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!
2016 |
Jordan E. Pierce; Jennifer E. McDowell Effects of preparation time and trial type probability on performance of anti- and pro-saccades Journal Article In: Acta Psychologica, vol. 164, pp. 188–194, 2016. @article{Pierce2016, Cognitive control optimizes responses to relevant task conditions by balancing bottom-up stimulus processing with top-down goal pursuit. It can be investigated using the ocular motor system by contrasting basic prosaccades (look toward a stimulus) with complex antisaccades (look away from a stimulus). Furthermore, the amount of time allotted between trials, the need to switch task sets, and the time allowed to prepare for an upcoming saccade all impact performance. In this study the relative probabilities of anti- and pro-saccades were manipulated across five blocks of interleaved trials, while the inter-trial interval and trial type cue duration were varied across subjects. Results indicated that inter-trial interval had no significant effect on error rates or reaction times (RTs), while a shorter trial type cue led to more antisaccade errors and faster overall RTs. Responses following a shorter cue duration also showed a stronger effect of trial type probability, with more antisaccade errors in blocks with a low antisaccade probability and slower RTs for each saccade task when its trial type was unlikely. A longer cue duration yielded fewer errors and slower RTs, with a larger switch cost for errors compared to a short cue duration. Findings demonstrated that when the trial type cue duration was shorter, visual motor responsiveness was faster and subjects relied upon the implicit trial probability context to improve performance. When the cue duration was longer, increased fixation-related activity may have delayed saccade motor preparation and slowed responses, guiding subjects to respond in a controlled manner regardless of trial type probability. |
F. Pieruccini-Faria; J. A. Jones; Q. J. Almeida Insight into dopamine-dependent planning deficits in Parkinson's disease: A sharing of cognitive & sensory resources Journal Article In: Neuroscience, vol. 318, pp. 219–229, 2016. @article{PierucciniFaria2016, Cognitive and sensorimotor processes are both needed for successful planning of footsteps during complex gait situations, but the interaction between these factors during motor planning, as well as their response to dopaminergic treatment is poorly understood in Parkinson's disease (PD). In the current study, we evaluated walking and gaze behaviors of individuals with PD while planning an approach toward an obstacle to be stepped over. The obstacle clearance task was completed both ON and OFF dopaminergic medication by individuals with Parkinson's disease (n = 20) and compared to healthy age-matched control participants (n = 19), as well as with and without an auditory digit monitoring dual task. In this novel protocol of synchronized gaze and gait data collection, each trial was split into an early and late phase prior to the obstacle, providing a unique opportunity to examine dopamine-dependent planning deficits in PD. Interestingly, only patients in the OFF medication state showed greater deceleration in the late phase (i.e., just before the obstacle) (F(1,37) = 45.42, p < 0.001), as well as an increase in step time variability (also in this late phase) with the additional demands of a dual task (F(2,74) = 3.49 |
Alessandro Piras; Ivan M. Lanzoni; Milena Raffi; Michela Persiani; Salvatore Squatrito The within-task criterion to determine successful and unsuccessful table tennis players Journal Article In: International Journal of Sports Science & Coaching, vol. 11, no. 4, pp. 523–531, 2016. @article{Piras2016, The aim of this study was to examine the differences in visual search behaviour between a group of expert-level and one of novice table tennis players, to determine the temporal and spatial aspects of gaze orientation associated with correct responses. Expert players were classified as successful or unsuccessful depending on their performance in a video-based test of anticipation skill involving two kinds of stroke techniques: forehand top spin and backhand drive. Eye movements were recorded binocularly with a video-based eye tracking system. Successful experts were more effective than novices and unsuccessful experts in accurately anticipating both type and direction of stroke, showing fewer fixations of longer duration. Participants fixated mainly on arm area during forehand top spin, and on hand–racket and trunk areas during backhand drive. This study can help to develop interventions that facilitate the acquisition of anticipatory skills by improving visual search strategies. |
Alessandro Piras; Milena Raffi; Michela Persiani; Monica Perazzolo; Salvatore Squatrito Effect of heading perception on microsaccade dynamics Journal Article In: Behavioural Brain Research, vol. 312, pp. 246–252, 2016. @article{Piras2016a, The present study shows the relationship between microsaccades and heading perception. Recent research demonstrates that microsaccades during fixation are necessary to overcome loss of vision due to continuous stimulation of the retinal receptors, even at the potential cost of a decrease in visual acuity. The goal of oculomotor fixational mechanisms might be not retinal stabilization, but controlled image motion adjusted to be optimal for visual processing. Thus, patterns of microsaccades may be exploited to help to understand the oculomotor system, aspects of visual perception, and the dynamics of visual attention. We presented an expansion optic flow in which the dot speed simulated a heading directed to the left or to the right of the subject, who had to signal the perceived heading by making a saccade toward the perceived direction. We recorded microsaccades during the optic flow stimulation to investigate their characteristics before and after the response. The time spent on heading perception was similar between right and left direction, and response latency was shorter during correct than incorrect responses. Furthermore, we observed that correct heading perception is associated with longer, larger and faster microsaccade characteristics. The time-course of microsaccade rate shows a modulation across the perception process similar to that seen for other local perception tasks, while the main direction is oriented toward the opposite side with respect to the perceived heading. Microsaccades enhance visual perception and, therefore, represent a fundamental motor process, with a specific effect for the build-up of global visual perception of space. |
Ewa Pluciennicka; Yann Coello; Solène Kalénine In: Cognitive Development, vol. 38, pp. 75–88, 2016. @article{Pluciennicka2016, This study assessed the implicit processing development of three types of semantic relations during manipulable artifact identification. Thirteen adults and thirty-nine children (age 6, 8, and 10 years) participated. Fixation temporal dynamics were used to assess competition effects from thematic (e.g., wood), specific function (e.g., axe), and general function (e.g., knife) distractors during target identification (e.g., saw). Competition effects were analyzed depending on distractor type and age group. Developmental results demonstrate emergence of competition effects with general function distractors with age, whereas competition effects with thematic and specific function distractors were stable from 6. Findings highlight fined-grained development of similarity-based semantic mechanism implicit use during object processing from 6 to adulthood. They further suggest that complementarity-based mechanism is efficiently used during object semantic processing starting from 6 and likely involved in processing both thematic and specific function relations. |
Ewa Pluciennicka; Yannick Wamain; Yann Coello; Solène Kalénine Impact of action primes on implicit processing of thematic and functional similarity relations: Evidence from eye-tracking Journal Article In: Psychological Research, vol. 80, no. 4, pp. 566–580, 2016. @article{Pluciennicka2016a, The aim of this study was to specify the role of action representations in thematic and functional similarity relations between manipulable artifact objects. Recent behavioral and neurophysiological evidence indicates that while they are all relevant for manipulable artifact concepts, semantic relations based on thematic (e.g., saw-wood), specific function similarity (e.g., saw-axe), and general function similarity (e.g., saw-knife) are differently processed, and may relate to different levels of action representation. Point-light displays of object-related actions previously encoded at the gesture level (e.g., "sawing") or at the higher level of action representation (e.g., "cutting") were used as primes before participants identified target objects (e.g., saw) among semantically related and unrelated distractors (e.g., wood, feather, piano). Analysis of eye movements on the different objects during target identification informed about the amplitude and the timing of implicit activation of the different semantic relations. Results showed that action prime encoding impacted the processing of thematic relations, but not that of functional similarity relations. Semantic competition with thematic distractors was greater and earlier following action primes encoded at the gesture level compared to action primes encoded at higher level. As a whole, these findings highlight the direct influence of action representations on thematic relation processing, and suggest that thematic relations involve gesture-level representations rather than intention-level representations. |
Ivo D. Popivanov; Philippe G. Schyns; Rufin Vogels Stimulus features coded by single neurons of a macaque body category selective patch Journal Article In: Proceedings of the National Academy of Sciences, vol. 113, no. 17, pp. E2450–E2459, 2016. @article{Popivanov2016, Body category-selective regions of the primate temporal cortex respond to images of bodies, but it is unclear which fragments of such images drive single neurons' responses in these regions. Here we applied the Bubbles technique to the responses of single macaque middle superior temporal sulcus (midSTS) body patch neurons to reveal the image fragments the neurons respond to. We found that local image fragments such as extremities (limbs), curved boundaries, and parts of the torso drove the large majority of neurons. Bubbles revealed the whole body in only a few neurons. Neurons coded the features in a manner that was tolerant to translation and scale changes. Most image fragments were excitatory but for a few neurons both inhibitory and excitatory fragments (opponent coding) were present in the same image. The fragments we reveal here in the body patch with Bubbles differ from those suggested in previous studies of face-selective neurons in face patches. Together, our data indicate that the majority of body patch neurons respond to local image fragments that occur frequently, but not exclusively, in bodies, with a coding that is tolerant to translation and scale. Overall, the data suggest that the body category selectivity of the midSTS body patch depends more on the feature statistics of bodies (e.g., extensions occur more frequently in bodies) than on semantics (bodies as an abstract category). |
Jennifer Malsert; Didier Grandjean Mixed saccadic paradigm releases top-down emotional interference in antisaccade and prosaccade trials Journal Article In: Experimental Brain Research, vol. 234, no. 10, pp. 2915–2922, 2016. @article{Malsert2016, Saccadic movements are well known to involve specific top-down or bottom-up processes depending on the task and paradigm characteristics. For example, after the Gap bottom-up effect, it has been shown that an Instruction effect, i.e., asking to identify a peripheral target instead of simply look toward it, reduces latencies in prosaccade (PS) but not in antisaccade (AS) tasks. Nevertheless, in a mixed task comprising AS, PS and nosaccade trials, such differences vanished. Thus, it has been suggested that a top-down effect could be dependent on tonic or phasic neuronal activation and that only the tonic frontal activation could enable interferences with other cortical regions involved. In this study, we tested the interference of emotional information with saccadic performance depending on cognitive cost of the task. We used emotional facial expression cues in block and mixed paradigms. Using a generalized linear mixed model for the analysis, we found a main effect of the paradigm, with task and emotional effects only in mixed saccadic task that could suggest a top-down effect of emotional information processing over the regions involved in saccadic performances. Moreover, we demonstrated that prosaccades latencies are significantly reduced by emotion, while antisaccades are significantly increased, suggesting a disinhibition of reflexive saccades. |
Sanjay G. Manohar; Masud Husain Human ventromedial prefrontal lesions alter incentivisation by reward Journal Article In: Cortex, vol. 76, pp. 104–120, 2016. @article{Manohar2016, Although medial frontal brain regions are implicated in valuation of rewards, evidence from focal lesions to these areas is scant, with many conflicting results regarding motivation and affect, and no human studies specifically examining incentivisation by reward. Here, 19 patients with isolated, focal damage in ventral and medial prefrontal cortex were selected from a database of 453 individuals with subarachnoid haemorrhage. Using a speeded saccadic task based on the oculomotor capture paradigm, we manipulated the maximum reward available on each trial using an auditory incentive cue. Modulation of behaviour by motivation permitted quantification of reward sensitivity. At the group level, medial frontal damage was overall associated with significantly reduced effects of reward on invigorating saccadic velocity and autonomic (pupil) responses compared to age-matched, healthy controls. Crucially, however, some individuals instead showed abnormally strong incentivisation effects for vigour. Increased sensitivity to rewards within the lesion group correlated with damage in subgenual ventromedial prefrontal cortex (vmPFC) areas, which have recently become the target for deep brain stimulation (DBS) in depression. Lesion correlations with clinical apathy suggested that the apathy associated with prefrontal damage is in fact reduced by damage at those coordinates. Reduced reward sensitivity showed a trend to correlate with damage near nucleus accumbens. Lesions did not, on the other hand, influence reward sensitivity of cognitive control, as measured by distractibility. Thus, although medial frontal lesions may generally reduce reward sensitivity, damage to key subregions paradoxically protect from this effect. |
Ran Manor; Liran Mishali; Amir B. Geva Multimodal neural network for rapid serial visual presentation brain computer interface Journal Article In: Frontiers in Computational Neuroscience, vol. 10, pp. 130, 2016. @article{Manor2016, Brain computer interfaces allow users to preform various tasks using only the electrical activity of the brain. BCI applications often present the user a set of stimuli and record the corresponding electrical response. The BCI algorithm will then have to decode the acquired brain response and perform the desired task. In rapid serial visual presentation (RSVP) tasks, the subject is presented with a continuous stream of images containing rare target images among standard images, while the algorithm has to detect brain activity associated with target images. In this work, we suggest a multimodal neural network for RSVP tasks. The network operates on the brain response and on the initiating stimulus simultaneously, providing more information for the BCI application. We present two variants of the multimodal network, a supervised model, for the case when the targets are known in advanced, and a semi-supervised model for when the targets are unknown. We test the neural networks with a RSVP experiment on satellite imagery carried out with two subjects. The multimodal networks achieve a significant performance improvement in classification metrics. We visualize what the networks has learned and discuss the advantages of using neural network models for BCI applications. |
Mauro Marchitto; Simone Benedetto; Thierry Baccino; José J. Cañas Air traffic control: Ocular metrics reflect cognitive complexity Journal Article In: International Journal of Industrial Ergonomics, vol. 54, pp. 120–130, 2016. @article{Marchitto2016, The objective of the study was to evaluate effects of complexity on cognitive workload in a simulated air traffic control conflict detection task by means of eye movements recording. We manipulated two complexity factors, convergence angle and aircrafts minimum distance at closest approach, in a multidimensional workload assessment method based on psychophysiological, performance, and subjective measures. Conflict trials resulted more complex and time-consuming than no conflicts, requiring more frequent fixations and saccades. Moreover, large saccades showed reduced burst power with higher task complexity. A motion-based and a ratio-based strategy were suggested for conflicts and no conflicts on the basis of ocular metrics analysis: aircrafts differential speed and distance to convergence point at trial start were considered determinant for strategy adoption. Relevance to industry: Eye metrics measurement for online workload assessment enhances better identification of workload-inducing scenarios and adopted strategy for traffic management. System design, as well as air traffic control operators training programs, might benefit from on line workload measurement. |
Viorica Marian; Henrike K. Blumenfeld; Max R. Freeman; Scott R. Schroeder; Susan C. Bobb Auditory word recognition across the lifespan: Links between linguistic and nonlinguistic inhibitory control in bilinguals and monolinguals Journal Article In: Linguistic Approaches to Bilingualism, vol. 6, no. 1-2, pp. 119–146, 2016. @article{Marian2016, Recent research suggests that bilingual experience reconfigures linguistic and nonlinguistic cognitive processes. We examined the relationship between linguistic competition resolution and nonlinguistic cognitive control in younger and older adults who were either bilingual or monolingual. Participants heard words in English and identified the referent among four pictures while eye-movements were recorded. Target pictures (e.g., cab ) appeared with a phonological competitor picture (e.g., cat ) and two filler pictures. After each eye-tracking trial, priming probes assessed residual activation and inhibition of target and competitor words. When accounting for processing speed, results revealed that age-related changes in activation and inhibition are smaller in bilinguals than in monolinguals. Moreover, younger and older bilinguals, but not monolinguals, recruited similar inhibition mechanisms during word identification and during a nonlinguistic Stroop task. Results suggest that, during lexical access, bilinguals show more consistent competition resolution and recruitment of cognitive control across the lifespan than monolinguals. |
Jonathan J. Marotta; Timothy J. Graham Cluttered environments: Differential effects of obstacle position on grasp and gaze locations Journal Article In: Canadian Journal of Experimental Psychology, vol. 70, no. 3, pp. 242–247, 2016. @article{Marotta2016, Previous research has investigated the effects of nontarget objects (NTOs) on reach trajectories, but their effects on eye-hand coordination remain to be determined. The current investigation utilized an eye-hand coordination paradigm, where a reaching and grasping task was performed in the presence of an NTO positioned exclusively in the right or left workspace of each right-handed participant. NTOs varied in their closeness to the subject and reach-path, between the starting location of the hand and the target-object of the reach. A control condition, where only the target was present, was also included. When an NTO was presented on the right (ipsilateral to the reaching hand), it pushed the final grasp and gaze locations on the target, shifting them to the left-away from the "obstacle." The impact of the ipsilateral NTO was increased as it was moved into positions closer to the participant that were of greater obstruction to the hand and arm. In contrast, when the NTO was contralateral, the risk of collision was low and participants developed a set reach plan that was repeated nearly identically for each contralateral NTO position. Our findings also indicate that the "invasiveness" of the NTO positions had a greater effect on grasp than it did on gaze position-demonstrating how the arrangement of clutter in an environment can differentially affect gaze and grasp when reaching for an object. |
