain and the time bins just after the directional cue onset and just before the saccadic execution were mainly useful for prediction. A saccade based BCI paradigm can be projected in the 2D space, and will hopefully provide an intuitive and convenient communication platform for users. |
Jiyeon Lee Time course of lexicalization during sentence production in Parkinson's Disease: Eye-tracking while speaking Journal Article In: Journal of Speech, Language, and Hearing Research, vol. 60, no. 4, pp. 924–936, 2017. @article{Lee2017b, Purpose: Growing evidence suggests that sentence formulation is affected in Parkinson's disease (PD); however, how speakers with PD coordinate sentence planning and speaking remains unclear. Within 2 competing models of sentence production, this study examined whether speakers with PD show advanced buffering of words to minimize disfluencies and increased demands during speech or whether they plan one word at a time, compromising accuracy and fluency of speech. Method: Participants described 3 computer-displayed pictures using the sentence "the A and the B are above the C." Name agreement (codability) was varied to be high (clock) or low (sofa/couch) for each object position (A, B, C), affecting difficulty of lexical selection. Participants' gaze durations to each object were recorded. Results: Speakers with PD showed incremental word-by-word planning, retrieving only the first lexical item (A) before speech onset, similar to controls. However, they produced greater word-finding errors and disfluencies compared to controls for the low-codable pictures, but not for high-codable pictures. Conclusions: These findings suggest that by following word-by-word incremental production, speakers with PD compromise fluency and accuracy of speech to a greater extent than healthy older speakers and that PD is associated with impaired inhibitory control during lexical selection. |
Miseon Lee Incremental processing of negation: Evidence from Korean Journal Article In: Linguistic Research, vol. 34, no. 2, pp. 205–224, 2017. @article{Lee2017c, The present study seeks to investigate whether negation is incrementally comprehended in Korean. Many of previous behavioral and neurological studies have found delays and errors in the comprehension of English negation. However, more recent studies have reported that negative sentences are incrementally processed as fast and accurately as affirmative sentences, given a pragmatically felicitous context. This discrepancy suggests that the poor comprehension of negation is mainly due to the absence of a felicitous context. In line with this, our hypothesis was that pragmatic felicity could help negation processing by establishing expectancies for using negation. In an eye-tracking task, we found that twenty-four Korean-speaking participants were equally fast and accurate in comprehending both affirmatives and negatives within a discourse context. Fixation analyses further showed that shortly after hearing the verb in a scrambled sentence, participants distinguished between negative and affirmative interpretations. These findings support the hypothesis that given a felicitous context, negation is incrementally processed by rapidly using the polarity information of the verb. |
Mallorie Leinenger; Mark Myslín; Keith Rayner; Roger P. Levy Do resource constraints affect lexical processing? Evidence from eye movements Journal Article In: Journal of Memory and Language, vol. 93, pp. 82–103, 2017. @article{Leinenger2017, Human language is massively ambiguous, yet we are generally able to identify the intended meanings of the sentences we hear and read quickly and accurately. How we manage and resolve ambiguity incrementally during real-time language comprehension given our cognitive resources and constraints is a major question in human cognition. Previous research investigating resource constraints on lexical ambiguity resolution has yielded conflicting results. Here we present results from two experiments in which we recorded eye movements to test for evidence of resource constraints during lexical ambiguity resolution. We embedded moderately biased homographs in sentences with neutral prior context and either long or short regions of text before disambiguation to the dominant or subordinate interpretation. The length of intervening material had no effect on ease of disambiguation. Instead, we found only a main effect of meaning at disambiguation, such that disambiguating to the subordinate meaning of the homograph was more difficult—results consistent with the reordered access model and contemporary probabilistic models, but inconsistent with the capacity-constrained model. |
Karolina M. Lempert; Sandra F. Lackovic; Russell H. Tobe; Paul W. Glimcher; Elizabeth A. Phelps Propranolol reduces reference-dependence in intertemporal choice Journal Article In: Social Cognitive and Affective Neuroscience, vol. 12, no. 9, pp. 1394–1401, 2017. @article{Lempert2017, In intertemporal choices between immediate and delayed rewards, people tend to prefer immediate rewards, often even when the delayed reward is larger. This is known as temporal discounting. It has been proposed that this tendency emerges because immediate rewards are more emotionally arousing than delayed rewards. However, in our previous research, we found no evidence for this but instead found that arousal responses (indexed with pupil dilation) in intertemporal choice are context-dependent. Specifically, arousal tracks the subjective value of the more variable reward option in the paradigm, whether it is immediate or delayed. Nevertheless, people tend to choose the less variable option in the choice task. In other words, their choices are reference-dependent and depend on variance in their recent history of offers. This suggests that there may be a causal relationship between reference-dependent choice and arousal, which we investigate here by reducing arousal pharmacologically using propranolol. Here, we show that propranolol reduces reference-dependence, leading to choices that are less influenced by recent history and more internally consistent. |
