All EyeLink Eye Tracker Publications
以下按年份列出了截至2024年（2025年初）的所有13000多篇同行评审的EyeLink研究出版物。您可以使用视觉搜索、平滑追求、帕金森氏症等关键字搜索出版物库。您还可以搜索单个作者的姓名。按研究领域分组的眼动追踪研究可以在解决方案页面上找到。如果我们错过了任何EyeLink眼动追踪论文，请给我们发电子邮件！
2015 |
Cheng Chen; Xianghui Chen; Min Gao; Qiong Yang; Hongmei Yan Contextual influence on the tilt after-effect in foveal and para-foveal vision Journal Article In: Neuroscience Bulletin, vol. 31, no. 3, pp. 307–316, 2015. @article{Chen2015c,A sensory stimulus can only be properly interpreted in light of the stimuli that surround it in space and time. The tilt illusion (TI) and tilt after-effect (TAE) provide good evidence that the perception of a target depends strongly on both its spatial and temporal context. In previous studies, the TI and TAE have typically been investigated separately, so little is known about their co-effects on visual perception and information processing mechanisms. Here, we considered the influence of the spatial context and the temporal effect together and asked how center- surround context affects the TAE in foveal and para- foveal vision. Our results showed that different center-surround spatial patterns signifi cantly affected the TAE for both foveal and para-foveal vision. In the fovea, the TAE was mainly produced by central adaptive gratings. Cross-oriented surroundings significantly inhibited the TAE, and iso-oriented surroundings slightly facilitated it; surround inhibition was much stronger than surround facilitation. In the para-fovea, the TAE was mainly decided by the surrounding patches. Likewise, a cross-oriented central patch inhibited the TAE, and an iso-oriented one facilitated it, but there was no significant difference between inhibition and facilitation. Our findings demonstrated, at the perceptual level, that our visual system adopts different mechanisms to process consistent or inconsistent central-surround orientation information and that the unequal magnitude magnitude of surround inhibition and facilitation is vitally important for the visual system to improve the detectability or discriminability of novel or incongruent stimuli. |
Alison C. Bowling; Peter Lindsay; Belinda G. Smith; Kerri Storok Saccadic eye movements as indicators of cognitive function in older adults Journal Article In: Aging, Neuropsychology, and Cognition, vol. 22, no. 2, pp. 201–219, 2015. @article{Bowling2015,Older adults appear to have greater difficulty ignoring distractions during day-to-day activities than younger adults. To assess these effects of age, the ability of adults aged between 50 and 80 years to ignore distracting stimuli was measured using the antisaccade and oculomotor capture tasks. In the antisaccade task, observers are instructed to look away from a visual cue, whereas in the oculomotor capture task, observers are instructed to look toward a colored singleton in the presence of a concurrent onset distractor. Index scores of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) were compared with capture errors, and with prosaccade errors on the antisaccade task. A higher percentage of capture errors were made on the oculomotor capture tasks by the older members of the cohort compared to the younger members. There was a weak relationship between the attention index and capture errors, but the visuospatial/constructional index was the strongest predictor of prosaccade error rate in the antisaccade task. The saccade reaction times (SRTs) of correct initial saccades in the oculomotor capture task were poorly correlated with age, and with the neurospsychological tests, but prosaccade SRTs in both tasks moderately correlated with antisaccade error rate. These results were interpreted in terms of a competitive integration (or race) model. Any variable that reduces the strength of the top-down neural signal to produce a voluntary saccade, or that increases saccade speed, will enhance the likelihood that a reflexive saccade to a stimulus with an abrupt onset will occur. |
Senne Braem; Ena Coenen; Klaas Bombeke; Marlies E. Bochove; Wim Notebaert Open your eyes for prediction errors Journal Article In: Cognitive, Affective, & Behavioral Neuroscience, vol. 15, no. 2, pp. 374–380, 2015. @article{Braem2015,Previous studies have demonstrated that autonomic arousal is increased following correct task performance on a difficult, relative to an easy, task. Here, we hypothesized that this arousal response reflects the (relative) surprise of correct performance following a difficult versus an easy task. Following this line of reasoning, we would expect to find a reversed pattern following erroneous responses, because errors are less expected during an easy than during a difficult task. To test this, participants performed a flanker task while pupil size was measured online. As predicted, the results demonstrated that pupil size was larger following difficult (incongruent) correct trials than following easy (congruent) correct trials, but smaller following difficult than following easy incorrect trials. Moreover, participants with larger congruency effects, and hence a larger difference in outcome expectancies between the two trial types, showed larger differences in pupil size after both correct and incorrect responses, further corroborating the idea that pupil size increased as a measure of performance prediction errors. |
Jan Brascamp; Randolph Blake; Tomas Knapen Negligible fronto-parietal BOLD activity accompanying unreportable switches in bistable perception Journal Article In: Nature Neuroscience, vol. 18, no. 11, pp. 1672–1678, 2015. @article{Brascamp2015,The human brain's executive systems have a vital role in deciding and selecting among actions. Selection among alternatives also occurs in the perceptual domain; for instance, when perception switches between interpretations during perceptual bistability. Whether executive systems also underlie this functionality remains debated, with known fronto-parietal concomitants of perceptual switches being variously interpreted as reflecting the switches' cause or as reflecting their consequences. We developed a procedure in which the two eyes receive different inputs and perception demonstrably switches between these inputs, yet the switches themselves are so inconspicuous as to become unreportable, minimizing their executive consequences. Fronto-parietal fMRI BOLD responses that accompanied perceptual switches were similarly minimized in this procedure, indicating that these reflect the switches' consequences rather than their cause. We conclude that perceptual switches do not always rely on executive brain areas and that processes responsible for selection among alternatives may operate outside the brain's executive systems. |
Signe Bray; Ramsha Almas; Aiden E. G. F. Arnold; Giuseppe Iaria; Glenda Macqueen Intraparietal sulcus activity and functional connectivity supporting spatial working memory manipulation Journal Article In: Cerebral Cortex, vol. 25, no. 5, pp. 1252–1264, 2015. @article{Bray2015,The intraparietal sulcus (IPS) is recruited during tasks requiring attention, maintenance and manipulation of information in working memory (WM). While WM tasks often show broad bilateral engagement along the IPS, topographic maps of contralateral (CL) visual space have been identified along the IPS, similar to retinotopic maps in visual cortex. In the present study, we asked how these visuotopic IPS regions are differentially involved in the maintenance and manipulation of spatial information in WM. Visuotopic mapping was performed in 26 participants to define regions of interest along the IPS, corresponding to previously described IPS0-4. In a separate task, we showed that while maintaining the location of a briefly flashed target in WM preferentially engaged CL IPS, manipulation of spatial information by mentally rotating the target around a circle engaged bilateral IPS, peaking in IPS1 in most participants. Functional connectivity analyses showed increased interaction between the IPS and prefrontal regions during manipulation, as well as interhemispheric interactions. Two control tasks demonstrated that covert attention shifts, and nonspatial manipulation (arithmetic), engaged patterns of IPS activation and connectivity that were distinct from WM manipulation. These findings add to our understanding of the role of IPS in spatial WM maintenance and manipulation. |
Eli Brenner; Jeroen B. J. Smeets How moving backgrounds influence interception Journal Article In: PLoS ONE, vol. 10, no. 3, pp. e0119903, 2015. @article{Brenner2015,Reaching movements towards an object are continuously guided by visual information about the target and the arm. Such guidance increases precision and allows one to adjust the movement if the target unexpectedly moves. On-going arm movements are also influenced by motion in the surrounding. Fast responses to motion in the surrounding could help cope with moving obstacles and with the consequences of changes in one's eye orientation and vantage point. To further evaluate how motion in the surrounding influences interceptive movements we asked subjects to tap a moving target when it reached a second, static target. We varied the direction and location of motion in the surrounding, as well as details of the stimuli that are known to influence eye movements. Subjects were most sensitive to motion in the background when such motion was near the targets. Whether or not the eyes were moving, and the direction of the background motion in relation to the direction in which the eyes were moving, had very little influence on the response to the background motion. We conclude that the responses to background motion are driven by motion near the target rather than by a global analysis of the optic flow and its relation with other information about self-motion. |
Scott L. Brincat; Earl K. Miller Frequency-specific hippocampal-prefrontal interactions during associative learning Journal Article In: Nature Neuroscience, vol. 18, no. 4, pp. 576–581, 2015. @article{Brincat2015,Much of our knowledge of the world depends on learning associations (for example, face-name), for which the hippocampus (HPC) and prefrontal cortex (PFC) are critical. HPC-PFC interactions have rarely been studied in monkeys, whose cognitive and mnemonic abilities are akin to those of humans. We found functional differences and frequency-specific interactions between HPC and PFC of monkeys learning object pair associations, an animal model of human explicit memory. PFC spiking activity reflected learning in parallel with behavioral performance, whereas HPC neurons reflected feedback about whether trial-and-error guesses were correct or incorrect. Theta-band HPC-PFC synchrony was stronger after errors, was driven primarily by PFC to HPC directional influences and decreased with learning. In contrast, alpha/beta-band synchrony was stronger after correct trials, was driven more by HPC and increased with learning. Rapid object associative learning may occur in PFC, whereas HPC may guide neocortical plasticity by signaling success or failure via oscillatory synchrony in different frequency bands. |
Antonia F. Ten Brink; Tanja C. W. Nijboer; Douwe P. Bergsma; Jason J. S. Barton; Stefan Van der Stigchel Lack of multisensory integration in hemianopia: No influence of visual stimuli on aurally guided saccades to the blind hemifield Journal Article In: PLoS ONE, vol. 10, no. 4, pp. e0122054, 2015. @article{Brink2015,In patients with visual hemifield defects residual visual functions may be present, a phenomenon called blindsight. The superior colliculus (SC) is part of the spared pathway that is considered to be responsible for this phenomenon. Given that the SC processes input from different modalities and is involved in the programming of saccadic eye movements, the aim of the present study was to examine whether multimodal integration can modulate oculomotor competition in the damaged hemifield. We conducted two experiments with eight patients who had visual field defects due to lesions that affected the retinogeniculate pathway but spared the retinotectal direct SC pathway. They had to make saccades to an auditory target that was presented alone or in combination with a visual stimulus. The visual stimulus could either be spatially coincident with the auditory target (possibly enhancing the auditory target signal), or spatially disparate to the auditory target (possibly competing with the auditory tar-get signal). For each patient we compared the saccade endpoint deviation in these two bi-modal conditions with the endpoint deviation in the unimodal condition (auditory target alone). In all seven hemianopic patients, saccade accuracy was affected only by visual stimuli in the intact, but not in the blind visual field. In one patient with a more limited quadrantano-pia, a facilitation effect of the spatially coincident visual stimulus was observed. We conclude that our results show that multisensory integration is infrequent in the blind field of patients with hemianopia. |
Meredith Brown; Anne Pier Salverda; Laura C. Dilley; Michael K. Tanenhaus Metrical expectations from preceding prosody influence perception of lexical stress Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 41, no. 2, pp. 306–323, 2015. @article{Brown2015,Two visual-world experiments tested the hypothesis that expectations based on preceding prosody influence the perception of suprasegmental cues to lexical stress. The results demonstrate that listeners' consideration of competing alternatives with different stress patterns (e.g., 'jury/gi'raffe) can be influ- enced by the fundamental frequency and syllable timing patterns across material preceding a target word. When preceding stressed syllables distal to the target word shared pitch and timing characteristics with the first syllable of the target word, pictures of alternatives with primary lexical stress on the first syllable (e.g., jury) initially attracted more looks than alternatives with unstressed initial syllables (e.g., giraffe). This effect was modulated when preceding unstressed syllables had pitch and timing characteristics similar to the initial syllable of the target word, with more looks to alternatives with unstressed initial syllables (e.g., giraffe) than to those with stressed initial syllables (e.g., jury). These findings suggest that expectations about the acoustic realization of upcoming speech include information about metrical organization and lexical stress and that these expectations constrain the initial interpretation of supraseg- mental stress cues. These distal prosody effects implicate online probabilistic inferences about the sources of acoustic–phonetic variation during spoken-word recognition. |
Meredith Brown; Anne Pier Salverda; Laura C. Dilley; Michael K. Tanenhaus Metrical expectations from preceding prosody influence spoken word recognition Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 41, no. 2, pp. 306–323, 2015. @article{Brown2015a,Two visual world experiments tested the hypothesis that ex- pectations based on preceding prosody influence the percep- tion of suprasegmental cues to lexical stress. Experiment 1 showed that phonemically overlapping words with different initial stress patterns compete for recognition. Experiment 2 further demonstrated that fundamental frequency and sylla- ble timing patterns across material preceding the target word can influence the relative activation of competing alternatives with different initial stress patterns. The activation of alter- natives with initial stress was higher when preceding stressed syllables had suprasegmental acoustic characteristics similar to the initial syllable of the target word. These findings sug- gest that expectations about the acoustic realization of an ut- terance include information about metrical organization and lexical stress, and that these expectations constrain the initial interpretation of suprasegmental stress cues. These results are interpreted as support for expectation-based forward models in which acoustic information in the speech stream is interpreted based on expectations created by prosody. |
