All EyeLink Eye Tracker Publications
All 13,000+ peer-reviewed EyeLink research publications up until 2024 (with some early 2025s) 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!
2013 |
Holger Mitterer; Eva Reinisch No delays in application of perceptual learning in speech recognition: Evidence from eye tracking Journal Article In: Journal of Memory and Language, vol. 69, no. 4, pp. 527–545, 2013. @article{Mitterer2013,Three eye-tracking experiments tested at what processing stage lexically-guided retuning of a fricative contrast affects perception. One group of participants heard an ambiguous fricative between /s/ and /f/ replace /s/ in s-final words, the other group heard the same ambiguous fricative replacing /f/ in f-final words. In a test phase, both groups of participants heard a range of ambiguous fricatives at the end of Dutch minimal pairs (e.g., roos-. roof, 'rose'-'robbery'). Participants who heard the ambiguous fricative replacing /f/ during exposure chose at test the f-final words more often than the other participants. During this test-phase, eye-tracking data showed that the effect of exposure exerted itself as soon as it could possibly have occurred, 200. ms after the onset of the fricative. This was at the same time as the onset of the effect of the fricative itself, showing that the perception of the fricative is changed by perceptual learning at an early level. Results converged in a time-window analysis and a Jackknife procedure testing the time at which effects reached a given proportion of their maxima. This indicates that perceptual learning affects early stages of speech processing, and supports the conclusion that perceptual learning is indeed perceptual rather than post-perceptual. |
Holger Mitterer; Kevin Russell How phonological reductions sometimes help the listener Journal Article In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 39, no. 3, pp. 977–984, 2013. @article{Mitterer2013a,In speech production, high-frequency words are more likely than low-frequency words to be phonologically reduced. We tested in an eye-tracking experiment whether listeners can make use of this correlation between lexical frequency and phonological realization of words. Participants heard prefixed verbs in which the prefix was either fully produced or reduced. Simultaneously, they saw a high-frequency verb and a low-frequency verb with this prefix-plus 2 distractors-on a computer screen. Participants were more likely to look at the high-frequency verb when they heard a reduced prefix than when they heard a fully produced prefix. Listeners hence exploit the correlation of lexical frequency and phonological reduction and assume that a reduced prefix is more likely to belong to a high-frequency word. This shows that reductions do not necessarily burden the listener but may in fact have a communicative function, in line with functional theories of phonology. |
Kristina Moll; Manon W. Jones Naming fluency in dyslexic and nondyslexic readers: Differential effects of visual crowding in foveal, parafoveal, and peripheral vision Journal Article In: Quarterly Journal of Experimental Psychology, vol. 66, no. 11, pp. 2085–2091, 2013. @article{Moll2013,Reading fluency is often indexed by performance on rapid automatized naming (RAN) tasks, which are known to reflect speed of access to lexical codes. We used eye tracking to investigate visual influences on naming fluency. Specifically, we examined how visual crowding affects fluency in a RAN-letters task on an item-by-item basis, by systematically manipulating the interletter spacing of items, such that upcoming letters in the array were viewed in the fovea, parafovea, or periphery relative to a given fixated letter. All lexical information was kept constant. Nondyslexic readers' gaze durations were longer in foveal than in parafoveal and peripheral trials, indicating that visual crowding slows processing even for fluent readers. Dyslexics' gaze durations were longer in foveal and parafoveal trials than in peripheral trials. Our results suggest that for dyslexic readers, influences of crowding on naming speed extend to a broader visual span (to parafoveal vision) than that for nondyslexic readers, but do not extend as far as peripheral vision. The findings extend previous research by elucidating the different visual spans within which crowding operates for dyslexic and nondyslexic readers in an online fluency task. |
Silvina Montrul; Israel Fuente; Justin Davidson; Rebecca Foote The role of experience in the acquisition and production of diminutives and gender in Spanish: Evidence from L2 learners and heritage speakers Journal Article In: Second Language Research, vol. 29, no. 1, pp. 87–118, 2013. @article{Montrul2013,This study examined whether type of early language experience provides advantages to heritage speakers over second language (L2) learners with morphology, and investigated knowledge of gender agreement and its interaction with diminutive formation. Diminutives are a hallmark of Child Directed Speech in early language development and a highly productive morphological mechanism that facilitates the acquisition of declensional noun endings in many languages (Savickiene˙ and Dressler, 2007). In Spanish, diminutives regularize gender marking in nouns with a non-canonical ending. Twenty-four Spanish native speakers, 29 heritage speakers and 37 L2 learners with intermediate to advanced proficiency completed two picture-naming tasks and an elicited production task. Results showed that the heritage speakers were more accurate than the L2 learners with gender agreement in general, and with non-canonical ending nouns in particular. This study confirms that early language experience and the type of input received confer some advantages to heritage speakers over L2 learners with early-acquired aspects of language, especially in oral production. |
Tommaso Mastropasqua; Massimo Turatto Perceptual grouping enhances visual plasticity Journal Article In: PLoS ONE, vol. 8, no. 1, pp. e53683, 2013. @article{Mastropasqua2013,Visual perceptual learning, a manifestation of neural plasticity, refers to improvements in performance on a visual task achieved by training. Attention is known to play an important role in perceptual learning, given that the observer's discriminative ability improves only for those stimulus feature that are attended. However, the distribution of attention can be severely constrained by perceptual grouping, a process whereby the visual system organizes the initial retinal input into candidate objects. Taken together, these two pieces of evidence suggest the interesting possibility that perceptual grouping might also affect perceptual learning, either directly or via attentional mechanisms. To address this issue, we conducted two experiments. During the training phase, participants attended to the contrast of the task-relevant stimulus (oriented grating), while two similar task-irrelevant stimuli were presented in the adjacent positions. One of the two flanking stimuli was perceptually grouped with the attended stimulus as a consequence of its similar orientation (Experiment 1) or because it was part of the same perceptual object (Experiment 2). A test phase followed the training phase at each location. Compared to the task-irrelevant no-grouping stimulus, orientation discrimination improved at the attended location. Critically, a perceptual learning effect equivalent to the one observed for the attended location also emerged for the task-irrelevant grouping stimulus, indicating that perceptual grouping induced a transfer of learning to the stimulus (or feature) being perceptually grouped with the task-relevant one. Our findings indicate that no voluntary effort to direct attention to the grouping stimulus or feature is necessary to enhance visual plasticity. |
Sebastiaan Mathôt; Jan Theeuwes A reinvestigation of the reference frame of the tilt-adaptation aftereffect Journal Article In: Scientific Reports, vol. 3, pp. 1152, 2013. @article{Mathot2013,The tilt-adaptation aftereffect (TAE) is the phenomenon that prolonged perception of a tilted ‘adapter' stimulus affects the perceived tilt ofa subsequent ‘tester' stimulus. Although it is clear that TAE is strongest when adapter and tester are presented at the same location, the reference frame ofthe effect is debated. Some authors have reported that TAE is spatiotopic (world centred): It occurs when adapter and tester are presented at the same display location, even when this corresponds to different retinal locations. Others have reported that TAE is exclusively retinotopic (eye centred): It occurs only when adapter and tester are presented at the same retinal location, even when this corresponds to different display locations. Because this issue is crucial for models oftranssaccadic perception, we reinvestigated the reference frame ofTAE.We report that TAE is exclusively retinotopic, supporting the notion that there is no transsaccadic integration of low-level visual information. |
Sebastiaan Mathôt; Lotje Linden; Jonathan Grainger; Françoise Vitu The pupillary light response reveals the focus of covert visual attention. Journal Article In: PLoS ONE, vol. 8, no. 10, pp. e78168, 2013. @article{Mathot2013a,The pupillary light response is often assumed to be a reflex that is not susceptible to cognitive influences. In line with recent converging evidence, we show that this reflexive view is incomplete, and that the pupillary light response is modulated by covert visual attention: Covertly attending to a bright area causes a pupillary constriction, relative to attending to a dark area under identical visual input. This attention-related modulation of the pupillary light response predicts cuing effects in behavior, and can be used as an index of how strongly participants attend to a particular location. Therefore, we suggest that pupil size may offer a new way to continuously track the focus of covert visual attention, without requiring a manual response from the participant. The theoretical implication of this finding is that the pupillary light response is neither fully reflexive, nor under complete voluntary control, but is instead best characterized as a stereotyped response to a voluntarily selected target. In this sense, the pupillary light response is similar to saccadic and smooth pursuit eye movements. Together, eye movements and the pupillary light response maximize visual acuity, stabilize visual input, and selectively filter visual information as it enters the eye. |
Masayuki Matsumoto; Masahiko Takada Distinct representations of cognitive and motivational signals in midbrain dopamine neurons Journal Article In: Neuron, vol. 79, no. 5, pp. 1011–1024, 2013. @article{Matsumoto2013,Dopamine is essential to cognitive functions. However, despite abundant studies demonstrating that dopamine neuron activity is related to reinforcement and motivation, little is known about what signals dopamine neurons convey to promote cognitive processing. We therefore examined dopamine neuron activity in monkeys performing a delayed matching-to-sample task that required working memory and visual search. We found that dopamine neurons responded to task events associated with cognitive operations. A subset of dopamine neurons were activated by visual stimuli if the monkey had to store the stimuli in working memory. These neurons were located dorsolaterally in the substantia nigra pars compacta, whereas ventromedial dopamine neurons, some in the ventral tegmental area, represented reward prediction signals. Furthermore, dopamine neurons monitored visual search performance, becoming active when the monkey made an internal judgment that the search was successfully completed. Our findings suggest an anatomical gradient of dopamine signals along the dorsolateral-ventromedial axis of the ventral midbrain. |
Maria Matziridi; Eli Brenner; Jeroen B. J. Smeets In: PLoS ONE, vol. 8, no. 4, pp. e62436, 2013. @article{Matziridi2013,A stimulus that is flashed around the time of a saccade tends to be mislocalized in the direction of the saccade target. Our question is whether the mislocalization is related to the position of the saccade target within the image or to the gaze position at the end of the saccade. We separated the two with a visual illusion that influences the perceived distance to the target of the saccade and thus saccade endpoint without affecting the perceived position of the saccade target within the image. We asked participants to make horizontal saccades from the left to the right end of the shaft of a Müller-Lyer figure. Around the time of the saccade, we flashed a bar at one of five possible positions and asked participants to indicate its location by touching the screen. As expected, participants made shorter saccades along the fins-in (<->) configuration than along the fins-out (>-<) configuration of the figure. The illusion also influenced the mislocalization pattern during saccades, with flashes presented with the fins-out configuration being perceived beyond flashes presented with the fins-in configuration. The difference between the patterns of mislocalization for bars flashed during the saccade for the two configurations corresponded quantitatively with a prediction based on compression towards the saccade endpoint considering the magnitude of the effect of the illusion on saccade amplitude. We conclude that mislocalization is related to the eye position at the end of the saccade, rather than to the position of the saccade target within the image. |
Ashleigh M. Maxcey-Richard; Andrew Hollingworth The strategic retention of task-relevant objects in visual working memory Journal Article In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 39, no. 3, pp. 760–772, 2013. @article{MaxceyRichard2013,The serial and spatially extended nature of many real-world visual tasks suggests the need for control over the content of visual working memory (VWM). We examined the management of VWM in a task that required participants to prioritize individual objects for retention during scene viewing. There were 5 principal findings: (a) Strategic retention of task-relevant objects was effective and was dissociable from the current locus of visual attention; (b) strategic retention was implemented by protection from interference rather than by preferential encoding; (c) this prioritization was flexibly transferred to a new object as task demands changed; (d) no-longer-relevant items were efficiently eliminated from VWM; and (e) despite this level of control, attended and fixated objects were consolidated into VWM regardless of task relevance. These results are consistent with a model of VWM control in which each fixated object is automatically encoded into VWM, replacing a portion of the content in VWM. However, task-relevant objects can be selectively protected from replacement. |
Olivia M. Maynard; Marcus R. Munafò; Ute Leonards Visual attention to health warnings on plain tobacco packaging in adolescent smokers and non-smokers Journal Article In: Addiction, vol. 108, no. 2, pp. 413–419, 2013. @article{Maynard2013,AIMS: Previous research with adults indicates that plain packaging increases visual attention to health warnings in adult non-smokers and weekly smokers, but not daily smokers. The present research extends this study to adolescents aged 14-19 years. DESIGN: Mixed-model experimental design, with smoking status as a between-subjects factor and pack type (branded or plain pack) and eye gaze location (health warning or branding) as within-subjects factors. SETTING: Three secondary schools in Bristol, UK. PARTICIPANTS: A convenience sample of adolescents comprising never-smokers (n = 26), experimenters (n = 34), weekly smokers (n = 13) and daily smokers (n = 14). MEASUREMENTS: Number of eye movements to health warnings and branding on plain and branded packs. FINDINGS: Analysis of variance, irrespective of smoking status revealed more eye movements to health warnings than branding on plain packs, but an equal number of eye movements to both regions on branded packs (P = 0.033). This was observed among experimenters (P < 0.001) and weekly smokers (P = 0.047), but not among never-smokers or daily smokers. CONCLUSION: Among experimenters and weekly smokers, plain packaging increases visual attention to health warnings and away from branding. Daily smokers, even relatively early in their smoking careers, seem to avoid the health warnings on cigarette packs. Adolescent never-smokers attend the health warnings preferentially on both types of packs, a finding which may reflect their decision not to smoke. |
Ulrich Mayr; David Kuhns; Miranda Rieter Eye movements reveal dynamics of task control Journal Article In: Journal of Experimental Psychology: General, vol. 142, no. 2, pp. 489–509, 2013. @article{Mayr2013,With the goal to determine the cognitive architecture that underlies flexible changes of control settings, we assessed within-trial and across-trial dynamics of attentional selection by tracking of eye movements in the context of a cued task-switching paradigm. Within-trial dynamics revealed a switch-induced, discrete delay in onset of task-congruent fixations, a result that is consistent with a higher level configuration process. Next, we derived predictions about the trial-to-trial dynamic coupling of control settings from competing models, assuming that control is achieved either through task-level competition or through higher level configuration processes. Empirical coupling dynamics between trial n-1 eye movements and trial n response times–estimated through mixed linear modeling–revealed a pattern that was consistent with the higher level configuration model. The results indicate that a combination of eye movement data and mixed modeling methods can yield new constraints on models of flexible control. This general approach can be useful in any domain in which theoretical progress depends on high-resolution information about dynamic relationships within individuals. |
Kathryn L. McCabe; Jessica L. Melville; Dominique Rich; Paul A. Strutt; Gavin Cooper; Carmel M. Loughland; Ulrich Schall; Linda E. Campbell Divergent patterns of social cognition performance in autism and 22q11.2 deletion syndrome (22q11DS) Journal Article In: Journal of Autism and Developmental Disorders, vol. 43, no. 8, pp. 1926–1934, 2013. @article{McCabe2013,Individuals with developmental disorders frequently report a range of social cognition deficits including difficulties identifying facial displays of emotion. This study examined the specificity of face emotion processing deficits in adolescents with either autism or 22q11DS compared to typically developing (TD) controls. Two tasks (face emotion recognition and weather scene recognition) were used to explore group differences in visual scanpath strategy and concurrent recognition accuracy. For faces, the autism and 22q11DS groups demonstrated lower emotion recognition accuracy and fewer fixations compared to the TD group. Individuals with autism demonstrated fewer fixations to some weather scene stimuli compared to 22q11DS and TD groups, yet achieved a level of recognition accuracy comparable to the TD group. These findings provide evidence for a divergent pattern of social cognition dysfunction in autism and 22q11DS. |