Rebekka Lencer; Annegret Meermeier; Karen Silling; Svenja Gremmler; Markus Lappe Instability of visual error processing for sensorimotor adaptation in schizophrenia Journal Article In: European Archives of Psychiatry and Clinical Neuroscience, vol. 267, no. 3, pp. 237–244, 2017. @article{Lencer2017, Saccadic adaptation can be used to study disturbances of sensory processing and motor learning. We investigated whether patients with schizophrenia can adjust saccadic amplitudes to account for an increase in visual error while the saccade is in flight, and whether they transfer this change to a visuo-manual localization task. Fourteen patients (mean 37.1 years) and 14 healthy controls (mean 35.1 years) performed 200 adaptation trials of 10° with target shifts of 4° in the outward direction. We determined the percent amplitude change during adaptation and adaptation speed. In addition, subjects localized a stimulus that was flashed 50 ms after saccade target onset to measure the transfer of change in visual space perception to visuo-manual coordination. Eye movements were recorded at 1000 Hz. Saccade amplitudes increased over adapta- tion trials by 11 % (p < 0.001) similarly in both groups. Amplitude variability during adaptation was higher in patients (1.06° ± 0.32°) than in controls (0.71° ± 0.14°; p = 0.001), while adaptation speed was slower in patients (0.02 ± 0.03) than in controls (0.11 ± 0.11; p = 0.01). Other pre- and post-adaptation saccade metrics did not differ between groups. The adaptation process shifted localization of the flashed target in the adaptation direction simi- larly in both groups. The use of error signals for the internal recalibration of sensorimotor systems and the transfer of this recalibration to visual space perception appear basically unimpaired in schizophrenia. Higher amplitude variability in patients suggests a certain instability of saccadic control in cerebellar systems. Patients seem to rely on visual error processing in frontal circuitry, resulting in slower adaptation speeds, despite unimpaired adaptation strength. |
Rebekka Lencer; L. J. Mills; N. Alliey-Rodriguez; R. Shafee; A. M. Lee; James L. Reilly; Andreas Sprenger; Jennifer E. McDowell; S. A. McCarroll; Matcheri S. Keshavan; Godfrey D. Pearlson; Carol A. Tamminga; Brett A. Clementz; Elliot S. Gershon; John A. Sweeney; J. R. Bishop Genome-wide association studies of smooth pursuit and antisaccade eye movements in psychotic disorders: findings from the B-SNIP study Journal Article In: Translational Psychiatry, vol. 7, pp. e1249, 2017. @article{Lencer2017a, Eye movement deviations, particularly deficits of initial sensorimotor processing and sustained pursuit maintenance, and antisaccade inhibition errors, are established intermediate phenotypes for psychotic disorders. We here studied eye movement measures of 849 participants from the Bipolar-Schizophrenia Network on Intermediate Phenotypes (B-SNIP) study (schizophrenia N = 230, schizoaffective disorder N = 155, psychotic bipolar disorder N = 206 and healthy controls N = 258) as quantitative phenotypes in relation to genetic data, while controlling for genetically derived ancestry measures, age and sex. A mixed-modeling genome-wide association studies approach was used including ~ 4.4 million genotypes (PsychChip and 1000 Genomes imputation). Across participants, sensorimotor processing at pursuit initiation was significantly associated with a single nucleotide polymorphism in IPO8 (12p11.21 |
Alexander Leube; Katharina Rifai; Siegfried Wahl Sampling rate influences saccade detection in mobile eye tracking of a reading task Journal Article In: Journal of Eye Movement Research, vol. 10, no. 3, pp. 3, 2017. @article{Leube2017, The purpose of this study was to compare saccade detection characteristics in two mobile eye trackers with different sampling rates in a natural task. Gaze data of 11 participants were recorded in one 60 Hz and one 120 Hz mobile eye tracker and compared directly to the saccades detected by a 1000 HZ stationary tracker while a reading task was performed. Saccades and fixations were detected using a velocity based algorithm and their properties analyzed. Results showed that there was no significant difference in the number of detect- ed fixations but mean fixation durations differed between the 60 Hz mobile and the sta- tionary eye tracker. The 120 Hz mobile eye tracker showed a significant increase in the detection rate of saccades and an improved estimation of the mean saccade duration, com- pared to the 60 Hz eye tracker. To conclude, for the detection and analysis of fast eye movements, such as saccades, it is better to use a 120 Hz mobile eye tracker. |
Laura Leuchs; Max Schneider; Michael Czisch; Victor I. Spoormaker Neural correlates of pupil dilation during human fear learning Journal Article In: NeuroImage, vol. 147, pp. 186–197, 2017. @article{Leuchs2017, Background: Fear conditioning and extinction are prevailing experimental and etiological models for normal and pathological anxiety. Pupil dilations in response to conditioned stimuli are increasingly used as a robust psychophysiological readout of fear learning, but their neural correlates remain unknown. We aimed at identifying the neural correlates of pupil responses to threat and safety cues during a fear learning task. Methods: Thirty-four healthy subjects underwent a fear conditioning and extinction paradigm with simultaneous functional magnetic resonance imaging (fMRI) and pupillometry. After a stringent preprocessing and artifact rejection procedure, trial-wise pupil responses to threat and safety cues were