Nabil Hasshim; Benjamin A. Parris In: Attention, Perception, & Psychophysics, vol. 77, no. 8, pp. 2601–2610, 2015. @article{Hasshim2015,Conflict in the Stroop task is thought to come from various stages of processing, including semantics. Two-to-one response mappings, in which two response-set colors share a common response location, have been used to isolate stimulus-stimulus (semantic) from stimulus-response conflict in the Stroop task. However, the use of congruent trials as a baseline means that the measured effects could be exaggerated by facilitation, and recent research using neutral, non-color-word trials as a baseline has supported this notion. In the present study, we sought to provide evidence for stimulus-stimulus conflict using an oculomotor Stroop task and an early, preresponse pupillometric measure of effort. The results provided strong (Bayesian) evidence for no statistical difference between two-to-one response-mapping trials and neutral trials in both saccadic response latencies and preresponse pupillometric measures, supporting the notion that the difference between same-response and congruent trials indexes facilitation in congruent trials, and not stimulus-stimulus conflict, thus providing evidence against the presence of semantic conflict in the Stroop task. We also demonstrated the utility of preresponse pupillometry in measuring Stroop interference, supporting the idea that pupillary effects are not simply a residue of making a response. |
Stefan Hawelka; Sarah Schuster; Benjamin Gagl; Florian Hutzler On forward inferences of fast and slow readers. An eye movement study Journal Article In: Scientific Reports, vol. 5, pp. 8432, 2015. @article{Hawelka2015,Unimpaired readers process words incredibly fast and hence it was assumed that top-down processing, such as predicting upcoming words, would be too slow to play an appreciable role in reading. This runs counter the major postulate of the predictive coding framework that our brain continually predicts probable upcoming sensory events. This means, it may generate predictions about the probable upcoming word during reading (dubbed forward inferences). Trying to asses these contradictory assumptions, we evaluated the effect of the predictability of words in sentences on eye movement control during silent reading. Participants were a group of fluent (i.e., fast) and a group of speed-impaired (i.e., slow) readers. The findings indicate that fast readers generate forward inferences, whereas speed-impaired readers do so to a reduced extent - indicating a significant role of predictive coding for fluent reading. |
Rebecca Haworth; Stephanie Sobey; Jill M. Chorney; Michael Bezuhly; Paul Hong Measuring attentional bias in children with prominent ears: A prospective eye-tracking study Journal Article In: Journal of Plastic, Reconstructive & Aesthetic Surgery, vol. 68, no. 12, pp. 1662–1666, 2015. @article{Haworth2015,Background and aim: When observing new faces, most people focus their attention on the central triangle of the face containing the eyes, nose and mouth. When viewing faces with prominent ears, observers may divert their attention from the central triangle. The objective of this study was to determine whether there was an objective attentional bias to prominent ears in comparison to non-prominent ears. Methods: A total of 24 naïve participants (13 female; mean age 22.88 years) viewed 15 photographs of children with bilateral prominent ears, unilateral prominent ears and non-prominent ears. Both pre- and post-otoplasty photographs of two patients were included. The eye movements of participants were recorded using the EyeLink 1000, a table-mounted eye-tracking device. Results: Overall, the participants spent more time looking at the ear regions for faces with prominent ears in comparison to faces without prominent ears (p = 0.007 |
Taylor R. Hayes; Alexander A. Petrov; Per B. Sederberg Do we really become smarter when our fluid-intelligence test scores improve? Journal Article In: Intelligence, vol. 48, pp. 1–14, 2015. @article{Hayes2015,Recent reports of training-induced gains on fluid intelligence tests have fueled an explosion of interest in cognitive training-now a billion-dollar industry. The interpretation of these results is questionable because score gains can be dominated by factors that play marginal roles in the scores themselves, and because intelligence gain is not the only possible explanation for the observed control-adjusted far transfer across tasks. Here we present novel evidence that the test score gains used to measure the efficacy of cognitive training may reflect strategy refinement instead of intelligence gains. A novel scanpath analysis of eye movement data from 35 participants solving Raven's Advanced Progressive Matrices on two separate sessions indicated that one-third of the variance of score gains could be attributed to test-taking strategy alone, as revealed by characteristic changes in eye-fixation patterns. When the strategic contaminant was partialled out, the residual score gains were no longer significant. These results are compatible with established theories of skill acquisition suggesting that procedural knowledge tacitly acquired during training can later be utilized at posttest. Our novel method and result both underline a reason to be wary of purported intelligence gains, but also provide a way forward for testing for them in the future. |
Tao He; Yun Ding; Zhiguo Wang Environment- and eye-centered inhibitory cueing effects are both observed after a methodological confound is eliminated Journal Article In: Scientific Reports, vol. 5, pp. 16586, 2015. @article{He2015,Inhibition of return (IOR), typically explored in cueing paradigms, is a performance cost associated with previously attended locations and has been suggested as a crucial attentional mechanism that biases orientation towards novelty. In their seminal IOR paper, Posner and Cohen (1984) showed that IOR is coded in spatiotopic or environment-centered coordinates. Recent studies, however, have consistently reported IOR effects in both spatiotopic and retinotopic (eye-centered) coordinates. One overlooked methodological confound of all previous studies is that the spatial gradient of IOR is not considered when selecting the baseline for estimating IOR effects. This methodological issue makes it difficult to tell if the IOR effects reported in previous studies were coded in retinotopic or spatiotopic coordinates, or in both. The present study addresses this issue with the incorporation of no-cue trials to a modified cueing paradigm in which the cue and target are always intervened by a gaze-shift. The results revealed that a) IOR is indeed coded in both spatiotopic and retinotopic coordinates, and b) the methodology of previous work may have underestimated spatiotopic and retinotopic IOR effects. |
Wei He; Jon Brock; Blake W. Johnson Face processing in the brains of pre-school aged children measured with MEG Journal Article In: NeuroImage, vol. 106, pp. 317–327, 2015. @article{He2015a,There are two competing theories concerning the development of face perception: a late maturation account and an early maturation account. Magnetoencephalography (MEG) neuroimaging holds promise for adjudicating between the two opposing accounts by providing objective neurophysiological measures of face processing, with sufficient temporal resolution to isolate face-specific brain responses from those associated with other sensory, cognitive and motor processes. The current study used a customized child MEG system to measure M100 and M170 brain responses in 15 children aged three to six years while they viewed faces, cars and their phase-scrambled counterparts. Compared to adults tested using the same stimuli in a conventional MEG system, children showed significantly larger and later M100 responses. Children's M170 responses, derived by subtracting the responses to phase-scrambled images from the corresponding images (faces or cars) were delayed in latency but otherwise resembled the adult M170. This component has not been obtained in previous studies of young children tested using conventional adult MEG systems. However children did show a markedly reduced M170 response to cars in comparison to adults. This may reflect children's lack of expertise with cars relative to faces. Taken together, these data are in accord with recent behavioural and neuroimaging data that support early maturation of the basic face processing functions. |
Wei He; Marta I. Garrido; Paul F. Sowman; Jon Brock; Blake W. Johnson Development of effective connectivity in the core network for face perception Journal Article In: Human Brain Mapping, vol. 36, no. 6, pp. 2161–2173, 2015. @article{He2015b,This study measured effective connectivity within the core face network in young children using a paediatric magnetoencephalograph (MEG). Dynamic casual modeling (DCM) of brain responses was performed in a group of adults (N = 14) and a group of young children aged from 3 to 6 years (N = 15). Three candidate DCM models were tested, and the fits of the MEG data to the three models were compared at both individual and group levels. The results show that the connectivity structure of the core face network differs significantly between adults and children. Further, the relative strengths of face network connections were differentially modulated by experimental conditions in the two groups. These results support the interpretation that the core face network undergoes significant structural configuration and functional specialization between four years of age and adulthood. |
Alison W. Heard; Michael E. J. Masson; Daniel N. Bub Time course of action representations evoked during sentence comprehension Journal Article In: Acta Psychologica, vol. 156, pp. 98–103, 2015. @article{Heard2015,The nature of hand-action representations evoked during language comprehension was investigated using a variant of the visual-world paradigm in which eye fixations were monitored while subjects viewed a screen displaying four hand postures and listened to sentences describing an actor using or lifting a manipulable object. Displayed postures were related to either a functional (using) or volumetric (lifting) interaction with an object that matched or did not match the object mentioned in the sentence. Subjects were instructed to select the hand posture that matched the action described in the sentence. Even before the manipulable object was mentioned in the sentence, some sentence contexts allowed subjects to infer the object's identity and the type of action performed with it and eye fixations immediately favored the corresponding hand posture. This effect was assumed to be the result of ongoing motor or perceptual imagery in which the action described in the sentence was mentally simulated. In addition, the hand posture related to the manipulable object mentioned in a sentence, but not related to the described action (e.g., a writing posture in the context of a sentence that describes lifting, but not using, a pencil), was favored over other hand postures not related to the object. This effect was attributed to motor resonance arising from conceptual processing of the manipulable object, without regard to the remainder of the sentence context. |
Hanna Heikkinen; Fariba Sharifian; Ricardo Vigario; Simo Vanni Feedback to distal dendrites links fMRI signals to neural receptive fields in a spiking network model of the visual cortex Journal Article In: Journal of Neurophysiology, vol. 114, no. 1, pp. 57–69, 2015. @article{Heikkinen2015,The blood oxygenation level-dependent (BOLD) response has been strongly associated with neuronal activity in the brain. However, some neuronal tuning properties are consistently different from the BOLD response. We studied the spatial extent of neural and hemodynamic responses in the primary visual cortex, where the BOLD responses spread and interact over much longer distances than the small receptive fields of individual neurons would predict. Our model shows that a feedforward-feedback loop between V1 and a higher visual area can account for the observed spread of the BOLD response. In particular, anisotropic landing of inputs to compartmental neurons were necessary to account for the BOLD signal spread, while retaining realistic spiking responses. Our work shows that simple dendrites can separate tuning at the synapses and at the action potential output, thus bridging the BOLD signal to the neural receptive fields with high fidelity. |
Florian Hintz; Antje S. Meyer Prediction and production of simple mathematical equations: Evidence from visual world eye-tracking Journal Article In: PLoS ONE, vol. 10, no. 7, pp. e0130766, 2015. @article{Hintz2015,The relationship between the production and the comprehension systems has recently become a topic of interest for many psycholinguists. It has been argued that these systems are tightly linked and in particular that listeners use the production system to predict upcoming content. In this study, we tested how similar production and prediction processes are in a novel version of the visual world paradigm. Dutch speaking participants (native speakers in Experiment 1; German-Dutch bilinguals in Experiment 2) listened to mathematical equations while looking at a clock face featuring the numbers 1 to 12. On alternating trials, they either heard a complete equation ("three plus eight is eleven") or they heard the first part ("three plus eight is") and had to produce the result ("eleven") themselves. Participants were encouraged to look at the relevant numbers throughout the trial. Their eye movements were recorded and analyzed. We found that the participants' eye movements in the two tasks were overall very similar. They fixated the first and second number of the equations shortly after they were mentioned, and fixated the result number well before they named it on production trials and well before the recorded speaker named it on comprehension trials. However, all fixation latencies were shorter on production than on comprehension trials. These findings suggest that the processes involved in planning to say a word and anticipating hearing a word are quite similar, but that people are more aroused or engaged when they intend to respond than when they merely listen to another person. |
Margit Hofler; Iain D. Gilchrist; Christof Korner Guidance toward and away from distractors in repeated visual search Journal Article In: Journal of Vision, vol. 15, no. 5, pp. 1–14, 2015. @article{Hofler2015,When searching for two targets consecutively in the same display, participants use memory of recently fixated distractors that become the target in the second search to find that target more quickly. Here we ask whether participants are also using memory for fixated distractors that do not become the target. In Experiment 1 we show that search is faster overall in the second search regardless of whether or not the second search target was fixated in the first search. We replicate this effect in Experiment 2 for different display sizes and further show that the effect is a result of the prioritization of locations that are more likely to contain the target. This suggests that representations of the fixated distractor items are retained across the two searches and that these representations can be used flexibly to optimize search performance. Furthermore, this suggests that the short-term memory processes that support search across consecutive searches not only facilitate guidance toward the target but also allow distractors to be excluded from the search process. |