Michael B. McCamy; Niamh Collins; Jorge Otero-Millan; Mohammed Al-Kalbani; Stephen L. Macknik; Davis Coakley; Xoana G. Troncoso; Gerard Boyle; Vinodh Narayanan; Thomas R. R. Wolf; Susana Martinez-Conde Simultaneous recordings of ocular microtremor and microsaccades with a piezoelectric sensor and a video-oculography system Journal Article In: PeerJ, vol. 1, pp. 1–18, 2013. @article{McCamy2013,Our eyes are in continuous motion. Even when we attempt to fix our gaze, we produce so called "fixational eye movements", which include microsaccades, drift, and ocular microtremor (OMT). Microsaccades, the largest and fastest type of fixational eye movement, shift the retinal image from several dozen to several hundred photoreceptors and have equivalent physical characteristics to saccades, only on a smaller scale (Martinez-Conde, Otero-Millan & Macknik, 2013). OMT occurs simultaneously with drift and is the smallest of the fixational eye movements (∼1 photoreceptor width, >0.5 arcmin), with dominant frequencies ranging from 70 Hz to 103 Hz (Martinez-Conde, Macknik & Hubel, 2004). Due to OMT's small amplitude and high frequency, the most accurate and stringent way to record it is the piezoelectric transduction method. Thus, OMT studies are far rarer than those focusing on microsaccades or drift. Here we conducted simultaneous recordings of OMT and microsaccades with a piezoelectric device and a commercial infrared video tracking system. We set out to determine whether OMT could help to restore perceptually faded targets during attempted fixation, and we also wondered whether the piezoelectric sensor could affect the characteristics of microsaccades. Our results showed that microsaccades, but not OMT, counteracted perceptual fading. We moreover found that the piezoelectric sensor affected microsaccades in a complex way, and that the oculomotor system adjusted to the stress brought on by the sensor by adjusting the magnitudes of microsaccades. |
Michael B. McCamy; Ali Najafian Jazi; Jorge Otero-Millan; Stephen L. Macknik; Susana Martinez-Conde The effects of fixation target size and luminance on microsaccades and square-wave jerks Journal Article In: PeerJ, vol. 1, pp. 1–12, 2013. @article{McCamy2013a,A large amount of classic and contemporary vision studies require subjects to fixate a target. Target fixation serves as a normalizing factor across studies, promoting the field's ability to compare and contrast experiments. Yet, fixation target parameters, including luminance, contrast, size, shape and color, vary across studies, potentially affecting the interpretation of results. Previous research on the effects of fixation target size and luminance on the control of fixation position rendered conflicting results, and no study has examined the effects of fixation target characteristics on square-wave jerks, the most common type of saccadic intrusion. Here we set out to determine the effects of fixation target size and luminance on the characteristics of microsaccades and square-wave jerks, over a large range of stimulus parameters. Human subjects fixated a circular target with varying luminance and size while we recorded their eye movements with an infrared video tracker (EyeLink 1000, SR Research). We detected microsaccades and SWJs automatically with objective algorithms developed previously. Microsaccade rates decreased linearly and microsaccade magnitudes increased linearly with target size. The percent of microsaccades forming part of SWJs decreased, and the time from the end of the initial SWJ saccade to the beginning of the second SWJ saccade (SWJ inter-saccadic interval; ISI) increased with target size. The microsaccadic preference for horizontal direction also decreased moderately with target size . Target luminance did not affect significantly microsaccades or SWJs, however. In the absence of a fixation target, microsaccades became scarcer and larger, while SWJ prevalence decreased and SWJ ISIs increased. Thus, the choice of fixation target can affect experimental outcomes, especially in human factors and in visual and oculomotor studies. These results have implications for previous and future research conducted under fixation conditions, and should encourage forthcoming studies to report the size of fixation targets to aid the interpretation and replication of their results. |
Richard McFarland; Hettie Roebuck; Yin Yan; Bonaventura Majolo; Wu Li; Kun Guo Social interactions through the eyes of macaques and humans Journal Article In: PLoS ONE, vol. 8, no. 2, pp. e56437, 2013. @article{McFarland2013,Group-living primates frequently interact with each other to maintain social bonds as well as to compete for valuable resources. Observing such social interactions between group members provides individuals with essential information (e.g. on the fighting ability or altruistic attitude of group companions) to guide their social tactics and choice of social partners. This process requires individuals to selectively attend to the most informative content within a social scene. It is unclear how non-human primates allocate attention to social interactions in different contexts, and whether they share similar patterns of social attention to humans. Here we compared the gaze behaviour of rhesus macaques and humans when free-viewing the same set of naturalistic images. The images contained positive or negative social interactions between two conspecifics of different phylogenetic distance from the observer; i.e. affiliation or aggression exchanged by two humans, rhesus macaques, Barbary macaques, baboons or lions. Monkeys directed a variable amount of gaze at the two conspecific individuals in the images according to their roles in the interaction (i.e. giver or receiver of affiliation/aggression). Their gaze distribution to non-conspecific individuals was systematically varied according to the viewed species and the nature of interactions, suggesting a contribution of both prior experience and innate bias in guiding social attention. Furthermore, the monkeys' gaze behavior was qualitatively similar to that of humans, especially when viewing negative interactions. Detailed analysis revealed that both species directed more gaze at the face than the body region when inspecting individuals, and attended more to the body region in negative than in positive social interactions. Our study suggests that monkeys and humans share a similar pattern of role-sensitive, species- and context-dependent social attention, implying a homologous cognitive mechanism of social attention between rhesus macaques and humans. |
Mindaugas Mozuraitis; Craig G. Chambers; Meredyth Daneman Younger and older adults' use of verb aspect and world knowledge in the online interpretation of discourse Journal Article In: Discourse Processes, vol. 50, no. 1, pp. 1–22, 2013. @article{Mozuraitis2013,Eye tracking was used to explore the role of grammatical aspect and world knowledge in establishing temporal relationships across sentences in discourse. Younger and older adult participants read short passages that included sentences such as Mrs. Adams was knitting/knitted a new sweater . . . She wore her new garment . . . . Readers had greater difficulty processing the second event (She wore...) if it followed the imperfective (was knitting) rather than the perfective (knitted) version of the earlier mentioned event. This suggests that aspect information is encoded online and that the “in progress” interpretation of the imperfective impeded integration of the second event into the discourse model. However, world knowledge modulated the effect: When the first event was of short duration (e.g., writing a check), the influence of aspect was not evident in the early moments of processing. These effects were independent of age group, suggesting that the mechanisms involved in coordinating temporal information in discourse are stable across the adult lifespan. |
Leigh A. Mrotek Following and intercepting scribbles: Interactions between eye and hand control Journal Article In: Experimental Brain Research, vol. 227, no. 2, pp. 161–174, 2013. @article{Mrotek2013,The smooth pursuit eye movement system appears to be importantly engaged during the planning and execution of interceptive hand movements. The present study sought to probe the interaction between eye and hand control systems by examining their responses during an interception task that included target speed perturbations. On 2/3 of trials the target increased or decreased speed at various times, ranging from about 300 ms before to 150 ms after the onset of a finger movement directed to intercept the target and was triggered by a GO signal. Additionally the same 2D sum- of-sines target trajectories were followed with the eyes without interception. The smooth pursuit system responded more quickly if the target speed perturbation occurred earlier during the reaction time (i.e., near the time of the GO signal). Similarly, the finger movement began more quickly if target speed was increased earlier during the reaction time. For early perturbation conditions, the initial direction of the finger movement matched the predicted target intercept using the new target speed. For perturbations occurring after finger movement onset initial direction of finger movement did not match target interception such that, the finger path began to curve toward the perturbed target after about 150–200 ms. The results support the idea of an active process of visual target path extrapolation simultaneously used to guide both the eye and hand. |
Sven Mucke; Niall C. Strang; Senay Aydin; Edward A. H. Mallen; Dirk Seidel; Velitchko Manahilov Spatial frequency selectivity of visual suppression during convergence eye movements Journal Article In: Vision Research, vol. 89, pp. 96–101, 2013. @article{Mucke2013,Visual suppression of low-spatial frequency information during eye movements is believed to contribute to a stable perception of our visual environment. While visual perception has been studied extensively during saccades, vergence has been somewhat neglected. Here, we show that convergence eye movements reduce contrast sensitivity to low spatial frequency information around the onset of the eye movements, but do not affect sensitivity to higher spatial frequencies. This suggests that visual suppression elicited by convergence eye movements may have the same temporal and spatial characteristics as saccadic suppression. |
Manon Mulckhuyse; Geert Crombez; Stefan Van der Stigchel Conditioned fear modulates visual selection Journal Article In: Emotion, vol. 13, no. 3, pp. 529–536, 2013. @article{Mulckhuyse2013,Eye movements reflect the dynamic interplay between top-down- and bottom-up-driven processes. For example, when we voluntarily move our eyes across the visual field, salient visual stimuli in the environment may capture our attention, our eyes, or modulate the trajectory of an eye movement. Previous research has shown that the behavioral relevance of a salient stimulus modulates these processes. This study investigated whether a stimulus signaling an aversive event modulates saccadic behavior. Using a differential fear-conditioning procedure, we presented a threatening (conditional stimulus: CS+) and a nonthreatening stimulus distractor (CS-) during an oculomotor selection task. The results show that short-latency saccades deviated more strongly toward the CS+ than toward the CS- distractor, whereas long-latency saccades deviated more strongly away from the CS+ than from the CS- distractor. Moreover, the CS+ distractor captured the eyes more often than the CS- distractor. Together, these results demonstrate that conditioned fear has a direct and immediate influence on visual selection. The findings are interpreted in terms of a neurobiological model of emotional visual processing. |
Romy Müller; Jens R. Helmert; Sebastian Pannasch; Boris M. Velichkovsky Gaze transfer in remote cooperation: Is it always helpful to see what your partner is attending to? Journal Article In: Quarterly Journal of Experimental Psychology, vol. 66, no. 7, pp. 1302–1316, 2013. @article{Mueller2013,Establishing common ground in remote cooperation is challenging because nonverbal means of ambiguity resolution are limited. In such settings, information about a partner's gaze can support cooperative performance, but it is not yet clear whether and to what extent the abundance of information reflected in gaze comes at a cost. Specifically, in tasks that mainly rely on spatial referencing, gaze transfer might be distracting and leave the partner uncertain about the meaning of the gaze cursor. To examine this question, we let pairs of participants perform a joint puzzle task. One partner knew the solution and instructed the other partner's actions by (1) gaze, (2) speech, (3) gaze and speech, or (4) mouse and speech. Based on these instructions, the acting partner moved the pieces under conditions of high or low autonomy. Performance was better when using either gaze or mouse transfer compared to speech alone. However, in contrast to the mouse, gaze transfer induced uncertainty, evidenced in delayed responses to the cursor. Also, participants tried to resolve ambiguities by engaging in more verbal effort, formulating more explicit object descriptions and fewer deictic references. Thus, gaze transfer seems to increase uncertainty and ambiguity, thereby complicating grounding in this spatial referencing task. The results highlight the importance of closely examining task characteristics when considering gaze transfer as a means of support. |
Jochen Müsseler; Jens Tiggelbeck The perceived onset position of a moving target: Effects of trial contexts are evoked by different attentional allocations Journal Article In: Attention, Perception, & Psychophysics, vol. 75, no. 2, pp. 349–357, 2013. @article{Muesseler2013,Previous studies have shown that the localization of the perceived onset position of a moving target varies with the trial context. When the moving target appeared at predictable positions to the left or right of fixation (constant context), localization judgments of the perceived onset positions were essentially displaced in motion direction (Fröhlich effect). In contrast, when the target appeared at unpredictable positions in the visual field (random context), localization judgments were at least drastically reduced. Four explanations of this influence of trial context on localization judgments were examined in three experiments. Findings ruled out an overcompensation mechanism effective in random-context conditions, a predictive mechanism effective in constant-context conditions and a detrimental mechanism originating from more trial repetitions in constant-context conditions. Instead, the results indicated that different attentional allocations are responsible for the localization differences. They also demonstrated that attentional mechanisms are at the basis of the Fröhlich effect. |
Terhi Mustonen; Mikko Berg; Jyrki Kaistinen; Takashi Kawai; Jukka Hakkinen Visual task performance using a monocular see-through head-mounted display (HMD) while walking Journal Article In: Journal of Experimental Psychology: Applied, vol. 19, pp. 333–344, 2013. @article{Mustonen2013,A monocular see-through head-mounted display (HMD) allows the user to view displayed information while simultaneously interacting with the surrounding environment. This configuration lets people use HMDs while they are moving, such as while walking. However, sharing attention between the display and environment can compromise a person's performance in any ongoing task, and controlling one's gait may add further challenges. In this study, the authors investigated how the requirements of HMD- administered visual tasks altered users' performance while they were walking. Twenty-four university students completed 3 cognitive tasks (high- and low-working memory load, visual vigilance) on an HMD while seated and while simultaneously performing a paced walking task in a controlled environment. The results show that paced walking worsened performance (d=, reaction time) in all HMD-administered tasks, but visual vigilance deteriorated more than memory performance. The HMD-administered tasks also worsened walking performance (speed, path overruns) in a manner that varied according to the overall demands of the task. These results suggest that people's ability to process information displayed on an HMD may worsen while they are in motion. Furthermore, the use of an HMD can critically alter a person's natural performance, such as their ability to guide and control their gait. In particular, visual tasks that involve constant monitoring of the HMD should be avoided. These findings highlight the need for careful consideration of the type and difficulty of information that can be presented through HMDs while still letting the user achieve an acceptable overall level of performance in various contexts of use. |
Andriy Myachykov; Rob Ellis; Angelo Cangelosi; Martin H. Fischer Visual and linguistic cues to graspable objects Journal Article In: Experimental Brain Research, vol. 229, no. 4, pp. 545–559, 2013. @article{Myachykov2013a,Two experiments investigated (1) how activation of manual affordances is triggered by visual and linguistic cues to manipulable objects and (2) whether graspable object parts play a special role in this process. Participants pressed a key to categorize manipulable target objects copresented with manipulable distractor objects on a computer screen. Three factors were varied in Experiment 1: (1) the target's and (2) the distractor's handles' orientation congruency with the lateral manual response and (3) the Visual Focus on one of the objects. In Experiment 2, a linguistic cue factor was added to these three factors-participants heard the name of one of the two objects prior to the target display onset. Analysis of participants' motor and oculomotor behaviour confirmed that perceptual and linguistic cues potentiated activation of grasp affordances. Both target- and distractor-related affordance effects were modulated by the presence of visual and linguistic cues. However, a differential visual attention mechanism subserved activation of compatibility effects associated with target and distractor objects. We also registered an independent implicit attention attraction effect from objects' handles, suggesting that graspable parts automatically attract attention during object viewing. This effect was further amplified by visual but not linguistic cues, thus providing initial evidence for a recent hypothesis about differential roles of visual and linguistic information in potentiating stable and variable affordances (Borghi in Language and action in cognitive neuroscience. Psychology Press, London, 2012). |
Andriy Myachykov; Christoph Scheepers; Simon Garrod; Dominic Thompson; Olga Fedorova Syntactic flexibility and competition in sentence production: The case of English and Russian Journal Article In: Quarterly Journal of Experimental Psychology, vol. 66, no. 8, pp. 1601–1619, 2013. @article{Myachykov2013,We analysed how syntactic flexibility influences sentence production in two different languages-English and Russian. In Experiment 1, speakers were instructed to produce as many structurally different descriptions of transitive-event pictures as possible. Consistent with the syntactically more flexible Russian grammar, Russian participants produced more descriptions and used a greater variety of structures than their English counterparts. In Experiment 2, a different sample of participants provided single-sentence descriptions of the same picture materials while their eye movements were recorded. In this task, English and Russian participants almost exclusively produced canonical subject-verb-object active-voice structures. However, Russian participants took longer to plan their sentences, as reflected in longer sentence onset latencies and eye-voice spans for the sentence-initial subject noun. This cross-linguistic difference in processing load diminished toward the end of the sentence. Stepwise generalized linear model analyses showed that the greater sentence-initial processing load registered in Experiment 2 corresponded to the greater amount of syntactic competition from available alternatives (Experiment 1), suggesting that syntactic flexibility is costly regardless of the language in use. |