Tom R. Marshall; Sophie Esterer; Jim D. Herring; Til O. Bergmann; Ole Jensen On the relationship between cortical excitability and visual oscillatory responses-A concurrent tDCS-MEG study Journal Article In: NeuroImage, vol. 140, pp. 41–49, 2016. @article{Marshall2016, Neuronal oscillations in the alpha band (8–12 Hz) in visual cortex are considered to instantiate ‘attentional gating' via the inhibition of activity in regions representing task-irrelevant parts of space. In contrast, visual gamma-band activity (40–100 Hz) is regarded as representing a bottom-up drive from incoming visual information, with increased synchronisation producing a stronger feedforward impulse for relevant information. However, little is known about the direct relationship between excitability of the visual cortex and these oscillatory mechanisms. In this study we used transcranial direct current stimulation (tDCS) in an Oz–Cz montage in order to stimulate visual cortex, concurrently recording whole-brain oscillatory activity using magnetoencephalography (MEG) whilst participants performed a visual task known to produce strong modulations of alpha- and gamma-band activity. We found that visual stimuli produced expected modulations of alpha and gamma – presenting a moving annulus stimulus led to a strong gamma increase and alpha decrease – and that this pattern was observable both during active (anodal and cathodal) tDCS and sham tDCS. However, tDCS did not seem to produce systematic alterations of these oscillatory responses. The present study thus demonstrates that concurrent tDCS/MEG of the visual system is a feasible tool for investigating visual neuronal oscillations, and we discuss potential reasons for the apparent inability of tDCS to effectively change the amplitude of visual stimulus induced oscillatory responses in the current study. |
Jun Maruta; Eva M. Palacios; Robert D. Zimmerman; Jamshid Ghajar; Pratik Mukherjee Chronic post-concussion neurocognitive deficits . I . Relationship with white matter integrity Journal Article In: Frontiers in Human Neuroscience, vol. 10, pp. 35, 2016. @article{Maruta2016, We previously identified visual tracking deficits and associated degradation of integrity in specific white matter tracts as characteristics of concussion. We re-explored these characteristics in adult patients with persistent post-concussive symptoms using independent new data acquired during 2009–2012. Thirty-two patients and 126 normal controls underwent cognitive assessments and MR-DTI. After data collection, a subset of control subjects was selected to be individually paired with patients based on gender and age. We identified patients' cognitive deficits through pairwise comparisons between patients and matched control subjects. Within the remaining 94 normal subjects, we identified white matter tracts whose integrity correlated with metrics that indicated performance degradation in patients. We then tested for reduced integrity in these white matter tracts in patients relative to matched controls. Most patients showed no abnormality in MR images unlike the previous study. Patients' visual tracking was generally normal. Patients' response times in an attention task were slowed, but could not be explained as reduced integrity of white matter tracts relating to normal response timing. In the present patient cohort, we did not observe behavioral or anatomical deficits that we previously identified as characteristic of concussion. The recent cohort likely represented those with milder injury compared to the earlier cohort. The discrepancy may be explained by a change in the patient recruitment pool circa 2007 associated with an increase in public awareness of concussion. |
Jun Maruta; Lisa A. Spielman; Brett B. Yarusi; Yushi Wang; Jonathan M. Silver; Jamshid Ghajar Chronic post-concussion neurocognitive deficits. II. Relationship with persistent symptoms Journal Article In: Frontiers in Human Neuroscience, vol. 10, pp. 45, 2016. @article{Maruta2016a, Individuals who sustain a concussion may continue to experience problems long after their injury. However, it has been postulated in the literature that the relationship between a concussive injury and persistent complaints attributed to it is mediated largely by the development of symptoms associated with posttraumatic stress disorder (PTSD) and depression. We sought to characterize cognitive deficits of adult patients who had persistent symptoms after a concussion and determine whether the original injury retains associations with these deficits after accounting for the developed symptoms that overlap with PTSD and depression. We compared the results of neurocognitive testing from 33 patients of both genders aged 18-55 at 3 months to 5 years post-injury with those from 140 control subjects. Statistical comparisons revealed that patients generally produced accurate responses on reaction time-based tests, but with reduced efficiency. On visual tracking, patients increased gaze position error variability following an attention demanding task, an effect that may reflect greater fatigability. When neurocognitive performance was examined in the context of demographic- and symptom-related variables, the original injury retained associations with reduced performance at a statistically significant level. For some patients, reduced cognitive efficiency and fatigability may represent key elements of interference when interacting with the environment, leading to varied paths of recovery after a concussion. Poor recovery may be better understood when these deficits are taken into consideration. |
Christina Marx; Florian Hutzler; Sarah Schuster; Stefan Hawelka On the development of parafoveal preprocessing: Evidence from the incremental boundary paradigm Journal Article In: Frontiers in Psychology, vol. 7, pp. 514, 2016. @article{Marx2016, Parafoveal preprocessing of upcoming words and the resultant preview benefit are key aspects of fluent reading. Evidence regarding the development of parafoveal preprocessing during reading acquisition, however, is scarce. The present developmental (cross-sectional) eye tracking study estimated the magnitude of parafoveal preprocessing of beginning readers with a novel variant of the classical boundary paradigm. Additionally, we assessed the association of parafoveal preprocessing with several reading-related psychometric measures. The participants were children learning to read the regular German orthography with about 1, 3, and 5 years of formal reading instruction (Grade 2, 4, and 6, respectively). We found evidence of parafoveal preprocessing in each Grade. However, an effective use of parafoveal information was related to the individual reading fluency of the participants (i.e., the reading rate expressed as words-per-minute) which substantially overlapped between the Grades. The size of the preview benefit was furthermore associated with the children's performance in rapid naming tasks and with their performance in a pseudoword reading task. The latter task assessed the children's efficiency in phonological decoding and our findings show that the best decoders exhibited the largest preview benefit. |
Sebastiaan Mathôt; Jean-Baptiste Melmi; Lotje Linden; Stefan Van Der Stigchel The mind-writing pupil: A human-computer interface based on decoding of covert attention through pupillometry Journal Article In: PLoS ONE, vol. 11, no. 2, pp. e0148805, 2016. @article{Mathot2016, We present a new human-computer interface that is based on decoding of attention through pupillometry. Our method builds on the recent finding that covert visual attention affects the pupillary light response: Your pupil constricts when you covertly (without looking at it) attend to a bright, compared to a dark, stimulus. In our method, participants covertly attend to one of several letters with oscillating brightness. Pupil size reflects the brightness of the selected letter, which allows us–with high accuracy and in real time–to determine which letter the par- ticipant intends to select. The performance of our method is comparable to the best covert- attention brain-computer interfaces to date, and has several advantages: no movement other than pupil-size change is required; no physical contact is required (i.e. no electrodes); it is easy to use; and it is reliable. Potential applications include: communication with totally locked-in patients, training of sustained attention, and ultra-secure password input. |
Annegret Meermeier; Svenja Gremmler; Markus Lappe The influence of image content on oculomotor plasticity Journal Article In: Journal of Vision, vol. 16, no. 8, pp. 1–12, 2016. @article{Meermeier2016, When we observe a scene, we shift our gaze to different points of interest via saccadic eye movements. Saccades provide high resolution views of objects and are essential for vision. The successful view of an interesting target might constitute a rewarding experience to the oculomotor system. We measured the influence of image content on learning efficiency in saccade control. We compared meaningful pictures to luminance and spatial frequency-matched random noise images in a saccadic adaptation paradigm. In this paradigm a shift of the target during the saccades results in a gradual increase of saccade amplitude. Stimuli were masked at different times after saccade onset. For immediate masking of the stimuli, as well as for their permanent visibility, saccadic adaptation was similar for both types of targets. However, when stimuli were masked 200 ms after saccade onset, adaptation of saccades directed toward the meaningful target stimuli was significantly greater than that of saccades directed toward noise targets. Thus, the percept of a meaningful image at the saccade landing position facilitates learning of the appropriate parameters for saccadic motor control when time constraints exist. We conclude that oculomotor learning, which is traditionally considered a low-level and highly automatized process, is modulated by the visual content of the image. |
Tobias Meilinger; Katsumi Watanabe Multiple strategies for spatial integration of 2D layouts within working memory Journal Article In: PLoS ONE, vol. 11, no. 4, pp. e0154088, 2016. @article{Meilinger2016, Prior results on the spatial integration of layouts within a room differed regarding the reference frame that participants used for integration. We asked whether these differences also occur when integrating 2D screen views and, if so, what the reasons for this might be. In four experiments we showed that integrating reference frames varied as a function of task familiarity combined with processing time, cues for spatial transformation, and information about action requirements paralleling results in the 3D case. Participants saw part of an object layout in screen 1, another part in screen 2, and reacted on the integrated layout in screen 3. Layout presentations between two screens coincided or differed in orientation. Aligning misaligned screens for integration is known to increase errors/latencies. The error/latency pattern was thus indicative of the reference frame used for integration. We showed that task familiarity combined with self-paced learning, visual updating, and knowing from where to act prioritized the integration within the reference frame of the initial presentation, which was updated later, and from where participants acted respectively. Participants also heavily relied on layout intrinsic frames. The results show how humans flexibly adjust their integration strategy to a wide variety of conditions. |
Martin Meißner; Andres Musalem; Joel C. Huber Eye tracking reveals processes that enable conjoint choices to become increasingly efficient with practice Journal Article In: Journal of Marketing Research, vol. 53, no. 1, pp. 1–17, 2016. @article{MeWIBBLEer2016, Choice-based conjoint is a popular way to characterize consumers' choices. Three eye-tracking studies reveal decision processes in conjoint choices that take less time and are more accurate with practice. We observe two simplification processes that are associated with greater speed and reliability. Alternative focus gradually shifts attention towards options that represent promising choices, while attribute focus directs attention to important attributes that are most likely to alter or confirm a decision. Alternative and attribute focus increase in intensity with practice. In terms of biases, we detect a small but consistent focus on positive aspects of the item chosen and negative aspects of the items not chosen. We also show that incidental exposures arising from the alternative first examined or from a central horizontal location increase attention but have a much more modest and often insignificant impact on conjoint choices. Overall, conjoint choice is revealed to be a process that is largely formed by goal-driven values that respondents bring to the task, one that is relatively free of distorting effects from task layout or random exposures. |
Céline Paeye; Alexander C. Schütz; Karl R. Gegenfurtner Visual reinforcement shapes eye movements in visual search Journal Article In: Journal of Vision, vol. 16, no. 10, pp. 1–15, 2016. @article{Paeye2016, We use eye movements to gain information about our visual environment; this information can indirectly be used to affect the environment. Whereas eye movements are affected by explicit rewards such as points or money, it is not clear whether the information gained by finding a hidden target has a similar reward value. Here we tested whether finding a visual target can reinforce eye movements in visual search performed in a noise background, which conforms to natural scene statistics and contains a large number of possible target locations. First we tested whether presenting the target more often in one specific quadrant would modify eye movement search behavior. Surprisingly, participants did not learn to search for the target more often in high probability areas. Presumably, participants could not learn the reward structure of the environment. In two subsequent experiments we used a gaze-contingent display to gain full control over the reinforcement schedule. The target was presented more often after saccades into a specific quadrant or a specific direction. The proportions of saccades meeting the reinforcement criteria increased considerably, and participants matched their search behavior to the relative reinforcement rates of targets. Reinforcement learning seems to serve as the mechanism to optimize search behavior with respect to the statistics of the task. |
Ascensión Pagán; Hazel I. Blythe; Simon P. Liversedge Parafoveal preprocessing of word initial trigrams during reading in adults and children Journal Article In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 42, no. 3, pp. 411–432, 2016. @article{Pagan2016a, Although previous research has shown that letter position information for the first letter of a parafoveal word is encoded less flexibly than internal word beginning letters (Johnson, Perea & Rayner, 2007; White et al., 2008), it is not clear how positional encoding operates over the initial trigram in English. This experiment explored the preprocessing of letter identity and position information of a parafoveal word's initial trigram by adults and children using the boundary paradigm during normal sentence reading. Seven previews were generated: Identity (captain); transposed letter and substituted letter nonwords in Positions 1 and 2 (acptain-imptain); 1 and 3 (pactain-gartain), and 2 and 3 (cpatain-cgotain). Results showed a transposed letter effect (TLE) in Position 13 for gaze duration in the pretarget word; and TLE in Positions 12 and 23 but not in Position 13 in the target word for both adults and children. These findings suggest that children, similar to adults, extract letter identity and position information flexibly using a spatial coding mechanism; supporting isolated word recognition models such as SOLAR (Davis, 1999, 2010) and SERIOL (Whitney, 2001) models. |
Ascensión Pagán; Kevin B. Paterson; Hazel I. Blythe; Simon P. Liversedge An inhibitory influence of transposed-letter neighbors on eye movements during reading Journal Article In: Psychonomic Bulletin & Review, vol. 23, no. 1, pp. 278–284, 2016. @article{Pagan2016, Previous research has shown that prior exposure to a word's substitution neighbor earlier in the same sentence can disrupt processing of that word, indicating that interword lexical priming occurs naturally during reading, due to the competition between lexical candidates during word identification. Through the present research, we extended these findings by investigating the effects of prior exposure to a word's transposed-letter neighbor (TLN) earlier in a sentence. TLNs are constituted from the same letters, but in different orders. The findings revealed an inhibitory TLN effect, with longer total reading times for target words, and increased regressions to prime and target words, when the target followed a TLN rather than a control word. These findings indicate that prior exposure to a TLN can disrupt word identification during reading. We suggest that this is caused by a failure of word identification, due to the initial misidentification of the target word (potentially as its TLN) triggering postlexical checking. |
Jinger Pan; Jochen Laubrock; Ming Yan In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 42, no. 8, pp. 1257–1273, 2016. @article{Pan2016, We examined how reading mode (i.e., silent vs. oral reading) influences parafoveal semantic and phonological processing during the reading of Chinese sentences, using the gaze-contingent boundary paradigm. In silent reading, we found in 2 experiments that reading times on target words were shortened with semantic previews in early and late processing, whereas phonological preview effects mainly occurred in gaze duration or second-pass reading. In contrast, results showed that phonological preview information is obtained early on in oral reading. Strikingly, in oral reading, we observed a semantic preview cost on the target word in Experiment 1 and a decrease in the effect size of preview benefit from first- to second-pass measures in Experiment 2, which we hypothesize to result from increased preview duration. Taken together, our results indicate that parafoveal semantic information can be obtained irrespective of reading mode, whereas readers more efficiently process parafoveal phonological information in oral reading. We discuss implications for notions of information processing priority and saccade generation during silent and oral reading. |
Raika Pancaroglu; Charlotte S. Hills; Alla Sekunova; Jayalakshmi Viswanathan; Brad Duchaine; Jason J. S. Barton Seeing the eyes in acquired prosopagnosia Journal Article In: Cortex, vol. 81, pp. 251–265, 2016. @article{Pancaroglu2016, Case reports have suggested that perception of the eye region may be impaired more than that of other facial regions in acquired prosopagnosia. However, it is unclear how frequently this occurs, whether such impairments are specific to a certain anatomic subtype of prosopagnosia, and whether these impairments are related to changes in the scanning of faces. We studied a large cohort of 11 subjects with this rare disorder, who had a variety of occipitotemporal or anterior temporal lesions, both unilateral and bilateral. Lesions were characterized by functional and structural imaging. Subjects performed a perceptual discrimination test in which they had to discriminate changes in feature position, shape, or external contour. Test conditions were manipulated to stress focused or divided attention across the whole face. In a second experiment we recorded eye movements while subjects performed a face memory task. We found that greater impairment for eye processing was more typical of subjects with occipitotemporal lesions than those with anterior temporal lesions. This eye selectivity was evident for both eye position and shape, with no evidence of an upper/lower difference for external contour. A greater impairment for eye processing was more apparent under attentionally more demanding conditions. Despite these perceptual deficits, most subjects showed a normal tendency to scan the eyes more than the mouth. We conclude that occipitotemporal lesions are associated with a partially selective processing loss for eye information and that this deficit may be linked to loss of the right fusiform face area, which has been shown to have activity patterns that emphasize the eye region. |