Andrew Hollingworth Visual working memory modulates within‐object metrics of saccade landing position Journal Article In: Annals of the New York Academy of Sciences, vol. 1339, no. 1, pp. 11–19, 2015. @article{Hollingworth2015,In two experiments, we examined the influence of visual working memory (VWM) on oculomotor selection, testing whether the landing positions of rapidly generated saccades are biased toward the region of an object that matches a feature held in VWM. Participants executed a saccade to the center of a single saccade target, divided into two colored regions and presented on the horizontal midline. Concurrently, participants maintained a color in VWM for an unrelated memory task. This color either matched one of the two regions or neither of the regions. Relative to the no-match baseline, the landing positions of rapidly generated saccades (mean latency < 150 ms) were biased toward the region that matched the remembered color. The results support the hypothesis that VWM modulates early, spatially organized sensory representations to bias selection toward locations with features that match VWM content. In addition, the results demonstrate that saccades to spatially extended objects are sensitive to within-object differences in salience. |
Seung Kweon Hong Comparison of vertical and horizontal eye movement times in the selection of visual targets by an eye input device Journal Article In: Journal of the Ergonomics Society of Korea, vol. 34, no. 1, pp. 19–27, 2015. @article{Hong2015,Objective: The aim of this study is to investigate how well eye movement times in visual target selection tasks by an eye input device follows the typical Fitts' Law and to compare vertical and horizontal eye movement times. Background: Typically manual pointing provides excellent fit to the Fitts' Law model. However, when an eye input device is used for the visual target selection tasks, there were some debates on whether the eye movement times in can be described by the Fitts' Law. More empirical studies should be added to resolve these debates. This study is an empirical study for resolving this debate. On the other hand, many researchers reported the direction of movement in typical manual pointing has some effects on the movement times. The other question in this study is whether the direction of eye movement also affects the eye movement times. Method: A cursor movement times in visual target selection tasks by both input devices were collected. The layout of visual targets was set up by two types. Cursor starting position for vertical movement times were in the top of the monitor and visual targets were located in the bottom, while cursor starting positions for horizontal movement times were in the right of the monitor and visual targets were located in the left. Results: Although eye movement time was described by the Fitts' Law, the error rate was high and correlation was relatively low (R2 = 0.80 for horizontal movements and R2 = 0.66 for vertical movements), compared to those of manual movement. According to the movement direction, manual movement times were not significantly different, but eye movement times were significantly different. Conclusion: Eye movement times in the selection of visual targets by an eye-gaze input device could be described and predicted by the Fitts' Law. Eye movement times were significantly different according to the direction of eye movement. Application: The results of this study might help to understand eye movement times in visual target selection tasks by the eye input devices. |
Benedetta Heimler; Wieske Zoest; Francesca Baruffaldi; Mieke Donk; Pasquale Rinaldi; Maria Cristina Caselli; Francesco Pavani Finding the balance between capture and control: Oculomotor selection in early deaf adults Journal Article In: Brain and Cognition, vol. 96, pp. 12–27, 2015. @article{Heimler2015,Previous work investigating the consequence of bilateral deafness on attentional selection suggests that experience-dependent changes in this population may result in increased automatic processing of stimulus-driven visual information (e.g., saliency). However, adaptive behavior also requires observers to prioritize goal-driven information relevant to the task at hand. In order to investigate whether auditory deprivation alters the balance between these two components of attentional selection, we assessed the time-course of overt visual selection in deaf adults. Twenty early-deaf adults and twenty hearing controls performed an oculomotor additional singleton paradigm. Participants made a speeded eye-movement to a unique orientation target, embedded among homogenous non-targets and one additional unique orientation distractor that was more, equally or less salient than the target. Saliency was manipulated through color. For deaf participants proficiency in sign language was assessed. Overall, results showed that fast initiated saccades were saliency-driven, whereas later initiated saccades were goal-driven. However, deaf participants were overall slower than hearing controls at initiating saccades and also less captured by task-irrelevant salient distractors. The delayed oculomotor behavior of deaf adults was not explained by any of the linguistic measures acquired. Importantly, a multinomial model applied to the data revealed a comparable evolution over time of the underlying saliency- and goal-driven processes between the two groups, confirming the crucial role of saccadic latencies in determining the outcome of visual selection performance. The present findings indicate that prioritization of saliency-driven information is not an unavoidable phenomenon in deafness. Possible neural correlates of the documented behavioral effect are also discussed. |
Daphna Heller; Jennifer E. Arnold; Natalie M. Klein; Michael K. Tanenhaus Inferring difficulty: Flexibility in the real-time processing of disfluency Journal Article In: Language and Speech, vol. 58, no. 2, pp. 190–203, 2015. @article{Heller2015,Upon hearing a disfluent referring expression, listeners expect the speaker to refer to an object that is previously unmentioned, an object that does not have a straightforward label, or an object that requires a longer description. Two visual-world eye-tracking experiments examined whether listeners directly associate disfluency with these properties of objects, or whether disfluency attribution is more flexible and involves situation-specific inferences. Since in natural situations reference to objects that do not have a straightforward label or that require a longer description is correlated with both production difficulty and with disfluency, we used a mini-artificial lexicon to dissociate difficulty from these properties, building on the fact that recently learned names take longer to produce than existing words in one's mental lexicon. The results demonstrate that disfluency attribution involves situation-specific inferences; we propose that in new situations listeners spontaneously infer what may cause production difficulty. However, the results show that these situation-specific inferences are limited in scope: listeners assessed difficulty relative to their own experience with the artificial names, and did not adapt to the assumed knowledge of the speaker. |
Christoph Helmchen; Evripides Livitzis; Andreas Sprenger; Peter Trillenberg Cerebellar ataxia with unilateral high frequency vestibulopathy and caloric disinhibition Journal Article In: Journal of the Neurological Sciences, vol. 358, no. 1-2, pp. 527–529, 2015. @article{Helmchen2015,Quantitative analysis of the head impulse test (qHIT), known as the Halmagyi–Curthoys test, has recently more commonly been used in standard diagnostic work up of patients with dizziness, due to modern videooculography systems. qHIT examines the high frequency, high acceleration components of the vestibulo-ocular reflex (VOR), in contrast to caloric irrigation which tests its low frequency components. Here we present a patient with a unilateral vestibulopathy during qHIT suspected to suffer from peripheral unilateral vestibulopathy who showed profoundly increased caloric responses on the lesion side. We provide some evidence that this probably indicates cerebellar disease. |
John M. Henderson; Wonil Choi Neural correlates of fixation duration during real-world scene viewing: Evidence from fixation-related (FIRE) fMRI Journal Article In: Journal of Cognitive Neuroscience, vol. 27, no. 6, pp. 1137–1145, 2015. @article{Henderson2015,During active scene perception, our eyes move from one location to another via saccadic eye movements, with the eyes fixating objects and scene elements for varying amounts of time. Much of the variability in fixation duration is accounted for by attentional, perceptual, and cognitive processes associated with scene analysis and comprehension. For this reason, current theories of active scene viewing attempt to account for the influence of attention and cognition on fixation duration. Yet almost nothing is known about the neurocognitive systems associated with variation in fixation duration during scene viewing. We addressed this topic using fixation-related fMRI, which involves coregistering high-resolution eye tracking and magnetic resonance scanning to conduct event-related fMRI analysis based on characteristics of eye movements. We observed that activation in visual and prefrontal executive control areas was positively correlated with fixation duration, whereas activation in ventral areas associated with scene en- coding and medial superior frontal and paracentral regions associated with changing action plans was negatively correlated with fixation duration. The results suggest that fixation duration in scene viewing is controlled by cognitive processes associated with real-time scene analysis interacting with motor planning, consistent with current computational models of active vision for scene perception. |
John M. Henderson; Wonil Choi; Steven G. Luke; Rutvik H. Desai Neural correlates of fixation duration in natural reading: Evidence from fixation-related fMRI Journal Article In: NeuroImage, vol. 119, pp. 390–397, 2015. @article{Henderson2015a,A key assumption of current theories of natural reading is that fixation duration reflects underlying attentional, language, and cognitive processes associated with text comprehension. The neurocognitive correlates of this relationship are currently unknown. To investigate this relationship, we compared neural activation associated with fixation duration in passage reading and a pseudo-reading control condition. The results showed that fixation duration was associated with activation in oculomotor and language areas during text reading. Fixation duration during pseudo-reading, on the other hand, showed greater involvement of frontal control regions, suggesting flexibility and task dependency of the eye movement network. Consistent with current models, these results provide support for the hypothesis that fixation duration in reading reflects attentional engagement and language processing. The results also demonstrate that fixation-related fMRI provides a method for investigating the neurocognitive bases of natural reading. |
Ehab W. Hermena; Denis Drieghe; Sam Hellmuth; Simon P. Liversedge Processing of Arabic diacritical marks: Phonological-syntactic disambiguation of homographic verbs and visual crowding effects Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 41, no. 2, pp. 494–507, 2015. @article{Hermena2015,Diacritics convey vowel sounds in Arabic, allowing accurate word pronunciation. Mostly, modern Arabic is printed nondiacritized. Otherwise, diacritics appear either only on homographic words when not disambiguated by surrounding text or on all words as in religious or educational texts. In an eye-tracking experiment, we examined sentence processing in the absence of diacritics and when diacritics were presented in either modes. Heterophonic homographic target verbs that have different pronunciations in active and passive were embedded in temporarily ambiguous sentences in which in the absence of diacritics, readers cannot be certain whether the verb was active or passive. Passive sentences were disambiguated by an extra word. Our results show that readers benefitted from the disambiguating diacritics when present only on the homographic verb. When disambiguating diacritics were absent, Arabic readers followed their parsing preference for active verb analysis, and garden path effects were observed. When reading fully diacritized sentences, readers incurred only a small cost, likely due to increased visual crowding, but did not extensively process the (mostly superfluous) diacritics, thus resulting in a lack of benefit from the disambiguating diacritics on the passive verb. |
Frouke Hermens Fixation instruction influences gaze cueing Journal Article In: Visual Cognition, vol. 23, no. 4, pp. 432–449, 2015. @article{Hermens2015a,Studies have shown that perceiving another person's gaze shift facilitates responses in the direction of the perceived gaze shift. While it is often assumed that participants in these experiments remain fixated on the cue in the cueing interval, eye gaze is not always recorded to confirm this. The data presented here suggest that the effect of gaze cues on responses to peripheral targets depends on whether participants make eye movements prior to the onset of the target. Participants who were required to fixate showed cueing effects at short cue-target intervals, but no cueing at later intervals. Participants who could look around, often chose to do so, and showed the same positive cueing effects at the shorter interval, but negative cueing effects (suggestive of inhibition of return) at the longer interval. |
Frouke Hermens In: Journal of Eye Movement Research, vol. 8, no. 1, pp. 1–17, 2015. @article{Hermens2015b,Whereas early studies of microsaccades have predominantly relied on custom-built eye trackers and manual tagging of microsaccades, more recent work tends to use video-based eye tracking and automated algorithms for microsaccade detection. While data from these newer studies suggest that microsaccades can be reliably detected with video-based systems, this has not been systematically evaluated. I here present a method and data examining microsaccade detection in an often used video-based system (the Eyelink II system) and a commonly used detection algorithm (Engbert & Kliegl, 2003; Engbert & Mergenthaler, 2006). Recordings from human participants and those obtained using a pair of dummy eyes, mounted on a pair of glasses either worn by a human participant (i.e., with head motion) or a dummy head (no head motion) were compared. Three experiments were conducted. The first experiment suggests that when microsaccade measurements make use of the pupil detection mode, microsaccade detections in the absence of eye movements are sparse in the absence of head movements, but frequent with head movements (despite the use of a chin rest). A second experiment demonstrates that by using measurements that rely on a combination of corneal reflection and pupil detection, false microsaccade detections can be largely avoided as long as a binocular criterion is used. A third experiment examines whether past results may have been affected by possible incorrect detections due to small head movements. It shows that despite the many detections due to head movements, the typical modulation of microsaccade rate after stimulus onset is found only when recording from the participants' eyes. |