entered as parametric modulations to the fMRI general linear models. Results: Trial-wise magnitude of pupil responses to both conditioned and safety stimuli correlated positively with activity in dorsal anterior cingulate cortex (dACC), thalamus, supramarginal gyrus and insula for the entire fear learning task, and with activity in the dACC during the fear conditioning phase in particular. Phasic pupil responses did not show habituation, but were negatively correlated with tonic baseline pupil diameter, which decreased during the task. Correcting phasic pupil responses for the tonic baseline pupil diameter revealed thalamic activity, which was also observed in an analysis employing a linear (declining) time modulation. Conclusion: Pupil dilations during fear conditioning and extinction provide useful readouts to track fear learning on a trial-by-trial level, particularly with simultaneous fMRI. Whereas phasic pupil responses reflect activity in brain regions involved in fear learning and threat appraisal, most prominently in dACC, tonic changes in pupil diameter may reflect changes in general arousal. |
Phillipp Kurtz; Katharine A. Shapcott; Jochen Kaiser; Joscha T. Schmiedt; Michael C. Schmid The influence of endogenous and exogenous spatial attention on decision confidence Journal Article In: Scientific Reports, vol. 7, pp. 6431, 2017. @article{Kurtz2017, Spatial attention allows us to make more accurate decisions about events in our environment. Decision confidence is thought to be intimately linked to the decision making process as confidence ratings are tightly coupled to decision accuracy. While both spatial attention and decision confidence have been subjected to extensive research, surprisingly little is known about the interaction between these two processes. Since attention increases performance it might be expected that confidence would also increase. However, two studies investigating the effects of endogenous attention on decision confidence found contradictory results. Here we investigated the effects of two distinct forms of spatial attention on decision confidence; endogenous attention and exogenous attention. We used an orientation-matching task, comparing the two attention conditions (endogenous and exogenous) to a control condition without directed attention. Participants performed better under both attention conditions than in the control condition. Higher confidence ratings than the control condition were found under endogenous attention but not under exogenous attention. This finding suggests that while attention can increase confidence ratings, it must be voluntarily deployed for this increase to take place. We discuss possible implications of this relative overconfidence found only during endogenous attention with respect to the theoretical background of decision confidence. |
Sol Lago; Shayne Sloggett; Zoe Schlueter; Wing Yee Chow; Alexander Williams; Ellen Lau; Colin Phillips Coreference and antecedent representation across languages Journal Article In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 43, no. 5, pp. 795–817, 2017. @article{Lago2017, Previous studies have shown that speakers of languages such as German, Spanish, and French reactivate the syntactic gender of the antecedent of a pronoun to license gender agreement. As syntactic gender is assumed to be stored in the lexicon, this has motivated the claim that pronouns in these languages reactivate the lexical entry of their antecedent noun. In contrast, in languages without syntactic gender such as English, lexical retrieval might be unnecessary. We used eye-tracking while reading to examine whether antecedent retrieval involves rapid semantic and phonological reactivation. We compared German and English. In German, we found early sensitivity to the semantic but not to the phonological features of the pronoun's antecedent. In English, readers did not immediately show either semantic or phonological effects specific to coreference. We propose that early semantic facilitation arises due to syntactic gender reactivation, and that antecedent retrieval varies cross-linguistically depending on the type of information relevant to the grammar of each language. |
Kaitlin E. W. Laidlaw; Alan Kingstone Fixations to the eyes aids in facial encoding; covertly attending to the eyes does not Journal Article In: Acta Psychologica, vol. 173, pp. 55–65, 2017. @article{Laidlaw2017, When looking at images of faces, people will often focus their fixations on the eyes. It has previously been demonstrated that the eyes convey important information that may improve later facial recognition. Whether this advantage requires that the eyes be fixated, or merely attended to covertly (i.e. while looking elsewhere), is unclear from previous work. While attending to the eyes covertly without fixating them may be sufficient, the act of using overt attention to fixate the eyes may improve the processing of important details used for later recognition. In the present study, participants were shown a series of faces and, in Experiment 1, asked to attend to them normally while avoiding looking at either the eyes or, as a control, the mouth (overt attentional avoidance condition); or in Experiment 2 fixate the center of the face while covertly attending to either the eyes or the mouth (covert attention condition). After the first phase, participants were asked to perform an old/new face recognition task. We demonstrate that a) when fixations to the eyes are avoided during initial viewing then subsequent face discrimination suffers, and b) covert attention to the eyes alone is insufficient to improve face discrimination performance. Together, these findings demonstrate that fixating the eyes provides an encoding advantage that is not availed by covert attention alone. |