Muriel T. N. Panouillères; Valérie Gaveau; Jeremy Debatisse; Patricia Jacquin; Marie LeBlond; Denis Pélisson Oculomotor adaptation elicited by intra-saccadic visual stimulation: Time-course of efficient visual target perturbation Journal Article In: Frontiers in Human Neuroscience, vol. 10, pp. 91, 2016. @article{Panouilleres2016, Perception of our visual environment strongly depends on saccadic eye movements, which in turn are calibrated by saccadic adaptation mechanisms elicited by systematic movement errors. Current models of saccadic adaptation assume that visual error signals are acquired only after saccade completion, because the high speed of saccade execution disturbs visual processing (saccadic “suppression” and “mislocalization”). Complementing a previous study from our group, here we report that visual information presented during saccades can drive adaptation mechanisms and we further determine the critical time window of such error processing. In 15 healthy volunteers, shortening adaptation of reactive saccades toward a ±8° visual target was induced by flashing the target for 2 msec less eccentrically than its initial location either near saccade peak velocity (‘PV' condition) or peak deceleration (‘PD') or saccade termination (‘END'). Results showed that, as compared to the ‘CONTROL' condition (target flashed at its initial location upon saccade termination), saccade amplitude decreased all throughout the ‘PD' and ‘END' conditions, reaching significant levels in the second adaptation and post- adaptation blocks. The results of 9 other subjects tested in a saccade lengthening adaptation paradigm with the target flashing near peak deceleration (‘PD' and ‘CONTROL' conditions) revealed no significant change of gain, confirming that saccade shortening adaptation is easier to elicit. Also, together with this last result, the stable gain observed in the ‘CONTROL' conditions of both experiments suggests that mislocalization of the target flash is not responsible for the saccade shortening adaptation demonstrated in the first group. Altogether, these findings reveal that the visual “suppression” and “mislocalization” phenomena related to saccade execution do not prevent brief visual information delivered ‘in-flight' from being processed to elicit oculomotor adaptation. |
Tyler R. Peel; Ziad M. Hafed; Suryadeep Dash; Stephen G. Lomber; Brian D. Corneil A causal role for the cortical frontal eye fields in microsaccade deployment Journal Article In: PLoS Biology, vol. 14, no. 8, pp. e1002531, 2016. @article{Peel2016, Microsaccades aid vision by helping to strategically sample visual scenes. Despite the importance of these small eye movements, no cortical area has ever been implicated in their generation. Here, we used unilateral and bilateral reversible inactivation of the frontal eye fields (FEF) to identify a cortical drive for microsaccades. Unexpectedly, FEF inactivation altered microsaccade metrics and kinematics. Such inactivation also impaired microsaccade deployment following peripheral cue onset, regardless of cue side or inactivation configuration. Our results demonstrate that the FEF provides critical top-down drive for microsaccade generation, particularly during the recovery of microsaccades after disruption by sensory transients. Our results constitute the first direct evidence, to our knowledge, for the contribution of any cortical area to microsaccade generation, and they provide a possible substrate for how cognitive processes can influence the strategic deployment of microsaccades. |
Ana Pellicer-Sánchez Incidental L2 vocabulary acquisition from and while reading: An eye-tracking study Journal Article In: Studies in Second Language Acquisition, vol. 38, no. 1, pp. 97–130, 2016. @article{PellicerSanchez2016, Previous studies have shown that reading is an important source of incidental second language (L2) vocabulary acquisition. However, we still do not have a clear picture of what happens when readers encounter unknown words. Combining offline (vocabulary tests) and online (eye-tracking) measures, the incidental acquisition of vocabulary knowledge from reading and the online reading of unknown lexical items were examined. L2 English learners read a story containing unknown items while their eye movements were recorded. After eight exposures, L2 readers recognized the form and the meaning of 86% and 75% of the target nonwords, respectively, whereas they recalled the meaning of 55% of the nonwords. After three to four encounters, nonwords were read significantly faster, and by eight encounters they were read in a similar manner to previously known real words. Results also showed a positive relationship between new vocabulary learning outcomes and online reading, with longer reading times associated with higher vocabulary recall test scores. The study was also conducted with first language (L1) readers to provide baseline data for comparison. Results confirmed the L2 findings while also indicating an interesting L1-L2 distinction in the rate rather than in the ultimate outcome of the acquisition process. |
Chad Peltier; Mark W. Becker Decision processes in visual search as a function of target prevalence Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 42, no. 9, pp. 1466–1476, 2016. @article{Peltier2016, The probability of missing a target increases in low target prevalence search tasks. Wolfe and Van Wert (2010) propose 2 causes of this effect: reducing the quitting threshold, and conservatively shifting the decision making criterion used to evaluate each item. Reducing the quitting threshold predicts that target absent responses will be made without fully inspecting the display, increasing misses due to never inspecting the target (selection errors). The shift in decision criterion increases the likelihood of failing to recognize an inspected target (identification errors). Though there is robust evidence that target prevalence rates shift quitting thresholds, the proposed shift in decision making criterion has little support. In Experiment 1 we eye-tracked participants during searches of high, medium, and low prevalence. Eye movements were used to classify misses as selection or identification errors. Identification errors increased as prevalence decreased, supporting the claim that decision criterion becomes more conservative as prevalence decreases. In addition, as prevalence decreased, the dwell time on targets increased while dwell times on distractors decreased. We propose that the effect of prevalence on decision making for individual items is best modeled as a shift in criterion in a drift diffusion model, rather than signal detection, as drift diffusion accounts for this pattern of decision times. In Experiment 2 we replicate these findings while presenting stimuli in an rapid serial visual presentation (RSVP) stream. Experiments 1 and 2 were consistent with the conclusion that prevalence rate influences the item-by-item decision criterion, and are consistent with a drift diffusion model of this decision process. |
Trevor B. Penney; Xiaoqin Cheng; Yan Ling Leow; Audrey Wei Ying Bay; Esther Wu; Sophie K. Herbst; Shih Cheng Yen Saccades and subjective time in seconds range duration reproduction Journal Article In: Timing & Time Perception, vol. 4, no. 2, pp. 187–206, 2016. @article{Penney2016, A transient suppression of visual perception during saccades ensures perceptual stability. In two experiments, we examined whether saccades affect time perception of visual and auditory stimuli in the seconds range. Specifically, participants completed a duration reproduction task in which they memorized the duration of a 6 s timing signal during the training phase and later reproduced that duration during the test phase. Four experimental conditions differed in saccade requirements and the presence or absence of a secondary discrimination task during the test phase. For both visual and auditory timing signals, participants reproduced longer durations when the secondary discrimination task required saccades to be made (i.e., overt attention shift) during reproduction as compared to when the discrimination task merely required fixation at screen center. Moreover, greater total saccade duration in a trial resulted in greater time distortion. However, in the visual modality, requiring participants to covertly shift attention (i.e., no saccade) to complete the discrimination task increased reproduced duration as much as making a saccade, whereas in the auditory modality making a saccade increased reproduced duration more than making a covert attention shift. In addition, we examined microsaccades in the conditions that did not require full saccades for both the visual and auditory experiments. Greater total microsaccade duration in a trial resulted in greater time distortion in both modalities. Taken together, the experiments suggest that saccades and microsaccades affect seconds range visual and auditory interval timing via attention and saccadic suppression mechanisms. |
Manuel Perea; Lourdes Giner; Ana Marcet; Pablo Gomez Does extra interletter spacing help text reading in skilled adult readers? Journal Article In: Spanish Journal of Psychology, vol. 19, pp. 1–7, 2016. @article{Perea2016, A number of experiments have shown that, in skilled adult readers, a small increase in interletter spacing speeds up the process of visual word recognition relative to the default settings (i.e., judge faster than judge). The goal of the present experiment was to examine whether this effect can be generalized to a more ecological scenario: text reading. Each participant read two stories (367 words each) taken from a standardized reading test. The stories were presented with the standard interletter spacing or with a small increase in interletter spacing (+1.2 points to default) in a within-subject design. An eyetracker was used to register the participants' eye movements. Comprehension scores were also examined. Results showed that, on average, fixation durations were shorter while reading the text with extra spacing than while reading the text with the default settings (237 vs. 245 ms, respectively; η2 =. 41 |
Melanie Perron; Annie Roy-Charland; Justin A. Chamberland; Carolyn Bleach; Annalie Pelot Differences between traces of negative emotions in smile judgment Journal Article In: Motivation and Emotion, vol. 40, no. 3, pp. 478–488, 2016. @article{Perron2016, While a smile can reflect felt happiness, it can also be voluntarily produced, for instance, to mask negative emotions. Masking strategies are not always perfect and traces of the negative emotion can leak. The current study examined the role of traces of anger, sadness, fear and disgust in the judgment of authenticity of smiles. Participants judged the authenticity of the smiles while their eye movements were recorded. They were also asked if the stimuli comprised another emotion and, if so, what the emotion was. Results revealed that participants were sensitive to traces of negative emotions. Variations were observed between emotions with performance being best for traces of fear and lowest for traces of anger in the eyebrows in the judgment task. However, when the pres- ence of a negative emotion was reported, participants were less accurate in identifying fear but more accurate in identifying anger. Furthermore, variations were observed as a function of the location of the trace whether in the mouth or eyes as a function of the emotion. Traces in the eyebrows were associated with better performance than traces in the mouth for sadness but the opposite was observed for anger. The performance at the judgment task was not linked to eye movement measures or explicit knowledge of the masked emotion. Future research should explore other explanation for the variations in performance in the judgments of authenticity of masking smiles such as emotional |
Matthew F. Peterson; Jing Lin; Ian Zaun; Nancy Kanwisher Individual differences in face-looking behavior generalize from the lab to the world Journal Article In: Journal of Vision, vol. 16, no. 7, pp. 1–18, 2016. @article{Peterson2016, Recent laboratory studies have found large, stable individual differences in the location people first fixate when identifying faces, ranging from the brows to the mouth. Importantly, this variation is strongly associated with differences in fixation-specific identification performance such that an individual's recognition ability is maximized when looking at their preferred location (Mehoudar, Arizpe, Baker, & Yovel, 2014; Peterson & Eckstein, 2013). This finding suggests that face representations are retinotopic and individuals enact gaze strategies that optimize identification, yet the extent to which this behavior reflects real-world gaze behavior is unknown. Here, we used mobile eye-trackers to test whether individual differences in face-gaze generalize from lab to real-world vision. In-lab fixations were measured with a speeded face identification task, while real-world behavior was measured as subjects freely walked around the MIT campus. We found a strong correlation between the patterns of individual differences in face-gaze in the laboratory and real-world settings. Our findings support the hypothesis that individuals optimize real-world face identification by consistently fixating the same location and thus strongly constraining the space of retinotopic input. The methods developed for this study entailed collecting a large set of high-definition, wide field-of-view natural videos from head-mounted cameras and the viewer's fixation position, allowing us to characterize subject's actually-experienced real-world retinotopic images. These images enable us to ask how vision is optimized not just for the statistics of the “natural images” found in web databases, but of the truly natural, retinotopic images that have landed on actual human retinae during real-world experience. |
Judith Peth; Kristina Suchotzki; Matthias Gamer Influence of countermeasures on the validity of the Concealed Information Test Journal Article In: Psychophysiology, vol. 53, no. 9, pp. 1429–1440, 2016. @article{Peth2016, The Concealed Information Test (CIT) is a psychophysiological technique that allows for detecting crime-related knowledge. Usually, autonomic response measures are used for this purpose, but ocular measures have also been proposed recently. Prior studies reported heterogeneous results for the usage of countermeasures (CM) to corrupt the CIT's validity, depending on the CM technique and the dependent measure. The current study systematically compared the application of physical and mental CM on autonomic and ocular measures during the CIT. Sixty participants committed a mock crime and were assigned to one of three guilty conditions: standard guilty (without CM), physical CM, or mental CM. An additional group of 20 innocents was investigated with the same CIT to calculate validity estimates. Electrodermal responses were more vulnerable for CM usage compared to heart rate and respiration, and physical CM were more effective than mental CM. Independent of CM usage, a combined score of autonomic responses enabled a valid differentiation between guilty and innocent examinees. Fixations and blinks also allowed for detecting crime-related knowledge, but these measures were more affected by CM application than autonomic responses. The current study delivered further evidence that CM differentially impact physiological and ocular responses in the CIT. Whereas individual data channels were strongly affected by CM usage, a combination of different response measures yielded a relatively stable differentiation of guilty and innocent examinees when mental CM were used. These findings are especially relevant for field applications and might inspire future studies to detect or prevent CM usage in CIT examinations. |
Christina U. Pfeuffer; Andrea Kiesel; Lynn Huestegge A look into the future: Spontaneous anticipatory saccades reflect processes of anticipatory action control Journal Article In: Journal of Experimental Psychology: General, vol. 145, no. 11, pp. 1530–1547, 2016. @article{Pfeuffer2016, According to ideomotor theory, human action control uses anticipations of one's own actions' future consequences, that is, action effect anticipations, as a means of triggering actions that will produce desired outcomes (e.g., Hommel, Müsseler, Aschersleben, & Prinz, 2001). Using the response-effect compatibility paradigm (Kunde, 2001), we demonstrate that the anticipation of one's own manual actions' future consequences not only triggers appropriate (i.e., instructed) actions, but simultaneously induces spontaneous (uninstructed) anticipatory saccades to the location of future action consequences. In contrast to behavioral response-effect compatibility effects that have been linked to processes of action selection and action planning, our results suggest that these anticipatory saccades serve the function of outcome evaluation, that is, the comparison of expected/intended and observed action outcomes. Overall, our results demonstrate the informational value of additionally analyzing uninstructed behavioral components complementary to instructed responses and allow us to specify essential mechanisms of the complex interplay between the manual and oculomotor control system in goal-directed action control. |
Andrea Phillipou; Larry Allen Abel; David Jonathan Castle; Matthew Edward Hughes; Richard Grant Nibbs; Caroline T. Gurvich; Susan Lee Rossell Resting state functional connectivity in anorexia nervosa Journal Article In: Psychiatry Research: Neuroimaging, vol. 251, pp. 45–52, 2016. @article{Phillipou2016, Anorexia Nervosa (AN) is a serious psychiatric illness characterised by a disturbance in body image, a fear of weight gain and significantly low body weight. The factors involved in the genesis and maintenance of AN are unclear, though the potential neurobiological underpinnings of the condition are of increasing interest. Through the investigation of functional connectivity of the brain at rest, information relating to neuronal communication and integration of information that may relate to behaviours and cognitive symptoms can be explored. The aim of this study was to investigate functional connectivity of the default mode network, and sensorimotor and visual networks in AN. 26 females with AN and 27 healthy control participants matched for age, gender and premorbid intelligence underwent a resting state functional magnetic resonance imaging scan. Default mode network functional connectivity did not differ between groups. AN participants displayed reduced functional connectivity between the sensorimotor and visual networks, in comparison to healthy controls. This finding is discussed in terms of differences in visuospatial processing in AN and the distortion of body image experienced by these individuals. Overall, the findings suggest that sensorimotor and visual network connectivity may be related to visuospatial processing in AN, though, further research is required. |
Andrea Phillipou; Susan Lee Rossell; Caroline T. Gurvich; David Jonathan Castle; Nikolaus F. Troje; Larry Allen Abel Body image in anorexia nervosa: Body size estimation utilising a biological motion task and eyetracking Journal Article In: European Eating Disorders Review, vol. 24, no. 2, pp. 131–138, 2016. @article{Phillipou2016a, OBJECTIVE: Anorexia nervosa (AN) is a psychiatric condition characterised by a distortion of body image. However, whether individuals with AN can accurately perceive the size of other individuals' bodies is unclear. METHOD: In the current study, 24 women with AN and 24 healthy control participants undertook two biological motion tasks while eyetracking was performed: to identify the gender and to indicate the walkers' body size. RESULTS: Anorexia nervosa participants tended to 'hyperscan' stimuli but did not demonstrate differences in how visual attention was directed to different body areas, relative to controls. Groups also did not differ in their estimation of body size. DISCUSSION: The hyperscanning behaviours suggest increased anxiety to disorder-relevant stimuli in AN. The lack of group difference in the estimation of body size suggests that the AN group was able to judge the body size of others accurately. The findings are discussed in terms of body image distortion specific to oneself in AN. |