Frouke Hermens; Sunčica Zdravković Information extraction from shadowed regions in images: An eye movement study Journal Article In: Vision Research, vol. 113, pp. 87–96, 2015. @article{Hermens2015,Natural scenes often contain variations in local luminance as a result of cast shadows and illumination from different directions. When making judgments about such scenes, it may be hypothesized that darker regions (with lower relative contrast due to a lack of illumination) are avoided as they may provide less detailed information than well-illuminated areas. We here test this hypothesis, first by presenting participants images of faces that were digitally modified to simulate the effect of a shadow over half of the image, and second by presenting photographs of faces taken with side illumination, also resulting in the appearance of a shadow across half of the face. While participants viewed these images, they were asked to perform different tasks on the images, to allow for the presentation of the different versions of each image (left shadow, right shadow, no shadow), and to distract the observers from the contrast and illumination manipulations. The results confirm our hypothesis and demonstrate that observers fixate the better illuminated regions of the images. |
Richard W. Hertle; Dongsheng Yang; Tonia Adkinson; Michael Reed Topical brinzolamide (Azopt) versus placebo in the treatment of infantile nystagmus syndrome (INS) Journal Article In: British Journal of Ophthalmology, vol. 99, no. 4, pp. 471–476, 2015. @article{Hertle2015,PURPOSE:To test the hypothesis that the topical carbonic anhydrase inhibitor brinzolamide (Azopt) has beneficial effects versus placebo on measures of nystagmus and visual acuity in adult subjects with infantile nystagmus syndrome (INS). DESIGN:Prospective, cross-over, double masked clinical trial. METHODS: SETTING:Single centre. STUDY POPULATION:Five subjects ≥18 years old with typical INS and best-binocular visual acuity in their primary position null zone ETDRS 55 letters to 85 letters (20/200 to 20/50) and had no previous treatment for nystagmus. INTERVENTION:In a randomised order, each subject received one drop of Azopt or placebo in both eyes three times a day separated by a washout period of at least a week followed by Azopt or placebo in both eyes three times a day; thus each subject got the drug and placebo, each acting as his or her own control. OUTCOME MEASURES:The nystagmus acuity function and INS waveforms obtained from eye movement recordings, binocular optotype visual acuity, using the ETDRS protocol analysed individually and as a group before and after Azopt and placebo. RESULTS:Versus placebo and baseline measures, topical Azopt significantly improved; INS waveform characteristics in the primary position null zone, group mean values of the nystagmus acuity function across gaze (p<0.01) and group mean ETDRS binocular letter visual acuity (p<0.05). There was a predictable decrease in intraocular pressure (IOP) without any systemic or ocular adverse events. CONCLUSIONS:Although a prospective large-scale clinical trial is needed to prove effectiveness, an eye-drop-based therapy for INS may emerge as a viable addition to optical, surgical, behavioural and systemic drug therapies for INS. |
Arvid Herwig; Katharina Weiß; Werner X. Schneider When circles become triangular: How transsaccadic predictions shape the perception of shape Journal Article In: Annals of the New York Academy of Sciences, vol. 1339, no. 1, pp. 97–105, 2015. @article{Herwig2015,Human vision is characterized by a consistent pattern of saccadic eye movements. With each saccade, internal object representations change their retinal position and spatial resolution. This raises the question as to how peripheral perception is affected by imminent saccadic eye movements. Here, we suggest that saccades are accompanied by a prediction of their perceptual consequences (i.e., the foveation of the target object). Accordingly, peripheral perception should be biased toward previously associated foveal input. In this study, we first exposed participants to an altered visual stimulation where one object systematically changed its shape during saccades. Subsequently, participants had to judge the shape of briefly presented peripheral saccade targets. The results showed that targets were perceived as less curved for objects that previously changed from more circular in the periphery to more triangular in the fovea. Similarly, shapes were perceived as more curved for objects that previously changed from triangular to circular. Thus, peripheral perception seems to depend not solely on the current input but also on memorized experiences, enabling predictions about the perceptual consequences of saccadic eye movements. |
Falk Huettig; Susanne Brouwer Delayed anticipatory spoken language processing in adults with dyslexia - Evidence from eye-tracking Journal Article In: Dyslexia, vol. 21, no. 2, pp. 97–122, 2015. @article{Huettig2015,It is now well established that anticipation of upcoming input is a key characteristic of spoken language comprehension. It has also frequently been observed that literacy influences spoken language processing. Here, we investigated whether anticipatory spoken language processing is related to individuals' word reading abilities. Dutch adults with dyslexia and a control group participated in two eye-tracking experiments. Experiment 1 was conducted to assess whether adults with dyslexia show the typical language-mediated eye gaze patterns. Eye movements of both adults with and without dyslexia closely replicated earlier research: spoken language is used to direct attention to relevant objects in the environment in a closely time-locked manner. In Experiment 2, participants received instructions (e.g., 'Kijk naar deCOM afgebeelde pianoCOM ', look at the displayed piano) while viewing four objects. Articles (Dutch 'het' or 'de') were gender marked such that the article agreed in gender only with the target, and thus, participants could use gender information from the article to predict the target object. The adults with dyslexia anticipated the target objects but much later than the controls. Moreover, participants' word reading scores correlated positively with their anticipatory eye movements. We conclude by discussing the mechanisms by which reading abilities may influence predictive language processing. |
Chia-Chun Hung; Cecil C. Yen; Jennifer L. Ciuchta; Daniel Papoti; Nicholas A. Bock; David A. Leopold; Afonso C. Silva Functional MRI of visual responses in the awake, behaving marmoset Journal Article In: NeuroImage, vol. 15, no. 120, pp. 1–11, 2015. @article{Hung2015,The visual brain is composed of interconnected subcortical and cortical structures that receive and process image information originating in the retina. The visual system of nonhuman primates, in particular macaques, has been studied in great detail in order to elucidate principles of human sensation and perception. The common marmoset (Callithrix jacchus) is a small New World monkey of growing interest as a primate model for neuroscience. Marmosets have advantages over macaques because of their small size, lissencephalic cortex, and growing potential for viral and genetic manipulations. Previous anatomical studies and electrophysiological recordings in anesthetized marmosets have shown that this species' cortical visual hierarchy closely resembles that of other primates, including humans. Until now, however, there have been no attempts to systematically study visual responses throughout the marmoset brain using fMRI. Here we show that awake marmosets readily learn to carry out a simple visual task inside the bore of an MRI scanner during functional mapping experiments. Functional scanning at 500μm in-plane resolution in a 30 cm horizontal bore at 7T revealed robust positive blood oxygenation level-dependent (BOLD) fMRI responses to visual stimuli throughout visual cortex and associated subcortical areas. Nonvisual sensory areas showed negative contrasts to visual stimuli compared to the fixation dot only baseline. Structured images of objects and faces led to stronger responses than scrambled control images at stages beyond early visual cortex. Our study establishes functionalMRI mapping of visual responses in awake, behaving marmosets is straightforward and valuable for assessing the functional organization of the primate brain at high resolution. |
Chia-Chun Hung; Cecil C. Yen; Jennifer L. Ciuchta; Daniel Papoti; Nicholas A. Bock; David A. Leopold; Afonso C. Silva Functional mapping of face-selective regions in the extrastriate visual cortex of the marmoset Journal Article In: Journal of Neuroscience, vol. 35, no. 3, pp. 1160–1172, 2015. @article{Hung2015a,The cerebral cortex of humans and macaques has specialized regions for processing faces and other visual stimulus categories. It is unknown whether a similar functional organization exists in New World monkeys, such as the common marmoset (Callithrix jacchus), a species of growing interest as a primate model in neuroscience. To address this question, we measured selective neural responses in the brain of four awake marmosets trained to fix their gaze upon images of faces, bodies, objects, and control patterns. In two of the subjects, we measured high gamma-range field potentials from electrocorticography arrays implanted over a large portion of the occipital and inferotemporal cortex. In the other two subjects, we measured BOLD fMRI responses across the entire brain. Both techniques revealed robust, regionally specific patterns of category-selective neural responses. We report that at least six face-selective patches mark the occipitotemporal pathway of the marmoset, with the most anterior patches showing the strongest preference for faces over other stimuli. The similar appearance of these patches to previous findings in macaques and humans, including their apparent arrangement in two parallel pathways, suggests that core elements of the face processing network were present in the common anthropoid primate ancestor living ∼35 million years ago. The findings also identify the marmoset as a viable animal model system for studying specialized neural mechanisms related to high-level social visual perception in humans. |
Tom Hunt; David Clark-Carter; David Sheffield Exploring the relationship between mathematics anxiety and performance: The role of intrusive thoughts Journal Article In: Journal of Education, Psychology and Social Sciences, vol. 29, pp. 226–231, 2015. @article{Hunt2015,The mechanisms underpinning the relationship between math anxiety and arithmetic performance are not fully understood. This study used an eye-tracking approach to measure a range of eye movements of 78 undergraduate students in response to performance on an arithmetic verification task. Results demonstrated a significant positive relationship between self-reported math anxiety and response time, indicating reduced processing efficiency. Analysis of eye-movement data reinforced the utility of an eye-tracking approach in studying arithmetic performance; specificdigit fixations, dwell time, saccades, and regressions all significantly predicted response time. Furthermore, findings highlighted significant positive correlations between math anxiety and fixations, dwell time, and saccades. Despite there being little evidence that eye move- ments mediate the math anxiety-to-performance relationship, relationships observed between math anxiety and eye movements provide a useful starting point for research using an eye-tracking methodology in studying math anxiety and performance; the present findings suggest future work should focus on calculation strategy. |
Heeju Hwang; Elsi Kaiser Accessibility effects on production vary cross-linguistically: Evidence from English and Korean Journal Article In: Journal of Memory and Language, vol. 84, pp. 190–204, 2015. @article{Hwang2015,Previous work on English suggests that accessibility of individual lexical items plays an important role in shaping speakers' choice of sentence structure, providing evidence for lexically incremental production. In order to investigate the role of accessibility in cross-linguistic production, we manipulated accessibility in English and Korean via semantic priming in Experiment 1 and visual cueing in Experiment 2. We recorded English and Korean speakers' speech and eye movements as they described pictured events. The production results show that English speakers' choice of sentence structure was significantly affected by semantic priming or visual cueing, consistent with the findings of prior research: Priming the patient entity significantly increased the production of passive sentences. In contrast, Korean speakers' choice of sentence structure was not influenced by accessibility of lexical items. Analyses of participants' eye-movements are consistent with the production results. In Experiment 1, English speakers fixated the semantically primed entity in the visual scene, whereas Korean speakers did not. Even when the visual cueing manipulation drew Korean speakers' focus of attention toward the cued entity in Experiment 2, Korean speakers' choice of the first referent was not influenced by the lexical accessibility. These findings strongly suggest that lexically incremental production is not a universal production mechanism. In light of the typological differences between English and Korean, we suggest that the relative contributions of accessibility during language production are mediated by the grammatical constraints of a language. |
Ignace T. C. Hooge; Marcus Nyström; Tim H. W. Cornelissen; Kenneth Holmqvist The art of braking: Post saccadic oscillations in the eye tracker signal decrease with increasing saccade size Journal Article In: Vision Research, vol. 112, pp. 55–67, 2015. @article{Hooge2015,Recent research has shown that the pupil signal from video-based eye trackers contains post saccadic oscillations (PSOs). These reflect pupil motion relative to the limbus (Nyström, Hooge, & Holmqvist, 2013). More knowledge about video-based eye tracker signals is essential to allow comparison between the findings obtained from modern systems, and those of older eye tracking technologies (e.g. coils and measurement of the Dual Purkinje Image-DPI). We investigated PSOs in horizontal and vertical saccades of different sizes with two high quality video eye trackers. PSOs were very similar within observers, but not between observers. PSO amplitude decreased with increasing saccade size, and this effect was even stronger in vertical saccades; PSOs were almost absent in large vertical saccades. Based on this observation we conclude that the occurrence of PSOs is related to deceleration at the end of a saccade. That PSOs are saccade size dependent and idiosyncratic is a problem for algorithmic determination of saccade endings. Careful description of the eye tracker, its signal, and the procedure used to extract saccades is required to enable researchers to compare data from different eye trackers. |
Jörn M. Horschig; Wouter Oosterheert; Robert Oostenveld; Ole Jensen Modulation of posterior alpha activity by spatial attention allows for controlling a continuous brain–computer interface Journal Article In: Brain Topography, vol. 28, no. 6, pp. 852–864, 2015. @article{Horschig2015,Here we report that the modulation of alpha activity by covert attention can be used as a control signal in an online brain-computer interface, that it is reliable, and that it is robust. Subjects were instructed to orient covert visual attention to the left or right hemifield. We decoded the direction of attention from the magnetoencephalogram by a template matching classifier and provided the classification outcome to the subject in real-time using a novel graphical user interface. Training data for the templates were obtained from a Posner-cueing task conducted just before the BCI task. Eleven subjects participated in four sessions each. Eight of the subjects achieved classification rates significantly above chance level. Subjects were able to significantly increase their performance from the first to the second session. Individual patterns of posterior alpha power remained stable throughout the four sessions and did not change with increased performance. We conclude that posterior alpha power can successfully be used as a control signal in brain-computer interfaces. We also discuss several ideas for further improving the setup and propose future research based on solid hypotheses about behavioral consequences of modulating neuronal oscillations by brain computer interfacing. |