Elke B. Lange; Fabian Zweck; Petra Sinn Microsaccade-rate indicates absorption by music listening Journal Article In: Consciousness and Cognition, vol. 55, pp. 59–78, 2017. @article{Lange2017, The power of music is a literary topos, which can be attributed to intense and personally significant experiences, one of them being the state of absorption. Such phenomenal states are difficult to grasp objectively. We investigated the state of musical absorption by using eye tracking. We utilized a load related definition of state absorption: multimodal resources are committed to create a unified representation of music. Resource allocation was measured indirectly by microsaccade rate, known to indicate cognitive processing load. We showed in Exp. 1 that microsaccade rate also indicates state absorption. Hence, there is cross-modal coupling between an auditory aesthetic experience and fixational eye movements. When removing the fixational stimulus in Exp. 2, saccades are no longer generated upon visual input and the cross-modal coupling disappeared. Results are interpreted in favor of the load hypothesis of microsaccade rate and against the assumption of general slowing by state absorption. |
Ryan W. Langridge; Jonathan J. Marotta In: Experimental Brain Research, vol. 235, no. 9, pp. 2705–2716, 2017. @article{Langridge2017, Participants executed right-handed reach-to-grasp movements toward horizontally translating targets. Visual feedback of the target when reaching, as well as the presence of additional cues placed above and below the target's path, was manipulated. Comparison of average fixations at reach onset and at the time of the grasp suggested that participants accurately extrapolated the occluded target's motion prior to reach onset, but not after the reach had been initiated, resulting in inaccurate grasp placements. Final gaze and grasp positions were more accurate when reaching for leftward moving targets, suggesting individuals use different grasp strategies when reaching for targets traveling away from the reaching hand. Additional cue presence appeared to impair participants' ability to extrapolate the disappeared target's motion, and caused grasps for occluded targets to be less accurate. Novel information is provided about the eye-hand strategies used when reaching for moving targets in unpredictable visual conditions. |
S. J. Larcombe; Christopher Kennard; H. Bridge Time course influences transfer of visual perceptual learning across spatial location Journal Article In: Vision Research, vol. 135, pp. 26–33, 2017. @article{Larcombe2017, Visual perceptual learning describes the improvement of visual perception with repeated practice. Previous research has established that the learning effects of perceptual training may be transferable to untrained stimulus attributes such as spatial location under certain circumstances. However, the mechanisms involved in transfer have not yet been fully elucidated. Here, we investigated the effect of altering training time course on the transferability of learning effects. Participants were trained on a motion direction discrimination task or a sinusoidal grating orientation discrimination task in a single visual hemifield. The 4000 training trials were either condensed into one day, or spread evenly across five training days. When participants were trained over a five-day period, there was transfer of learning to both the untrained visual hemifield and the untrained task. In contrast, when the same amount of training was condensed into a single day, participants did not show any transfer of learning. Thus, learning time course may influence the transferability of perceptual learning effects. |
Amelia K. Lewis; Melanie A. Porter; Tracey A. Williams; Samantha Bzishvili; Kathryn N. North; Jonathan M. Payne Facial emotion recognition, face scan paths, and face perception in children with neurofibromatosis type Journal Article In: Neuropsychology, vol. 31, no. 4, pp. 361–370, 2017. @article{Lewis2017, OBJECTIVE: This study aimed to investigate face scan paths and face perception abilities in children with Neurofibromatosis Type 1 (NF1) and how these might relate to emotion recognition abilities in this population. METHOD: The authors investigated facial emotion recognition, face scan paths, and face perception in 29 children with NF1 compared to 29 chronological age-matched typically developing controls. Correlations between facial emotion recognition, face scan paths, and face perception in children with NF1 were examined. RESULTS: Children with NF1 displayed significantly poorer recognition of fearful expressions compared to controls, as well as a nonsignificant trend toward poorer recognition of anger. Athough there was no significant difference between groups in time spent viewing individual core facial features (eyes, nose, mouth, and nonfeature regions), children with NF1 spent significantly less time than controls viewing the face as a whole. Children with NF1 also displayed significantly poorer face perception abilities than typically developing controls. Facial emotion recognition deficits were not significantly associated with aberrant face scan paths or face perception abilities in the NF1 group. CONCLUSIONS: These results suggest that impairments in the perception, identification, and interpretation of information from faces are important aspects of the social-cognitive phenotype of NF1. |