Andrea Phillipou; Susan Lee Rossell; Caroline T. Gurvich; Matthew Edward Hughes; David Jonathan Castle; Richard Grant Nibbs; Larry Allen Abel Saccadic eye movements in Anorexia Nervosa Journal Article In: PLoS ONE, vol. 11, no. 3, pp. e0152338, 2016. @article{Phillipou2016b, Background: Anorexia Nervosa (AN) has a mortality rate among the highest of any mental illness, though the factors involved in the condition remain unclear. Recently, the potential neurobiological underpinnings of the condition have become of increasing interest. Saccadic eye movement tasks have proven useful in our understanding of the neurobiology of some other psychiatric illnesses as they utilise known brain regions, but to date have not been examined in AN. The aim of this study was to investigate whether individuals with AN differ from healthy individuals in performance on a range of saccadic eye movements tasks. Methods: 24 females with AN and 25 healthy individuals matched for age, gender and premorbid intelligence participated in the study. Participants were required to undergo memory-guided and self-paced saccade tasks, and an interleaved prosaccade/antisaccade/no-go saccade task while undergoing functional magnetic resonance imaging (fMRI). Results: AN participants were found to make prosaccades of significantly shorter latency than healthy controls. AN participants also made an increased number of inhibitory errors on the memory-guided saccade task. Groups did not significantly differ in antisaccade, no-go saccade or self-paced saccade performance, or fMRI findings. Discussion: The results suggest a potential role of GABA in the superior colliculus in the psychopathology of AN. |
Zhongling Pi; Jianzhong Hong Learning process and learning outcomes of video podcasts including the instructor and PPT slides: A Chinese case Journal Article In: Innovations in Education and Teaching International, vol. 53, no. 2, pp. 135–144, 2016. @article{Pi2016, Video podcasts have become one of the fastest developing trends in learning and teaching. The study explored the effect of the presenting mode of educational video podcasts on the learning process and learning outcomes. Prior to viewing a video podcast, the 94 Chinese undergraduates participating in the study completed a demographic questionnaire and prior knowledge test. The learning process was investigated by eye-tracking and the learning outcome by a learning test. The results revealed that the participants using the video podcast with both the instructor and PPT slides gained the best learning outcomes. It was noted that they allocated much more visual attention to the instructor than to the PPT slides. It was additionally found that the 22 min was the time at which the participants reached the peak of mental fatigue. The results of our study imply that the use of educational technology is culture bound. |
Manon W. Jones; Margaret J. Snowling; Kristina Moll What automaticity deficit? Activation of lexical information by readers with dyslexia in a rapid automatized naming Stroop-switch task Journal Article In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 42, no. 3, pp. 465–474, 2016. @article{Jones2016, Reading fluency is often predicted by rapid automatized naming (RAN) speed, which as the name implies, measures the automaticity with which familiar stimuli (e.g., letters) can be retrieved and named. Readers with dyslexia are considered to have less "automatized" access to lexical information, reflected in longer RAN times compared with nondyslexic readers. We combined the RAN task with a Stroop-switch manipulation to test the automaticity of dyslexic and nondyslexic readers' lexical access directly within a fluency task. Participants named letters in 10 × 4 arrays while eye movements and speech responses were recorded. Upon fixation, specific letter font colors changed from black to a different color, whereupon the participant was required to rapidly switch from naming the letter to naming the letter color. We could therefore measure reading group differences on "automatic" lexical processing, insofar as it was task-irrelevant. Readers with dyslexia showed obligatory lexical processing and a timeline for recognition that was overall similar to typical readers, but a delay emerged in the output (naming) phase. Further delay was caused by visual-orthographic competition between neighboring stimuli. Our findings outline the specific processes involved when researchers speak of "impaired automaticity" in dyslexic readers' fluency, and are discussed in the context of the broader literature in this field. |
Sung Jun Joo; Leor N. Katz; Alexander C. Huk Decision-related perturbations of decision-irrelevant eye movements Journal Article In: Proceedings of the National Academy of Sciences, vol. 113, no. 7, pp. 1925–1930, 2016. @article{Joo2016, It is well established that ongoing cognitive functions affect the trajectories of limb movements mediated by corticospinal circuits, suggesting an interaction between cognition and motor action. Although there are also many demonstrations that decision formation is reflected in the ongoing neural activity in oculomotor brain circuits, it is not known whether the decision-related activity in those oculomotor structures interacts with eye movements that are decision irrelevant. Here we tested for an interaction between decisions and instructed saccades unrelated to the perceptual decision. Observers performed a direction-discrimination decisionmaking task, but made decision-irrelevant saccades before registering their motion decision with a button press. Probing the oculomotor circuits with these decision-irrelevant saccades during decision making revealed that saccade reaction times and peak velocities were influenced in proportion to motion strength, and depended on the directional congruence between decisions about visual motion and decision-irrelevant saccades. These interactions disappeared when observers passively viewed the motion stimulus but still made the same instructed saccades, and when manual reaction times were measured instead of saccade reaction times, confirming that these interactions result from decision formation as opposed to visual stimulation, and are specific to the oculomotor system. Our results demonstrate that oculomotor function can be affected by decision formation, even when decisions are communicated without eye movements, and that this interaction has a directionally specific component. These results not only imply a continuous and interactive mixture of motor and decision signals in oculomotor structures, but also suggest nonmotor recruitment of oculomotor machinery in decision making. |
Timothy R. Jordan; Jasmine Dixon; Victoria A. Mcgowan; Stoyan Kurtev; Kevin B. Paterson Fast and slow readers and the effectiveness of the spatial frequency content of text : Evidence from reading times and eye movements Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 42, no. 8, pp. 1066–1071, 2016. @article{Jordan2016, Text contains a range of different spatial frequencies but the effectiveness of spatial frequencies for normal variations in skilled adult reading ability is unknown. Accordingly, young skilled adult readers showing fast or slow reading ability read sentences displayed as normal or filtered to contain only very low, low, medium, high, or very high spatial frequencies. Reading times and eye movement measures of fixations and saccades assessed the effectiveness of these displays for reading. Reading times showed that, for each reading ability, medium, high, and very high spatial frequencies were all more effective than lower spatial frequencies. Indeed, for each reading ability, reading times for normal text were maintained when text contained only medium, high, or very high spatial frequencies. However, reading times for normal text and for each spatial frequency were all substantially shorter for fast readers than for slow readers, and this advantage for fast readers was similar for normal, medium, high, and very high spatial frequencies but much larger for low and very low spatial frequencies. In addition, fast readers made fewer and shorter fixations, fewer and shorter regressions, and longer forward saccades, than slow readers, and these differences were generally similar in size for normal, medium, high, and very high spatial frequencies, but larger when spatial frequencies were lower. These findings suggest that fast and slow adult readers can each use a range of different spatial frequencies for reading but fast readers make more effective use of these spatial frequencies and especially those that are lower. |
Timothy R. Jordan; Jasmine Dixon; Victoria A. McGowan; Stoyan Kurtev; Kevin B. Paterson Effects of spatial frequencies on word identification by fast and slow readers: Evidence from eye movements Journal Article In: Frontiers in Psychology, vol. 7, pp. 1433, 2016. @article{Jordan2016b, Recent research has shown that differences in the effectiveness of spatial frequencies for fast and slow skilled adult readers may be an important component of differences in reading ability in the skilled adult reading population (Jordan, McGowan, Dixon, Kurtev & Paterson, 2016). But the precise nature of this influence on lexical processing during reading remains to be fully determined. Accordingly, to gain more insight into the use of spatial frequencies by skilled adult readers with fast and slow reading abilities, the present study looked at effects of spatial frequencies on the processing of specific target words in sentences. These target words were of either high or low lexical frequency and each sentence was displayed as normal or filtered to contain only very low, low, medium, high, or very high spatial frequencies. Eye movement behavior for target words was closest to normal for each reading ability when text was shown in medium or higher spatial frequency displays, although reading occurred for all spatial frequencies. Moreover, typical word frequency effects (the processing advantage for words with higher lexical frequencies) were observed for each reading ability across a broad range of spatial frequencies, indicating that many different spatial frequencies provide access to lexical representations during textual reading for both fast and slow skilled adult readers. Crucially, however, target word fixations were fewer and shorter for fast readers than for slow readers for all display types, and this advantage for fast readers appeared to be similar for normal, medium, high and very high spatial frequencies but larger for low and very low spatial frequencies. Therefore, although fast and slow skilled adult readers can both use a broad range of spatial frequencies when reading, fast readers make more effective use of these spatial frequencies, and especially those that are lower, when processing the identities of words. |
Timothy R. Jordan; Victoria A. McGowan; Stoyan Kurtev; Kevin B. Paterson A further look at postview effects in reading: An eye-movements study of influences from the left of fixation Journal Article In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 42, no. 2, pp. 296–307, 2016. @article{Jordan2016a, When reading from left to right, useful information acquired during each fixational pause is widely assumed to extend 14 to 15 characters to the right of fixation but just 3 to 4 characters to the left, and certainly no further than the beginning of the fixated word. However, this leftward extent is strikingly small and seems inconsistent with other aspects of reading performance and with the general horizontal symmetry of visual input. Accordingly, 2 experiments were conducted to examine the influence of text located to the left of fixation during each fixational pause using an eye-tracking paradigm in which invisible boundaries were created in sentence displays. Each boundary corresponded to the leftmost edge of each word so that, as each sentence was read, the normal letter content of text to the left of each fixated word was corrupted by letter replacements that were either visually similar or visually dissimilar to the originals. The proximity of corrupted text to the left of fixation was maintained at 1, 2, 3, or 4 words from the left boundary of each fixated word. In both experiments, relative to completely normal text, reading performance was impaired when each type of letter replacement was up to 2 words to the left of fixated words but letter replacements further from fixation produced no impairment. These findings suggest that key aspects of reading are influenced by information acquired during each fixational pause from much further leftward than is usually assumed. Some of the implications of these findings for reading are discussed. |
Emilie L. Josephs; Dejan Draschkow; Jeremy M. Wolfe; Melissa L. -H. Võ Gist in time: Scene semantics and structure enhance recall of searched objects Journal Article In: Acta Psychologica, vol. 169, pp. 100–108, 2016. @article{Josephs2016, Previous work has shown that recall of objects that are incidentally encountered as targets in visual search is better than recall of objects that have been intentionally memorized (Draschkow, Wolfe, & Võ, 2014). However, this counter-intuitive result is not seen when these tasks are performed with non-scene stimuli. The goal of the current paper is to determine what features of search in a scene contribute to higher recall rates when compared to a memorization task. In each of four experiments, we compare the free recall rate for target objects following a search to the rate following a memorization task. Across the experiments, the stimuli include progressively more scene-related information. Experiment 1 provides the spatial relations between objects. Experiment 2 adds relative size and depth of objects. Experiments 3 and 4 include scene layout and semantic information. We find that search leads to better recall than explicit memorization in cases where scene layout and semantic information are present, as long as the participant has ample time (2500 ms) to integrate this information with knowledge about the target object (Exp. 4). These results suggest that the integration of scene and target information not only leads to more efficient search, but can also contribute to stronger memory representations than intentional memorization. |
Siddhartha Joshi; Yin Li; Rishi M. Kalwani; Joshua I. Gold Relationships between pupil diameter and neuronal activity in the locus coeruleus, colliculi, and cingulate cortex Journal Article In: Neuron, vol. 89, no. 1, pp. 221–234, 2016. @article{Joshi2016, Changes in pupil diameter that reflect effort and other cognitive factors are often interpreted in terms of the activity of norepinephrine-containing neurons in the brainstem nucleus locus coeruleus (LC), but there is little direct evidence for such a relationship. Here, we show that LC activation reliably anticipates changes in pupil diameter that either fluctuate naturally or are driven by external events during near fixation, as in many psychophysical tasks. This relationship occurs on as fine a temporal and spatial scale as single spikes from single units. However, this relationship is not specific to the LC. Similar relationships, albeit with delayed timing and different reliabilities across sites, are evident in the inferior and superior colliculus and anterior and posterior cingulate cortex. Because these regions are interconnected with the LC, the results suggest that non-luminance-mediated changes in pupil diameter might reflect LC-mediated coordination of neuronal activity throughout some parts of the brain. Joshi et al. found that changes in pupil diameter can reflect neural activity in the locus coeruleus (LC) and, less reliably, several other interconnected structures. The results suggest that LC-mediated arousal may coordinate activity throughout some parts of the brain. |
Jakob Kaiser; Graham C. L. Davey; Thomas Parkhouse; Jennifer Meeres; Ryan B. Scott Emotional facial activation induced by unconsciously perceived dynamic facial expressions Journal Article In: International Journal of Psychophysiology, vol. 110, pp. 207–211, 2016. @article{Kaiser2016, Do facial expressions of emotion influence us when not consciously perceived? Methods to investigate this question have typically relied on brief presentation of static images. In contrast, real facial expressions are dynamic and unfold over several seconds. Recent studies demonstrate that gaze contingent crowding (GCC) can block awareness of dynamic expressions while still inducing behavioural priming effects. The current experiment tested for the first time whether dynamic facial expressions presented using this method can induce unconscious facial activation. Videos of dynamic happy and angry expressions were presented outside participants' conscious awareness while EMG measurements captured activation of the zygomaticus major (active when smiling) and the corrugator supercilii (active when frowning). Forced-choice classification of expressions confirmed they were not consciously perceived, while EMG revealed significant differential activation of facial muscles consistent with the expressions presented. This successful demonstration opens new avenues for research examining the unconscious emotional influences of facial expressions. |
Marta Kajzer-Wietrzny; Bogusława Whyatt; Katarzyna Stachowiak Simplification in inter- and intralingual translation – combining corpus linguistics, key logging and eye-tracking Journal Article In: Poznan Studies in Contemporary Linguistics, vol. 52, no. 2, pp. 235–267, 2016. @article{KajzerWietrzny2016, As some scholars view inter- and intralingual translation as a parallel activity, it is vital to establish to what extent the products of these processes are alike, and whether the processes themselves differ. This paper investigates stylistic simplification, a frequently hypothesised translation universal which involves, among others, breaking up long sentences in the process of translation (Laviosa 2002). One of the parameters commonly used in the investigations of simplification in translations is the average sentence length. In the present study we focus on sentence length to see if the tendency to incorporate stylistic simplification is equally present in the products of inter- and intralingual translation; what phases of the translation process are decisive for sentence length; whether the scope of consultation with the source text affects sentence length. Finally, we will try to verify if average sentence length is dependent on the level of translation experience. |
Yuki Kamide; Shane Lindsay; Christoph Scheepers; Anuenue Kukona Event processing in the visual world: Projected motion paths during spoken sentence comprehension Journal Article In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 42, no. 5, pp. 804–812, 2016. @article{Kamide2016, Motion events in language describe the movement of an entity to another location along a path. In 2 eye-tracking experiments, we found that comprehension of motion events involves the online construction of a spatial mental model that integrates language with the visual world. In Experiment 1, participants listened to sentences describing the movement of an agent to a goal while viewing visual scenes depicting the agent, goal, and empty space in between. Crucially, verbs suggested either upward (e.g., jump) or downward (e.g., crawl) paths. We found that in the rare event of fixating the empty space between the agent and goal, visual attention was biased upward or downward in line with the verb. In Experiment 2, visual scenes depicted a central obstruction, which imposed further constraints on the paths and increased the likelihood of fixating the empty space between the agent and goal. The results from this experiment corroborated and refined the previous findings. Specifically, eye-movement effects started immediately after hearing the verb and were in line with data from an additional mouse-tracking task that encouraged a more explicit spatial reenactment of the motion event. In revealing how event comprehension operates in the visual world, these findings suggest a mental simulation process whereby spatial details of motion events are mapped onto the world through visual attention. The strength and detectability of such effects in overt eye-movements is constrained by the visual world and the fact that perceivers rarely fixate regions of empty space. |