Gernot Horstmann; Arvid Herwig Surprise attracts the eyes and binds the gaze Journal Article In: Psychonomic Bulletin & Review, vol. 22, no. 3, pp. 743–749, 2015. @article{Horstmann2015,In recent years, researchers have become increasingly interested in the effects that deviations fromexpectations have on cognitive processing and, in particular, on the deployment of attention. Previous evidence for a surprise–attention link had been based on indirect measures of attention allocation. Here we used eyetracking to directly observe the impact of a novel color on its unannounced first presentation, which we regarded as a surprise condition. The results show that the novel color was quickly responded to with an eye movement, and that gaze was not turned away for a considerable amount of time. These results are direct evidence that deviations from expectations bias attentional priorities and lead to enhanced processing of the deviating stimulus. |
Michael C. Hout; Stephen D. Goldinger Target templates: The precision of mental representations affects attentional guidance and decision-making in visual search Journal Article In: Attention, Perception, & Psychophysics, vol. 77, no. 1, pp. 128–149, 2015. @article{Hout2015,When people look for things in the environment, they use target templates—mental representations of the objects they are attempting to locate—to guide attention and to assess incoming visual input as potential targets. However, unlike laboratory participants, searchers in the real world rarely have perfect knowledge regarding the potential appearance of targets. In seven experiments, we examined how the precision of target templates affects the ability to conduct visual search. Specifically, we degraded template precision in two ways: 1) by contaminating searchers' templateswith inaccurate features, and 2) by introducing extraneous features to the template that were unhelpful.We recorded eye movements to allow inferences regarding the relative extents to which attentional guidance and decision-making are hindered by template imprecision. Our findings support a dual-function theory of the target template and highlight the importance of examining template precision in visual search. |
Michael C. Hout; Stephen C. Walenchok; Stephen D. Goldinger; Jeremy M. Wolfe Failures of perception in the low-prevalence effect: Evidence from active and passive visual search Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 41, no. 4, pp. 977–994, 2015. @article{Hout2015a,In visual search, rare targets are missed disproportionately often. This low-prevalence effect (LPE) is a robust problem with demonstrable societal consequences. What is the source of the LPE? Is it a perceptual bias against rare targets or a later process, such as premature search termination or motor response errors? In 4 experiments, we examined the LPE using standard visual search (with eye tracking) and 2 variants of rapid serial visual presentation (RSVP) in which observers made present/absent decisions after sequences ended. In all experiments, observers looked for 2 target categories (teddy bear and butterfly) simultaneously. To minimize simple motor errors, caused by repetitive absent responses, we held overall target prevalence at 50%, with 1 low-prevalence and 1 high-prevalence target type. Across conditions, observers either searched for targets among other real-world objects or searched for specific bears or butterflies among within-category distractors. We report 4 main results: (a) In standard search, high-prevalence targets were found more quickly and accurately than low-prevalence targets. (b) The LPE persisted in RSVP search, even though observers never terminated search on their own. (c) Eye-tracking analyses showed that high-prevalence targets elicited better attentional guidance and faster perceptual decisions. And (d) even when observers looked directly at low-prevalence targets, they often (12%-34% of trials) failed to detect them. These results strongly argue that low-prevalence misses represent failures of perception when early search termination or motor errors are controlled. |
Yufen Hsieh; Julie E. Boland Semantic support and parallel parsing in Chinese Journal Article In: Journal of Psycholinguistic Research, vol. 44, no. 3, pp. 251–276, 2015. @article{Hsieh2015,Two eye-tracking experiments were conducted using written Chinese sentences that contained a multi-word ambiguous region. The goal was to determine whether readers maintained multiple interpretations throughout the ambiguous region or selected a single interpretation at the point of ambiguity. Within the ambiguous region, we manipulated the strength of support for the complement clause (CC) analysis and the relative clause (RC) analysis of the ambiguous construction Verb NP1 de NP2. In Experiment 1, the critical sentences were disambiguated to the dispreferred CC interpretation; in Experiment 2, the sentences were disambiguated as the preferred RC interpretation. Unsurprisingly, processing difficulty at the point of disambiguation was observed only in Experiment 1. As predicted by a parallel mechanism, greater processing difficulty arose at disambiguation when the RC interpretation was much more strongly supported by semantic cues relative to the CC alternative, than when the two analyses were semantically supported to a similar degree. Regression analyses confirmed that the degree of semantic support predicted processing difficulty at disambiguation. The findings provide evidence for a parallel constraint-based parsing mechanism. |
Tai-Hsiang Huang; Su-Ling Yeh; Yung-Hao Yang; Hsin-I Liao; Ya-Yeh Tsai; Pai-Ju Chang; Homer H. Chen Method and experiments of subliminal cueing for real-world images Journal Article In: Multimedia Tools and Applications, vol. 74, no. 22, pp. 10111–10135, 2015. @article{Huang2015,Unconscious attention shift triggered by a subliminal cue has been shown to be automatic; however, whether it can be brought into effect for images of real-world scenes remains to be investigated. We present a subliminal cueing method that flashes briefly a visual cue before presenting a real-world image to the viewer. The effectiveness of the method is verified by experiments using three types of cues (spatial cue, face cue, and object cue) of varied durations. Results show that depending on the cue type, the viewer's visual attention is directed to the cued visual hemifield or the cued location without engaging the viewer's awareness. The experiments demonstrate that a brief subliminal cue presented prior to the color image of a real-world complex scene can attract human visual attention. The method is useful for many applications that require efficient, unresisting attention shift to a target image area. |
Stefan Huber; Sonja Cornelsen; Korbinian Moeller; Hans-Christoph Nuerk Toward a model framework of generalized parallel componential processing of multi-symbol numbers Journal Article In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 41, no. 3, pp. 732–745, 2015. @article{Huber2015,In this article, we propose and evaluate a new model framework of parallel componential multi-symbol number processing, generalizing the idea of parallel componential processing of multi-digit numbers to the case of negative numbers by considering the polarity signs similar to single digits. In a first step, we evaluated this account by defining and investigating a sign-decade compatibility effect for the comparison of positive and negative numbers, which extends the unit-decade compatibility effect in 2-digit number processing. Then, we evaluated whether the model is capable of accounting for previous findings in negative number processing. In a magnitude comparison task, in which participants had to single out the larger of 2 integers, we observed a reliable sign-decade compatibility effect with prolonged reaction times for incompatible (e.g., −97 vs. +53; in which the number with the larger decade digit has the smaller, i.e., negative polarity sign) as compared with sign-decade compatible number pairs (e.g., −53 vs. +97). Moreover, an analysis of participants' eye fixation behavior corroborated our model of parallel componential processing of multi-symbol numbers. These results are discussed in light of concurrent theoretical notions about negative number processing. On the basis of the present results, we propose a generalized integrated model framework of parallel componential multi-symbol processing. |
Matthew Haigh; Jean François Bonnefon Conditional sentences create a blind spot in theory of mind during narrative comprehension Journal Article In: Acta Psychologica, vol. 160, pp. 194–201, 2015. @article{Haigh2015a,We identify a blind spot in the early Theory of Mind processing of conditional sentences that describe a protagonist's potential action, and its predictable consequences. We propose that such sentences create expectations through two independent channels. A decision theoretic channel creates an expectation that the action will be taken (viz., not taken) if it has desirable (viz., undesirable) consequences, but a structural channel acts in parallel to create an expectation that the action will be taken, irrespective of desirability. Accordingly, reading should be disrupted when a protagonist avoids an action with desirable consequences, but reading should not be disrupted when a protagonist takes an action with undesirable consequences. This prediction was supported by the eye movements of participants reading systematically varied vignettes. Reading was always disrupted when the protagonist avoided an action with desirable consequences, but disruptions were either delayed (Experiment 1) or recovered from faster (Experiment 2) when the protagonist took an action with undesirable consequences. |
Matthew Haigh; Jean François Bonnefon Eye movements reveal how readers infer intentions from the beliefs and desires of others Journal Article In: Experimental Psychology, vol. 62, no. 3, pp. 206–213, 2015. @article{Haigh2015,We examine how the beliefs and desires of a protagonist are used by readers to predict their intentions as a narrative vignette unfolds. Eye movement measures revealed that readers rapidly inferred an intention when the protagonist desired an outcome, even when this inference was not licensed by the protagonist's belief state. Reading was immediately disrupted when participants encountered a described action that contradicted this inference. During intermediate processing, desire inferences were moderated by the protagonist's belief state. Effects that emerged later in the text were again driven solely by the protagonist's desires. These data suggest that desire-based inferences are initially drawn irrespective of belief state, but are then quickly inhibited if not licensed by relevant beliefs. This inhibition of desire-based inferences may be an effortful process as it was not systematically sustained in later steps of processing. |
Tuomo Häikiö; Jukka Hyönä; Raymond Bertram The role of syllables in word recognition among beginning Finnish readers: Evidence from eye movements during reading Journal Article In: Journal of Cognitive Psychology, vol. 27, no. 5, pp. 562–577, 2015. @article{Haeikioe2015,The eye movements of Finnish first and second graders were monitored as they read sentences where polysyllabic words were either hyphenated at syllable boundaries, alternatingly coloured (every second syllable black, every second red) or had no explicit syllable boundary cues (e.g., ta-lo vs. talo vs. talo = “house”). The results showed that hyphenation at syllable boundaries slows down reading of first and second graders even though syllabification by hyphens is very common in Finnish reading instruction, as all first-grade textbooks include hyphens at syllable boundaries. When hyphens were positioned within a syllable (t-alo vs. ta-lo), beginning readers were even more disrupted. Alternate colouring did not affect reading speed, no matter whether colours signalled syllable structure or not. The results show that beginning Finnish readers prefer to process polysyllabic words via syllables rather than letter by letter. At the same time they imply that hyphenation encourages sequential syllable processing, which slows down the reading of children, who are already capable of parallel syllable processing or recognising words directly via the whole-word route. |
Harry H. Haladjian; Ella Wufong; Tamara L. Watson Spatial compression: Dissociable effects at the time of saccades and blinks Journal Article In: Journal of Vision, vol. 15, no. 9, pp. 1–19, 2015. @article{Haladjian2015,Various studies have identified systematic errors, such as spatial compression, when observers report the locations of objects displayed around the time of saccades. Localization errors also occur when holding spatial representations in visual working memory. Such errors, however, have not been examined in the context of eye blinks. In this study, we examined the effects of blinks and saccades when observers reproduced the locations of a set of briefly presented, randomly placed discs. Performance was compared with a fixation-only condition in which observers simply held these representations in working memory for the same duration; this allowed us to elucidate the relationship between the perceptual phenomena related to blinks, saccades, and visual working memory. Our results indicate that the same amount of spatial compression is experienced prior to a blink as is experienced in the control fixation-only condition, suggesting that blinks do not increase compression above that occurring from holding a spatial representation in visual memory. Saccades, however, tend to increase these compression effects and produce translational shifts both toward and away from saccade targets (depending on the time of the saccade onset in relation to the stimulus offset). A higher numerosity recall capacity was also observed when stimuli were presented prior to a blink in comparison with the other conditions. These findings reflect key differences underlying blinks and saccades in terms of spatial compression and translational shifts. Such results suggest that separate mechanisms maintain perceptual stability across these visual events. |
Shahrbanoo Hamel; Dominique Houzet; Denis Pellerin; Nathalie Guyader Does color influence eye movements while exploring videos? Journal Article In: Journal of Eye Movement Research, vol. 8, no. 1, pp. 1–10, 2015. @article{Hamel2015,Although visual attention studies consider color as one of the most important features in guiding visual attention, few studies have investigated how color influences eye movements while viewing natural scenes without any particular task. To better understand the visual features that drive attention, the aim of this paper was to quantify the influence of color on eye movements when viewing dynamic natural scenes. The influence of color was investigated by comparing the eye positions of several observers eye-tracked while viewing video stimuli in two conditions: color and grayscale. The comparison was made using the dispersion between the eye positions of observers, the number of attractive regions measured with a clustering method applied to the eye positions, and by comparing eye positions to the predictions of a saliency model. The mean amplitude of saccades and the mean duration of fixations were compared as well. Globally, a slight influence of color on eye movements was measured; only the number of attractive regions for color stimuli was slightly higher than for grayscale stimuli. However, a luminance-based saliency model predicts the eye positions for color stimuli as efficiently as for grayscale stimuli. |