Fang Li; Willem M. Mak; Jacqueline Evers-Vermeul; Ted J. M. Sanders On the online effects of subjectivity encoded in causal connectives Journal Article In: Review of Cognitive Linguistics, vol. 15, no. 1, pp. 34–57, 2017. @article{Li2017d, Causal relations between sentences differ in terms of subjectivity: They can be objective (based on facts) or subjective (based on reasoning). Subjective relations lead to longer reading times than objective relations. Causal connectives differ in the degree to which they encode this subjectivity. The Chinese connectives kejian 'so' and yin'er 'so' specify a high and low degree of subjectivity, respectively, whereas suoyi 'so' is underspecified for subjectivity. In an eye-tracking experiment we compare the effect of the specificity of these connectives in subjective and objective relations. In objective relations, the specificity of the connective has no effect on reading times. In subjective relations, reading times are shorter in sentences with the specified connective kejian than in sentences with the underspecified connective suoyi. These results suggest that readers prefer to interpret a relation as objective. Computing subjective relations requires extra processing time, which is diminished when the connective encodes the subjectivity. |
Hui Li; Xu Liu; Ian M. Andolina; Xiaohong Li; Yiliang Lu; Lothar Spillmann; Wei Wang Asymmetries of Dark and Bright Negative Afterimages Are Paralleled by Subcortical ON and OFF Poststimulus Responses Journal Article In: Journal of Neuroscience, vol. 37, no. 8, pp. 1984–1996, 2017. @article{Li2017b, Humans are more sensitive to luminance decrements than increments, as evidenced by lower thresholds and shorter latencies for dark stimuli. This asymmetry is consistent with results of neurophysiological recordings in dorsal lateral geniculate nucleus (dLGN) and primary visual cortex (V1) of cat and monkey. Specifically, V1 population responses demonstrate that darks elicit higher levels of activation than brights, and the latency ofOFF responses in dLGN and V1 is shorter than that ofON responses. The removal ofa dark or bright disc often generates the perception of a negative afterimage, and here we ask whether there also exist asymmetries for negative afterimages elicited bydarkand bright discs. If so, do the poststimulus responses ofsubcortical ON and OFF cells parallel such afterimage asymmetries? To test these hypotheses, we performed psychophysical experiments in humans and single-cell/S-potential recordings in cat dLGN. Psychophysically, we found that bright afterimages elicited by luminance decrements are stronger and last longer than dark afterimages elicited by luminance increments ofequal sizes. Neurophysiologically, we found that ON cells responded to the removal ofa dark disc with higher firing rates that were maintained for longer than OFF cells to the removal of a bright disc. The ON and OFF cell asymmetry was most pronounced at long stimulus durations in the dLGN. We conclude that subcortical response strength differences between ON and OFF channels parallel the asymmetries between bright and dark negative afterimages, further supporting a subcortical origin ofbright and dark afterimage perception. |
Kuei-An Li; Su-Ling Yeh Mean size estimation yields left-side bias: Role of attention on perceptual averaging Journal Article In: Attention, Perception, and Psychophysics, vol. 79, no. 8, pp. 2538–2551, 2017. @article{Li2017, The human visual system can estimate mean size of a set of items effectively; however, little is known about whether information on each visual field contributes equally to the mean size estimation. In this study, we examined wheth- er a left-side bias (LSB)—perceptual judgment tends to de- pend more heavily on left visual field'sinputs—affects mean size estimation. Participants were instructed to estimate the mean size of 16 spots. In half of the trials, the mean size of the spots on the left side was larger than that on the right side (the left-larger condition) and vice versa (the right-larger con- dition). Our results illustrated an LSB: A larger estimated mean size was found in the left-larger condition than in the right-larger condition (Experiment 1), and the LSB vanished when participants' attention was effectively cued to the right side (Experiment 2b). Furthermore, the magnitude of LSB increased with stimulus-onset asynchrony (SOA), when spots on the left side were presented earlier than the right side. In contrast, the LSB vanished and then induced a reversed effect with SOAwhen spots on the right side were presented earlier (Experiment 3). This study offers the first piece of evidence suggesting that LSB does have a significant influence on mean size estimation of a group of items, which is induced by a leftward attentional bias that enhances the prior entry effect on the left side. |
Lin Li; Sha Li; Jingxin Wang; Victoria A. McGowan; Pingping Liu; Timothy R. Jordan; Kevin B. Paterson Aging and the optimal viewing position effect in visual word recognition: Evidence from English Journal Article In: Psychology and Aging, vol. 32, no. 4, pp. 367–376, 2017. @article{Li2017c, Words are recognized most efficiently by young adults when fixated at an optimal viewing position (OVP), which for English is between a word's beginning and middle letters. How this OVP effect changes with age is unknown but may differ for older adults due to visual declines in later life. Accordingly, a lexical decision experiment was conducted in which short (5-letter) and long (9-letter) words were fixated at various letter positions. The older adults produced slower responses. But, crucially, effects of fixation location for each word-length did not differ substantially across age groups, indicating that OVP effects are preserved in older age. |