Marnix Naber; George A. Alvarez; Ken Nakayama Tracking the allocation of attention using human pupillary oscillations Journal Article In: Frontiers in Psychology, vol. 4, pp. 1–12, 2013. @article{Naber2013,The muscles that control the pupil are richly innervated by the autonomic nervous system. While there are central pathways that drive pupil dilations in relation to arousal, there is no anatomical evidence that cortical centers involved with visual selective attention innervate the pupil. In this study, we show that such connections must exist. Specifically, we demonstrate a novel Pupil Frequency Tagging (PFT) method, where oscillatory changes in stimulus brightness over time are mirrored by pupil constrictions and dilations. We find that the luminance-induced pupil oscillations are enhanced when covert attention is directed to the flicker stimulus and when targets are correctly detected in an attentional tracking task. These results suggest that the amplitudes of pupil responses closely follow the allocation of focal visual attention and the encoding of stimuli. PFT provides a new opportunity to study top-down visual attention itself as well as identifying the pathways and mechanisms that support this unexpected phenomenon. |
Marnix Naber; Stefan Frassle; Ueli Rutishauser; Wolfgang Einhäuser Pupil size signals novelty and predicts later retrieval success for declarative memories of natural scenes Journal Article In: Journal of Vision, vol. 13, no. 2, pp. 1–20, 2013. @article{Naber2013a,Declarative memories of personal experiences are a key factor in defining oneself as an individual, which becomes particularly evident when this capability is impaired. Assessing the physiological mechanisms of human declarative memory is typically restricted to patients with specific lesions and requires invasive brain access or functional imaging. We investigated whether the pupil, an accessible physiological measure, can be utilized to probe memories for complex natural visual scenes. During memory encoding, scenes that were later remembered elicited a stronger pupil constriction compared to scenes that were later forgotten. Thus, pupil size predicts success or failure of memory formation. In contrast, novel scenes elicited stronger pupil constriction than familiar scenes during retrieval. When viewing previously memorized scenes, those that were forgotten (misjudged as novel) still elicited stronger pupil constrictions than those correctly judged as familiar. Furthermore, pupil constriction was influenced more strongly if images were judged with high confidence. Thus, we propose that pupil constriction can serve as a marker of novelty. Since stimulus novelty modulates the efficacy of memory formation, our pupil measurements during learning indicate that the later forgotten images were perceived as less novel than the later remembered pictures. Taken together, our data provide evidence that pupil constriction is a physiological correlate of a neural novelty signal during formation and retrieval of declarative memories for complex, natural scenes. |
Marnix Naber; Ken Nakayama Pupil responses to high-level image content Journal Article In: Journal of Vision, vol. 13, no. 6, pp. 1–8, 2013. @article{Naber2013b,The link between arousal and pupil dilation is well studied, but it is less known that other cognitive processes can trigger pupil responses. Here we present evidence that pupil responses can be induced by high- level scene processing, independent of changes in low- level features or arousal. In Experiment 1, we recorded changes in pupil diameter of observers while they viewed a variety of natural scenes with or without a sun that were presented either upright or inverted. Image inversion had the strongest effect on the pupil responses. The pupil constricted more to the onset of upright images as compared to inverted images. Furthermore, the amplitudes of pupil constrictions to viewing images containing a sun were larger relative to control images. In Experiment 2, we presented cartoon versions of upright and inverted pictures that included either a sun or a moon. The image backgrounds were kept identical across conditions. Similar to Experiment 1, upright images triggered pupil constrictions with larger amplitudes than inverted images and images of the sun evoked greater pupil contraction than images of the moon. We suggest that the modulations of pupil responses were due to higher-level interpretations of image content. |
Kristin Michod Gagnier; Christopher A. Dickinson; Helene Intraub Fixating picture boundaries does not eliminate boundary extension: Implications for scene representation Journal Article In: Quarterly Journal of Experimental Psychology, vol. 66, no. 11, pp. 2161–2186, 2013. @article{MichodGagnier2013,Observers frequently remember seeing more of a scene than was shown (boundary extension). Does this reflect a lack of eye fixations to the boundary region? Single-object photographs were presented for 14-15 s each. Main objects were either whole or slightly cropped by one boundary, creating a salient marker of boundary placement. All participants expected a memory test, but only half were informed that boundary memory would be tested. Participants in both conditions made multiple fixations to the boundary region and the cropped region during study. Demonstrating the importance of these regions, test-informed participants fixated them sooner, longer, and more frequently. Boundary ratings (Experiment 1) and border adjustment tasks (Experiments 2-4) revealed boundary extension in both conditions. The error was reduced, but not eliminated, in the test-informed condition. Surprisingly, test knowledge and multiple fixations to the salient cropped region, during study and at test, were insufficient to overcome boundary extension on the cropped side. Results are discussed within a traditional visual-centric framework versus a multisource model of scene perception. |
Sébastien Miellet; Luca Vizioli; Lingnan He; Xinyue Zhou; Roberto Caldara Mapping face recognition information use across cultures Journal Article In: Frontiers in Psychology, vol. 4, pp. 34, 2013. @article{Miellet2013,Face recognition is not rooted in a universal eye movement information-gathering strategy. Western observers favor a local facial feature sampling strategy, whereas Eastern observers prefer sampling face information from a global, central fixation strategy. Yet, the precise qualitative (the diagnostic) and quantitative (the amount) information underlying these cultural perceptual biases in face recognition remains undetermined. To this end, we monitored the eye movements of Western and Eastern observers during a face recognition task, with a novel gaze-contingent technique: the Expanding Spotlight. We used 2° Gaussian apertures centered on the observers' fixations expanding dynamically at a rate of 1° every 25 ms at each fixation - the longer the fixation duration, the larger the aperture size. Identity-specific face information was only displayed within the Gaussian aperture; outside the aperture, an average face template was displayed to facilitate saccade planning. Thus, the Expanding Spotlight simultaneously maps out the facial information span at each fixation location. Data obtained with the Expanding Spotlight technique confirmed that Westerners extract more information from the eye region, whereas Easterners extract more information from the nose region. Interestingly, this quantitative difference was paired with a qualitative disparity. Retinal filters based on spatial-frequency decomposition built from the fixations maps revealed that Westerners used local high-spatial-frequency information sampling, covering all the features critical for effective face recognition (the eyes and the mouth). In contrast, Easterners achieved a similar result by using global low-spatial-frequency information from those facial features. Our data show that the face system flexibly engages into local or global eye movement strategies across cultures, by relying on distinct facial information span and culturally tuned spatially filtered information. Overall, our findings challenge the view of a unique putative process for face recognition. |
Jared E. Miller; Laura A. Carlson; J. Devin McAuley When what you hear influences when you see: Listening to an auditory rhythm influences the temporal allocation of visual attention Journal Article In: Psychological Science, vol. 24, no. 1, pp. 11–18, 2013. @article{Miller2013,The three experiments reported here demonstrated a cross-modal influence of an auditory rhythm on the temporal allocation of visual attention. In Experiment 1, participants moved their eyes to a test dot with a temporal onset that was either synchronous or asynchronous with a preceding auditory rhythm. Saccadic latencies were faster for the synchronous condition than for the asynchronous conditions. In Experiment 2, the effect was replicated in a condition in which the auditory context stopped prior to the onset of the test dot, and the effect did not occur in a condition in which auditory tones were presented at irregular intervals. Experiment 3 replicated the effect using an accuracy measure within a nontimed visual task. Together, the experiments' findings support a general entrainment perspective on attention to events over time. |
Patrick J. Mineault; Theodoros P. Zanos; Christopher C. Pack Local field potentials reflect multiple spatial scales in V4 Journal Article In: Frontiers in Computational Neuroscience, vol. 7, pp. 21, 2013. @article{Mineault2013,Local field potentials (LFP) reflect the properties of neuronal circuits or columns recorded in a volume around a microelectrode (Buzsáki et al., 2012). The extent of this integration volume has been a subject of some debate, with estimates ranging from a few hundred microns (Katzner et al., 2009; Xing et al., 2009) to several millimeters (Kreiman et al., 2006). We estimated receptive fields (RFs) of multi-unit activity (MUA) and LFPs at an intermediate level of visual processing, in area V4 of two macaques. The spatial structure of LFP receptive fields varied greatly as a function of time lag following stimulus onset, with the retinotopy of LFPs matching that of MUAs at a restricted set of time lags. A model-based analysis of the LFPs allowed us to recover two distinct stimulus-triggered components: an MUA-like retinotopic component that originated in a small volume around the microelectrodes (~350 μm), and a second component that was shared across the entire V4 region; this second component had tuning properties unrelated to those of the MUAs. Our results suggest that the LFP reflects neural activity across multiple spatial scales, which both complicates its interpretation and offers new opportunities for investigating the large-scale structure of network processing. |
Daniel Mirman; Allison E. Britt; Qi Chen Effects of phonological and semantic deficits on facilitative and inhibitory consequences of item repetition in spoken word comprehension Journal Article In: Neuropsychologia, vol. 51, no. 10, pp. 1848–1856, 2013. @article{Mirman2013,Repeating a word can have both facilitative and inhibitory effects on subsequent processing. The present study investigated these dynamics by examining the facilitative and inhibitory consequences of different kinds of item repetition in two individuals with aphasia and a group of neurologically intact control participants. The two individuals with aphasia were matched on overall aphasia severity, but had deficits at different levels of processing: one with a phonological deficit and spared semantic processing, the other with a semantic deficit and spared phonological processing. Participants completed a spoken word-to-picture matching task in which they had to pick which of four object images matched the spoken word. The trials were grouped into pairs such that exactly two objects from the first trial in a pair were present on screen during the second trial in the pair. When the second trial's target was the same as the first trial's target, compared to control participants, both participants with aphasia exhibited equally larger repetition priming effects. When the second trial's target was one of the new items, the participant with a phonological deficit exhibited a significantly more negative effect (i.e., second trial response slower than first trial response) than the control participants and the participant with a semantic deficit. Simulations of a computational model confirmed that this pattern of results could arise from (1) normal residual activation being functionally more significant when overall lexical processing is slower and (2) residual phonological activation of the previous trial's target having a particularly strong inhibitory effect specifically when phonological processing is impaired because the task was phonologically-driven (the spoken input specified the target). These results provide new insights into perseveration errors and lexical access deficits in aphasia. |
Eugene McSorley; Carien M. Van Reekum The time course of implicit affective picture processing: An eye movement study Journal Article In: Emotion, vol. 13, no. 4, pp. 769–773, 2013. @article{McSorley2013,Consistent with a negativity bias account, neuroscientific and behavioral evidence demonstrates modulation of even early sensory processes by unpleasant, potentially threat-relevant information. The aim of this research is to assess the extent to which pleasant and unpleasant visual stimuli presented extrafoveally capture attention and impact eye movement control. We report an experiment examining deviations in saccade metrics in the presence of emotional image distractors that are close to a nonemotional target. We additionally manipulate the saccade latency to test when the emotional distractor has its biggest impact on oculomotor control. The results demonstrate that saccade landing position was pulled toward unpleasant distractors, and that this pull was due to the quick saccade responses. Overall, these findings support a negativity bias account of early attentional control and call for the need to consider the time course of motivated attention when affect is implicit. |
Benjamin P. Meek; Keri Locheed; Jane M. Lawrence-Dewar; Paul Shelton; Jonathan J. Marotta Posterior cortical atrophy: An investigation of scan paths generated during face matching tasks Journal Article In: Frontiers in Human Neuroscience, vol. 7, pp. 309, 2013. @article{Meek2013,When viewing a face, healthy individuals focus more on the area containing the eyes and upper nose in order to retrieve important featural and configural information. In contrast, individuals with face blindness (prosopagnosia) tend to direct fixations toward individual facial features-particularly the mouth. Presented here is an examination of face perception deficits in individuals with Posterior Cortical Atrophy (PCA). PCA is a rare progressive neurodegenerative disorder that is characterized by atrophy in occipito-parietal and occipito-temporal cortices. PCA primarily affects higher visual processing, while memory, reasoning, and insight remain relatively intact. A common symptom of PCA is a decreased effective field of vision caused by the inability to "see the whole picture." Individuals with PCA and healthy control participants completed a same/different discrimination task in which images of faces were presented as cue-target pairs. Eye-tracking equipment and a novel computer-based perceptual task-the Viewing Window paradigm-were used to investigate scan patterns when faces were presented in open view or through a restricted-view, respectively. In contrast to previous prosopagnosia research, individuals with PCA each produced unique scan paths that focused on non-diagnostically useful locations. This focus on non-diagnostically useful locations was also present when using a restricted viewing aperture, suggesting that individuals with PCA have difficulty processing the face at either the featural or configural level. In fact, it appears that the decreased effective field of view in PCA patients is so severe that it results in an extreme dependence on local processing, such that a feature-based approach is not even possible. |
M. Meeter; Stefan Van der Stigchel Visual priming through a boost of the target signal: Evidence from saccadic landing positions Journal Article In: Attention, Perception, & Psychophysics, vol. 75, no. 7, pp. 1336–1341, 2013. @article{Meeter2013,The present study focuses on the effects of priming on visual selection. Repetition breeds success. This is the case over the long run, when repeating a certain act leads to learning, but also in the very short one: Over and over again, it has been found that the action that was performed last is primed to be performed again. In the visual search literature, such repetition priming has been studied extensively. Priming in visual search has been found for different target features: for the layout of the search scene, for its size, for the to-be given response, and for interactions between these factors. Using reaction time measures, as is typically done in priming studies, these possibilities cannot be disentangled from one another, since the measures reflect both pre- and post attentional processing and cannot dissociate the strength of the individual signals of target and distractor. Priming refers to a broad range of behavioral phenomena. It would be hard to argue that an enhancement of the target signal is the only mechanism involved in priming. For instance, distractor repetition speeds search even when target features are not repeated, suggesting that some form of distractor suppression or discounting also plays a role. |
Noya Meital; Sebastian Peter Korinth; Avi Karni Plasticity in the adult oculomotor system: Offline consolidation phase gains in saccade sequence learning Journal Article In: Brain Research, vol. 1528, pp. 42–48, 2013. @article{Meital2013,When do adults gain in learning an oculomotor sequence? Here we show that oculomotor training can result not only in performance gains within the training session, but also induce robust offline gains in both speed and accuracy. Participants were trained and tested over two consecutive days to perform a sequence of successive saccades. Saccades were directed to four target letters, presented simultaneously at fixed positions. A two alternative-forced choice question, after each trial, ensured that all targets were perceived. Eye tracking measures were tested at the beginning and end of the training session as well as at 24 h post-training. Practice resulted in within-session gains in accuracy and a reduction of target fixation duration (although total trial duration remained unchanged). In addition, the total average path length traveled by the eye increased, reflecting a decrease in undershoot saccades. At 24 h post-training, however, additional gains were expressed in both speed and accuracy of performance; the total trial duration as well as the fixation-position-offsets and the number of corrective saccades decreased. The expression of delayed gains indicates offline skill consolidation processes in the eye-movement control system. Our results show that the optimization of some aspect, specifically saccade speed parameters, of oculomotor sequence performance evolves mainly offline, during the post-training consolidation phase, a pattern suggestive of learning in an expert system. |