Bruce C. Hansen; Pamela J. Rakhshan; Arnold K. Ho; Sebastian Pannasch Looking at others through implicitly or explicitly prejudiced eyes Journal Article In: Visual Cognition, vol. 23, no. 5, pp. 612–642, 2015. @article{Hansen2015,It is well known that we utilize internalized representations (or schemas) to direct our eyes when exploring visual stimuli. Interestingly, our schemas for human faces are known to reflect systematic differences that are consistent with one's level of racial prejudice. However, whether one's level or type of racial prejudice can differentially regulate how we visually explore faces that are the target of prejudice is currently unknown. Here, White participants varying in their level of implicit or explicit prejudice viewed Black faces and White faces (with the latter serving as a control) while having their gaze behaviour recorded with an eye-tracker. The results show that, regardless of prejudice type (i.e., implicit or explicit), participants high in racial prejudice examine faces differently than those low in racial prejudice. Specifically, individuals high in explicit racial prejudice were more likely to fixate on the mouth region of Black faces when compared to individuals low in explicit prejudice, and exhibited less consistency in their scanning of faces irrespective of race. On the other hand, individuals high in implicit racial prejudice tended to focus on the region between the eyes, regardless of face race. It therefore seems that racial prejudice guides target-race specific patterns of looking behaviour, and may also contribute to general patterns oflooking behaviour when visually exploring human faces. |
Anthony M. Harris; Stefanie I. Becker; Roger W. Remington Capture by colour: Evidence for dimension-specific singleton capture Journal Article In: Attention, Perception, & Psychophysics, vol. 77, no. 7, pp. 2305–2321, 2015. @article{Harris2015a,Previous work on attentional capture has shown the attentional system to be quite flexible in the stimulus properties it can be set to respond to. Several different attentional "modes" have been identified. Feature search mode allows attention to be set for specific features of a target (e.g., red). Singleton detection mode sets attention to respond to any discrepant item ("singleton") in the display. Relational search sets attention for the relative properties of the target in relation to the distractors (e.g., redder, larger). Recently, a new attentional mode was proposed that sets attention to respond to any singleton within a particular feature dimension (e.g., colour; Folk & Anderson, 2010). We tested this proposal against the predictions of previously established attentional modes. In a spatial cueing paradigm, participants searched for a colour target that was randomly either red or green. The nature of the attentional control setting was probed by presenting an irrelevant singleton cue prior to the target display and assessing whether it attracted attention. In all experiments, the cues were red, green, blue, or a white stimulus rapidly rotated (motion cue). The results of three experiments support the existence of a "colour singleton set," finding that all colour cues captured attention strongly, while motion cues captured attention only weakly or not at all. Notably, we also found that capture by motion cues in search for colour targets was moderated by their frequency; rare motion cues captured attention (weakly), while frequent motion cues did not. |
Jesse A. Harris Structure modulates similarity-based interference in sluicing: An eye tracking study Journal Article In: Frontiers in Psychology, vol. 6, pp. 1839, 2015. @article{Harris2015,In cue-based content-addressable approaches to memory, a target and its competitors are retrieved in parallel from memory via a fast, associative cue-matching procedure under a severely limited focus of attention. Such a parallel matching procedure could in principle ignore the serial order or hierarchical structure characteristic of linguistic relations. I present an eye tracking while reading experiment that investigates whether the sentential position of a potential antecedent modulates the strength of similarity-based interference, a well-studied effect in which increased similarity in features between a target and its competitors results in slower and less accurate retrieval overall. The manipulation trades on an independently established Locality bias in sluiced structures to associate a wh-remnant (which ones) in clausal ellipsis with the most local correlate (some wines), as in "The tourists enjoyed some wines, but I don't know which ones." The findings generally support cue-based parsing models of sentence processing that are subject to similarity-based interference in retrieval, and provide additional support to the growing body of evidence that retrieval is sensitive to both the structural position of a target antecedent and its competitors, and the specificity of retrieval cues. |
Jonathan W. Harris; Christopher D. Cowper-Smith; Raymond M. Klein; David A. Westwood Further evidence against a momentum explanation for IOR Journal Article In: PLoS ONE, vol. 10, no. 4, pp. e0123666, 2015. @article{Harris2015b,Reaction times to targets presented in the same location as a preceding cue are greater than those to targets presented opposite the cued location. This observation can be explained as a result of inhibition at the attended location (IOR), or as facilitation at the location opposite the cue (opposite facilitation effect or OFE). Past research has demonstrated that IOR is observed reliably, whereas OFE is observed only occasionally. The present series of four experiments allows us to determine whether or not OFE can be explained by eye movements as suggested by previous authors. Participants' eye movements were monitored as they were presented with an array of four placeholders aligned with the four cardinal axes. Exogenous cues and targets were presented successively. Participants (N=37) completed either: i.) cue-manual and cue-saccade experiments, ignoring the cue and then responding with a keypress or saccade, respectively, or ii.) manual-manual and saccade-saccade experiments, responding to both the cue and the target with a keypress or saccade respectively. Results demonstrated a reliable IOR effect in each of the four experiments (reaction time greater for same versus adjacent and opposite cue-target trials). None of the four experiments demonstrated evidence of an OFE (reaction times were not significantly lower for opposite versus adjacent cue-target trials). These results are inconsistent with a momentum-based account of cue-target task performance, and furthermore suggest that the OFE cannot be attributed to occasional eye movements to the cue and/or target in previous studies. |
James J. Harrison; Tom C. A. Freeman; Petroc Sumner Saccadic compensation for reflexive optokinetic nystagmus just as good as compensation for volitional pursuit Journal Article In: Journal of Vision, vol. 15, no. 1, pp. 1–13, 2015. @article{Harrison2015a,The natural viewing behavior of moving observers ideally requires target-selecting saccades to be coordinated with automatic gaze-stabilizing eye movements such as optokinetic nystagmus. However, it is unknown whether saccade plans can compensate for reflexive movement of the eye during the variable saccade latency period, and it is unclear whether reflexive nystagmus is even accompanied by extraretinal signals carrying the eye movement information that could potentially underpin such compensation. We show that saccades do partially compensate for optokinetic nystagmus that displaces the eye during the saccade latency period. Moreover, this compensation is as good as for displacements due to voluntary smooth pursuit. In other words, the saccade system appears to be as well coordinated with reflexive nystagmus as it is with volitional pursuit, which in turn implies that extraretinal signals accompany nystagmus and are just as informative as those accompanying pursuit. |
James J. Harrison; Petroc Sumner; Matt J. Dunn; Jonathan T. Erichsen; Tom C. A. Freeman Quick phases of infantile nystagmus show the saccadic inhibition effect Journal Article In: Investigative Ophthalmology & Visual Science, vol. 56, no. 3, pp. 1594–1600, 2015. @article{Harrison2015,PURPOSE: Infantile nystagmus (IN) is a pathological, involuntary oscillation of the eyes consisting of slow, drifting eye movements interspersed with rapid reorienting quick phases. The extent to which quick phases of IN are programmed similarly to saccadic eye movements remains unknown. We investigated whether IN quick phases exhibit 'saccadic inhibition,' a phenomenon typically related to normal targeting saccades, in which the initiation of the eye movement is systematically delayed by task-irrelevant visual distractors. METHODS: We recorded eye position from 10 observers with early-onset idiopathic nystagmus while task-irrelevant distractor stimuli were flashed along the top and bottom of a large screen at ±10° eccentricity. The latency distributions of quick phases were measured with respect to these distractor flashes. Two additional participants, one with possible albinism and one with fusion maldevelopment nystagmus syndrome, were also tested. RESULTS: All observers showed that a distractor flash delayed the execution of quick phases that would otherwise have occurred approximately 100 ms later, exactly as in the standard saccadic inhibition effect. The delay did not appear to differ between the two main nystagmus types under investigation (idiopathic IN with unidirectional and bidirectional jerk). CONCLUSIONS: The presence of the saccadic inhibition effect in IN quick phases is consistent with the idea that quick phases and saccades share a common programming pathway. This could allow quick phases to take on flexible, goal-directed behavior, at odds with the view that IN quick phases are stereotyped, involuntary eye movements. |
Ameqrane Ilhame; Wattiez Nicolas; Pouget Pierre; Missal Marcus A subanesthetic dose of ketamine in the Rhesus monkey reduces the occurrence of anticipatory saccades Journal Article In: Psychopharmacology, vol. 232, no. 19, pp. 3563–3572, 2015. @article{Ilhame2015,RATIONALE: It has been shown that antagonism of the glutamatergic N-methyl-D-aspartate (NMDA) receptor with subanesthetic doses of ketamine perturbs the perception of elapsed time. Anticipatory eye movements are based on an internal representation of elapsed time. Therefore, the occurrence of anticipatory saccades could be a particularly sensitive indicator of abnormal time perception due to NMDA receptors blockade. OBJECTIVES: The objective of this study was to determine whether the occurrence of anticipatory saccades could be selectively altered by a subanesthetic dose of ketamine. METHODS: Three Rhesus monkeys were trained in a simple visually guided saccadic task with a variable delay. Monkeys were rewarded for making a visually guided saccade at the end of the delay. Premature anticipatory saccades to the future position of the eccentric target initiated before the end of the delay were not rewarded. A subanesthetic dose of ketamine (0.25 mg/kg) or a saline solution of the same volume was injected i.m. during the task. RESULTS: We found that the injected dose of ketamine did not induce sedation or abnormal behavior. However, in ∼4 min, ketamine induced a strong reduction of the occurrence of anticipatory saccades but did not reduce the occurrence of visually guided saccades. CONCLUSION: This unexpected reduction of anticipatory saccade occurrence could be interpreted as resulting from an altered use of the perception of elapsed time during the delay period induced by NMDA receptors antagonism. |
David E. Irwin; Maria M. Robinson Detection of stimulus displacements across saccades is capacity-limited and biased in favor of the saccade target Journal Article In: Frontiers in Systems Neuroscience, vol. 9, pp. 161, 2015. @article{Irwin2015,Retinal image displacements caused by saccadic eye movements are generally unnoticed. Recent theories have proposed that perceptual stability across saccades depends on a local evaluation process centered on the saccade target object rather than on remapping and evaluating the positions of all objects in a display. In three experiments, we examined whether objects other than the saccade target also influence perceptual stability by measuring displacement detection thresholds across saccades for saccade targets and a variable number of non-saccade objects. We found that the positions of multiple objects are maintained across saccades, but with variable precision, with the saccade target object having priority in the perception of displacement, most likely because it is the focus of attention before the saccade and resides near the fovea after the saccade. The perception of displacement of objects that are not the saccade target is affected by acuity limitations, attentional limitations, and limitations on memory capacity. Unlike previous studies that have found that a postsaccadic blank improves the detection of displacement direction across saccades, we found that postsaccadic blanking hurt the detection of displacement per se by increasing false alarms. Overall, our results are consistent with the hypothesis that visual working memory underlies the perception of stability across saccades. |
Inbal Itzhak; Shari R. Baum Misleading bias-driven expectations in referential processing and the facilitative role of contrastive accent Journal Article In: Journal of Psycholinguistic Research, vol. 44, no. 5, pp. 623–650, 2015. @article{Itzhak2015,Probabilistic preferences are often facilitative in language processing and may assist in discourse prediction. However, occasionally these sources of information may lead to inaccurate expectations. The current study investigated a test case of this scenario. An eye-tracking experiment examined the interpretation of ambiguous personal pronouns in the context of implicit causality biases. We tested whether reference resolution may be facilitated online by contrastive accent in cases of a bias-inconsistent referent. Implicit causality biases directed looks to the biased noun phrase; however, when the name of the bias-inconsistent antecedent was accented (e.g., JOHN envied Bill because he [Formula: see text]), this tendency was modulated. Contrastive accent seems to dampen the occasionally confusing prediction of implicit causality biases in referential processing. This demonstrates one way in which the spoken language comprehension system copes with occasional misguidance of otherwise helpful probabilistic information. |