Feifei Liang; Hazel I. Blythe; Xuejun Bai; Guoli Yan; Xin Li; Chuanli Zang; Simon P. Liversedge The role of character positional frequency on Chinese word learning during natural reading Journal Article In: PLoS ONE, vol. 12, no. 11, pp. e0187656, 2017. @article{Liang2017a, Readers' eye movements were recorded to examine the role of character positional frequency on Chinese lexical acquisition during reading and its possible modulation by word spacing. In Experiment 1, three types of pseudowords were constructed based on each character's positional frequency, providing congruent, incongruent, and no positional word segmentation information. Each pseudoword was embedded into two sets of sentences, for the learning and the test phases. In the learning phase, half the participants read sentences in word-spaced format, and half in unspaced format. In the test phase, all participants read sentences in unspaced format. The results showed an inhibitory effect of character positional frequency upon the efficiency of word learning when processing incongruent pseudowords both in the learning and test phase, and also showed facilitatory effect of word spacing in the learning phase, but not at test. Most importantly, these two characteristics exerted independent influences on word segmentation. In Experiment 2, three analogous types of pseudowords were created whilst controlling for orthographic neighborhood size. The results of the two experiments were consistent, except that the effect of character positional frequency was absent in the test phase in Experiment 2. We argue that the positional frequency of a word's constituent characters may influence the character-to-word assignment in a process that likely incorporates both lexical segmentation and identification. |
Lixin Liang; Yang Zhou; Mingsha Zhang; Yujun Pan Revealing the radial effect on orientation discrimination by manual reaction time Journal Article In: Frontiers in Neuroscience, vol. 11, pp. 638, 2017. @article{Liang2017, It has been shown that the sensitivity and accuracy of orientation perception in the periphery is significantly better when the orientations are radial with respect to the fixation point than when they are tangential. However, since perception and action may be dissociated, it is unclear whether the perceptual radial effect has a counterpart in reaction time (RT) of motor responses. Furthermore, it is unknown whether or how stimulus-response-compatibility (SRC) effect interacts with the radial effect to determine reaction time. To address these questions, we measured subjects' manual RT to grating stimuli that appeared across upper visual field (VF). We found that (1) RTs were significantly shorter when a grating was oriented closer to the radial direction than when it was oriented closer to the tangential direction even though the perceptual accuracies for the more radial and more tangential orientations were not significantly different under our experimental condition; (2) This RT version of the radial effect was larger in the left VF than in the right VF; (3) The radial effect and SRC effect interacted with each other to determine the overall reaction time. These results suggest that the RT radial effect reported here is not a passive reflection of the radial effect in perceptual accuracy, but instead, represents different processing time of radial and tangential orientations along the sensorimotor pathway. |
Limor Lichtenstein-Vidne; Shai Gabay; N. Cohen; A. Henik Lateralisation of emotions: Evidence from pupil size measurement Journal Article In: Cognition and Emotion, vol. 31, no. 4, pp. 699–711, 2017. @article{LichtensteinVidne2017, The way our brain processes emotional stimuli has been studied intensively. One of the main issues still under debate is the laterality of valence processing. Herein, we employed the fact that pupil size increases under conditions of higher mental effort and during emotional processing, in order to contrast three proposed hypotheses in the field. We used different manual response mapping for emotional stimuli: Participants responded with their right hand for positive and with their left hand for negative facial expressions, or vice versa. The hands position was either regular (Experiment 1) or crossed (Experiment 2) in order to rule out a "spatial-valence association" alternate explanation. A third experiment was conducted by employing a passive viewing procedure of peripheral emotional stimuli. In the first two experiments, pupil size was larger when participants responded to positive stimuli with their left hand and to negative with their right hand, compared with the opposite mapping. Results of Experiment 3 strengthen the findings of Experiments 1 and 2. These findings provide significant psychophysiological evidence for the valence hypothesis: Processing positive stimuli involves the left hemisphere, while processing negative stimuli involves the right hemisphere. These results are discussed in relation to contemporary theories of emotion processing. |
Pascal Lienert; Bernadette Sütterlin; Michael Siegrist The influence of high-voltage power lines on the feelings evoked by different Swiss surroundings Journal Article In: Energy Research and Social Science, vol. 23, pp. 46–59, 2017. @article{Lienert2017, The planned transition from nuclear power to decentralized renewable energy sources in Switzerland requires the modification and expansion of the electricity grid. However, public acceptance of high-voltage power lines (HVPLs) is generally low. Drawing on the importance of affect in the context of technology acceptance, the goal of the present work was to shed light on people's affective responses to HVPLs, as well as to examine the influence of different siting options. Results of an online study (N = 94) showed that pictures of landscapes featuring HVPLs evoke significantly stronger negative feelings than pictures of the same landscapes without HVPLs. These differences were greater for positively perceived surroundings such as rural landscapes than for negatively perceived surroundings such as urban landscapes. In a second step, an eye tracking study (N = 95) was conducted to validate these findings and gain insights into people's decision making. Results show that people pay more attention to HVPLs when they are sited in positively perceived landscapes than when they are sited in negatively perceived landscapes. Furthermore, increased attention on HVPLs was related to a more negative affective evaluation of otherwise positively perceived landscapes. The results underline the importance of siting decisions in the context of grid infrastructure projects. |