Efthymia C. Kapnoula; Bob McMurray Training alters the resolution of lexical interference: Evidence for plasticity of competition and inhibition Journal Article In: Journal of Experimental Psychology: General, vol. 145, no. 1, pp. 8–30, 2016. @article{Kapnoula2016, Language learning is generally described as a problem of acquiring new information (e.g., new words). However, equally important are changes in how the system processes known information. For example, a wealth of studies has suggested dramatic changes over development in how efficiently children recognize familiar words, but it is unknown what kind of experience-dependent mechanisms of plasticity give rise to such changes in real-time processing. We examined the plasticity of the language processing system by testing whether a fundamental aspect of spoken word recognition, lexical interference, can be altered by experience. Adult participants were trained on a set of familiar words over a series of 4 tasks. In the high-competition (HC) condition, tasks were designed to encourage coactivation of similar words (e.g., net and neck) and to require listeners to resolve this competition. Tasks were similar in the low-competition (LC) condition, but did not enhance this competition. Immediately after training, interlexical interference was tested using a visual world paradigm task. Participants in the HC group resolved interference to a fuller degree than those in the LC group, demonstrating that experience can shape the way competition between words is resolved. TRACE simulations showed that the observed late differences in the pattern of interference resolution can be attributed to differences in the strength of lexical inhibition. These findings inform cognitive models in many domains that involve competition/interference processes, and suggest an experience-dependent mechanism of plasticity that may underlie longer term changes in processing efficiency associated with both typical and atypical development. |
Efthymia C. Kapnoula; Bob McMurray Newly learned word forms are abstract and integrated immediately after acquisition Journal Article In: Psychonomic Bulletin & Review, vol. 23, no. 2, pp. 491–499, 2016. @article{Kapnoula2016a, A hotly debated question in word learning concerns the conditions under which newly learned words compete or interfere with familiar words during spoken word recognition. This has recently been described as a key marker of the integration of a new word into the lexicon and was thought to require consolidation Dumay & Gaskell, (Psychological Science, 18, 35-39, 2007; Gaskell & Dumay, Cognition, 89, 105-132, 2003). Recently, however, Kapnoula, Packard, Gupta, and McMurray, (Cognition, 134, 85-99, 2015) showed that interference can be observed immediately after a word is first learned, implying very rapid integration of new words into the lexicon. It is an open question whether these kinds of effects derive from episodic traces of novel words or from more abstract and lexicalized representations. Here we addressed this question by testing inhibition for newly learned words using training and test stimuli presented in different talker voices. During training, participants were exposed to a set of nonwords spoken by a female speaker. Immediately after training, we assessed the ability of the novel word forms to inhibit familiar words, using a variant of the visual world paradigm. Crucially, the test items were produced by a male speaker. An analysis of fixations showed that even with a change in voice, newly learned words interfered with the recognition of similar known words. These findings show that lexical competition effects from newly learned words spread across different talker voices, which suggests that newly learned words can be sufficiently lexicalized, and abstract with respect to talker voice, without consolidation. |
Loes T. E. Kessels; Peter R. Harris; Robert A. C. Ruiter; William M. P. Klein Attentional effects of self-affirmation in response to graphic antismoking images Journal Article In: Health Psychology, vol. 35, no. 8, pp. 891–897, 2016. @article{Kessels2016, Objective: Self-affirmation has been shown to reduce defensive responding to threatening information. However, little is known about the cognitive and attentional processes underlying these effects. In the current eye-movement study, the authors explored whether self-affirmation affects attention allocation (i.e., number of fixations) among those for whom a threatening health message is self-relevant. Methods: After a self-affirmation manipulation, 47 smokers and 52 nonsmokers viewed a series of cigarette packs displaying high or low threat smoking-related images accompanied by a brief smoking message containing risk, coping or neutral textual information. Results: Self-affirmed smokers made more fixations to the cigarette packs than did nonaffirmed smokers (across both high and low threat images), whereas self-affirmed nonsmokers made fewer fixations to the cigarette packs than did nonaffirmed nonsmokers (again across both image types). The textual information did not moderate responses. Conclusions: Findings indicate attention-increasing effects of self-affirmation among those for whom the information is self-relevant (smokers) and attention-decreasing effects of self-affirmation among those for whom the information is not self-relevant (nonsmokers). Such findings are consistent with the calibration model of self-affirmation (Griffin & Harris, 2011) in which self-affirmation increases sensitivity to the self-relevance of health-risk information. The use of an implicit measure of visual orienting informs our understanding of the working mechanisms of self-affirmation when encoding health information, and may also hold practical implications for the design and delivery of graphic warning labels. |
Aarlenne Zein Khan; Douglas P. Munoz; Naomi Takahashi; Gunnar Blohm; Robert M. McPeek Effects of a pretarget distractor on saccade reaction times across space and time in monkeys and humans Journal Article In: Journal of Vision, vol. 16, no. 7, pp. 1–20, 2016. @article{Khan2016, Previous studies have shown that the influence of a behaviorally irrelevant distractor on saccade reaction times (SRTs) varies depending on the temporal and spatial relationship between the distractor and the saccade target. We measured distractor influence on SRTs to a subsequently presented target, varying the spatial location and the timing between the distractor and the target. The distractor appeared at one of four equally eccentric locations, followed by a target (either 50 ms or 200 ms after) at one of 136 different locations encompassing an area of 20° square. We extensively tested two humans and two monkeys on this task to determine interspecies similarities and differences, since monkey neurophysiology is often used to interpret human behavioral findings. Results were similar across species; for the short interval (50 ms), SRTs were shortest to a target presented close to or at the distractor location and increased primarily as a function of the distance from the distractor. There was also an effect of distractor-target direction and visual field. For the long interval (200 ms) the results were inverted; SRTs were longest for short distances between the distractor and target and decreased as a function of distance from distractor. Both SRT patterns were well captured by a two-dimensional dynamic field model with short-distance excitation and long-distance inhibition, based upon known functional connectivity found in the superior colliculus that includes wide-spread excitation and inhibition. Based on these findings, we posit that the different time-dependent patterns of distractor-related SRTs can emerge from the same underlying neuronal mechanisms common to both species. |
Jason J. Ki; Simon P. Kelly; Lucas C. Parra Attention strongly modulates reliability of neural responses to naturalistic narrative stimuli Journal Article In: Journal of Neuroscience, vol. 36, no. 10, pp. 3092–3101, 2016. @article{Ki2016, Attentional engagement is a major determinant of how effectively we gather information through our senses. Alongside the sheer growth in the amount and variety of information content that we are presented with through modern media, there is increased variability in the degree to which we "absorb" that information. Traditional research on attention has illuminated the basic principles of sensory selection to isolated features or locations, but it provides little insight into the neural underpinnings of our attentional engagement with modern naturalistic content. Here, we show in human subjects that the reliability of an individual's neural responses with respect to a larger group provides a highly robust index of the level of attentional engagement with a naturalistic narrative stimulus. Specifically, fast electroencephalographic evoked responses were more strongly correlated across subjects when naturally attending to auditory or audiovisual narratives than when attention was directed inward to a mental arithmetic task during stimulus presentation. This effect was strongest for audiovisual stimuli with a cohesive narrative and greatly reduced for speech stimuli lacking meaning. For compelling audiovisual narratives, the effect is remarkably strong, allowing perfect discrimination between attentional state across individuals. Control experiments rule out possible confounds related to altered eye movement trajectories or order of presentation. We conclude that reliability of evoked activity reproduced across subjects viewing the same movie is highly sensitive to the attentional state of the viewer and listener, which is aided by a cohesive narrative. |
Dovin Kiernan; Gerome Manson; Matthew Heath; Luc Tremblay; Timothy N. Welsh Corrections in saccade endpoints scale to the amplitude of target displacements in a double-step paradigm Journal Article In: Neuroscience Letters, vol. 611, pp. 46–50, 2016. @article{Kiernan2016, It is widely held that discrete goal-directed eye movements (saccades) are ballistic in nature because their durations are too short to allow for sensory-based online correction. Recent studies, however, have provided evidence that saccadic endpoints can be mediated via online corrections. Specifically, it has been reported that saccade trajectories adapt to the eccentricity of an unexpectedly perturbed target location (i.e., target 'jump' paradigm). If saccades are subject to online correction mechanisms, then the magnitude of such changes should scale to the amplitude of the target jump. To test this hypothesis, saccadic endpoints for trials on which the target jumped one of three amplitudes (Small: 2.5°, Medium: 5.0°, and Large: 7.5° i.e., Jump trials) immediately after saccade onset were compared with the endpoints of trials in which the target location did not change (i.e., Reference trials). Results showed that primary saccade endpoints for Jump trials were longer than for Reference trials. Importantly, the magnitude of this increase in endpoint scaled with the amplitude of the target jump. Thus, these results support emerging and coalescent evidence that saccade trajectories are subject to online corrections. |
Atsushi Kikumoto; Jason Hubbard; Ulrich Mayr Dynamics of task-set carry-over: evidence from eye-movement analyses Journal Article In: Psychonomic Bulletin & Review, vol. 23, no. 3, pp. 899–906, 2016. @article{Kikumoto2016, Trial-to-trial carry-over of task sets (i.e., task-set inertia) is often considered as a primary reason for task-switch costs. Yet, we know little about the dynamics of such carry-over effects, in particular how much they are driven by the most recent trial rather than characterized by a more continuous memory gradient. Using eye-tracking, we examined in a 3-task, switching paradigm whether there is a greater probability of non-target fixations to stimuli associated with the previously relevant attentional set than to those associated with the less-recent set. Indeed, we found strong evidence for more interference (expressed in terms of non-target fixations) from recent than from less-recent tasks and that in particular the interference from pre-switch trials contributed substantially to the overall pattern of response-time switch costs. Moreover, task-set carry-over was dominated by the most-recent trial when subjects could expect task repetitions (with a 33 % switch rate). In comparison, when tasks were selected randomly (with a 66 % switch rate), interference from the most recent trial decreased, whereas interference from less-recent trials increased. In sum, carry-over interference dynamics were characterized both by a gradual recency gradient and expectations about task-transition probabilities. Beyond that, there was little evidence for a unique role of the most-recent trial. |
Markku Kilpeläinen; Jan Theeuwes Efficient avoidance of the penalty zone in human eye movements Journal Article In: PLoS ONE, vol. 11, no. 12, pp. e0167956, 2016. @article{Kilpelaeinen2016, People use eye movements extremely effectively to find objects of interest in a cluttered visual scene. Distracting, task-irrelevant attention capturing regions in the visual field should be avoided as they jeopardize the efficiency of search. In the current study, we used eye tracking to determine whether people are able to avoid making saccades to a predetermined visual area associated with a financial penalty, while making fast and accurate saccades towards stimuli placed near the penalty area. We found that in comparison to the same task without a penalty area, the introduction of a penalty area immediately affected eye movement behaviour: the proportion of saccades to the penalty area was immediately reduced. Also, saccadic latencies increased, but quite modestly, and mainly for saccades towards stimuli near the penalty area. We conclude that eye movement behaviour is under efficient cognitive control and thus quite flexible: it can immediately be adapted to changing environ- mental conditions to improve reward outcome. |
Esther S. Kim; Shannon F. Lemke Behavioural and eye-movement outcomes in response to text-based reading treatment for acquired alexia Journal Article In: Neuropsychological Rehabilitation, vol. 26, no. 1, pp. 60–86, 2016. @article{Kim2016, Text-based reading treatments, such as Multiple Oral Rereading (MOR) and Oral Reading for Language in Aphasia (ORLA) have been used successfully to remediate reading impairments in individuals with acquired alexia, but the mechanisms underlying such improvements are not well understood. In this study, an individual with acquired alexia who demonstrated reliance on a sub-lexical reading strategy (i.e., presence of spelling regularity effect and phonologically plausible errors) underwent 12 weeks of text-based reading treatment combining MOR and ORLA procedures. Behavioural assessments of single-word and text reading, along with eye-tracking assessments were conducted pre-treatment, post-treatment and at 5 month follow-up. Improved reading fluency (rate, accuracy) was observed for both trained and untrained passages. Evidence from behavioural and eye-tracking assessment suggested text-based reading treatment facilitated use of a lexical-semantic reading strategy. Increased frequency and lexicality effects, as well as a shift in initial landing position towards the centre of the word (the "optimal viewing position") were observed at post-treatment and follow-up assessments. These results demonstrate the potential utility of using eye movements as a parameter of interest in addition to traditional behavioural outcomes when investigating response to reading treatment. |
Sihem Kime; Francesco Galluppi; Xavier Lagorce; Ryad B. Benosman; Jean Lorenceau Psychophysical assessment of perceptual performance with varying display frame rates Journal Article In: Journal of Display Technology, vol. 12, no. 11, pp. 1372–1382, 2016. @article{Kime2016, This study assesses the impact of display refresh rate on the perception of dynamic visual stimuli in humans. A projection platform was developed in that context, allowing control of the frame rate on a trial-by-trial basis. Using this display, we introduce a series of psychophysical experiments aimed to quantitatively assess objective perceptual performance at different frame rates. Tasks that are often implicitly performed when watching movies on a television set, or when wearing a head mounted display, were chosen: speed discrimination, spatial discrimination, and reading abilities, with stimuli undergoing horizontal motion in awide range ofspeeds (16–38 deg/s). The results show that whatever the stimuli or the task, performance is significantly better at high frame rate (HFR) compared to 60 Hz, providing clear-cut evidence that low refresh rates limit the ability to reliably analyze moving stimuli. These results extend those of previous psychophysical experiments performed at low refresh rates, further characterize genuine visual performance in humans and provide an objective benchmarking methodology allowing to assess visual performance with a variety of displays. Results indicate that for low resolution displays, where increasing spatial resolution is not an option, increasing frame rate could benefit motion perception. We discuss these results and their implications with regards to current and emerging categories of visual displays, such as head mounted displays. |
John Kingston; Joshua Levy; Amanda Rysling; Adrian Staub Eye movement evidence for an immediate Ganong effect Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 42, no. 12, pp. 1969–1988, 2016. @article{Kingston2016, Listeners tend to categorize an ambiguous speech sound so that it forms a word with its context (Ganong, 1980). This effect could reflect feedback from the lexicon to phonemic activation (McClelland & Elman, 1986), or the operation of a task-specific phonemic decision system (Norris, McQueen, & Cutler, 2000). Because the former account involves feedback between lexical and phonemic levels, it predicts that the lexicon's influence on phonemic decisions should be delayed and should gradually increase in strength. Previous response time experiments have not delivered a clear verdict as to whether this is the case, however. In 2 experiments, listeners' eye movements were tracked as they categorized phonemes using visually displayed response options. Lexically relevant information in the signal, the timing of which was confirmed by separate gating experiments, immediately increased eye movements toward the lexically supported response. This effect on eye movements then diminished over the course of the trial rather than continuing to increase. These results challenge the lexical feedback account. The present work also introduces a novel method for analyzing data from ‘visual-world' type tasks, designed to assess when an experimental manipulation influences the probability of an eye movement toward the target. |
Anna Klapetek; Donatas Jonikaitis; Heiner Deubel Attention allocation before antisaccades Journal Article In: Journal of Vision, vol. 16, no. 1, pp. 1–16, 2016. @article{Klapetek2016, In the present study, we investigated the distribution of attention before antisaccades. We used a dual task paradigm, in which participants made prosaccades or antisaccades and discriminated the orientation of a visual probe shown at the saccade goal, the visual cue location (antisaccade condition), or a neutral location. Moreover, participants indicated whether they had made a correct antisaccade or an erroneous prosaccade. We observed that, while spatial attention in the prosaccade task was allocated only to the saccade goal, attention in the antisaccade task was allocated both to the cued location and to the antisaccade goal. This suggests parallel attentional selection of the cued and antisaccade locations. We further observed that in error trials—in which participants made an incorrect prosaccade instead of an antisaccade—spatial attention was biased towards the prosaccade goal. These erroneous prosaccades were mostly unnoticed and were often followed by corrective antisaccades with very short latencies (<100 ms). Data from error trials therefore provide further evidence for the parallel programming of the reflexive prosaccade to the cue and the antisaccade to the intended location. Taken together, our results suggest that attention allocation and saccade goal selection in the antisaccade task are mediated by a common competitive process. |