Elisha P. Merriam; Justin L. Gardner; J. Anthony Movshon; David J. Heeger Modulation of visual responses by gaze direction in human visual cortex Journal Article In: Journal of Neuroscience, vol. 33, no. 24, pp. 9879–9889, 2013. @article{Merriam2013,To locate visual objects, the brain combines information about retinal location and direction of gaze. Studies in monkeys have demon-strated that eye position modulates the gain of visual signals with " gain fields, " so that single neurons represent both retinotopic location and eye position. We wished to know whether eye position and retinotopic stimulus location are both represented in human visual cortex. Using functional magnetic resonance imaging, we measured separately for each of several different gaze positions cortical responses to stimuli that varied periodically in retinal locus. Visually evoked responses were periodic following the periodic retinotopic stimulation. Only the response amplitudes depended on eye position; response phases were indistinguishable across eye positions. We used multi-voxel pattern analysis to decode eye position from the spatial pattern of response amplitudes. The decoder reliably discriminated eye position in five of the early visual cortical areas by taking advantage of a spatially heterogeneous eye position-dependent modulation of cortical activity. We conclude that responses in retinotopically organized visual cortical areas are modulated by gain fields qualitatively similar to those previously observed neurophysiologically. |
Andrey R. Nikolaev; Peter Jurica; Chie Nakatani; Gijs Plomp; Cees Leeuwen Visual encoding and fixation target selection in free viewing: Presaccadic brain potentials Journal Article In: Frontiers in Systems Neuroscience, vol. 7, pp. 26, 2013. @article{Nikolaev2013,In scrutinizing a scene, the eyes alternate between fixations and saccades. During a fixation, two component processes can be distinguished: visual encoding and selection of the next fixation target. We aimed to distinguish the neural correlates of these processes in the electrical brain activity prior to a saccade onset. Participants viewed color photographs of natural scenes, in preparation for a change detection task. Then, for each participant and each scene we computed an image heat map, with temperature representing the duration and density of fixations. The temperature difference between the start and end points of saccades was taken as a measure of the expected task-relevance of the information concentrated in specific regions of a scene. Visual encoding was evaluated according to whether subsequent change was correctly detected. Saccades with larger temperature difference were more likely to be followed by correct detection than ones with smaller temperature differences. The amplitude of presaccadic activity over anterior brain areas was larger for correct detection than for detection failure. This difference was observed for short "scrutinizing" but not for long "explorative" saccades, suggesting that presaccadic activity reflects top-down saccade guidance. Thus, successful encoding requires local scanning of scene regions which are expected to be task-relevant. Next, we evaluated fixation target selection. Saccades "moving up" in temperature were preceded by presaccadic activity of higher amplitude than those "moving down". This finding suggests that presaccadic activity reflects attention deployed to the following fixation location. Our findings illustrate how presaccadic activity can elucidate concurrent brain processes related to the immediate goal of planning the next saccade and the larger-scale goal of constructing a robust representation of the visual scene. |
Eun Ju Noh; Hyeree Choo; Sungryong Koh Processing metalinguistic negation: Evidence from eye-tracking experiments Journal Article In: Journal of Pragmatics, vol. 57, pp. 1–18, 2013. @article{Noh2013,This paper investigates the interpretative process of metalinguistic negation (MN), as opposed to descriptive negation (DN), by using eye-tracking experiments on negative sentences in Korean. It has been suggested that negation is interpreted as descriptive by default and that an MN interpretation is taken only after the DN interpretation turns out to be a semantic contradiction to the clarification clause (a semantic account). Another suggestion is that the type of negation is chosen by considering optimal relevance. That is, people take an interpretation that yields greater cognitive effects with less processing effort (a cognitive account). Eye-tracking experiments were conducted on MN-DN pairs that received similarly high ratings on sensicality: the first with external negation and the second with long-form negation. In each pair, the two negative clauses were followed by the same clarification clause. In the experiments, clarification clauses showed no significant differences in the processing time between MNs and DNs. The results provide no evidence of the semantic account that the participants interpreted negation as descriptive by default. We suggest that they decided on the type of negation when they read the clarification clause, so that their processing times at the clarification clauses were not different between MNs and DNs, which is consistent with the cognitive account. |
Antje Nuthmann On the visual span during object search in real-world scenes Journal Article In: Visual Cognition, vol. 21, no. 7, pp. 803–837, 2013. @article{Nuthmann2013,The current study investigated from how large a region around their current point of gaze viewers can take in information when searching for objects in real-world scenes. Visual span size was estimated using the gaze-contingent moving window paradigm. Experiment 1 featured window radii measuring 1, 3, 4, 4.7, 5.4, and 6.1°. Experiment 2 featured six window radii measuring between 5 and 10°. Each scene occupied a 24.8 × 18.6° field of view. Inside the moving window, the scene was presented in high resolution. Outside the window, the scene image was low-pass filtered to impede the parsing of the scene into constituent objects. Visual span was defined as the window size at which object search times became indistinguishable from search times in the no-window control condition; this occurred with windows measuring 8° and larger. Notably, as long as central vision was fully available (window radii ≥ 5°), the distance traversed by the eyes through the scene to the search target was comparable to baseline performance. However, to move their eyes to the target, viewers made shorter saccades, requiring more fixations to cover the same image space, and thus more time. Moreover, a gaze-data based decomposition of search time revealed disruptions in specific subprocesses of search. In addition, nonlinear mixed models analyses demonstrated reliable individual differences in visual span size and parameters of the search time function. |
Antje Nuthmann Not fixating at the line of text comes at a cost Journal Article In: Attention, Perception, & Psychophysics, vol. 75, no. 8, pp. 1604–1609, 2013. @article{Nuthmann2013a,Previous research on eye guidance in reading has investigated systematic tendencies with respect to horizontal fixation locations on letters within words and the relationship between fixation location in a word and the duration of the fixation. The present study investigates where readers place their eyes vertically on the line of text and how vertical fixation location is related to fixation duration. Analyses were based on a large corpus of eye movement recordings from single-sentence reading. The vertical preferred viewing location was found to be within the vertical extent of the font, but fixations beyond the vertical boundaries of the text also frequently occurred. Analyzing fixation duration as a function of vertical fixation location revealed a vertical optimal viewing position (vOVP) effect: Fixations were shortest when placed optimally on the line of text, and fixation duration gradually increased for fixations that fell above or below the line of text. The vOVP effect can be explained by the limits of visual resolution along the vertical meridian. It is concluded that vertical and horizontal landing positions in single-sentence reading are associated with differences in fixation durations in opposite ways. |
Enkhbold Nyamsuren; Niels A. Taatgen Set as an instance of a real-world visual-cognitive task Journal Article In: Cognitive Science, vol. 37, no. 1, pp. 146–175, 2013. @article{Nyamsuren2013,Complex problem solving is often an integration of perceptual processing and deliberate planning. But what balances these two processes, and how do novices differ from experts? We investigate the interplay between these two in the game of SET. This article investigates how people combine bottom-up visual processes and top-down planning to succeed in this game. Using combinatorial and mixed-effect regression analysis of eye-movement protocols and a cognitive model of a human player, we show that SET players deploy both bottom-up and top-down processes in parallel to accomplish the same task. The combination of competition and cooperation of both types of processes is a major factor of success in the game. Finally, we explore strategies players use during the game. Our findings suggest that within-trial strategy shifts can occur without the need of explicit meta-cognitive control, but rather implicitly as a result of evolving memory activations. |
Enkhbold Nyamsuren; Niels A. Taatgen The effect of visual representation style in problem-solving: A perspective from cognitive processes Journal Article In: PLoS ONE, vol. 8, no. 11, pp. e80550, 2013. @article{Nyamsuren2013a,Using results from a controlled experiment and simulations based on cognitive models, we show that visual presentation style can have a significant impact on performance in a complex problem-solving task. We compared subject performances in two isomorphic, but visually different, tasks based on a card game of SET. Although subjects used the same strategy in both tasks, the difference in presentation style resulted in radically different reaction times and significant deviations in scanpath patterns in the two tasks. Results from our study indicate that low-level subconscious visual processes, such as differential acuity in peripheral vision and low-level iconic memory, can have indirect, but significant effects on decision making during a problem-solving task. We have developed two ACT-R models that employ the same basic strategy but deal with different presentations styles. Our ACT-R models confirm that changes in low-level visual processes triggered by changes in presentation style can propagate to higher-level cognitive processes. Such a domino effect can significantly affect reaction times and eye movements, without affecting the overall strategy of problem solving. |
Tamami Nakano; Noriko Higashida; Shigeru Kitazawa Facilitation of face recognition through the retino-tectal pathway Journal Article In: Neuropsychologia, vol. 51, no. 10, pp. 2043–2049, 2013. @article{Nakano2013,Humans can shift their gazes faster to human faces than to non-face targets during a task in which they are required to choose between face and non-face targets. However, it remains unclear whether a direct projection from the retina to the superior colliculus is specifically involved in this facilitated recognition of faces. To address this question, we presented a pair of face and non-face pictures to participants modulated in greyscale (luminance-defined stimuli) in one condition and modulated in a blue-yellow scale (S-cone-isolating stimuli) in another. The information of the S-cone-isolating stimuli is conveyed through the retino-geniculate pathway rather than the retino-tectal pathway. For the luminance stimuli, the reaction time was shorter towards a face than towards a non-face target. The facilitatory effect while choosing a face disappeared with the S-cone stimuli. Moreover, fearful faces elicited a significantly larger facilitatory effect relative to neutral faces, when the face (with or without emotion) and non-face stimuli were presented in greyscale. The effect of emotional expressions disappeared with the S-cone stimuli. In contrast to the S-cone stimuli, the face facilitatory effect was still observed with negated stimuli that were prepared by reversing the polarity of the original colour pictures and looked as unusual as the S-cone stimuli but still contained luminance information. These results demonstrate that the face facilitatory effect requires the facial and emotional information defined by luminance, suggesting that the luminance information conveyed through the retino-tectal pathway is responsible for the faster recognition of human faces. |
Chie Nakatani; Mojtaba Chehelcheraghi; Behnaz Jarrahi; Hironori Nakatani; Cees Leeuwen Cross-frequency phase synchrony around the saccade period as a correlate of perceiver's internal state Journal Article In: Frontiers in Systems Neuroscience, vol. 7, pp. 18, 2013. @article{Nakatani2013a,In active vision, eye-movements depend on perceivers' internal state. We investigated peri-fixation brain activity for internal state-specific tagging. Human participants performed a task, in which a visual object was presented for identification in lateral visual field, to which they moved their eyes as soon as possible from a central fixation point. Next, a phrase appeared in the same location; the phrase could either be an easy or hard question about the object, answered by pressing one of two alternative response buttons, or it could be an instruction to simply press one of these two buttons. Depending on whether these messages were blocked or randomly mixed, one of two different internal states was induced: either the task was known in advance or it wasn't. Eye movements and electroencephalogram (EEG) were recorded simultaneously during task performance. Using eye-event-time-locked averaging and independent component analysis, saccade- and fixation-related components were identified. Coss-frequency phase-synchrony was observed between the alpha/beta1 ranges of fixation-related and beta2/gamma1 ranges of saccade-related activity 50 ms prior to fixation onset in the mixed-phrase condition only. We interpreted this result as evidence for internal state-specific tagging. |
Hironori Nakatani; Cees Leeuwen Antecedent occipital alpha band activity predicts the impact of oculomotor events in perceptual switching Journal Article In: Frontiers in Systems Neuroscience, vol. 7, pp. 19, 2013. @article{Nakatani2013,Oculomotor events such as blinks and saccades transiently interrupt the visual input and, even though this mostly goes undetected, these brief interruptions could still influence the percept. In particular, both blinking and saccades facilitate switching in ambiguous figures such as the Necker cube. To investigate the neural state antecedent to these oculomotor events during the perception of an ambiguous figure, we measured the human scalp electroencephalogram (EEG). When blinking led to perceptual switching, antecedent occipital alpha band activity exhibited a transient increase in amplitude. When a saccade led to switching, a series of transient increases and decreases in amplitude was observed in the antecedent occipital alpha band activity. Our results suggest that the state of occipital alpha band activity predicts the impact of oculomotor events on the percept. |
Mark B. Neider; Cher Wee Ang; Michelle W. Voss; Ronald Carbonari; Arthur F. Kramer Training and transfer of training in rapid visual search for camouflaged targets Journal Article In: PLoS ONE, vol. 8, no. 12, pp. e83885, 2013. @article{Neider2013,Previous examinations of search under camouflage conditions have reported that performance improves with training and that training can engender near perfect transfer to similar, but novel camouflage-type displays [1]. What remains unclear, however, are the cognitive mechanisms underlying these training improvements and transfer benefits. On the one hand, improvements and transfer benefits might be associated with higher-level overt strategy shifts, such as through the restriction of eye movements to target-likely (background) display regions. On the other hand, improvements and benefits might be related to the tuning of lower-level perceptual processes, such as figure-ground segregation. To decouple these competing possibilities we had one group of participants train on camouflage search displays and a control group train on non-camouflage displays. Critically, search displays were rapidly presented, precluding eye movements. Before and following training, all participants completed transfer sessions in which they searched novel displays. We found that search performance on camouflage displays improved with training. Furthermore, participants who trained on camouflage displays suffered no performance costs when searching novel displays following training. Our findings suggest that training to break camouflage is related to the tuning of perceptual mechanisms and not strategic shifts in overt attention. |
Ronaldo Vigo; Derek E. Zeigler; Phillip A. Halsey Gaze and informativeness during category learning: Evidence for an inverse relation Journal Article In: Visual Cognition, vol. 21, no. 4, pp. 446–476, 2013. @article{Vigo2013,In what follows, we explore the general relationship between eye gaze during a category learning task and the information conveyed by each member of the learned category. To understand the nature of this relationship empirically, we used eye tracking during a novel object classification paradigm. Results suggest that the average fixation time per object during learning is inversely proportional to the amount of information that object conveys about its category. This inverse relationship may seem counterintuitive; however, objects that have a high-information value are inherently more representative of their category. Therefore, their generality captures the essence of the category structure relative to less representative objects. As such, it takes relatively less time to process these objects than their less informative companions. We use a general information measure referred to as representational information theory (Vigo, 2011a, 2013a) to articulate and interpret the results from our experiment and compare its predictions to those of three models of prototypicality. |
Melaina T. Vinski; Scott Watter Being a grump only makes things worse: A transactional account of acute stress on mind wandering Journal Article In: Frontiers in Psychology, vol. 4, pp. 730, 2013. @article{Vinski2013,The current work investigates the influence of acute stress on mind wandering. Participants completed the Positive and Negative Affect Schedule as a measure of baseline negative mood, and were randomly assigned to either the high-stress or low-stress version of the Trier Social Stress Test. Participants then completed the Sustained Attention to Response Task as a measure of mind-wandering behavior. In Experiment 1, participants reporting a high degree of negative mood that were exposed to the high-stress condition were more likely to engage in a variable response time, make more errors, and were more likely to report thinking about the stressor relative to participants that report a low level of negative mood. These effects diminished throughout task performance, suggesting that acute stress induces a temporary mind-wandering state in participants with a negative mood. The temporary affect-dependent deficits observed in Experiment 1 were replicated in Experiment 2, with the high negative mood participants demonstrating limited resource availability (indicated by pupil diameter) immediately following stress induction. These experiments provide novel evidence to suggest that acute psychosocial stress briefly suppresses the availability of cognitive resources and promotes an internally oriented focus of attention in participants with a negative mood. |