Steffen Klingenhoefer; Bart Krekelberg Perisaccadic visual perception Journal Article In: Journal of Vision, vol. 17, no. 9, pp. 1–14, 2017. @article{Klingenhoefer2017, Primates use frequent, rapid eye movements to sample their visual environment. This is a fruitful strategy to make the best use of the highly sensitive foveal part of the retina, but it requires neural mechanisms to bind the rapidly changing visual input into a single, stable percept. Studies investigating these neural mechanisms have typically assumed that perisaccadic perception in nonhuman primates matches that of humans. We tested this assumption by performing identical experiments in human and nonhuman primates. Our data confirm that perisaccadic visual perception of macaques and humans is qualitatively similar. Specifically, we found a reduction in detectability and mislocalization of targets presented at the time of saccades. We also found substantial differences between human and nonhuman primates. Notably, in nonhuman primates, localization that requires knowledge of eye position was less precise, nonhuman primates detected fewer perisaccadic stimuli, and perisaccadic compression was not towards the saccade target. The qualitative similarities between species support the view that the nonhuman primate is ideally suited to study aspects of brain function-such as those relying on foveal vision-that are uniquely developed in primates. The quantitative differences, however, demonstrate the need for a reassessment of the models purportedly linking neural response changes at the time of saccades with the behavioral phenomena of perisaccadic reduction of detectability and mislocalization. |
Mathias Klinghammer; Gunnar Blohm; Katja Fiehler Scene configuration and object reliability affect the use of allocentric information for memory-guided reaching Journal Article In: Frontiers in Neuroscience, vol. 11, pp. 204, 2017. @article{Klinghammer2017, Previous research has shown that egocentric and allocentric information is used for coding target locations for memory-guided reaching movements. Especially, task-relevance determines the use of objects as allocentric cues. Here, we investigated the influence of scene configuration and object reliability as a function of task-relevance on allocentric coding for memory-guided reaching. For that purpose, we presented participants images of a naturalistic breakfast scene with five objects on a table and six objects in the background. Six of these objects served as potential reach-targets (= task-relevant objects). Participants explored the scene and after a short delay, a test scene appeared with one of the task-relevant objects missing, indicating the location of the reach target. After the test scene vanished, participants performed a memory-guided reaching movement toward the target location. Besides removing one object from the test scene, we also shifted the remaining task-relevant and/or task-irrelevant objects left- or rightwards either coherently in the same direction or incoherently in opposite directions. By varying object coherence, we manipulated the reliability of task-relevant and task-irrelevant objects in the scene. In order to examine the influence of scene configuration (distributed vs. grouped arrangement of task-relevant objects) on allocentric coding, we compared the present data with our previously published data set (Klinghammer et al., 2015). We found that reaching errors systematically deviated in the direction of object shifts, but only when the objects were task-relevant and their reliability was high. However, this effect was substantially reduced when task-relevant objects were distributed across the scene leading to a larger target-cue distance compared to a grouped configuration. No deviations of reach endpoints were observed in conditions with shifts of only task-irrelevant objects or with low object reliability irrespective of task-relevancy. Moreover, when solely task-relevant objects were shifted incoherently, the variability of reaching endpoints increased compared to coherent shifts of task-relevant objects. Our results suggest that the use of allocentric information for coding targets for memory-guided reaching depends on the scene configuration, in particular the average distance of the reach target to task-relevant objects, and the reliability of task-relevant allocentric information. |
P. Christiaan Klink; Danique Jeurissen; Jan Theeuwes; Damiaan Denys; Pieter R. Roelfsema Working memory accuracy for multiple targets is driven by reward expectation and stimulus contrast with different time-courses Journal Article In: Scientific Reports, vol. 7, pp. 9082, 2017. @article{Klink2017, The richness of sensory input dictates that the brain must prioritize and select information for further processing and storage in working memory. Stimulus salience and reward expectations influence this prioritization but their relative contributions and underlying mechanisms are poorly understood. Here we investigate how the quality of working memory for multiple stimuli is determined by priority during encoding and later memory phases. Selective attention could, for instance, act as the primary gating mechanism when stimuli are still visible. Alternatively, observers might still be able to shift priorities across memories during maintenance or retrieval. To distinguish between these possibilities, we investigated how and when reward cues determine working memory accuracy and found that they were only effective during memory encoding. Previously learned, but currently non-predictive, color-reward associations had a similar influence, which gradually weakened without reinforcement. Finally, we show that bottom-up salience, manipulated through varying stimulus contrast, influences memory accuracy during encoding with a fundamentally different time-course than top-down reward cues. While reward-based effects required long stimulus presentation, the influence of contrast was strongest with brief presentations. Our results demonstrate how memory resources are distributed over memory targets and implicates selective attention as a main gating mechanism between sensory and memory systems. |