Hinze Hogendoorn Voluntary saccadic eye movements ride the attentional rhythm Journal Article In: Journal of Cognitive Neuroscience, vol. 28, no. 10, pp. 1625–1635, 2016. @article{Hogendoorn2016, Visual perception seems continuous, but recent evidence suggests that the underlying perceptual mechanisms are in fact periodic—particularly visual attention. Because visual attention is closely linked to the preparation of saccadic eye movements, the question arises how periodic attentional processes interact with the preparation and execution of voluntary saccades. In two experiments, human observers made voluntary saccades between two placeholders, monitoring each one for the presentation of a threshold-level target. Detection performance was evaluated as a function of latency with respect to saccade landing. The time course ofdetection performance revealed oscillations at around 4 Hz both before the saccade at the saccade origin and after the saccade at the saccade destination. Furthermore, oscillations before and after the saccade were in phase, meaning that the saccade did not disrupt or reset the ongoing attentional rhythm. Instead, it seems that voluntary saccades are executed as part of an ongoing attentional rhythm, with the eyes in flight during the troughs of the attentional wave. This finding for the first time demonstrates that periodic attentional mechanisms affect not only perception but also overt motor behavior. |
Tiffany Hon; Ravi K. Das; Sunjeev K. Kamboj The effects of cognitive reappraisal following retrieval-procedures designed to destabilize alcohol memories in high-risk drinkers Journal Article In: Psychopharmacology, vol. 233, no. 5, pp. 851–861, 2016. @article{Hon2016, RATIONALE: Addiction is a disorder of motivational learning and memory. Maladaptive motivational memories linking drug-associated stimuli to drug seeking are formed over hundreds of reinforcement trials and accompanied by aberrant neuroadaptation in the mesocorticolimbic reward system. Such memories are resistant to extinction. However, the discovery of retrieval-dependent memory plasticity has opened up the possibility of permanent modification of established (long-term) memories during 'reconsolidation'.$backslash$n$backslash$nOBJECTIVES: Here, we investigate whether reappraisal of maladaptive alcohol cognitions performed after procedures designed to destabilize alcohol memory networks affected subsequent alcohol memory, craving, drinking and attentional bias.$backslash$n$backslash$nMETHODS: Forty-seven at-risk drinkers attended two sessions. On the first lab session, participants underwent one of two prediction error-generating procedures in which outcome expectancies were violated while retrieving alcohol memories (omission and value prediction error groups). Participants in a control group retrieved non-alcohol memories. Participants then reappraised personally relevant maladaptive alcohol memories and completed measures of reappraisal recall, alcohol verbal fluency and craving. Seven days later, they repeated these measures along with attentional bias assessment.$backslash$n$backslash$nRESULTS: Omission prediction error (being unexpectedly prevented from drinking beer), but not a value prediction error (drinking unexpectedly bitter-tasting beer) or control procedure (drinking unexpectedly bitter orange juice), was associated with significant reductions in verbal fluency for positive alcohol-related words. No other statistically robust outcomes were detected.$backslash$n$backslash$nCONCLUSIONS: This study provides partial preliminary support for the idea that a common psychotherapeutic strategy used in the context of putative memory retrieval-destabilization can alter accessibility of alcohol semantic networks. Further research delineating the necessary and sufficient requirements for producing alterations in alcohol memory performance based on memory destabilization is still required. |
Ha Hong; Daniel L. K. Yamins; Najib J. Majaj; James J. DiCarlo Explicit information for category-orthogonal object properties increases along the ventral stream Journal Article In: Nature Neuroscience, vol. 19, no. 4, pp. 613–622, 2016. @article{Hong2016, Extensive research has revealed that the ventral visual stream hierarchically builds a robust representation for supporting visual object categorization tasks. We systematically explored the ability of multiple ventral visual areas to support a variety of 'category-orthogonal' object properties such as position, size and pose. For complex naturalistic stimuli, we found that the inferior temporal (IT) population encodes all measured category-orthogonal object properties, including those properties often considered to be low-level features (for example, position), more explicitly than earlier ventral stream areas. We also found that the IT population better predicts human performance patterns across properties. A hierarchical neural network model based on simple computational principles generates these same cross-area patterns of information. Taken together, our empirical results support the hypothesis that all behaviorally relevant object properties are extracted in concert up the ventral visual hierarchy, and our computational model explains how that hierarchy might be built. |
Ignace T. C. Hooge; Kenneth Holmqvist; Marcus Nyström In: Vision Research, vol. 128, pp. 6–18, 2016. @article{Hooge2016, Most modern video eye trackers use the p-CR (pupil minus CR) technique to deal with small relative movements between the eye tracker camera and the eye. We question whether the p-CR technique is appropriate to investigate saccade dynamics. In two experiments we investigated the dynamics of pupil, CR and gaze signals obtained from a standard SMI Hi-Speed eye tracker. We found many differences between the pupil and the CR signals. Differences concern timing of the saccade onset, saccade peak velocity and post-saccadic oscillation (PSO). We also obtained that pupil peak velocities were higher than CR peak velocities. Saccades in the eye trackers' gaze signal (that is constructed from p-CR) appear to be excessive versions of saccades in the pupil signal. We conclude that the pupil-CR technique is not suitable for studying detailed dynamics of eye movements. |
Lauren S. Hopkins; Fred J. Helmstetter; Deborah E. Hannula Eye movements are captured by a perceptually simple conditioned stimulus in the absence of explicit contingency knowledge Journal Article In: Emotion, vol. 16, no. 8, pp. 1157–1171, 2016. @article{Hopkins2016, Past reports suggest that threatening materials can impact the efficiency of goal-directed behavior. However, questions remain about whether a conditional stimulus (CS) can capture attention as previous results may have been influenced by voluntary prioritization of a to-be-ignored CS. In 2 experiments, eye tracking was used to evaluate whether neutral, perceptually simple materials capture attention when they take on aversive properties via probabilistic fear conditioning with strict methods in place to eliminate voluntary CS prioritization. During training, participants attempted to fixate search targets (i.e., horizontally or vertically oriented rectangles) as quickly as possible to avoid shock. In reality, shock administration was related to rectangle orientation so that 1 rectangle (CS+) predicted shock more often than the other (CS-). Subsequently rectangles became distractors and were to be ignored. At this point, participants were instructed to fixate a new target and incidences of CS capture were examined. Results showed that saccades were made more quickly to the CS+ than the CS- as training progressed, and that oculomotor capture by irrelevant rectangles occurred more often for the CS+ than the CS-. An independent physiological index (skin conductance response) confirmed that contingencies had been learned, as SCR magnitude was greater for CS+ than CS- trials early in the test phase. These effects were documented despite the absence of explicit contingency knowledge, assessed using a postexperimental questionnaire. Collectively, these outcomes indicate that a CS can capture attention despite being task-irrelevant, and that these effects do not depend on conscious awareness of learned contingencies. |
Gernot Horstmann; Stefanie I. Becker; Daniel Ernst Perceptual salience captures the eyes on a surprise trial Journal Article In: Attention, Perception, and Psychophysics, vol. 78, no. 7, pp. 1889–1900, 2016. @article{Horstmann2016a, A number of characteristics of the visual system and of the visual stimulus are invoked to explain involuntary control of attention, including goals, novelty, and perceptual salience. The present experiment tested perceptual salience on a surprise trial, that is, on its unannounced first presentation following trials lacking any salient items, thus eliminating possible confounds by current goals. Moreover, the salient item's location was not singled out by a novel feature, thus eliminating a possible confound by novelty in directing attention. Eye tracking was used to measure involuntary attention. Results show a prioritization of the salient item. However, contrary to predictions of prominent neuro-computational and psychological salience models, prioritization was not fast-acting. Rather the observers' gaze was attracted only as the secondfixationonaverage or later (dependingoncondition) and with a latency of more than 500 ms on average. These results support the general proposition that salience can control attention. However, contrary to most salience models, the present results indicate that salience changes attentional priority only in novel environments. |
Gernot Horstmann; Arvid Herwig Novelty biases attention and gaze in a surprise trial Journal Article In: Attention, Perception, and Psychophysics, vol. 78, no. 1, pp. 69–77, 2016. @article{Horstmann2016, While the classical distinction between task- driven and stimulus-driven biasing of attention appears to be a dichotomy at first sight, there seems to be a third category that depends on the contrast or discrepancy be- tween active representations and the upcoming stimulus, and may be termed novelty, surprise, or prediction failure. For previous demonstrations of the discrepancy-attention link, stimulus-driven components (saliency) may have played a decisive role. The present study was conducted to evaluate the discrepancy-attentionlinkinadisplay where novel and familiar stimuli are equated for saliency. Eye tracking was used to determine fixations on novel and familiar stimuli as a proxy for attention. Results show a prioritization of attention by the novel color, and a de- prioritization of the familiar color, which is clearly present at the second fixation, and spans over the next couple of fixations. Saliency, on the other hand, did not prioritize items in the display. The results thus reinforce the notion that novelty captures and binds attention. |
Gernot Horstmann; Arvid Herwig; Stefanie I. Becker Distractor dwelling, skipping, and revisiting determine target absent performance in difficult visual search Journal Article In: Frontiers in Psychology, vol. 7, pp. 1152, 2016. @article{Horstmann2016b, Some targets in visual search are more difficult to find than others. In particular, a target that is similar to the distractors is more difficult to find than a target that is dissimilar to the distractors. Efficiency differences between easy and difficult searches are manifest not only in target-present trials but also in target-absent trials. In fact, even physically identical displays are searched through with different efficiency depending on the searched-for target. Here, we monitored eye movements in search for a target similar to the distractors (difficult search) versus a target dissimilar to the distractors (easy search). We aimed to examine three hypotheses concerning the causes of differential search efficiencies in target-absent trials: (a) distractor dwelling (b) distractor skipping, and (c) distractor revisiting. Reaction times increased with target similarity which is consistent with existing theories and replicates earlier results. Eye movement data indicated guidance in target trials, even though search was very slow. Dwelling, skipping, and revisiting contributed to low search efficiency in difficult search, with dwelling being the strongest factor. It is argued that differences in dwell time account for a large amount of total search time differences. |
Nina S. Hsu; Jared M. Novick Dynamic engagement of cognitive control modulates recovery from misinterpretation during real-time language processing Journal Article In: Psychological Science, vol. 27, no. 4, pp. 572–582, 2016. @article{Hsu2016, Speech unfolds swiftly, yet listeners keep pace by rapidly assigning meaning to what they hear. Sometimes, though, initial interpretations turn out to be wrong. How do listeners revise misinterpretations of language input moment by moment to avoid comprehension errors? Cognitive control may play a role by detecting when processing has gone awry and then initiating behavioral adjustments accordingly. However, no research to date has investigated a cause-and-effect interplay between cognitive-control engagement and the overriding of erroneous interpretations in real time. Using a novel cross-task paradigm, we showed that Stroop-conflict detection, which mobilizes cognitive-control procedures, subsequently facilitates listeners' incremental processing of temporarily ambiguous spoken instructions that induce brief misinterpretation. When instructions followed incongruent Stroop items, compared with congruent Stroop items, listeners' eye movements to objects in a scene reflected more transient consideration of the false interpretation and earlier recovery of the correct one. Comprehension errors also decreased. Cognitive-control engagement therefore accelerates sentence-reinterpretation processes, even as linguistic input is still unfolding. |
Po Sheng Huang; Hsuan-Chih Chen Gender differences in eye movements in solving text-and-diagram science problems Journal Article In: International Journal of Science and Mathematics Education, vol. 14, pp. S327–S346, 2016. @article{Huang2016a, The main purpose of this study was to examine possible gender differences in how junior high school students integrate printed texts and diagrams while solving science problems. We proposed the response style hypothesis and the spatial working memory hypothesis to explain possible gender differences in the integration process. Eye-tracking technique was used to explore these hypotheses. The results of eye-movement indices support the response style hypothesis. Compared to male students, female students spent more time and displayed more fixations in solving science problems. The female students took more time to read the print texts and compare the information between print-based texts and visual-based diagrams more frequently during the problem-solving process than the male students. However, no gender differences were found in the accuracy of their responses to the science problems or their performances in the spatial working memory task. Implications for psychological theory and educational practice are discussed. |
Yi Ting Huang; Alison R. Arnold Word learning in linguistic context: Processing and memory effects Journal Article In: Cognition, vol. 156, pp. 71–87, 2016. @article{Huang2016, During language acquisition, children exploit syntactic cues within sentences to learn the meanings of words. Yet, it remains unknown how this strategy develops alongside an ability to access cues during real-time language comprehension. This study investigates how on-line sensitivity to syntactic cues impacts off-line interpretation and recall of word meanings. Adults and 5-year-olds heard novel words embedded in sentences that were (1) consistent with an agent-first bias (e.g., “The blicket will be eating the seal” → “the blicket” is an agent), (2) required revision of this bias (e.g., “The blicket will be eaten by the seal” → “the blicket” is a theme), or (3) weakened this bias through a familiar NP1 (e.g., “The seal will be eating/eaten by the blicket” → “the seal” is an agent or theme). Across both ages, eye-movements during sentences revealed decreased sensitivity to syntactic cues in contexts that required syntactic revision. In children, the magnitude of on-line sensitivity was positively associated with the accuracy of learning after the sentence. Parsing challenges during the word-learning task also negatively impacted children's later memory for word meanings during a recall task. Altogether, these results suggest that real-time demands impact word learning, through interpretive failures and memory interference. |
Christoph Huber-Huber; Thomas Ditye; María Marchante Fernández; Ulrich Ansorge Using temporally aligned event-related potentials for the investigation of attention shifts prior to and during saccades Journal Article In: Neuropsychologia, vol. 92, pp. 129–141, 2016. @article{HuberHuber2016, According to the pre-motor theory of attention, attention is shifted to a saccade's landing position before the saccade is executed. Such pre-saccadic attention shifts are usually studied in psychophysical dual-task conditions, with a target-discrimination task before saccade onset. Here, we present a novel approach to investigate pre-saccadic attention shifts with the help of event-related potentials (ERPs). Participants executed one or two saccades to color-defined targets while ERPs and eye-movements were recorded. In single-target blocks participants executed a single saccade. In two-targets blocks participants made either a single saccade to one of the targets, or two successive saccades to both targets. Importantly, in two-targets blocks, targets could appear on the same or on opposite sides of the vertical midline. This allowed us to study contra-to-ipsilateral ERP differences (such as the N2pc or PCN) that reflect attention shifts to the targets, prior to saccade onset and during saccades. If pre-saccadic attention shifts to saccade target locations are necessary for saccade execution and if searched-for saccade targets capture attention, there should be enhanced attentional competition (1) between two targets compared to single targets; (2) between two opposite-sides targets compared to two same-side targets; and (3) in two saccades rather than one saccade conditions: More attentional competition was expected to delay saccade latency and to weaken pre-saccadic laterality effects in ERPs. Hypotheses were tested by means of temporally aligned ERPs that were simultaneously time-locked to stimulus onsets, saccade onsets, and saccade offsets. Predictions (1) and (2) were partly and fully confirmed, respectively, but no evidence was found for (3). We explain the implications of our results for the role of attention during saccade preparation, and we point out how temporally aligned ERPs compare to ICA-based electroencephalogram (EEG) artifact correction procedures and to psychophysical dual-task approaches. |
Lynn Huestegge; Anne Böckler Out of the corner of the driver's eye: Peripheral processing of hazards in static traffic scenes Journal Article In: Journal of Vision, vol. 16, no. 2, pp. 1–15, 2016. @article{Huestegge2016, Effective gaze control in traffic, based on peripheral visual information, is important to avoid hazards. Whereas previous hazard perception research mainly focused on skill-component development (e.g., orientation and hazard processing), little is known about the role and dynamics of peripheral vision in hazard perception. We analyzed eye movement data from a study in which participants scanned static traffic scenes including medium-level versus dangerous hazards and focused on characteristics of fixations prior to entering the hazard region. We found that initial saccade amplitudes into the hazard region were substantially longer for dangerous (vs. medium-level) hazards, irrespective of participants' driving expertise. An analysis of the temporal dynamics of this hazard-level dependent saccade targeting distance effect revealed that peripheral hazard-level processing occurred around 200–400 ms during the course of the fixation prior to entering the hazard region. An additional psychophysical hazard detection experiment, in which hazard eccentricity was manipulated, revealed better detection for dangerous (vs. medium-level) hazards in both central and peripheral vision. Furthermore, we observed a significant perceptual decline from center to periphery for medium (but not for highly) dangerous hazards. Overall, the results suggest that hazard processing is remarkably effective in peripheral vision and utilized to guide the eyes toward potential hazards. |