Lena A. Jäger; Lena Benz; Jens Roeser; Brian W. Dillon; Shravan Vasishth Teasing apart retrieval and encoding interference in the processing of anaphors Journal Article In: Frontiers in Psychology, vol. 6, pp. 506, 2015. @article{Jaeger2015,Two classes of account have been proposed to explain the memory processes subserving the processing of reflexive-antecedent dependencies. Structure-based accounts assume that the retrieval of the antecedent is guided by syntactic tree-configurational information without considering other kinds of information such as gender marking in the case of English reflexives. By contrast, unconstrained cue-based retrieval assumes that all available information is used for retrieving the antecedent. Similarity-based interference effects from structurally illicit distractors which match a non-structural retrieval cue have been interpreted as evidence favoring the unconstrained cue-based retrieval account since cue-based retrieval interference from structurally illicit distractors is incompatible with the structure-based account. However, it has been argued that the observed effects do not necessarily reflect interference occurring at the moment of retrieval but might equally well be accounted for by interference occurring already at the stage of encoding or maintaining the antecedent in memory, in which case they cannot be taken as evidence against the structure-based account. We present three experiments (self-paced reading and eye-tracking) on German reflexives and Swedish reflexive and pronominal possessives in which we pit the predictions of encoding interference and cue-based retrieval interference against each other. We could not find any indication that encoding interference affects the processing ease of the reflexive-antecedent dependency formation. Thus, there is no evidence that encoding interference might be the explanation for the interference effects observed in previous work. We therefore conclude that invoking encoding interference may not be a plausible way to reconcile interference effects with a structure-based account of reflexive processing. |
Lena A. Jäger; Zhong Chen; Qiang Li; Chien-Jer Charles Lin; Shravan Vasishth The subject-relative advantage in Chinese: Evidence for expectation-based processing Journal Article In: Journal of Memory and Language, vol. 79-80, pp. 97–120, 2015. @article{Jaeger2015a,Chinese relative clauses are an important test case for pitting the predictions of expectation-based accounts against those of memory-based theories. The memory-based accounts predict that object relatives are easier to process than subject relatives because, in object relatives, the distance between the relative clause verb and the head noun is shorter. By contrast, expectation-based accounts such as surprisal predict that the less frequent object relative should be harder to process. In previous studies on Chinese relative clause comprehension, local ambiguities may have rendered a comparison between relative clause types uninterpretable. We designed experimental materials in which no local ambiguities confound the comparison. We ran two experiments (self-paced reading and eye-tracking) to compare reading difficulty in subject and object relatives which were placed either in subject or object modifying position. The evidence from our studies is consistent with the predictions of expectation-based accounts but not with those of memory-based theories. |
Lena A. Jäger; Felix Engelmann; Shravan Vasishth Retrieval interference in reflexive processing: Experimental evidence from Mandarin, and computational modeling Journal Article In: Frontiers in Psychology, vol. 6, pp. 617, 2015. @article{Jaeger2015b,We conducted two eye-tracking experiments investigating the processing of the Mandarin reflexive ziji in order to tease apart structurally constrained accounts from standard cue-based accounts of memory retrieval. In both experiments, we tested whether structurally inaccessible distractors that fulfill the animacy requirement of ziji influence processing times at the reflexive. In Experiment 1, we manipulated animacy of the antecedent and a structurally inaccessible distractor intervening between the antecedent and the reflexive. In conditions where the accessible antecedent mismatched the animacy cue, we found inhibitory interference whereas in antecedent-match conditions, no effect of the distractor was observed. In Experiment 2, we tested only antecedent-match configurations and manipulated locality of the reflexive-antecedent binding (Mandarin allows non-local binding). Participants were asked to hold three distractors (animate vs. inanimate nouns) in memory while reading the target sentence. We found slower reading times when animate distractors were held in memory (inhibitory interference). Moreover, we replicated the locality effect reported in previous studies. These results are incompatible with structure-based accounts. However, the cue-based ACT-R model of Lewis and Vasishth (2005) cannot explain the observed pattern either. We therefore extend the original ACT-R model and show how this model not only explains the data presented in this article, but is also able to account for previously unexplained patterns in the literature on reflexive processing. |
Sharna D. Jamadar; Beth P. Johnson; Meaghan Clough; Gary F. Egan; Joanne Fielding Behavioral and neural plasticity of ocular motor control: Changes in performance and fMRI activity following antisaccade training Journal Article In: Frontiers in Human Neuroscience, vol. 9, no. 653, pp. 1–13, 2015. @article{Jamadar2015,The antisaccade task provides a model paradigm that sets the inhibition of a reflexively driven behavior against the volitional control of a goal-directed behavior. The stability and adaptability of antisaccade performance was investigated in 23 neurologically healthy individuals. Behavior and brain function were measured using functional magnetic resonance imaging (fMRI) prior to and immediately following 2 weeks of daily antisaccade training. Participants performed antisaccade trials faster with no change in directional error rate following 2 weeks of training; however this increased speed came at the cost of the spatial accuracy of the saccade (gain) which became more hypometric following training. Training on the antisaccade task resulted in increases in fMRI activity in the fronto-basal ganglia-parietal-cerebellar ocular motor network. Following training, antisaccade latency was positively associated with fMRI activity in the frontal and supplementary eye fields, anterior cingulate and intraparietal sulcus; antisaccade gain was negatively associated with fMRI activity in supplementary eye fields, anterior cingulate, intraparietal sulcus, and cerebellar vermis. In sum, the results suggest that following training, larger antisaccade latency is associated with larger activity in fronto-parietal-cerebellar ocular motor regions, and smaller antisaccade gain is associated with larger activity in fronto-parietal ocular motor regions. |
Christian P. Janssen; Preeti Verghese Stop before you saccade: Looking into an artificial peripheral scotoma Journal Article In: Journal of Vision, vol. 15, no. 5, pp. 1–19, 2015. @article{Janssen2015,We investigated whether adults with healthy vision can move their eyes toward an informative target area that is initially hidden by a gaze-contingent scotoma in the periphery when they are under time pressure. In the experimental task, participants had to perform an object-comparison task requiring a same-different judgment about two silhouettes. One silhouette was visible, whereas the other was hidden under the scotoma. Despite time pressure and the presence of the visible silhouette, most participants were able to move their eyes toward the informative region to reveal the hidden silhouette. Saccades to the hidden stimulus occurred when the visible stimulus was presented directly opposite in either fixed or variable locations and when the visible stimulus was presented at an adjacent location. Older participants were also able to perform this task. First saccades in the direction of the hidden stimulus had longer latencies compared with saccades toward the visible stimulus. This suggests the use of a deliberate, nonreflexive saccade strategy ("stop before you saccade"). A subset of participants occasionally made curved saccades that were aimed first toward the visible stimulus and then toward the hidden stimulus. We discuss the implications of our findings for patients who have a biological scotoma, for example, in macular degeneration. |
Malou Janssen; Britta K. Ischebeck; Jurryt De Vries; Gert Jan Kleinrensink; Maarten A. Frens; Josef N. Geest Smooth pursuit eye movement deficits in patients with whiplash and neck pain are modulated by target predictability Journal Article In: Spine, vol. 40, no. 19, pp. E1052–E1057, 2015. @article{Janssen2015a,STUDY DESIGN This is a cross-sectional study. OBJECTIVE The purpose of this study is to support and extend previous observations on oculomotor disturbances in patients with neck pain and whiplash-associated disorders (WADs) by systematically investigating the effect of static neck torsion on smooth pursuit in response to both predictably and unpredictably moving targets using video-oculography. SUMMARY OF BACKGROUND DATA Previous studies showed that in patients with neck complaints, for instance due to WAD, extreme static neck torsion deteriorates smooth pursuit eye movements in response to predictably moving targets compared with healthy controls. METHODS Eye movements in response to a smoothly moving target were recorded with video-oculography in a heterogeneous group of 55 patients with neck pain (including 11 patients with WAD) and 20 healthy controls. Smooth pursuit performance was determined while the trunk was fixed in 7 static rotations relative to the head (from 45° to the left to 45° to right), using both predictably and unpredictably moving stimuli. RESULTS Patients had reduced smooth pursuit gains and smooth pursuit gain decreased due to neck torsion. Healthy controls showed higher gains for predictably moving targets compared with unpredictably moving targets, whereas patients with neck pain had similar gains in response to both types of target movements. In 11 patients with WAD, increased neck torsion decreased smooth pursuit performance, but only for predictably moving targets. CONCLUSION Smooth pursuit of patients with neck pain is affected. The previously reported WAD-specific decline in smooth pursuit due to increased neck torsion seems to be modulated by the predictability of the movement of the target. The observed oculomotor disturbances in patients with WAD are therefore unlikely to be induced by impaired neck proprioception alone. LEVEL OF EVIDENCE 3. |
Tommaso Mastropasqua; Jessica Galliussi; David Pascucci; Massimo Turatto Location transfer of perceptual learning: Passive stimulation and double training Journal Article In: Vision Research, vol. 108, pp. 93–102, 2015. @article{Mastropasqua2015,Specificity has always been considered one of the hallmarks of perceptual learning, suggesting that performance improvement would reflect changes at early stages of visual analyses (e.g., V1). More recently, however, this view has been challenged by studies documenting complete transfer of learning among different spatial locations or stimulus orientations when a double-training procedure is adopted. Here, we further investigate the conditions under which transfer of visual perceptual learning takes place, confirming that the passive stimulation at the transfer location seems to be insufficient to overcome learning specificity. By contrast, learning transfer is complete when performing a secondary task at the transfer location. Interestingly, (i) transfer emerges when the primary and secondary tasks are intermingled on a trial-by-trial basis, and (ii) the effects of learning generalization appear to be reciprocal, namely the primary task also serves to enable transfer of the secondary task. However, if the secondary task is not performed for a sufficient number of trials, then transfer is not enabled. Overall, the results lend support to the recent view that task-relevant perceptual learning may involve high-level stages of visual analyses. |
Tommaso Mastropasqua; Peter U. Tse; Massimo Turatto Learning of monocular information facilitates breakthrough to awareness during interocular suppression Journal Article In: Attention, Perception, & Psychophysics, vol. 77, no. 3, pp. 790–803, 2015. @article{Mastropasqua2015a,Continuous flash suppression (CFS) is a potent method of inducing binocular rivalry, wherein a rapid succession of high-contrast images presented to one eye effectively blocks from awareness a low-contrast image presented to the other eye. Here we addressed whether the contents of the suppressed image can break through to awareness with extended CFS exposure. On 2/3 of the trials, we presented a faint bar (the target) to the nondominant eye while a high-contrast flickering Mondrian (the mask) was displayed to the dominant eye. Participants were first asked to report whether the target had broken through the CFS mask. Furthermore, on target-present trials, the participants were then asked to guess whether the target had appeared above or below the fixation point. In Experiment 1, the target was presented with a fixed orientation for four blocks of trials, whereas in the fifth block, the target could also have the orthogonal orientation. In Experiment 2, the target was always presented with a fixed orientation, but in the fifth block, unbeknownst to participants, the target and the mask were swapped across the eyes. We found that awareness of the target rapidly improved with training in both experiments. However, whereas Experiment 1 revealed that the improvement largely generalized across stimulus orientations, Experiment 2 showed that the effect of practice was eye-specific. The results suggest that increased breakthrough with training was due to a monocular form of learning. Finally, a control experiment was conducted to exclude the possibility that the monocular learning we reported could have been due to sensory adaptation caused by the masks. |
Sebastiaan Mathôt; Jean-Baptiste Melmi; Eric Castet Intrasaccadic perception triggers pupillary constriction Journal Article In: PeerJ, vol. 3, pp. 1–16, 2015. @article{Mathot2015,It is commonly believed that vision is impaired during saccadic eye movements. However, here we report that some visual stimuli are clearly visible during saccades, and trigger a constriction of the eye's pupil. Participants viewed sinusoid gratings that changed polarity 150 times per second (every 6.67 ms). At this rate of flicker, the gratings were perceived as homogeneous surfaces while participants fixated. However, the flickering gratings contained ambiguous motion: rightward and leftward motion for vertical gratings; upward and downward motion for horizontal gratings. When participants made a saccade perpendicular to the gratings' orientation (e.g., a leftward saccade for a vertical grating), the eye's peak velocity matched the gratings' motion. As a result, the retinal image was approximately stable for a brief moment during the saccade, and this gave rise to an intrasaccadic percept: A normally invisible stimulus became visible when eye velocity was maximal. Our results confirm and extend previous studies by demonstrating intrasaccadic perception using a reflexive measure (pupillometry) that does not rely on subjective report. Our results further show that intrasaccadic perception affects all stages of visual processing, from the pupillary response to visual awareness. |
Sebastiaan Mathôt; Alisha Siebold; Mieke Donk; Françoise Vitu Large pupils predict goal-driven eye movements Journal Article In: Journal of Experimental Psychology: General, vol. 144, no. 3, pp. 513–521, 2015. @article{Mathot2015a,Here we report that large pupils predict fixations of the eye on low-salient, inconspicuous parts of a visual scene. We interpret this as showing that mental effort, reflected by a dilation of the pupil, is required to guide gaze toward objects that are relevant to current goals, but that may not be very salient. When mental effort is low, reflected by a constriction of the pupil, the eyes tend to be captured by high-salient parts of the image, irrespective of top-down goals. The relationship between pupil size and visual saliency was not driven by luminance or a range of other factors that we considered. Crucially, the relationship was strongest when mental effort was invested exclusively in eye-movement control (i.e., reduced in a dual-task setting), which suggests that it is not due to general effort or arousal. Our finding illustrates that goal-driven control during scene viewing requires mental effort, and that pupil size can be used as an online measure to track the goal-drivenness of behavior. |