Renée M. Visser; H. Steven Scholte; Tinka Beemsterboer; Merel Kindt Neural pattern similarity predicts long-term fear memory Journal Article In: Nature Neuroscience, vol. 16, no. 4, pp. 388–390, 2013. @article{Visser2013,Although certain changes in the brain may reflect fear learning, there are no known markers that indicate whether an aversive experience will develop into fear memory. We examined the moment-to-moment dynamics of human fear learning by applying multi-voxel pattern analysis to single-trial blood oxygen level–dependent magnetic resonance imaging data. We found that the long-term behavioral expression of fear memory could be predicted from neural patterns at the time of learning. |
Jayalakshmi Viswanathan; Jason J. S. Barton The global effect for antisaccades Journal Article In: Experimental Brain Research, vol. 225, no. 2, pp. 247–259, 2013. @article{Viswanathan2013,In the global effect, prosaccades are deviated to a position intermediate between two targets or between a distractor and a target, which may reflect spatial averaging in a map encoded by the superior colliculus. Antisaccades differ from prosaccades in that they dissociate the locations of the stimulus and goal and generate weaker collicular activity. We used these antisaccade properties to determine whether the global effect was generated in stimulus or goal computations, and whether the global effect would be larger for antisaccades, as predicted by collicular averaging. In the first two experiments, human subjects performed antisaccades while distractors were placed in the vicinity of either the stimulus or the saccadic goal. Global effects occurred only for goal-related and not for stimulus-related distractors, indicating that this effect emerges from interactions with motor representations. In the last experiment, subjects performed prosaccades and antisaccades with and without goal-related distractors. When the results were adjusted for differences in response latency, the global effect for rapid responses was three to four times larger for antisaccades than for prosaccades. Finally, we compared our findings with predictions from collicular models, to quantitatively test the spatial averaging hypothesis: we found that our results were consistent with the predictions of a collicular model. We conclude that the antisaccade global effect shows properties compatible with spatial averaging in collicular maps and likely originates in layers with neural activity related to goal rather than stimulus representations. |
Melissa L. -H. Võ; Jeremy M. Wolfe The interplay of episodic and semantic memory in guiding repeated search in scenes. Journal Article In: Cognition, vol. 126, no. 2, pp. 198–212, 2013. @article{Vo2013,It seems intuitive to think that previous exposure or interaction with an environment should make it easier to search through it and, no doubt, this is true in many real-world situations. However, in a recent study, we demonstrated that previous exposure to a scene does not necessarily speed search within that scene. For instance, when observers performed as many as 15 searches for different objects in the same, unchanging scene, the speed of search did not decrease much over the course of these multiple searches (Vo & Wolfe, 2012). Only when observers were asked to search for the same object again did search become considerably faster. We argued that our naturalistic scenes provided such strong "semantic" guidance-e.g., knowing that a faucet is usually located near a sink-that guidance by incidental episodic memory-having seen that faucet previously-was rendered less useful. Here, we directly manipulated the availability of semantic information provided by a scene. By monitoring observers' eye movements, we found a tight coupling of semantic and episodic memory guidance: Decreasing the availability of semantic information increases the use of episodic memory to guide search. These findings have broad implications regarding the use of memory during search in general and particularly during search in naturalistic scenes. |
J. Gablentz; Andreas Sprenger; M. Heldmann; T. F. Münte; Christoph Helmchen Acquired pendular nystagmus and its therapy in progressive supranuclear palsy (PSP) due to inferior olivary hypertrophy Journal Article In: Journal of Neurology, vol. 260, no. 9, pp. 2424–2426, 2013. @article{Gablentz2013,The hallmark of progressive supranuclear palsy (PSP) is a slowing of vertical saccades which may lead to gaze- dependent blurred vision [2]. Oscillopsia, the illusion of a moving visual world, is usually caused by nystagmus or saccadic intrusions. However, oscillopsia and nystagmus usually do not belong to symptoms and signs of PSP patients. We report about a PSP patient who complained about oscillopsia due to acquired pendular nystagmus (APN), which was secondary to bilateral hypertrophy of the inferior olivary nucleus (IOH). APN and oscillopsia were reduced by gabapentin. This sheds some light on the brainstem manifestations of PSP, mechanisms of ocular oscillations in PSP, its therapy and the differential diag- nosis of blurred vision in PSP. |
Titus Malsburg; Shravan Vasishth Scanpaths reveal syntactic underspecification and reanalysis strategies Journal Article In: Language and Cognitive Processes, vol. 28, no. 10, pp. 1545–1578, 2013. @article{Malsburg2013,What theories best characterise the parsing processes triggered upon encountering ambiguity, and what effects do these processes have on eye movement patterns in reading? The present eye-tracking study, which investigated processing of attachment ambiguities of an adjunct in Spanish, suggests that readers sometimes underspecify attachment to save memory resources, consistent with the good-enough account of parsing. Our results confirm a surprising prediction of the good-enough account: high-capacity readers commit to an attachment decision more often than low-capacity participants, leading to more errors and a greater need to reanalyse in garden-path sentences. These results emerged only when we separated functionally different types of regressive eye movements using a scanpath analysis; conventional eye-tracking measures alone would have led to different conclusions. The scanpath analysis also showed that rereading was the dominant strategy for recovering from garden-pathing. Our results may also have broader implications for models of reading processes: reanalysis effects in eye movements occurred late, which suggests that the coupling of oculo-motor control and the parser may not be as tight as assumed in current computational models of eye movement control in reading. |
Adrian Mühlenen; Derrick G. Watson; Daniel O. A. Gunnell Blink and you won't miss it: The preview benefit in visual marking survives internally generated eyeblinks Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 39, no. 5, pp. 1279–1290, 2013. @article{Muehlenen2013,People are able to ignore old (previewed) stimuli in order to prioritize the processing of newly appearing items–the preview benefit (D. G. Watson & G. W. Humphreys, 1997, "Visual marking: Prioritizing selection for new objects by top-down attentional inhibition of old objects," Psychological Review, Vol. 104, pp. 90-122). According to the inhibitory visual marking account, this is achieved by the top-down and capacity-limited inhibition of old stimuli already in the field, which leads to a selection advantage for new items when they appear. In contrast, according to the abrupt luminance onset account (M. Donk & J. Theeuwes, 2001, "Visual marking beside the mark: Prioritizing selection by abrupt onsets," Perception & Psychophysics, Vol. 63, pp. 891-900), new items capture attention automatically simply because they generate luminance onset signals. Here, we demonstrate that new items can be partially prioritized over old items even when they appear during an eyeblink and so have no unique luminance transients associated with their appearance. Overall, the findings suggest that both the inhibition of old items and attention capture by luminance changes contribute to time-based selection. |
Lisa Stockhausen; Sara Koeser; Sabine Sczesny The gender typicality of faces and its impact on visual processing and on hiring decisions Journal Article In: Experimental Psychology, vol. 60, no. 6, pp. 444–452, 2013. @article{Stockhausen2013,Past research has shown that the gender typicality of applicants' faces affects leadership selection irrespective of a candidate's gender: A masculine facial appearance is congruent with masculine-typed leadership roles, thus masculine-looking applicants are hired more certainly than feminine-looking ones. In the present study, we extended this line of research by investigating hiring decisions for both masculine- and feminine-typed professional roles. Furthermore, we used eye tracking to examine the visual exploration of applicants' portraits. Our results indicate that masculine-looking applicants were favored for the masculine-typed role (leader) and feminine-looking applicants for the feminine-typed role (team member). Eye movement patterns showed that information about gender category and facial appearance was integrated during first fixations of the portraits. Hiring decisions, however, were not based on this initial analysis, but occurred at a second stage, when the portrait was viewed in the context of considering the applicant for a specific job. |
Nathalie Van Humbeeck; Nadine Schmitt; Frouke Hermens; Johan Wagemans; Udo A. Ernst The role of eye movements in a contour detection task Journal Article In: Journal of Vision, vol. 13, no. 14, pp. 5, 2013. @article{VanHumbeeck2013,Vision combines local feature integration with active viewing processes, such as eye movements, to perceive complex visual scenes. However, it is still unclear how these processes interact and support each other. Here, we investigated how the dynamics of saccadic eye movements interact with contour integration, focusing on situations in which contours are difficult to find or even absent. We recorded observers' eye movements while they searched for a contour embedded in a background of randomly oriented elements. Task difficulty was manipulated by varying the contour's path angle. An association field model of contour integration was employed to predict potential saccade targets by identifying stimulus locations with high contour salience. We found that the number and duration of fixations increased with the increasing path angle of the contour. In addition, fixation duration increased over the course of a trial, and the time course of saccade amplitude depended on the percept of observers. Model fitting revealed that saccades fully compensate for the reduced saliency of peripheral contour targets. Importantly, our model predicted fixation locations to a considerable degree, indicating that observers fixated collinear elements. These results show that contour integration actively guides eye movements and determines their spatial and temporal parameters. |
Anouk Mariette Loon; Tomas Knapen; H. Steven Scholte; Elexa St. John-Saaltink; Tobias H. Donner; Victor A. F. Lamme GABA shapes the dynamics of bistable perception Journal Article In: Current Biology, vol. 23, no. 9, pp. 823–827, 2013. @article{Loon2013,Sometimes, perception fluctuates spontaneously between two distinct interpretations of a constant sensory input. These bistable perceptual phenomena provide a unique window into the neural mechanisms that create the contents of conscious perception [1]. Models of bistable perception posit that mutual inhibition between stimulus-selective neural populations in visual cortex plays a key role in these spontaneous perceptual fluctuations [2, 3]. However, a direct link between neural inhibition and bistable perception has not yet been established experimentally. Here, we link perceptual dynamics in three distinct bistable visual illusions (binocular rivalry, motion-induced blindness, and structure from motion) to measurements of gamma-aminobutyric acid (GABA) concentrations in human visual cortex (as measured with magnetic resonance spectroscopy) and to pharmacological stimulation of the GABAAreceptor by means of lorazepam. As predicted by a model of neural interactions underlying bistability, both higher GABA concentrations in visual cortex and lorazepam administration induced slower perceptual dynamics, as reflected in a reduced number of perceptual switches and a lengthening of percept durations. Thus, we show that GABA, the main inhibitory neurotransmitter, shapes the dynamics of bistable perception. These results pave the way for future studies into the competitive neural interactions across the visual cortical hierarchy that elicit conscious perception. |
Stan Van Pelt; Pascal Fries Visual stimulus eccentricity affects human gamma peak frequency Journal Article In: NeuroImage, vol. 78, pp. 439–447, 2013. @article{VanPelt2013,The peak frequency of neuronal gamma-band synchronization has received much attention in recent years. Gamma peak frequency shifts to higher frequency values for higher contrast, faster moving, and attended stimuli. In monkey V1, gamma peak frequency for a drifting grating is higher for a parafoveal as compared to an eccentric stimulus (Lima et al., 2010). This effect might be due to the cortical magnification factor: the higher cortical magnification for parafoveal stimuli increases the velocity with which the cortical representations of the moving grating stripes move across the cortical surface. Since faster moving stimuli lead to higher gamma frequency, a faster moving cortical representation might do the same. This explanation predicts that the eccentricity effect on gamma peak frequency is absent for stationary stimuli. To test this, we investigated the effect of eccentricity on gamma peak frequency by recording magnetoencephalography in human subjects while they viewed moving or stationary gratings. We found that both the moving and the stationary stimuli induced lower peak frequencies for larger eccentricities, arguing against an explanation based on the cortical magnification factor. We further investigated whether this eccentricity effect was explained by differences in the size or the spatial frequency of the expected cortical activation. Neither of those explained the eccentricity effect. We propose that the different stimulus and top-down factors leading to higher gamma peak frequency all result in higher stimulus salience, that salience is translated into gamma peak frequency, and that gamma peak frequency might subserve the preferential processing of neuronal activity induced by salient stimuli. |
Kathleen Vancleef; Johan Wagemans; Glyn W. Humphreys Impaired texture segregation but spared contour integration following damage to right posterior parietal cortex Journal Article In: Experimental Brain Research, vol. 230, no. 1, pp. 41–57, 2013. @article{Vancleef2013,We examined the relations between texture segregation and contour integration in patients with deficits in spatial attention leading to left or right hemisphere extinction. Patients and control participants were presented with texture and contour stimuli consisting of oriented elements. We induced regularity in the stimuli by manipulating the element orientations resulting in an implicit texture border or explicit contour. Participants had to discriminate curved from straight shapes without making eye movements, while the stimulus presentation time was varied using a QUEST procedure. The results showed that only patients with right hemisphere extinction had a spatial bias, needing a longer presentation time to determine the shape of the border or contour on the contralesional side, especially for borders defined by texture. These results indicate that texture segregation is modulated by attention-related brain areas in the right posterior parietal cortex. |
Signe Vangkilde; Anders Petersen; Claus Bundesen Temporal expectancy in the context of a theory of visual attention Journal Article In: Philosophical Transactions of the Royal Society B: Biological Sciences, vol. 368, pp. 1–11, 2013. @article{Vangkilde2013,Temporal expectation is expectation with respect to the timing of an event such as the appearance of a certain stimulus. In this paper, temporal expectancy is investigated in the context of the theory of visual attention (TVA), and we begin by summarizing the foundations of this theoretical framework. Next, we present a parametric experiment exploring the effects of temporal expectation on perceptual processing speed in cued single-stimulus letter recognition with unspeeded motor responses. The length of the cue-stimulus foreperiod was exponentially distributed with one of six hazard rates varying between blocks. We hypothesized that this manipulation would result in a distinct temporal expectation in each hazard rate condition. Stimulus exposures were varied such that both the temporal threshold of conscious perception (t0 ms) and the perceptual processing speed (v letters s(-1)) could be estimated using TVA. We found that the temporal threshold t0 was unaffected by temporal expectation, but the perceptual processing speed v was a strikingly linear function of the logarithm of the hazard rate of the stimulus presentation. We argue that the effects on the v values were generated by changes in perceptual biases, suggesting that our perceptual biases are directly related to our temporal expectations. |
Hadas Velan; Avital Deutsch; Ram Frost The flexibility of letter-position flexibility: Evidence from eye movements in reading Hebrew Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 39, no. 4, pp. 1143–1152, 2013. @article{Velan2013,Hebrew provides an intriguing contrast to European languages. On the one hand, like any European language, it has an alphabetic script. On the other hand, being a Semitic language, it differs in the structure of base words. By monitoring eye movements, we examined the time-course of processing letter transpositions in Hebrew and assessed their impact on reading different types of Hebrew words that differ in their internal structure. We found that letter transposition resulted in dramatic reading costs for words with Semitic word structure, and much smaller costs for non-Semitic words. Moreover, the strongest impact of transposition occurred where root–letter transposition resulted in a pseudo-root, where significant interference emerged already in first fixation duration. Our findings thus suggest that Hebrew readers differentiate between Semitic and non-Semitic forms already at first fixation, at the early phase of word recognition. Moreover, letters are differentially processed across the visual array, given their morphological structure and their contribution to recovering semantic meaning. We conclude that flexibility or rigidity in encoding letter position is determined by cues regarding the internal structure of printed words. |