Falk Huettig; Esther Janse Individual differences in working memory and processing speed predict anticipatory spoken language processing in the visual world Journal Article In: Language, Cognition and Neuroscience, vol. 31, no. 1, pp. 80–93, 2016. @article{Huettig2016, Several mechanisms of predictive language processing have been proposed. The possible influence of mediating factors such as working memory and processing speed, however, has largely been ignored. We sought to find evidence for such an influence using an individual differences approach. 105 participants from 32–77 years of age received spoken instructions (e.g. “Kijk naar deCOM afgebeelde pianoCOM”– look at the displayed piano) while viewing 4 objects. Articles (Dutch “het” or “de”) were gender-marked such that the article agreed in gender only with the target. Participants could thus use article gender information to predict the target. Multiple regression analyses showed that enhanced working memory abilities and faster processing speed predicted anticipatory eye movements. Models of predictive language processing therefore must take mediating factors into account. More generally, our results are consistent with the notion that working memory grounds language in space and time, linking linguistic and visual–spatial representations. |
A. Hummer; M. Ritter; M. Tik; A. A. Ledolter; M. Woletz; G. E. Holder; Serge O. Dumoulin; U. Schmidt-Erfurth; C. Windischberger Eyetracker-based gaze correction for robust mapping of population receptive fields Journal Article In: NeuroImage, vol. 142, pp. 211–224, 2016. @article{Hummer2016, Functional MRI enables the acquisition of a retinotopic map that relates regions of the visual field to neural populations in the visual cortex. During such a “population receptive field” (PRF) experiment, stable gaze fixation is of utmost importance in order to correctly link the presented stimulus patterns to stimulated retinal regions and the resulting Blood Oxygen Level Dependent (BOLD) response of the appropriate region within the visual cortex. A method is described that compensates for unstable gaze fixation by recording gaze position via an eyetracker and subsequently modifies the input stimulus underlying the PRF analysis according to the eyetracking measures. Here we show that PRF maps greatly improve when the method is applied to data acquired with either saccadic or smooth eye movements. We conclude that the technique presented herein is useful for studies involving subjects with unstable gaze fixation, particularly elderly patient populations. |
Bianca Huurneman; F. Nienke Boonstra; Jeroen Goossens Perceptual learning in children with infantile nystagmus: Effects on visual performance Journal Article In: Investigative Ophthalmology & Visual Science, vol. 57, no. 10, pp. 4216–4228, 2016. @article{Huurneman2016a, PURPOSE: To evaluate whether computerized training with a crowded or uncrowded letter-discrimination task reduces visual impairment (VI) in 6- to 11-year-old children with infantile nystagmus (IN) who suffer from increased foveal crowding, reduced visual acuity, and reduced stereopsis. METHODS: Thirty-six children with IN were included. Eighteen had idiopathic IN and 18 had oculocutaneous albinism. These children were divided in two training groups matched on age and diagnosis: a crowded training group (n = 18) and an uncrowded training group (n = 18). Training occurred two times per week during 5 weeks (3500 trials per training). Eleven age-matched children with normal vision were included to assess baseline differences in task performance and test-retest learning. Main outcome measures were task-specific performance, distance and near visual acuity (DVA and NVA), intensity and extent of (foveal) crowding at 5 m and 40 cm, and stereopsis. RESULTS: Training resulted in task-specific improvements. Both training groups also showed uncrowded and crowded DVA improvements (0.10 ± 0.02 and 0.11 ± 0.02 logMAR) and improved stereopsis (670 ± 249″). Crowded NVA improved only in the crowded training group (0.15 ± 0.02 logMAR), which was also the only group showing a reduction in near crowding intensity (0.08 ± 0.03 logMAR). Effects were not due to test-retest learning. CONCLUSIONS: Perceptual learning with or without distractors reduces the extent of crowding and improves visual acuity in children with IN. Training with distractors improves near vision more than training with single optotypes. Perceptual learning also transfers to DVA and NVA under uncrowded and crowded conditions and even stereopsis. Learning curves indicated that improvements may be larger after longer training. |
Bianca Huurneman; F. Nienke Boonstra; Jeroen Goossens Perceptual learning in children with infantile Nystagmus: Effects on 2D oculomotor behavior Journal Article In: Investigative Ophthalmology & Visual Science, vol. 57, no. 10, pp. 4229–4238, 2016. @article{Huurneman2016, PURPOSE: To determine changes in oculomotor behavior after 10 sessions of perceptual learning on a letter discrimination task in children with infantile nystagmus (IN). METHODS: Children with IN (18 children with idiopathic IN and 18 with oculocutaneous albinism accompanied by IN) aged 6 to 11 years were divided into two training groups matched on diagnosis: an uncrowded training group (n = 18) and a crowded training group (n = 18). Target letters always appeared briefly (500 ms) at an eccentric location, forcing subjects to quickly redirect their gaze. Training occurred twice per week for 5 consecutive weeks (3500 trials total). Norm data and test-retest values were collected from children with normal vision (n = 11). Outcome measures were: nystagmus characteristics (amplitude, frequency, intensity, and the expanded nystagmus acuity function); fixation stability (the bivariate contour ellipse area and foveation time); and saccadic eye movements (latencies and accuracy) made during a simple saccade task and a crowded letter-identification task. RESULTS: After training, saccadic responses of children with IN improved on the saccade task (latencies decreased by 14 ± 4 ms and gains increased by 0.03 ± 0.01), but not on the crowded letter task. There were also no training-induced changes in nystagmus characteristics and fixation stability. Although children with normal vision had shorter latencies in the saccade task (47 ± 14 ms at baseline), test-retest changes in their saccade gains and latencies were almost equal to the training effects observed in children with IN. CONCLUSIONS: Our results suggest that the improvement in visual performance after perceptual learning in children with IN is primarily due to improved sensory processing rather than improved two-dimensional oculomotor behavior. |
Jukka Hyönä; Miia Ekholm Background speech effects on sentence processing during reading: An eye movement study Journal Article In: PLoS ONE, vol. 11, no. 3, pp. e0152133, 2016. @article{Hyoenae2016, Effects of background speech on reading were examined by playing aloud different types of background speech, while participants read long, syntactically complex and less complex sentences embedded in text. Readers' eye movement patterns were used to study online sentence comprehension. Effects of background speech were primarily seen in rereading time. In Experiment 1, foreign-language background speech did not disrupt sentence pro- cessing. Experiment 2 demonstrated robust disruption in reading as a result of semantically and syntactically anomalous scrambled background speech preserving normal sentence- like intonation. Scrambled speech that was constructed from the text to-be read did not dis- rupt reading more than scrambled speech constructed from a different, semantically unre- lated text. Experiment 3 showed that scrambled speech exacerbated the syntactic complexity effect more than coherent background speech, which also interfered with read- ing. Experiment 4 demonstrated that both semantically and syntactically anomalous speech produced no more disruption in reading than semantically anomalous but syntactically cor- rect background speech. The pattern of results is best explained by a semantic account that stresses the importance of similarity in semantic processing, but not similarity in semantic content, between the reading task and background speech. Introduction |
Kohitij Kar; Bart Krekelberg Testing the assumptions underlying fMRI adaptation using intracortical recordings in area MT Journal Article In: Cortex, vol. 80, pp. 21–34, 2016. @article{Kar2016, We investigated how neural activity in the middle temporal area of the macaque monkey changes after 3 sec of exposure to a visual stimulus and used this to gain insight into the assumptions underlying the fMRI adaptation method (fMRIa). We studied both changes in tuning curves following weak and strong motion stimuli (adaptation) and the differences between a first and second exposure to the same stimulus (repetition suppression). Typically, tuning curves had smaller amplitudes and narrower tuning widths after strong adaptation; this was true for single neurons, multi-unit activity (MUA), the evoked local field potential (LFP), as well as gamma band activity. Repetition typically led to reduced responses. This reduction was correlated with direction selectivity and not explained by neural fatigue. Our data, however, warn against a simplistic view of the consequences of adaptation. First, a considerable fraction of neurons and sites showed response enhancements after adaptation, especially when probed with a stimulus that moved opposite to the direction of the adapting stimulus. Second, adaptation was stimulus selective only on a time scale of ∼100 msec. Third, aggregate measures of neural activity (MUA, LFPs) had substantially different adaptation effects. Fourth, there were qualitative differences between our findings in MT and earlier findings in IT cortex. We conclude that selective adaptation effects in fMRIa are relatively easy to miss even when they exist (for instance by presenting stimuli for too long, or because neurons that enhance after adaptation cancel out the effect of neurons that suppress). Moreover, we argue that adaptation should be understood in the context of the computations that a neural circuit perform. Using fMRIa as a tool to uncover neural selectivity requires a better understanding of this circuitry and its consequences for adaptation. |
Omid Kardan; John M. Henderson; Grigori Yourganov; Marc G. Berman Observers' cognitive states modulate how visual inputs relate to gaze control Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 42, no. 9, pp. 1429–1442, 2016. @article{Kardan2016, Previous research has shown that eye-movements change depending on both the visual features of our environment, and the viewer's top-down knowledge. One important question that is unclear is the degree to which the visual goals of the viewer modulate how visual features of scenes guide eye-movements. Here, we propose a systematic framework to investigate this question. In our study, participants performed 3 different visual tasks on 135 scenes: search, memorization, and aesthetic judgment, while their eye-movements were tracked. Canonical correlation analyses showed that eye-movements were reliably more related to low-level visual features at fixations during the visual search task compared to the aesthetic judgment and scene memorization tasks. Different visual features also had different relevance to eye-movements between tasks. This modulation of the relationship between visual features and eye-movements by task was also demonstrated with classification analyses, where classifiers were trained to predict the viewing task based on eye movements and visual features at fixations. Feature loadings showed that the visual features at fixations could signal task differences independent of temporal and spatial properties of eye-movements. When classifying across participants, edge density and saliency at fixations were as important as eye-movements in the successful prediction of task, with entropy and hue also being significant, but with smaller effect sizes. When classifying within participants, brightness and saturation were also significant contributors. Canonical correlation and classification results, together with a test of moderation versus mediation, suggest that the cognitive state of the observer moderates the relationship between stimulus-driven visual features and eye-movements. |
Hossein Karimi; Fernanda Ferreira Informativity renders a referent more accessible: Evidence from eyetracking Journal Article In: Psychonomic Bulletin & Review, vol. 23, no. 2, pp. 507–525, 2016. @article{Karimi2016, The amount of information attached to a noun phrase (henceforth, NP) has been shown to enhance accessibility and increase pronominal reference in language production. However, both the effect of information quantity on the comprehension of ambiguous pronouns and the time course of any informativity effect have been left unexplored. In two eyetracking experiments, we investigated how additional information on the part of NP referents influenced the resolution of following ambiguous pronouns. The results of the first experiment revealed an informativity effect, with more looks to the informationally richer referent than to the competitor. However, the effect of additional information emerged late in time when the referent was the object of the verb. The second experiment replicated the results of the first and also showed that, consistent with the online results, an ambiguous pronoun is interpreted as referring to the informationally richer NP in an offline, explicit pronoun resolution tas k. The results lend support to theories of language processing that assume that explicit information increases the accessibility of the associated concept, in contrast to approaches that assume that accessibility is associated with givenness. |
Benjawan Kasisopa; Ronan G. Reilly; Sudaporn Luksaneeyanawin; Denis Burnham Child readers' eye movements in reading Thai Journal Article In: Vision Research, vol. 123, pp. 8–19, 2016. @article{Kasisopa2016, It has recently been found that adult native readers of Thai, an alphabetic scriptio continua language, engage similar oculomotor patterns as readers of languages written with spaces between words; despite the lack of inter-word spaces, first and last characters of a word appear to guide optimal placement of Thai readers' eye movements, just to the left of word-centre. The issue addressed by the research described here is whether eye movements of Thai children also show these oculomotor patterns. Here the effect of first and last character frequency and word frequency on the eye movements of 18 Thai children when silently reading normal unspaced and spaced text was investigated. Linear mixed-effects model analyses of viewing time measures (first fixation duration, single fixation duration, and gaze duration) and of landing site location revealed that Thai children's eye movement patterns were similar to their adult counterparts. Both first character frequency and word frequency played important roles in Thai children's landing sites; children tended to land their eyes further into words, close to the word centre, if the word began with higher frequency first characters, and this effect was facilitated in higher frequency words. Spacing also facilitated more effective use of first character frequency and it also assisted in decreasing children's viewing time. The use of last-character frequency appeared to be a later development, affecting mainly single fixation duration and gaze duration. In general, Thai children use the same oculomotor control mechanisms in reading spaced and unspaced texts as Thai adults, who in turn have similar oculomotor control as readers of spaced texts. Thus, it appears that eye movements in reading converge on the optimal landing site using whatever cues are available to guide such placement. |
Anna-Maria Kasparbauer; Inga Meyhöfer; Maria Steffens; Bernd Weber; Merve Aydin; Veena Kumari; Rene Hurlemann; Ulrich Ettinger Neural effects of methylphenidate and nicotine during smooth pursuit eye movements Journal Article In: NeuroImage, vol. 141, pp. 52–59, 2016. @article{Kasparbauer2016, Introduction: Nicotine and methylphenidate are putative cognitive enhancers in healthy and patient populations. Although they stimulate different neurotransmitter systems, they have been shown to enhance performance on overlapping measures of attention. So far, there has been no direct comparison of the effects of these two stimulants on behavioural performance or brain function in healthy humans. Here, we directly compare the two compounds using a well-established oculomotor biomarker in order to explore common and distinct behavioural and neural effects. Methods: Eighty-two healthy male non-smokers performed a smooth pursuit eye movement task while lying in an fMRI scanner. In a between-subjects, double-blind design, subjects either received placebo (placebo patch and capsule), nicotine (7 mg nicotine patch and placebo capsule), or methylphenidate (placebo patch and 40 mg methylphenidate capsule). Results: There were no significant drug effects on behavioural measures. At the neural level, methylphenidate elicited higher activation in left frontal eye field compared to nicotine, with an intermediate response under placebo. Discussion: The reduced activation of task-related regions under nicotine could be associated with more efficient neural processing, while increased hemodynamic response under methylphenidate is interpretable as enhanced processing of task-relevant networks. Together, these findings suggest dissociable neural effects of these putative cognitive enhancers. |
Ioanna Katidioti; Jelmer P. Borst; Douwe J. Bierens de Haan; Tamara Pepping; Marieke K. Vugt; Niels A. Taatgen Interrupted by your pupil: An interruption management system based on pupil dilation Journal Article In: International Journal of Human-Computer Interaction, vol. 32, no. 10, pp. 791–801, 2016. @article{Katidioti2016a, Interruptions are prevalent in everyday life and can be very disruptive. An important factor that affects the level of disruptiveness is the timing of the interruption: Interruptions at low-workload moments are known to be less disruptive than interruptions at high-workload moments. In this study, we developed a task-independent interruption management system (IMS) that interrupts users at low-workload moments in order to minimize the disruptiveness of interruptions. The IMS identifies low-workload moments in real time by measuring users' pupil dilation, which is a well-known indicator of workload. Using an experimental setup we showed that the IMS succeeded in finding the optimal moments for interruptions and marginally improved performance. Because our IMS is task-independent—it does not require a task analysis—it can be broadly applied. |
Ioanna Katidioti; Jelmer P. Borst; Marieke K. Vugt; Niels A. Taatgen Interrupt me: External interruptions are less disruptive than self-interruptions Journal Article In: Computers in Human Behavior, vol. 63, pp. 906–915, 2016. @article{Katidioti2016, Interruptions are part of everyday life and are known to be disruptive. With the current study we investigated which kind of interruption is more disruptive: external interruptions or self-interruptions. We conducted two experiments, one behavioral experiment (28 participants) and one in which pupil dilation was measured (21 participants). In both experiments, self-interruptions made participants complete the main task slower than external interruptions (occurring at similar moments in the task as the self-interruptions). However, there was no difference between the two kinds of interruptions in the time needed to resume the main task (resumption lag). Instead, the pupil dilation data revealed that the decision to self-interrupt takes about 1 s, resulting in slower performance overall. |