Jessica Klusek; Joseph Schmidt; Amanda J. Fairchild; Anna Porter; Jane E. Roberts Altered sensitivity to social gaze in the FMR1 premutation and pragmatic language competence Journal Article In: Journal of Neurodevelopmental Disorders, vol. 9, no. 1, pp. 1–10, 2017. @article{Klusek2017, Background: The FMR1 premutation affects 1:291 women and is associated with a range of cognitive, affective, and physical health complications, including deficits in pragmatic language (i.e., social language). This study investigated attention to eye gaze as a fundamental social-cognitive skill that may be impaired in the FMR1 premutation and could underlie pragmatic deficits. Given the high prevalence of the FMR1 premutation, efforts to define its phenotype and mechanistic underpinnings have significant public health implications. Methods: Thirty-five women with the FMR1 premutation and 20 control women completed an eye-tracking paradigm that recorded time spent dwelling within the eye region in response to a face displaying either direct or averted gaze. Pragmatic language ability was coded from a conversational sample using the Pragmatic Rating Scale. Results: Women with the FMR1 premutation failed to show attentional preference to direct gaze and spent more time dwelling on the averted eyes relative to controls. While dwelling on the eyes was associated with better pragmatic language performance in controls, these variables were unrelated in the women with the FMR1 premutation. Conclusions: Altered sensitivity to social gaze, characterized by increased salience of averted gaze, was observed among womenwiththe FMR1 premutation. Furthermore, women with the FMR1 premutation wereunabletocapitalizeon information conveyed through the eyes to enhance social-communicative engagement, which differed from patterns seen in controls. These findings contribute to the growing characterization of social and communication phenotypes associated with the FMR1 premutation. |
Kathryn Koehler; Miguel P. Eckstein Temporal and peripheral extraction of contextual cues from scenes during visual search Journal Article In: Journal of Vision, vol. 17, no. 2, pp. 1–32, 2017. @article{Koehler2017a, Scene context is known to facilitate object recognition and guide visual search, but little work has focused on isolating image-based cues and evaluating their contributions to eye movement guidance and search performance. Here, we explore three types of contextual cues (a co-occurring object, the configuration of other objects, and the superordinate category of background elements) and assess their joint contributions to search performance in the framework of cue-combination and the temporal unfolding of their extraction. We also assess whether observers' ability to extract each contextual cue in the visual periphery is a bottleneck that determines the utilization and contribution of each cue to search guidance and decision accuracy. We find that during the first four fixations of a visual search task observers first utilize the configuration of objects for coarse eye movement guidance and later use co-occurring object information for finer guidance. In the absence of contextual cues, observers were suboptimally biased to report the target object as being absent. The presence of the co-occurring object was the only contextual cue that had a significant effect in reducing decision bias. The early influence of object-based cues on eye movements is corroborated by a clear demonstration of observers' ability to extract object cues up to 16 degrees into the visual periphery. The joint contributions of the cues to decision search accuracy approximates that expected from the combination of statistically independent cues and optimal cue combination. Finally, the lack of utilization and contribution of the background-based contextual cue to search guidance cannot be explained by the availability of the contextual cue in the visual periphery; instead it is related to background cues providing the least inherent information about the precise location of the target in the scene. |
Kathryn Koehler; Miguel P. Eckstein Beyond scene gist: Objects guide search more than scene background Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 43, no. 6, pp. 1177–1193, 2017. @article{Koehler2017, Although the facilitation of visual search by contextual information is well established, there is little understanding of the independent contributions of different types of contextual cues in scenes. Here we manipulated 3 types of contextual information: object co-occurrence, multiple object configurations, and background category. We isolated the benefits of each contextual cue to target detectability, its impact on decision bias, confidence, and the guidance of eye movements. We find that object-based information guides eye movements and facilitates perceptual judgments more than scene background. The degree of guidance and facilitation of each contextual cue can be related to its inherent informativeness about the target spatial location as measured by human explicit judgments about likely target locations. Our results improve the understanding of the contributions of distinct contextual scene components to search and suggest that the brain's utilization of cues to guide eye movements is linked to the cue's informativeness about the target's location. |