Eva Wiese; Jan Zwickel; Hermann J. Müller The importance of context information for the spatial specificity of gaze cueing Journal Article In: Attention, Perception, & Psychophysics, vol. 75, no. 5, pp. 967–982, 2013. @article{Wiese2013,In three experiments, we investigated the spatial allocation of attention in response to central gaze cues. In particular, we examined whether the allocation of attentional resources is influenced by context information-that is, the presence or absence of reference objects (i.e., placeholders) in the periphery. On each trial, gaze cues were followed by a target stimulus to which participants had to respond by keypress or by performing a target-directed saccade. Targets were presented either in an empty visual field (Exps. 1 and 2) or in previewed location placeholders (Exp. 3) and appeared at one of either 18 (Exp. 1) or six (Exps. 2 and 3) possible positions. The spatial distribution of attention was determined by comparing response times as a function of the distance between the cued and target positions. Gaze cueing was not specific to the exact cued position, but instead generalized equally to all positions in the cued hemifield, when no context information was provided. However, gaze direction induced a facilitation effect specific to the exact gazed-at position when reference objects were presented. We concluded that the presence of possible objects in the periphery to which gaze cues could refer is a prerequisite for attention shifts being specific to the gazed-at position. |
Melonie Williams; Pierre Pouget; Leanne Boucher; Geoffrey F. Woodman Visual-spatial attention aids the maintenance of object representations in visual working memory Journal Article In: Memory & Cognition, vol. 41, no. 5, pp. 698–715, 2013. @article{Williams2013,Theories have proposed that the maintenance of object representations in visual working memory is aided by a spatial rehearsal mechanism. In this study, we used two different approaches to test the hypothesis that overt and covert visual-spatial attention mechanisms contribute to the maintenance of object representations in visual working memory. First, we tracked observers' eye movements while they remembered a variable number of objects during change-detection tasks. We observed that during the blank retention interval, participants spontaneously shifted gaze to the locations that the objects had occupied in the memory array. Next, we hypothesized that if attention mechanisms contribute to the maintenance of object representations, then drawing attention away from the object locations during the retention interval should impair object memory during these change-detection tasks. Supporting this prediction, we found that attending to the fixation point in anticipation of a brief probe stimulus during the retention interval reduced change-detection accuracy, even on the trials in which no probe occurred. These findings support models of working memory in which visual-spatial selection mechanisms contribute to the maintenance of object representations. |
Tracey A. Williams; Melanie A. Porter; Robyn Langdon Viewing social scenes: A visual scan-path study comparing fragile X syndrome and williams syndrome Journal Article In: Journal of Autism and Developmental Disorders, vol. 43, no. 8, pp. 1880–1894, 2013. @article{Williams2013a,Fragile X syndrome (FXS) and Williams syndrome (WS) are both genetic disorders which present with similar cognitive-behavioral problems, but distinct social phenotypes. Despite these social differences both syndromes display poor social relations which may result from abnormal social processing. This study aimed to manipulate the location of socially salient information within scenes to investigate the visual attentional mechanisms of: capture, disengagement, and/or general engagement. Findings revealed that individuals with FXS avoid social information presented centrally, at least initially. The WS findings, on the other hand, provided some evidence that difficulties with attentional disengagement, rather than attentional capture, may play a role in the WS social phenotype. These findings are discussed in relation to the distinct social phenotypes of these two disorders. |
Vickie M. Williamson; Mary Hegarty; Ghislain Deslongchamps; Kenneth C. Williamson; Mary Jane Shultz Identifying student use of ball-and-stick images versus electrostatic potential map images via eye tracking Journal Article In: Journal of Chemical Education, vol. 90, no. 2, pp. 159–164, 2013. @article{Williamson2013,This pilot study examined students' use of ball-and-stick images versus electrostatic potential maps when asked questions about electron density, positive charge, proton attack, and hydroxide attack with six different molecules (two alcohols, two carboxylic acids, and two hydroxycarboxylic acids). Students' viewing of these dual images was measured by monitoring eye fixations of the students while they read and answered questions. Results showed that students spent significantly more time with the ball-and-stick image when asked questions about proton or hydroxide attack, but equal time on the images when asked about electron density or positive charge. When comparing accuracy and time spent on the images, students who spent more time on the ball-and-stick when asked about positive charge were less likely to be correct, while those who spent more time with the potential map were more likely to be correct. The paper serves to introduce readers to eye-tracker data and calls for replication with a larger subject pool and for the inclusion of eye tracking as a chemical education research tool. |
Niklas Wilming; Simon Harst; Nico Schmidt; Peter König Saccadic momentum and facilitation of return saccades contribute to an optimal foraging strategy Journal Article In: PLoS Computational Biology, vol. 9, no. 1, pp. e1002871, 2013. @article{Wilming2013,The interest in saccadic IOR is funneled by the hypothesis that it serves a clear functional purpose in the selection of fixation points: the facilitation of foraging. In this study, we arrive at a different interpretation of saccadic IOR. First, we find that return saccades are performed much more often than expected from the statistical properties of saccades and saccade pairs. Second, we find that fixation durations before a saccade are modulated by the relative angle of the saccade, but return saccades show no sign of an additional temporal inhibition. Thus, we do not find temporal saccadic inhibition of return. Interestingly, we find that return locations are more salient, according to empirically measured saliency (locations that are fixated by many observers) as well as stimulus dependent saliency (defined by image features), than regular fixation locations. These results and the finding that return saccades increase the match of individual trajectories with a grand total priority map evidences the return saccades being part of a fixation selection strategy that trades off exploration and exploitation. |
Paula M. Winke The effects of input enhancement on grammar learning and comprehension Journal Article In: Studies in Second Language Acquisition, vol. 35, no. 2, pp. 323–352, 2013. @article{Winke2013a,In his 2007 study Effects of Textual Enhancement and Topic Familiarity on Korean EFL Students' Reading Comprehension and Learning of Passive Form, Lee demonstrated that learners were better able to correct written sentences that contained incorrect English passive forms after exposure to texts flooded with enhanced (versus nonenhanced) passive forms. But with enhanced forms, learners did worse on comprehension tests, which arguably demonstrated a trade-off: More attention to forms resulted in less to meaning. In this study, a conceptual replication of Lee's using eye-movement data, I assessed how English passive construction enhancement affects English language learners' (a) learning of the form (via pre-and posttest gains on passive construction tests) and (b) text comprehension. In contrast to Lee's results, I found enhancement did not significantly increase form correction gain scores, nor did enhancement significantly detract from comprehension. There was no trade-off effect. Form learning and comprehension did not correlate. By recording learners' eye movements while reading, I found enhancement significantly impacted learners' noticing of the passive forms through longer gaze durations and rereading times. Thus, enhancement in this study functioned as intuitively and originally (Sharwood Smith, 1991, 1993) proposed; it promoted noticing, but, in this case, without further explicit instruction, it appeared to have done little else. Copyright © Cambridge University Press 2013. |
Paula Winke; Susan M. Gass; Tetyana Sydorenko Factors influencing the use of captions by foreign language learners: An eye-tracking study Journal Article In: The Modern Language Journal, vol. 97, no. 1, pp. 254–275, 2013. @article{Winke2013,This study investigates caption-reading behavior by foreign language (L2) learners and, through eye-tracking methodology, explores the extent to which the relationship between the native and target language affects that behavior. Second-year (4th semester) English-speaking learners of Arabic, Chinese, Russian, and Spanish watched 2 videos differing in content familiarity, each dubbed and captioned in the target language. Results indicated that time spent on captions differed significantly by language: Arabic learners spent more time on captions than learners of Spanish and Russian. A significant interaction between language and content familiarity occurred: Chinese learners spent less time on captions in the unfamiliar content video than the familiar, while others spent comparable times on each. Based on dual‐processing and cognitive load theories, we posit that the Chinese learners experienced a split‐attention effect when verbal processing was difficult and that, overall, captioning benefits during the 4th semester of language learning are constrained by L2 differences, including differences in script, vocabulary knowledge, concomitant L2 proficiency, and instructional methods. Results are triangulated with qualitative findings from interviews |
Heather Winskel The emotional Stroop task and emotionality rating of negative and neutral words in late Thai-English bilinguals Journal Article In: International Journal of Psychology, vol. 48, no. 6, pp. 1090–1098, 2013. @article{Winskel2013,The current study investigated how emotions are represented in the lexicon of late Thai–English bilinguals and a comparison group of native English speakers. Two tasks were used. In the emotional Stroop task, which taps into an automatic early lexical level of processing, the bilingual participants did not display the same automatic level of activation in their second language (L2) as in their first language (L1). In the emotionality-rating task, which involves a later, more in-depth conscious level of processing than the preceding task, similar results were found in both languages spoken by the bilinguals. These findings are interpreted as indicating that late bilinguals do not automatically respond to the emotional arousal associated with the meanings of L2 words to the same extent as in the L1, and this is likely to be mediated by language proficiency and the context in which the language is learned. |
Heather Winskel; Manuel Perea Consonant/vowel asymmetries in letter position coding during normal reading: Evidence from parafoveal previews in Thai Journal Article In: Journal of Cognitive Psychology, vol. 25, no. 1, pp. 119–130, 2013. @article{Winskel2013a,Studies have revealed that consonants and vowels serve different roles$backslash$nduring linguistic processing. Masked transposed-letter priming effects (i.e., faster word-identification times for words preceded by a transposed-letter than substitution-letter prime) occur for consonants but not for vowels in lexical decision (Perea & Lupker, 2004).Potential differences in letter position coding for consonants and vowels during silent normal reading were investigated in Thai using the boundary paradigm (Rayner, 1975). Thai has a distinctive alphabetic script with vowels taking a relatively subsidiary role in relation to consonants. Parafoveal processing of nonadjacent transposed-letter effects involving consonants and vowels was examined. Results for gaze durations revealed a transposition effect involving consonants but not vowelsthus extending previous findings with the masked priming technique but in a more ecological setting. Similar differential effects for consonants and vowels for first and single fixations were not found. An explanation is that consonants and vowels are not differentiated at this initial low level stage of processing (Johnson, 2007; Perea & Acha, 2009); it is only later in processing (as measured by gaze durations) that consonant/vowel status comes into play. Results support the claim that there are some fundamental processing asymmetries between vowels and consonants in normal reading. |
Stephanie C. Wissig; Carlyn A. Patterson; Adam Kohn Adaptation improves performance on a visual search task Journal Article In: Journal of Vision, vol. 13, no. 2, pp. 15, 2013. @article{Wissig2013,Temporal context, or adaptation, profoundly affects visual perception. Despite the strength and prevalence of adaptation effects, their functional role in visual processing remains unclear. The effects of spatial context and their functional role are better understood: these effects highlight features that differ from their surroundings and determine stimulus salience. Similarities in the perceptual and physiological effects of spatial and temporal context raise the possibility that they serve similar functions. We therefore tested the possibility that adaptation can enhance stimulus salience. We measured the effects of prolonged (40 s) adaptation to a counterphase grating on performance in a search task in which targets were defined by an orientation offset relative to a background of distracters. We found that, for targets with small orientation offsets, adaptation reduced reaction times and decreased the number of saccades made to find targets. Our results provide evidence that adaptation may function to highlight features that differ from the temporal context in which they are embedded. |
Kacey L. Wochna; Barbara J. Juhasz Context length and reading novel words: An eye-movement investigation Journal Article In: British Journal of Psychology, vol. 104, no. 3, pp. 347–363, 2013. @article{Wochna2013,The current study investigated the effects of context length on the processing of novel words. Participants read real adjectives or novel words embedded in either sentence or paragraph contexts while their eye movements were recorded. The results extend the literature on novel word reading by exploring the time-course of word processing using realistic contexts derived from existing sources. Eye-movement measures demonstrated that readers were very sensitive to the presence of novel words. Novel words were more likely to be fixated and had longer reading times than real words. In addition, words in sentence contexts had longer gaze durations than words in paragraphs. The effect of novelty on reading the target word did not vary as a function of the context length. While performance on the surprise post-test did not demonstrate significant word learning, participants did report higher confidence in correct responses than incorrect, suggesting that some learning took place. |
Felicity D. A. Wolohan; Sarah J. V. Bennett; Trevor J. Crawford Females and attention to eye gaze: Effects of the menstrual cycle Journal Article In: Experimental Brain Research, vol. 227, no. 3, pp. 379–386, 2013. @article{Wolohan2013,It is well known that an observer will attend to the location cued by another's eye gaze and that in some circumstances, this effect is enhanced when the emotion expressed is threat-related. This study explored whether attention to the gaze of threat-related faces is potentiated in the luteal phase of the menstrual cycle when detection of threat is suggested to be enhanced, compared to the follicular phase. Female participants were tested on a gaze cueing task in their luteal (N = 13) or follicular phase (N = 15). Participants were presented with various emotional expressions with an averted eye gaze that was either spatially congruent or incongruent with a forthcoming target. Females in the luteal phase responded faster overall to targets on trials with a 200-ms stimulus onset asynchrony interval. The results suggest that during the luteal phase, females show a general and automatic hypersensitivity to respond to stimuli associated with socially and emotionally relevant cues. This may be a part of an adaptive biological mechanism to protect foetal development. |
Jason H. Wong; Matthew S. Peterson What we remember affects how we see: Spatial working memory steers saccade programming Journal Article In: Attention, Perception, & Psychophysics, vol. 75, no. 2, pp. 308–321, 2013. @article{Wong2013,Relationships between visual attention, saccade programming, and visual working memory have been hypothesized for over a decade. Awh, Jonides, and Reuter-Lorenz (Journal of Experimental Psychology: Human Perception and Performance 24(3):780-90, 1998) and Awh et al. (Psychological Science 10(5):433-437, 1999) proposed that rehearsing a location in memory also leads to enhanced attentional processing at that location. In regard to eye movements, Belopolsky and Theeuwes (Attention, Perception & Psychophysics 71(3):620-631, 2009) found that holding a location in working memory affects saccade programming, albeit negatively. In three experiments, we attempted to replicate the findings of Belopolsky and Theeuwes (Attention, Perception & Psychophysics 71(3):620-631, 2009) and determine whether the spatial memory effect can occur in other saccade-cuing paradigms, including endogenous central arrow cues and exogenous irrelevant singletons. In the first experiment, our results were the opposite of those in Belopolsky and Theeuwes (Attention, Perception & Psychophysics 71(3):620-631, 2009), in that we found facilitation (shorter saccade latencies) instead of inhibition when the saccade target matched the region in spatial working memory. In Experiment 2, we sought to determine whether the spatial working memory effect would generalize to other endogenous cuing tasks, such as a central arrow that pointed to one of six possible peripheral locations. As in Experiment 1, we found that saccade programming was facilitated when the cued location coincided with the saccade target. In Experiment 3, we explored how spatial memory interacts with other types of cues, such as a peripheral color singleton target or irrelevant onset. In both cases, the eyes were more likely to go to either singleton when it coincided with the location held in spatial working memory. On the basis of these results, we conclude that spatial working memory and saccade programming are likely to share common overlapping circuitry. |