Leor N. Katz; Jacob L. Yates; Jonathan W. Pillow; Alexander C. Huk Dissociated functional significance of decision-related activity in the primate dorsal stream Journal Article In: Nature, vol. 535, pp. 285–288, 2016. @article{Katz2016, During decision making, neurons in multiple brain regions exhibit responses that are correlated with decisions. However, it remains uncertain whether or not various forms of decision-related activity are causally related to decision making. Here we address this question by recording and reversibly inactivating the lateral intraparietal (LIP) and middle temporal (MT) areas of rhesus macaques performing a motion direction discrimination task. Neurons in area LIP exhibited firing rate patterns that directly resembled the evidence accumulation process posited to govern decision making, with strong correlations between their response fluctuations and the animal's choices. Neurons in area MT, in contrast, exhibited weak correlations between their response fluctuations and choices, and had firing rate patterns consistent with their sensory role in motion encoding. The behavioural impact of pharmacological inactivation of each area was inversely related to their degree of decision-related activity: while inactivation of neurons in MT profoundly impaired psychophysical performance, inactivation in LIP had no measurable impact on decision-making performance, despite having silenced the very clusters that exhibited strong decision-related activity. Although LIP inactivation did not impair psychophysical behaviour, it did influence spatial selection and oculomotor metrics in a free-choice control task. The absence of an effect on perceptual decision making was stable over trials and sessions and was robust to changes in stimulus type and task geometry, arguing against several forms of compensation. Thus, decision-related signals in LIP do not appear to be critical for computing perceptual decisions, and may instead reflect secondary processes. Our findings highlight a dissociation between decision correlation and causation, showing that strong neuron-decision correlations do not necessarily offer direct access to the neural computations underlying decisions. |
Krista R. Kelly; Joost Felius; Santoshi Ramachandran; Blesson A. John; Reed M. Jost; Eileen E. Birch Congenitally impaired disparity vergence in children with infantile Esotropia Journal Article In: Investigative Ophthalmology & Visual Science, vol. 57, no. 6, pp. 2545–2551, 2016. @article{Kelly2016, PURPOSE. We examined whether congenital impairment of disparity vergence in infantile esotropia (ET) exists in children with short duration ET (<=3 months) compared with longduration ET and healthy controls. A short duration of misalignment would allow for a substantial amount of balanced binocular input during the critical period of binocular disparity development. METHODS. A total of 19 children aged 5 to 12 years and treated for infantile ET with a short (<=3 months; n = 10) or long (>=5 months; n = 9) duration of constant misalignment before alignment were enrolled. A total of 22 healthy control children were enrolled as a comparison group. Eye movements during disparity vergence and accommodative vergence were recorded using an EyeLink 1000 binocular eye tracker. Mean response gain was compared between and within groups to determine the effect of duration of misalignment and viewing condition. RESULTS. Compared with controls, children with short (P = 0.002) and long (P <0.001) duration infantile ET had reduced response gains for disparity vergence, but not for accommodative vergence (P = 0.19). CONCLUSIONS. Regardless of duration of misalignment, children with infantile ET had reduced disparity vergence, consistent with a congenital impairment of disparity vergence in infantile ET. Although early correction of misalignment increases the likelihood that some level of binocular disparity sensitivity will be present, normal levels may never be achieved. |
Guilhem Ibos; David J. Freedman Interaction between spatial and feature attention in posterior parietal cortex Journal Article In: Neuron, vol. 91, no. 4, pp. 931–943, 2016. @article{Ibos2016, Lateral intraparietal (LIP) neurons encode a vast array of sensory and cognitive variables. Recently, we proposed that the flexibility of feature representations in LIP reflect the bottom-up integration of sensory signals, modulated by feature-based attention (FBA), from upstream feature-selective cortical neurons. Moreover, LIP activity is also strongly modulated by the position of space-based attention (SBA). However, the mechanisms by which SBA and FBA interact to facilitate the representation of task-relevant spatial and non-spatial features in LIP remain unclear. We recorded from LIP neurons during performance of a task that required monkeys to detect specific conjunctions of color, motion direction, and stimulus position. Here we show that FBA and SBA potentiate each other's effect in a manner consistent with attention gating the flow of visual information along the cortical visual pathway. Our results suggest that linear bottom-up integrative mechanisms allow LIP neurons to emphasize task-relevant spatial and non-spatial features. |
Akiko Ikkai; Sangita Dandekar; Clayton E. Curtis Lateralization in alpha-band oscillations predicts the locus and spatial distribution of attention Journal Article In: PLoS ONE, vol. 11, no. 5, pp. e0154796, 2016. @article{Ikkai2016, Attending to a task-relevant location changes how neural activity oscillates in the alpha band (8-13Hz) in posterior visual cortical areas. However, a clear understanding of the relationships between top-down attention, changes in alpha oscillations in visual cortex, and attention performance are still poorly understood. Here, we tested the degree to which the posterior alpha power tracked the locus of attention, the distribution of attention, and how well the topography of alpha could predict the locus of attention. We recorded magnetoencephalographic (MEG) data while subjects performed an attention demanding visual discrimination task that dissociated the direction of attention from the direction of a saccade to indicate choice. On some trials, an endogenous cue predicted the target's location, while on others it contained no spatial information. When the target's location was cued, alpha power decreased in sensors over occipital cortex contralateral to the attended visual field. When the cue did not predict the target's location, alpha power again decreased in sensors over occipital cortex, but bilaterally, and increased in sensors over frontal cortex. Thus, the distribution and the topography of alpha reliably indicated the locus of covert attention. Together, these results suggest that alpha synchronization reflects changes in the excitability of populations of neurons whose receptive fields match the locus of attention. This is consistent with the hypothesis that alpha oscillations reflect the neural mechanisms by which top-down control of attention biases information processing and modulate the activity of neurons in visual cortex. |
Masato Inoue; Motoaki Uchimura; Shigeru Kitazawa Error signals in motor cortices drive adaptation in reaching Journal Article In: Neuron, vol. 90, no. 5, pp. 1114–1126, 2016. @article{Inoue2016, Reaching movements are subject to adaptation in response to errors induced by prisms or external perturbations. Motor cortical circuits have been hypothesized to provide execution errors that drive adaptation, but human imaging studies to date have reported that execution errors are encoded in parietal association areas. Thus, little evidence has been uncovered that supports the motor hypothesis. Here, we show that both primary motor and premotor cortices encode information on end-point errors in reaching. We further show that post-movement microstimulation to these regions caused trial-by-trial increases in errors, which subsided exponentially when the stimulation was terminated. The results indicate for the first time that motor cortical circuits provide error signals that drive trial-by-trial adaptation in reaching movements. |
Monika Intaitė; João Valente Duarte; Miguel Castelo-Branco Working memory load influences perceptual ambiguity by competing for fronto-parietal attentional resources Journal Article In: Brain Research, vol. 1650, pp. 142–151, 2016. @article{Intaite2016, A visual stimulus is defined as ambiguous when observers perceive it as having at least two distinct and spontaneously alternating interpretations. Neuroimaging studies suggest an involvement of a right fronto-parietal network regulating the balance between stable percepts and the triggering of alternative interpretations. As spontaneous perceptual reversals may occur even in the absence of attention to these stimuli, we investigated neural activity patterns in response to perceptual changes of ambiguous Necker cube under different amounts of working memory load using a dual-task design. We hypothesized that the same regions that process working memory load are involved in perceptual switching and confirmed the prediction that perceptual reversals led to fMRI responses that linearly depended on load. Accordingly, posterior Superior Parietal Lobule, anterior Prefrontal and Dorsolateral Prefrontal cortices exhibited differential BOLD signal changes in response to perceptual reversals under working memory load. Our results also suggest that the posterior Superior Parietal Lobule may be directly involved in the emergence of perceptual reversals, given that it specifically reflects both perceptual versus real changes and load levels. The anterior Prefrontal and Dorsolateral Prefrontal cortices, showing a significant interaction between reversal levels and load, might subserve a modulatory role in such reversals, in a mirror symmetric way: in the former activation is suppressed by the highest loads, and in the latter deactivation is reduced by highest loads, suggesting a more direct role of the aPFC in reversal generation. |
Jessica L. Irons; Andrew B. Leber Choosing attentional control settings in a dynamically changing environment Journal Article In: Attention, Perception, and Psychophysics, vol. 78, no. 7, pp. 2031–2048, 2016. @article{Irons2016, Goal-directed attentional control supports efficient visual search by prioritizing relevant stimuli in the environment. Previous research has shown that goal-directed control can be configured in many ways, and often multiple control settings can be used to achieve the same goal. However, little is known about how control settings are selected. We explored the extent to which the configuration of goal-directed control is driven by performance maximization (optimally configuring settings to maximize speed and accuracy) and effort minimization (selecting the least effortful settings). We used a new paradigm, adaptive choice visual search, which allows participants to choose one of two available targets (a red or a blue square) on each trial. Distractor colors vary predictively across trials, such that the optimal target switches back and forth throughout the experiment. Results (N = 43) show that participants chose the optimal target most often, updating to the new target when the environment changed, supporting performance maximization. However, individuals were sluggish to update to the optimal color, consistent with effort minimization. Additionally, we found a surprisingly high rate of nonoptimal choices and switching between targets, which could not be explained by either factor. Analysis of participants' self-reported search strategy revealed substantial individual differences in the control strategies used. In sum, the adaptive choice visual search enables a fresh approach to studying goal-directed control. The results contribute new evidence that control is partly determined by both performance maximization and effort minimization, as well as at least one additional factor, which we speculate to include novelty seeking. |
David E. Irwin; Maria M. Robinson Perceiving a continuous visual world across voluntary eye blinks Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 42, no. 10, pp. 1490–1496, 2016. @article{Irwin2016, People blink their eyes every few seconds, but the changes in retinal illumination that accompany eyeblinks are hardly noticed. Furthermore, despite the loss of visual input, visual experience remains continuous across eyeblinks. Two hypotheses were investigated to account for these phenomena. The first proposes that perceptual information is maintained across a blink whereas the second proposes that perceptual information is not maintained but rather postblink perceptual experience is antedated to the beginning of the blink. Two experiments found no evidence for temporal antedating of a stimulus presented during a voluntary eyeblink. In a third experiment subjects judged the temporal duration of a stimulus that was interrupted by a voluntary eyeblink with that of a stimulus presented while the eyes were open. The duration of stimuli that were interrupted by eyeblinks was judged to be 117 ms shorter than that of stimuli presented while the eyes remained open, indicating that blink duration was not accounted for in the perception of stimulus duration. This suggests that perceptual experience is neither maintained nor antedated across eyeblinks, but rather is ignored, perhaps in response to the extraretinal signal that accompanies the eyeblink. |
Anja Ischebeck; Marina Weilharter; Christof Körner Eye movements reflect and shape strategies in fraction comparison Journal Article In: Quarterly Journal of Experimental Psychology, vol. 69, no. 4, pp. 713–727, 2016. @article{Ischebeck2016, The comparison of fractions is a difficult task that can often be facilitated by separately comparing components (numerators and denominators) of the fractions-that is, by applying so-called component-based strategies. The usefulness of such strategies depends on the type of fraction pair to be compared. We investigated the temporal organization and the flexibility of strategy deployment in fraction comparison by evaluating sequences of eye movements in 20 young adults. We found that component-based strategies could account for the response times and the overall number of fixations observed for the different fraction pairs. The analysis of eye movement sequences showed that the initial eye movements in a trial were characterized by stereotypical scanning patterns indicative of an exploratory phase that served to establish the kind of fraction pair presented. Eye movements that followed this phase adapted to the particular type of fraction pair and indicated the deployment of specific comparison strategies. These results demonstrate that participants employ eye movements systematically to support strategy use in fraction comparison. Participants showed a remarkable flexibility to adapt to the most efficient strategy on a trial-by-trial basis. Our results confirm the value of eye movement measurements in the exploration of strategic adaptation in complex tasks. |
Miho Iwasaki; Yasuki Noguchi Hiding true emotions: Micro-expressions in eyes retrospectively concealed by mouth movements Journal Article In: Scientific Reports, vol. 6, pp. 22049, 2016. @article{Iwasaki2016, When we encounter someone we dislike, we may momentarily display a reflexive disgust expression, only to follow-up with a forced smile and greeting. Our daily lives are replete with a mixture of true and fake expressions. Nevertheless, are these fake expressions really effective at hiding our true emotions? Here we show that brief emotional changes in the eyes (micro-expressions, thought to reflect true emotions) can be successfully concealed by follow-up mouth movements (e.g. a smile). In the same manner as backward masking, mouth movements of a face inhibited conscious detection of all types of micro-expressions in that face, even when viewers paid full attention to the eye region. This masking works only in a backward direction, however, because no disrupting effect was observed when the mouth change preceded the eye change. These results provide scientific evidence for everyday behaviours like smiling to dissemble, and further clarify a major reason for the difficulty we face in discriminating genuine from fake emotional expressions. |
Gunnar Jacob; Claudia Felser Reanalysis and semantic persistence in native and non-native garden-path recovery Journal Article In: Quarterly Journal of Experimental Psychology, vol. 69, no. 5, pp. 907–925, 2016. @article{Jacob2016, We report the results from an eye-movement monitoring study investigating how native and non-native speakers of English process temporarily ambiguous sentences such as While the gentleman was eating the burgers were still being reheated in the microwave, in which an initially plausible direct-object analysis is first ruled out by a syntactic disambiguation (were) and also later on by semantic information (being reheated). Both participant groups showed garden-path effects at the syntactic disambiguation, with native speakers showing significantly stronger effects of ambiguity than non-native speakers in later eye-movement measures but equally strong effects in first-pass reading times. Ambiguity effects at the semantic disambiguation and in participants' end-of-trial responses revealed that for both participant groups, the incorrect direct-object analysis was frequently maintained beyond the syntactic disambiguation. The non-native group showed weaker reanalysis effects at the syntactic disambiguation and was more likely to misinterpret the experimental sentences than the native group. Our results suggest that native language (L1) and non-native language (L2) parsing are similar with regard to sensitivity to syntactic and semantic error signals, but different with regard to processes of reanalysis. |
Sharna D. Jamadar; Gary F. Egan; Vince D. Calhoun; Beth P. Johnson; Joanne Fielding In: Brain Connectivity, vol. 6, no. 6, pp. 505–517, 2016. @article{Jamadar2016, Intrinsic brain activity provides the functional framework for the brain's full repertoire of behavioural responses; that is, a common mechanism underlies intrinsic and extrinsic neural activity, with extrinsic activity building upon the underlying baseline intrinsic activity. The generation of a motor movement in response to sensory stimulation is one of the most fundamental functions of the central nervous system. Since saccadic eye movements are among our most stereotyped motor responses, we hypothesized that individual variability in the ability to inhibit a prepotent saccade and make a voluntary antisaccade would be related to individual variability in intrinsic connectivity. Twenty-three individuals completed the antisaccade task and resting-state functional magnetic resonance imaging (fMRI). A multivariate analysis of covariance identified relationships between fMRI oscillations (0.01-0.2Hz) of resting-state networks determined using high-dimensional independent component analysis (ICA) and antisaccade performance (latency, error rate). Significant multivariate relationships between antisaccade latency and directional error rate were obtained in independent components across the entire brain. Some of the relationships were obtained in components that overlapped substantially with the task, however many were obtained in components that showed little overlap with the task. The current results demonstrate that even in the absence of a task, spectral power in regions showing little overlap with task activity predicts an individual's performance on a saccade task. |
Seon-Kyeong Jang; Sujin Kim; Chai-Youn Kim; Hyeon-Seung Lee; Kee-Hong Choi Attentional processing of emotional faces in schizophrenia: Evidence from eye tracking Journal Article In: Journal of Abnormal Psychology, vol. 125, no. 7, pp. 894–906, 2016. @article{Jang2016, Severe emotional disturbances such as anxiety and depression have been closely related to aberrant attentional processing of emotional stimuli. However, this has been little studied in schizophrenia, which is also characterized by marked emotional impairments such as heightened negative affect and anhedonia. In the current study, we investigated temporal dynamics of motivated attention to emotional stimuli in schizophrenia. For this purpose, we tracked eye movements of 22 individuals with schizophrenia or schizoaffective disorder (ISZs) and 19 healthy controls (HCs) to emotional (i.e., happy, sad, angry) and neutral face pairs presented either for 500 ms or 1,500 ms. Initial fixation direction and viewing time at 3 successive intervals (0–500, 500–1,000, 1,000–1,500 ms) were calculated. The results showed that both ISZs and HCs were more likely to orient initial fixations and exhibited longer viewing times to emotional than neutral faces. However, compared with HCs, ISZs allocated less attention to overall faces during the late stage (1,000–1,500 ms) when one of the paired faces displayed negative emotions. Furthermore, positive symptoms were highly associated with initial fixation avoidance to angry faces while depressive symptoms were related to later avoidance of angry faces. Both social amotivation and poor interpersonal functioning were closely related to diminished sustained attention to happy faces. This suggests that early attentional capture of emotional salience may be relatively preserved in schizophrenia, but the people with this disorder display an atypical late attentional process characterized by generalized attentional avoidance of negative stimuli. Of note, aberrant attentional processes of social threat and reward were closely associated with major symptoms and functioning in this disorder. |