Robin Walker An iPad app as a low-vision aid for people with macular disease Journal Article In: British Journal of Ophthalmology, vol. 97, no. 1, pp. 110–112, 2013. @article{Walker2013,Age-related macular degeneration (AMD) is the single most common cause of vision loss in people over the age of 50. Individuals with low vision caused by macular disease, experience severe difficulty with everyday tasks such as reading, which has profound detrimental consequences for their quality of life. We have developed an app for the iPad (the MD evReader) that aims to improve reading (of electronic books) by enhancing the effectiveness of the eccentric viewing technique (EV) using dynamic text presentation. Eccentric viewing is a simple strategy adopted by individuals with AMD that involves using the relatively preserved peripheral region of their retina in order to see. A limiting factor of the EV technique is that it relies on the individual holding their gaze away from the focus of interest and suppressing the natural and strong, tendency to make eye-movements (saccades). During normal reading, for example, a stereotypical pattern of horizontal saccades are made, from left-to-right, enabling fixations to be made on each word4 – Figure 1a). The natural inclination to make saccades is, however, difficult to suppress and limits the effectiveness of eccentric viewing in people with macular disease. |
Robin Walker; Valerie Benson Remote distractor effects and saccadic inhibition: Spatial and temporal modulation Journal Article In: Journal of vision, vol. 13, no. 11, pp. 1–21, 2013. @article{Walker2013a,The onset of a visual distractor remote from a saccade target is known to increase saccade latency (the remote distractor effect [RDE]). In addition, distractors may also selectively inhibit saccades that would be initiated about 90 ms after distractor onset (termed saccadic inhibition [SI]). Recently, it has been proposed that the transitory inhibition of saccades (SI) may underlie the increase in mean latency (RDE). In a first experiment, the distractor eccentricity was manipulated, and a robust RDE that was strongly modulated by distractor eccentricity was observed. However, the underlying latency distributions did not reveal clear evidence of SI. A second experiment manipulated distractor spatial location and the timing of the distractor onset in relation to the target. An RDE was again observed with remote distractors away from the target axis and under conditions with early-onset distractors that would be unlikely to produce SI, whereas later distractor onsets produced an RDE along with some evidence of an SI effect. A third experiment using a mixed block of target-distractor stimulus-onset asynchronies (SOAs) revealed an RDE that varied with both distractor eccentricity and SOA and changes to latency distributions consistent with the timing of SI. We argue that the notion that SI underpins the RDE is similar to the earlier argument that express saccades underlie the fixation offset (gap) effect and that changes in mean latency and to the shape of the underlying latency distributions following a visual onset may involve more than one inhibitory process. |
Julian M. Wallace; Michael K. Chiu; Anirvan S. Nandy; Bosco S. Tjan Crowding during restricted and free viewing Journal Article In: Vision Research, vol. 84, pp. 50–59, 2013. @article{Wallace2013,Crowding impairs the perception of form in peripheral vision. It is likely to be a key limiting factor of form vision in patients without central vision. Crowding has been extensively studied in normally sighted individuals, typically with a stimulus duration of a few hundred milliseconds to avoid eye movements. These restricted testing conditions do not reflect the natural behavior of a patient with central field loss. Could unlimited stimulus duration and unrestricted eye movements change the properties of crowding in any fundamental way? We studied letter identification in the peripheral vision of normally sighted observers in three conditions: (i) a fixation condition with a brief stimulus presentation of 250. ms, (ii) another fixation condition but with an unlimited viewing time, and (iii) an unrestricted eye movement condition with an artificial central scotoma and an unlimited viewing time. In all conditions, contrast thresholds were measured as a function of target-to-flanker spacing, from which we estimated the spatial extent of crowding in terms of critical spacing. We found that presentation duration beyond 250. ms had little effect on critical spacing with stable gaze. With unrestricted eye movements and a simulated central scotoma, we found a large variability in critical spacing across observers, but more importantly, the variability in critical spacing was well correlated with the variability in target eccentricity. Our results assure that the large body of findings on crowding made with briefly presented stimuli remains relevant to conditions where viewing time is unconstrained. Our results further suggest that impaired oculomotor control associated with central vision loss can confound peripheral form vision beyond the limits imposed by crowding. |
Mark M. G. Walton; Seiji Ono; Michael J. Mustari Stimulation of pontine reticular formation in monkeys with strabismus Journal Article In: Investigative Ophthalmology & Visual Science, vol. 54, no. 10, pp. 7125–7136, 2013. @article{Walton2013,PURPOSE: Saccade disconjugacy in strabismus could result from any of a number of factors, including abnormalities of eye muscles, the plant, motoneurons, near response cells, or atypical tuning of neurons in saccade-related areas of the brain. This study was designed to investigate the possibility that saccade disconjugacy in strabismus is associated with abnormalities in paramedian pontine reticular formation (PPRF). METHODS: We applied microstimulation to 22 sites in PPRF and 20 sites in abducens nucleus in three rhesus macaque monkeys (one normal, one esotrope, and one exotrope). RESULTS: When mean velocity was compared between the two eyes, a slight difference was found for 1/5 sites in the normal animal. Significant differences were found for 5/6 sites in an esotrope and 10/11 sites in an exotrope. For five sites in the strabismic monkeys, the directions of evoked movements differed by more than 40° between the two eyes. When stimulation was applied to abducens nucleus (20 sites), the ipsilateral eye moved faster for 4/6 sites in the normal animal and all nine sites in the esotrope. For the exotrope, however, the left eye always moved faster, even for three sites on the right side. For the strabismic animals, stimulation of abducens nucleus often caused a different eye to move faster than stimulation of PPRF. CONCLUSIONS: These data suggest that PPRF is organized at least partly monocularly in strabismus and that disconjugate saccades are at least partly a consequence of unbalanced saccadic commands being sent to the two eyes. |
Chin-An Wang; Albrecht W. Inhoff Extraction of linguistic information from successive words during reading: Evidence for spatially distributed lexical processing Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 39, no. 3, pp. 662–677, 2013. @article{Wang2013,Two experiments examined whether word recognition progressed from one word to the next during reading, as maintained by sequential attention shift models such as the E-Z Reader model. The boundary technique was used to control the visibility of to-be-identified short target words, so that they were either previewed in the parafovea or masked. The eyes skipped a masked target on more than a quarter of the trials, and the following fixation must have been mislocated, if word recognition and saccade targeting progressed from one word to the next. Readers responded to the skipping parafoveally masked target words with relatively long viewing duration for the following posttarget word or with corrective saccades that returned the eyes from the posttarget word to the target. Experiment 2 manipulated the time-line of posttarget onset after target skipping, so that the posttarget word was either visible immediately upon fixation or after a short delay. The delay influenced posttarget viewing even when attention should have been focused at the target location according to E-Z Reader 10 simulations. These findings favor theoretical conceptions according to which lexical processing can encompass more than one word at a time. |
Hsueh-Cheng Wang; Elizabeth R. Schotter; Bernhard Angele; Jinmian Yang; Dan Simovici; Marc Pomplun; Keith Rayner Using singular value decomposition to investigate degraded Chinese character recognition: Evidence from eye movements during reading Journal Article In: Journal of Research in Reading, vol. 36, no. SUPPL.1, pp. S35–S50, 2013. @article{Wang2013a,Previous research indicates that removing initial strokes from Chinese characters makes them harder to read than removing final or internal ones. In the present study, we examined the contribution of important components to character configuration via singular value decomposition. The results indicated that when the least important segments, which did not seriously alter the configuration (contour) of the character, were deleted, subjects read as fast as when no segments were deleted. When the most important segments, which are located in the left side of a character and written first, were deleted, reading speed was greatly slowed. These results suggest that singular value decomposition, which has no information about stroke writing order, can identify the most important strokes for Chinese character identification. Furthermore, they also suggest that contour may be correlated with stroke writing order. |
Jingxin Wang; Jing Tian; Rong Wang; Valerie Benson Increased attentional focus modulates eye movements in a mixed antisaccade task for younger and older adults Journal Article In: PLoS ONE, vol. 8, no. 4, pp. e61566, 2013. @article{Wang2013b,We examined performance in the antisaccade task for younger and older adults by comparing latencies and errors in what we defined as high attentional focus (mixed antisaccades and prosaccades in the same block) and low attentional focus (antisaccades and prosaccades in separate blocks) conditions. Shorter saccade latencies for correctly executed eye movements were observed for both groups in mixed, compared to blocked, antisaccade tasks, but antisaccade error rates were higher for older participants across both conditions. The results are discussed in relation to the inhibitory hypothesis, the goal neglect theory and attentional control theory. |
Suiping Wang; Deyuan Mo; Ming Xiang; Ruiping Xu; Hsuan-Chih Chen The time course of semantic and syntactic processing in reading Chinese: Evidence from ERPs Journal Article In: Language and Cognitive Processes, vol. 28, no. 4, pp. 577–596, 2013. @article{Wang2013c,The time course of semantic and syntactic processing in reading Chinese was examined by recording event-related brain potentials (ERPs) as native Chinese speakers read individually presented sentences for comprehension and performed semantic plausibility judgments. The transitivity of the verbs in Chinese ba/bei constructions was manipulated to form three types of stimuli: Congruent sentences (CON), sentences with semantic violation (SEM), and sentences with combined semantic and syntactic violation (SEM'SYN). Compared with the critical words in CON, those in SEM and SEM'SYN elicited an N400-P600 biphasic pattern. The N400 effects in both violation conditions were of similar size and distribution, but the P600 in SEM'SYN was bigger than that in SEM. Overall, the lack of a difference between SEM and SEM'SYN in the earlier time window (i.e., N400 window) suggested that syntactic processing in Chinese does not necessarily occur earlier than semantic processing. |
David E. Warren; Matthew J. Thurtell; Joy N. Carroll; Michael Wall In: Investigative Ophthalmology & Visual Science, vol. 54, no. 8, pp. 5778–5787, 2013. @article{Warren2013,PURPOSE. Using a novel automated perimetry technique, we tested the hypothesis that older adults will have increased latency and decreased accuracy of saccades, as well as higher visual thresholds, to peripheral visual stimuli when compared with younger adults. METHODS. We tested 20 healthy subjects aged 18 to 30 years (‘‘young'') and 21 healthy subjects at least 60 years old (‘‘older'') for detection of briefly flashed peripheral stimuli of differing sizes in eight locations along the horizontal meridian (648, 6128, 6208, and 6288). With the left eye occluded, subjects were instructed to look quickly toward any seen stimuli. Right eye movements were recorded with an EyeLink 1000 infrared camera system. Limiting our analysis to the four stimulus positions in the nasal hemifield (?48, ?128, ?208, and ?288), we evaluated for group-level differences in saccadic latency, accuracy, and visual threshold at each stimulus location. RESULTS. Saccadic latency increased as stimulus size decreased in both groups. Older subjects had significantly increased saccadic latencies (at all locations; P < 0.05), decreased accuracies (at all locations; P < 0.05), and higher visual thresholds (at the ?128, ?208, and ?288 locations; P < 0.05). Additionally, there were significant relationships between visual threshold and latency, visual threshold and accuracy, and latency and accuracy (P < 0.0001). CONCLUSIONS. Older adults have increased latency and decreased accuracy of saccades, as well as higher visual thresholds, to peripheral visual stimuli when compared with younger adults. Saccadic latency and accuracy are related to visual threshold, suggesting that saccadic latency and accuracy could be useful as perimetric outcome measures. |
S. V. Wass; T. J. Smith; M. H. Johnson Parsing eye-tracking data of variable quality to provide accurate fixation duration estimates in infants and adults Journal Article In: Behavior Research Methods, vol. 45, no. 1, pp. 229–250, 2013. @article{Wass2013,Researchers studying infants' spontaneous allocation of attention have traditionally relied on hand-coding infants' direction of gaze from videos; these techniques have low temporal and spatial resolution and are labor intensive. Eye-tracking technology potentially allows for much more precise measurement of how attention is allocated at the subsecond scale, but a number of technical and methodological issues have given rise to caution about the quality and reliability of high temporal resolution data obtained from infants. We present analyses suggesting that when standard dispersal-based fixation detection algorithms are used to parse eye-tracking data obtained from infants, the results appear to be heavily influenced by interindividual variations in data quality. We discuss the causes of these artifacts, including fragmentary fixations arising from flickery or unreliable contact with the eyetracker and variable degrees of imprecision in reported position of gaze. We also present new algorithms designed to cope with these problems by including a number of new post hoc verification checks to identify and eliminate fixations that may be artifactual. We assess the results of our algorithms by testing their reliability using a variety of methods and on several data sets. We contend that, with appropriate data analysis methods, fixation duration can be a reliable and stable measure in infants. We conclude by discussing ways in which studying fixation durations during unconstrained orienting may offer insights into the relationship between attention and learning in naturalistic settings. |
Matteo Valsecchi; Karl R. Gegenfurtner; Alexander C. Schutz Saccadic and smooth-pursuit eye movements during reading of drifting texts Journal Article In: Journal of Vision, vol. 13, no. 10, pp. 8–8, 2013. @article{Valsecchi2013a,Reading is a complex visuomotor behavior characterized by an alternation of fixations and saccadic eye movements. Despite the widespread use of drifting texts in various settings, very little is known about eye movements under these conditions. Here we investigated oculomotor behavior during reading of texts which were drifting horizontally or vertically at different speeds. Consistent with previous reports, drifting texts were read by an alternation of smooth-pursuit and saccadic eye movements. Detailed analysis revealed several interactions between smooth pursuit and saccades. On one side, the gain of smooth pursuit was increased after the execution of a saccade. On the other side, the peak velocity of saccades was reduced for the horizontally drifting text, in which saccades and pursuit were executed in opposite directions. In addition, we show that well-known findings from the reading of static texts extend to drifting text, such as the preferred viewing location, the inverted optimal viewing position, and the correlation between saccade amplitude and subsequent pursuit/fixation duration. In general, individual eye-movement parameters such as saccade amplitude and fixation/pursuit durations were correlated across self-paced reading of static text and time-constrained reading of static and drifting texts. These results show that findings from basic oculomotor research also apply to the reading of drifting texts. Similarly, basic reading principles apply to the reading of static and drifting texts in a similar way. This exemplifies the reading of drifting text as a visuomotor behavior which is influenced by low-level eye-movement control as well as by cognitive and linguistic processing. |
Matteo Valsecchi; Matteo Toscani; Karl R. Gegenfurtner Perceived numerosity is reduced in peripheral vision Journal Article In: Journal of Vision, vol. 13, no. 13, pp. 7–7, 2013. @article{Valsecchi2013,In four experiments we investigated the perception of numerosity in the peripheral visual field. We found that the perceived numerosity of a peripheral cloud of dots was judged to be inferior to the one of a central cloud of dots, particularly when the dots were highly clustered. Blurring the stimuli accordingly to peripheral spatial frequency sensitivity did not abolish the effect and had little impact on numerosity judgments. In a dedicated control experiment we ruled out that the reduction in peripheral perceived numerosity is secondary to a reduction of perceived stimulus size. We suggest that visual crowding might be at the origin of the observed reduction in peripheral perceived numerosity, implying that numerosity could be partly estimated through the individuation of the elements populating the array. |
Christian Valuch; Stefanie I. Becker; Ulrich Ansorge Priming of fixations during recognition of natural scenes Journal Article In: Journal of Vision, vol. 13, no. 3, pp. 1–22, 2013. @article{Valuch2013,Eye fixations allow the human viewer to perceive scene content with high acuity. If fixations drive visual memory for scenes, a viewer might repeat his/her previous fixation pattern during recognition of a familiar scene. However, visual salience alone could account for similarities between two successive fixation patterns by attracting the eyes in a stimulus-driven, task-independent manner. In the present study, we tested whether the viewer's aim to recognize a scene fosters fixations on scene content that repeats from learning to recognition as compared to the influence of visual salience alone. In Experiment 1 we compared the gaze behavior in a recognition task to that in a free- viewing task. By showing the same stimuli in both tasks, the task-independent influence of salience was held constant. We found that during a recognition task, but not during (repeated) free viewing, viewers showed a pronounced preference for previously fixated scene content. In Experiment 2 we tested whether participants remembered visual input that they fixated during learning better than salient but nonfixated visual input. To that end we presented participants with smaller cutouts from learned and new scenes. We found that cutouts featuring scene content fixated during encoding were recognized better and faster than cutouts featuring nonfixated but highly salient scene content from learned scenes. Both experiments supported the hypothesis that fixations during encoding and maybe during recognition serve visual memory over and above a stimulus-driven influence of visual salience |
Eva Van Assche; Wouter Duyck; Marc Brysbaert Verb processing by bilinguals in sentence contexts: The effect of cognate status and verb tense Journal Article In: Studies in Second Language Acquisition, vol. 35, no. 2, pp. 237–259, 2013. @article{VanAssche2013,Many studies on bilingual language processing have shown that lexical access is not selective with respect to language. These studies typically used nouns as word stimuli. The aim of the present study was to extend the previous findings on noun processing to verb processing. In the first experiment, Dutch-English bilinguals performed a lexical decision task in their second language and were faster to recognize cognate verbs (e.g., Dutch-English geven-give) presented out of context than control words. This verb cognate facilitation effect was not modulated by verb tense. In a second experiment, cognates and controls were presented in sentence contexts while eye movements were recorded. In contrast to the strong cognate facilitation effects on early and later reading time measures for nouns found in earlier studies, cognate facilitation was only observed on a later reading time measure (i.e., go-past time). An interpretation of the results within current models of bilingual language processing and lexical organization is provided. |
Marlies E. Bochove; Lise Van Der Haegen; Wim Notebaert; Tom Verguts Blinking predicts enhanced cognitive control Journal Article In: Cognitive, Affective, & Behavioral Neuroscience, vol. 13, no. 2, pp. 346–354, 2013. @article{Bochove2013,Recent models have suggested an important role for neuromodulation in explaining trial-to-trial adaptations in cognitive control. The adaptation-by-binding model (Verguts & Notebaert, Psychological review, 115(2), 518-525, 2008), for instance, suggests that increased cognitive control in response to conflict (e.g., incongruent flanker stimulus) is the result of stronger binding of stimulus, action, and context representations, mediated by neuromodulators like dopamine (DA) and/or norepinephrine (NE). We presented a flanker task and used the Gratton effect (smaller congruency effect following incongruent trials) as an index of cognitive control. We investigated the Gratton effect in relation to eye blinks (DA related) and pupil dilation (NE related). The results for pupil dilation were not unequivocal, but eye blinks clearly modulated the Gratton effect: The Gratton effect was enhanced after a blink trial, relative to after a no-blink trial, even when controlling for correlated variables. The latter suggests an important role for DA in cognitive control on a trial-to-trial basis. © 2012 Psychonomic Society, Inc. |
Marieke E. Nieuwenhuijzen; A. R. Backus; A. Bahramisharif; Christian F. Doeller; Ole Jensen; Marcel A. J. Gerven MEG-based decoding of the spatiotemporal dynamics of visual category perception Journal Article In: NeuroImage, vol. 83, pp. 1063–1073, 2013. @article{Nieuwenhuijzen2013,Visual processing is a complex task which is best investigated using sensitive multivariate analysis methods that can capture representation-specific brain activity over both time and space. In this study, we applied a multivariate decoding algorithm to MEG data of subjects engaged in passive viewing of images of faces, scenes, bodies and tools. We used reconstructed source-space time courses as input to the algorithm in order to localize brain regions involved in optimal image discrimination. Applying this method to the interval of 115 to 315. ms after stimulus onset, we show a focal localization of regression coefficients in the inferior occipital, middle occipital, and lingual gyrus that drive decoding of the different perceived image categories. Classifier accuracy was highest (over 90% correctly classified trials, compared to a chance level accuracy of 50%) when dissociating the perception of faces from perception of other object categories. Furthermore, we applied this method to each single time point to extract the temporal evolution of visual perception. This allowed for the detection of differences in visual category perception as early as 85. ms after stimulus onset. Furthermore, localizing the corresponding regression coefficients of each time point allowed us to capture the spatiotemporal dynamics of visual category perception. This revealed initial involvement of sources in the inferior occipital, inferior temporal and superior occipital gyrus. During sustained stimulation additional sources in the anterior inferior temporal gyrus and superior parietal gyrus became involved. We conclude that decoding of source-space MEG data provides a suitable method to investigate the spatiotemporal dynamics of ongoing cognitive processing. |
Emanuel N. Broeke; D. M. Hartgerink; J. Butler; Julien Lambert; André Mouraux Central sensitization increases the pupil dilation elicited by mechanical pinprick stimulation Journal Article In: Journal of Neurophysiology, vol. 53, no. 9, pp. 1689–1699, 2013. @article{Broeke2013,High frequency electrical stimulation (HFS) of skin nociceptors triggers central sensitization (CS), manifested as increased pinprick sensitivity of the skin surrounding the site of HFS. Our aim was to assess the effect of CS on pinprick‐evoked pupil dilation responses (PDRs) and pinprick‐evoked brain potentials (PEPs). We hypothesized that the increase in the positive wave of PEPs following HFS would result from an enhanced pinprick‐evoked phasic response of the locus coeruleus‐noradrenergic system (LC‐NS), indicated by enhanced PDRs. In fourteen healthy volunteers, 64 and 96 mN pinprick stimuli were delivered to the left and right forearms, before and twenty minutes after applying HFS to one of the two forearms. Both PEPs and pinprick‐evoked PDRs were recorded. After HFS, pinprick stimuli were perceived as more intense at the HFS treated arm compared to baseline and control site, and this increase was similar for both stimulation intensities. Importantly, the pinprick‐ evoked PDR was also increased and the increase was stronger for 64 as compared to 96 mN stimulation. This is in line with our previous results showing a stronger increase of the PEP positivity at 64 vs. 96 mN stimulation and suggests that the increase in PEP positivity observed in previous studies could relate, at least in part, to enhance LC‐NS activity. However, there was no increase of the PEP positivity in the present study, indicating that enhanced LC‐NS activity is not the only determinant of the HFS‐induced enhancement of PEPs. Altogether, our results indicate that PDRs are more sensitive for detecting CS than PEPs. |
Stefan Van der Stigchel; Richard A. I. Bethlehem; Barrie P. Klein; Tos T. J. M. Berendschot; Tanja C. W. Nijboer; Serge O. Dumoulin Macular degeneration affects eye movement behavior during visual search Journal Article In: Frontiers in Psychology, vol. 4, pp. 579, 2013. @article{VanderStigchel2013,Patients with a scotoma in their central vision (e.g., due to macular degeneration, MD) commonly adopt a strategy to direct the eyes such that the image falls onto a peripheral location on the retina. This location is referred to as the preferred retinal locus (PRL). Although previous research has investigated the characteristics of this PRL, it is unclear whether eye movement metrics are modulated by peripheral viewing with a PRL as measured during a visual search paradigm. To this end, we tested four MD patients in a visual search paradigm and contrasted their performance with a healthy control group and a healthy control group performing the same experiment with a simulated scotoma. The experiment contained two conditions. In the first condition the target was an unfilled circle hidden among c-shaped distractors (serial condition) and in the second condition the target was a filled circle (pop-out condition). Saccadic search latencies for the MD group were significantly longer in both conditions compared to both control groups. Results of a subsequent experiment indicated that this difference between the MD and the control groups could not be explained by a difference in target selection sensitivity. Furthermore, search behavior of MD patients was associated with saccades with smaller amplitudes toward the scotoma, an increased intersaccadic interval and an increased number of eye movements necessary to locate the target. Some of these characteristics, such as the increased intersaccadic interval, were also observed in the simulation group, which indicate that these characteristics are related to the peripheral viewing itself. We suggest that the combination of the central scotoma and peripheral viewing can explain the altered search behavior and no behavioral evidence was found for a possible reorganization of the visual system associated with the use of a PRL. Thus the switch from a fovea-based to a PRL-based reference frame impairs search efficiency. |
Stefan Van der Stigchel; Tanja C. W. Nijboer How global is the global effect? The spatial characteristics of saccade averaging Journal Article In: Vision Research, vol. 84, pp. 6–15, 2013. @article{VanderStigchel2013c,When a target and a distractor are presented in close proximity, an eye movement will generally land in between these two elements. This is known as the 'global effect' and has been claimed to be a reflection of the averaged saccade programs towards both locations. The aim of the present study was to systematically investigate whether there is only a limited area in the saccade map in which saccade averaging occurs. To this end, we examined various distances between target and distractor in two experiments and investigated whether the majority of eye movements landed in between the target and the distractor. Results indicated that the endpoint distribution was unimodal for distances up to 35° (in polar coordinates), with saccades generally landing in between the target and the distractor. When the distance was higher than 45°, the saccade endpoint distribution was predominantly bimodal, with saccades landing either on the target or on the distractor. The decrease in saccade averaging was linear until almost no averaging saccades were observed for the longest distances. As saccades landing in between target and distractor reflect a weak, or absent, top-down signal, the present study indicated that top-down information is unable to strongly influence the oculomotor system when target and distractor are presented in close proximity. In this situation, the resulting eye movement is determined by the weighted average of saccade vectors present in a restricted region in the motor map. |
Stefan Van der Stigchel; Tanja C. W. Nijboer; Janet H. Bultitude; Robert D. Rafal Delayed oculomotor inhibition in patients with lesions to the human frontal oculomotor cortex: Evidence from a study on saccade averaging Journal Article In: Brain and Cognition, vol. 82, no. 2, pp. 192–200, 2013. @article{VanderStigchel2013a,The frontal oculomotor cortex is known to play an important role in oculomotor selection. The aim of the current study was to examine whether previously observed findings concerning the role of the frontal oculomotor cortex in the speed of saccade initiation and oculomotor inhibition might be related to a common underlying role of these areas in oculomotor selection. To this end, six patients with lesions to the frontal oculomotor cortex performed a double stimulus paradigm in which two elements were presented simultaneously in close proximity. Patients performed a block in which no specific task instruction was given and a block in which an instruction was provided about which of the two elements was the target. The rationale behind this manipulation was that the introduction of a specific task instruction would require a stronger involvement of top-down factors. In contrast to the block without a specific task instruction, saccade latencies to the contralesional visual field were longer than the ipsilesional visual field when a task instruction was given. This effect was strongest for saccades that landed away from the target and the distractor, reflecting trials in which strong oculomotor inhibition was applied. The observed deficits can be explained in terms of a slowing of the inhibitory signals associated with the rejection of a distractor. Given the known role of the Frontal Eye Fields and the location of the lesions, we attribute these findings to the Frontal Eye Fields, revealing their important role in the voluntary control of eye movements. |
Stefan Van der Stigchel; Robert D. Rafal; Janet H. Bultitude Temporal dynamics of error correction in a double step task in patients with a lesion to the lateral intra-parietal cortex Journal Article In: Neuropsychologia, vol. 51, no. 14, pp. 2988–2994, 2013. @article{VanderStigchel2013b,Five patients with lesions involving intra-parietal cortex (IPCx) were tested in a rapid version of the double step paradigm to investigate the role of the IPCx in the rapid, online, updating of a saccade program. Saccades were executed to a single target in either the contra- or the ipsilesional visual field. In two thirds of the trials, a step change in target position required that the saccade shifted to a new location within the same field but in the contra- or the ipsilesional direction, allowing us to investigate whether patients are able to update their saccade program given new exogenous information about the required endpoint of the saccade. This set-up resulted in three types of initial saccades: saccades to the target on no-step trials, uncorrected saccades to the original target location on step trials and corrected saccades to the new target location on step trials. Furthermore, if the updating of the original eye movement program failed, patients performed a second saccade to the new target location that required a rapid error correction. The analysis of the double-step task on a group level indicated that latencies for all trial types were longer when saccades were directed to the contralesional versus the ipsilesional field. Furthermore, longer latencies were required for patients to initiate a corrective second saccade after making an uncorrected first saccade in their contralesional compared to ipsilesional field. There were no differences in the ultimate landing positions of the eye movements for such corrected saccades. These results reveal that deficits in updating of saccade programs only seem to be present if the updating must occur after the gaze has shifted to a new location, pointing to a role of intra-parietal cortex in the processes involved in updating information when the current reference frame has to be updated. In conclusion, the paradigm deployed in the current study allows for a refinement of the role of the intra-parietal cortex in the updating of saccade programs. |
Wei Wei; Xingshan Li; Alexander Pollatsek Word properties of a fixated region affect outgoing saccade length in Chinese reading Journal Article In: Vision Research, vol. 80, pp. 1–6, 2013. @article{Wei2013,In two experiments, we investigated how forward saccades are targeted in Chinese reading. In Experiment 1, the critical region was a 4-character string which was either a word (one-word condition) or two 2-character word phrases (two-word condition). In Experiment 2, the critical region was either a high frequency word or a low frequency word. The outgoing saccade length from the last fixation on the critical region was longer in the one-word condition than the two-word condition in Experiment 1 and was longer in the high frequency condition than in the low frequency condition in Experiment 2. These results indicate that the properties of words in a fixated region affect the length of the outgoing saccade. We propose a processing-based strategy for saccade target selection in Chinese reading in which readers estimate how many characters they can process on each fixation, and then program their next saccade so that the eyes fixate somewhere beyond them. As a consequence, the easier the processing of the fixated region is, the longer the outgoing saccade is. |
Kristin M. Weingartner; Jerome L. Myers Effects of changes in narrative time on eye movements and recognition responses Journal Article In: Journal of Cognitive Psychology, vol. 25, no. 3, pp. 283–298, 2013. @article{Weingartner2013,In two experiments we examined how temporal aspects of narrative events influence comprehension. In Experiment 1 participants read paragraphs in which a critical event was followed by a phrase that signaled a time shift (After an hour versus After a moment). Consistent with earlier findings (e.g., Zwaan, 1996), fixation durations were longer on the phrase that signaled a larger time shift. However, there was no evidence that a larger time shift affected the accessibility of event information in Experiment 1, when the dependent measure was ease of anaphor comprehension, or in Experiment 2, when a recognition probe task was used. Although the discontinuation of an event (Maurice stopped versus was painting) did not affect anaphor reading times, it did lead to longer recognition times for the event. These results indicate that at least some event aspects remain accessible following a change in time and that the dependent measure can have a critical impact on the conclusions. |
Jessica Werthmann; Anne Roefs; Chantal Nederkoorn; Anita Jansen Desire lies in the eyes: Attention bias for chocolate is related to craving and self-endorsed eating permission Journal Article In: Appetite, vol. 70, pp. 81–89, 2013. @article{Werthmann2013,The present study tested the impact of experimentally manipulated perceived availability of chocolate on attention for chocolate stimuli, momentary (state) craving for chocolate and consumption of chocolate in healthy weight female students. It was hypothesized that eating forbiddance would be related to attentional avoidance (thus diminished attention focus on food cues in an attempt to prevent oneself from processing food cues) and that eating motivation would be related to attentional approach (thus maintained attentional focus on food cues). High chronic chocolate cravers (n= 40) and low cravers (n= 40) participated in one of four perceived availability contexts (required to eat, forbidden to eat, individual choice to eat, and 50% chance to eat) following a brief chocolate exposure. Attention for chocolate was measured using eye-tracking; momentary craving from self-report; and the consumption of chocolate was assessed from direct observation. The perceived availability of chocolate did not significantly influence attention allocation for chocolate stimuli, momentary craving or chocolate intake. High chocolate cravers reported significantly higher momentary craving for chocolate (d= 1.29, p<. .001), and showed longer initial duration of gaze on chocolate, than low cravers (d= 0.63, p<. .01). In contrast, participants who indicated during the manipulation check that they would not have permitted themselves to eat chocolate, irrespective of the availability instruction they received, showed significantly less craving (d= 0.96, p<. .01) and reduced total dwell time for chocolate stimuli than participants who permitted themselves to eat chocolate (d= 0.53, p<. .05). Thus, this study provides evidence that attention biases for food stimuli reflect inter-individual differences in eating motivation, - such as chronic chocolate craving, and self-endorsed eating permission. |