Sebastiaan Mathôt; Lotje Linden; Jonathan Grainger; Françoise Vitu The pupillary light response reflects eye-movement preparation Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 41, no. 1, pp. 28–35, 2015. @article{Mathot2015b,When the eyes are exposed to an increased influx of light, the pupils constrict. The pupillary light response (PLR) is traditionally believed to be purely reflexive and not susceptible to cognitive influences. In contrast to this traditional view, we report that preparation of a PLR occurs in parallel with preparation of a saccadic eye movement toward a bright (or dark) stimulus, even before the eyes set in motion. Participants fixated a central gray area and made a saccade toward a peripheral target. Using gaze-contingent display changes, we manipulated whether or not the brightness of the target background was the same during and after saccade preparation. More specifically, on some trials we changed the brightness of the target background during the saccade, thus dissociating the preparatory PLR (i.e., to the brightness of the target background before the saccade) from the regular PLR (i.e., to the brightness after the saccade). We show that preparation triggers a pupillary response to the brightness of a to-be-fixated target background already before the eyes have landed on it. We link our findings to the presaccadic shift of attention: The pupil prepares to adjust its size to the brightness of a to-be-fixated stimulus as soon as attention covertly shifts toward that stimulus. Our findings illustrate that the PLR is a dynamic movement that is tightly linked to visual attention and eye-movement preparation. |
Shunichi Matsuda; Hideyuki Matsumoto; Toshiaki Furubayashi; Hideki Fukuda; Ritsuko Hanajima; Shoji Tsuji; Yoshikazu Ugawa; Yasuo Terao Visual scanning area is abnormally enlarged in hereditary pure Cerebellar ataxia Journal Article In: Cerebellum, vol. 14, no. 2, pp. 63–71, 2015. @article{Matsuda2015,The aim of paper was to investigate abnormalities in visual scanning using an eye-tracking device with patients with spinocerebellar ataxia type 6 (SCA6) and SCA31, pure cerebellar types of spinocerebellar degeneration. Nineteen SCA patients (12 patients with SCA6 and 7 patients with SCA31) and 19 normal subjects in total participated in the study. While the subjects viewed images of varying complexity for later recall, we compared the visual scanning parameters between SCA patients and normal subjects. SCA patients had lower image recall scores. The scanned area in SCA patients was consistently larger than that in normal subjects. The amplitude of saccades was slightly larger in SCA patients than that in normal subjects, although it did not statistically differ between the two groups and correlated significantly with the scanned area in most images in SCA patients. The instability ratio of fixation, reflecting gaze-evoked nystagmus and downbeat nystagmus, was higher in SCA patients than that in normal subjects. Since SCA patients showed low scores despite wide visual scanning, the scanned area is considered to be abnormally enlarged. The larger scanned area in SCA patients was supposed mainly to result from the slightly larger saccade amplitude. Additionally, SCA patients showed prominent fixation disturbances probably due to gaze-evoked nystagmus and downbeat nystagmus. Consequently, SCA patients suffer from recognizing various objects in daily life, probably due to the impaired saccade control and impaired fixation. |
Maria Matziridi; Eli Brenner; Jeroen B. J. Smeets The role of temporal information in perisaccadic mislocalization Journal Article In: PLoS ONE, vol. 10, no. 9, pp. e0134081, 2015. @article{Matziridi2015,In dynamic environments, it is crucial to accurately consider the timing of information. For instance, during saccades the eyes rotate so fast that even small temporal errors in relating retinal stimulation by flashed stimuli to extra-retinal information about the eyes' orientations will give rise to substantial errors in where the stimuli are judged to be. If spatial localization involves judging the eyes' orientations at the estimated time of the flash, we should be able to manipulate the pattern of mislocalization by altering the estimated time of the flash. We reasoned that if we presented a relevant flash within a short rapid sequence of irrelevant flashes, participants' estimates of when the relevant flash was presented might be shifted towards the centre of the sequence. In a first experiment, we presented five bars at different positions around the time of a saccade. Four of the bars were black. Either the second or the fourth bar in the sequence was red. The task was to localize the red bar. We found that when the red bar was presented second in the sequence, it was judged to be further in the direction of the saccade than when it was presented fourth in the sequence. Could this be because the red bar was processed faster when more black bars preceded it? In a second experiment, a red bar was either presented alone or followed by two black bars. When two black bars followed it, it was judged to be further in the direction of the saccade. We conclude that the spatial localization of flashed stimuli involves judging the eye orientation at the estimated time of the flash. |
Gerrit W. Maus; Elena Potapchuk; Scott N. J. Watamaniuk; Stephen J. Heinen Different time scales of motion integration for anticipatory smooth pursuit and perceptual adaptation Journal Article In: Journal of Vision, vol. 15, no. 2, pp. 16–16, 2015. @article{Maus2015,When repeatedly exposed to moving stimuli, the oculomotor system elicits anticipatory smooth pursuit (ASP) eye movements, even before the stimulus moves. ASP is affected oppositely to perceptual speed judgments of repetitive moving stimuli: After a sequence of fast stimuli, ASP velocity increases, whereas perceived speed decreases. These two effects-perceptual adaptation and oculomotor priming-could result from adapting a single common internal speed representation that is used for perceptual comparisons and for generating ASP. Here we test this hypothesis by assessing the temporal dependence of both effects on stimulus history. Observers performed speed discriminations on moving random dot stimuli, either while pursuing the movement or maintaining steady fixation. In both cases, responses showed perceptual adaptation: Stimuli preceded by fast speeds were perceived as slower, and vice versa. To evaluate oculomotor priming, we analyzed ASP velocity as a function of average stimulus speed in preceding trials and found strong positive dependencies. Interestingly, maximal priming occurred over short stimulus histories (~two trials), whereas adaptation was maximal over longer histories (~15 trials). The temporal dissociation of adaptation and priming suggests different underlying mechanisms. It may be that perceptual adaptation integrates over a relatively long period to robustly calibrate the operating range of the motion system, thereby avoiding interference from transient changes in stimulus speed. On the other hand, the oculomotor system may rapidly prime anticipatory velocity to efficiently match it to that of the pursuit target. |
Bastian Mayerhofer; Annekathrin Schacht From incoherence to mirth: Neuro-cognitive processing of garden-path jokes Journal Article In: Frontiers in Psychology, vol. 6, pp. 550, 2015. @article{Mayerhofer2015,In so-called garden-path jokes, an initial semantic representation is violated, and semantic revision reestablishes a coherent representation. 48 jokes were manipulated in three conditions: (i) a coherent ending, (ii) a joke ending, and (iii) a discourse-incoherent ending. A reading times study (N =24) and three studies with recordings of ERP and pupil changes (N = 21, 24, and 24, respectively) supported the hypothesized cognitive processes. Jokes showed increased reading times of the final word compared to coherent endings. ERP data mainly indicated semantic integration difficulties (N400). Larger pupil diameters to joke endings presumably reflect emotional responses. ERP evidence for increased discourse processing efforts and emotional responses, as assumed to be reflected in late left anterior negativity and LLAN modulations and an enhanced late frontal positivity (fP600), respectively, remains however incomplete. Processing of incoherent endings was also accompanied by increased reading times, a stronger and sustained N400, and context-sensitive P600 effects. Together, these findings provide evidence for a sequential, non-monotonic, and incremental discourse comprehension of garden-path jokes. |
J. Patrick Mayo; Amie R. DiTomasso; Marc A. Sommer; Matthew A. Smith Dynamics of visual receptive fields in the macaque frontal eye field Journal Article In: Journal of Neurophysiology, vol. 114, no. 6, pp. 3201–3210, 2015. @article{Mayo2015,Neuronal receptive fields (RFs) provide the foundation for understanding systems-level sensory processing. In early visual areas, investigators have mapped RFs in detail using stochastic stimuli and sophisticated analytical approaches. Much less is known about RFs in prefrontal cortex. Visual stimuli used for mapping RFs in prefrontal cortex tend to cover a small range of spatial and temporal parameters, making it difficult to understand their role in visual processing. To address these shortcomings, we implemented a generalized linear model to measure the RFs of neurons in the macaque frontal eye field (FEF) in response to sparse, full-field stimuli. Our high-resolution, probabilistic approach tracked the evolution of RFs during passive fixation, and we validated our results against conventional measures. We found that FEF neurons exhibited a surprising level of sensitivity to stimuli presented as briefly as 10 ms or to multiple dots presented simultaneously, suggesting that FEF visual responses are more precise than previously appreciated. FEF RF spatial structures were largely maintained over time and between stimulus conditions. Our results demonstrate that the application of probabilistic RF mapping to FEF and similar association areas is an important tool for clarifying the neuronal mechanisms of cognition. |
Michael B. McCamy; Jorge Otero-Millan; R. John Leigh; Susan A. King; Rosalyn M. Schneider; Stephen L. Macknik; Susana Martinez-Conde Simultaneous recordings of human microsaccades and drifts with a contemporary video eye tracker and the search coil technique Journal Article In: PLoS ONE, vol. 10, no. 6, pp. e0128428, 2015. @article{McCamy2015,Human eyes move continuously, even during visual fixation. These " fixational eye move-ments " (FEMs) include microsaccades, intersaccadic drift and oculomotor tremor. Re-search in human FEMs has grown considerably in the last decade, facilitated by the manufacture of noninvasive, high-resolution/speed video-oculography eye trackers. Due to the small magnitude of FEMs, obtaining reliable data can be challenging, however, and de-pends critically on the sensitivity and precision of the eye tracking system. Yet, no study has conducted an in-depth comparison of human FEM recordings obtained with the search coil (considered the gold standard for measuring microsaccades and drift) and with contempo-rary, state-of-the art video trackers. Here we measured human microsaccades and drift si-multaneously with the search coil and a popular state-of-the-art video tracker. We found that 95% of microsaccades detected with the search coil were also detected with the video tracker, and 95% of microsaccades detected with video tracking were also detected with the search coil, indicating substantial agreement between the two systems. Peak/mean ve-locities and main sequence slopes of microsaccades detected with video tracking were sig-nificantly higher than those of the same microsaccades detected with the search coil, however. Ocular drift was significantly correlated between the two systems, but drift speeds were higher with video tracking than with the search coil. Overall, our combined results suggest that contemporary video tracking now approaches the search coil for measuring FEMs. |
Carol McDonald Connor; Ralph Radach; Christian Vorstius; Stephanie L. Day; Leigh McLean; Frederick J. Morrison Individual differences in fifth graders' literacy and academic language predict comprehension monitoring development: An eye-movement study Journal Article In: Scientific Studies of Reading, vol. 19, no. 2, pp. 114–134, 2015. @article{McDonaldConnor2015,In this study, we investigated fifth graders' (n = 52) fall literacy, academic language, and motivation and how these skills predicted fall and spring comprehension monitoring on an eye movement task. Comprehension monitoring was defined as the identification and repair of misunderstandings when reading text. In the eye movement task, children read two sentences; the second included either a plausible or implausible word in the context of the first sentence. Stronger readers had shorter reading times overall suggesting faster processing of text. Generally fifth graders reacted to the implausible word (i.e., longer gaze duration on the implausible vs. the plausible word, which reflects lexical access). Students with stronger academic language, compared to those with weaker academic language, generally spent more time rereading the implausible target compared to the plausible target. This difference increased from fall to spring. Results support the centrality of academic language for meaning integration, setting standards of coherence, and utilizing comprehension repair strategies. |
Gerald P. McDonnell; Mark Mills; Leslie McCuller; Michael D. Dodd How does implicit learning of search regularities alter the manner in which you search? Journal Article In: Psychological Research, vol. 79, no. 2, pp. 183–193, 2015. @article{McDonnell2015,Individuals are highly sensitive to statistical regularities in their visual environment, even when these patterns do not reach conscious awareness. Here, we examine whether oculomotor behavior is systematically altered when distractor/target configurations rarely repeat, but target location on an initial trial predicts the location of a target on the subsequent trial. The purpose of the current study was to explore whether this temporal-spatial contextual cueing in a conjunction search task influences both reaction time to the target and participant's search strategy. Participants searched for a target through a gaze-contingent window in a display consisting of a large number of distractors, providing a target-present/absent response. Participants were faster to respond to the target on the predicted trial relative to the predictor trial in an implicit contextual cueing task but were no more likely to fixate first to the target quadrant on the predicted trial (Experiment 1). Furthermore, implicit learning was interrupted when instructing participants to vary their searching strategy across trials to eliminate visual scan similarity (Experiment 2). In Experiment 3, when participants were explicitly informed that a pattern was present at the start of the experiment, explicit learning was observed in both reaction time and eye movements. The present experiments provide evidence that implicit learning of sequential regularities regarding target locations is not based on learning more efficient scan paths, but is due to some other mechanism. |
Victoria A. McGowan; Sarah J. White; Kevin B. Paterson The effects of interword spacing on the eye movements of young and older readers Journal Article In: Journal of Cognitive Psychology, vol. 27, no. 5, pp. 609–621, 2015. @article{McGowan2015,Recent evidence indicates that older adults (aged 65+) are more disrupted by removing interword spaces than young adults (aged 18–30). However, it is not known whether older readers also show greater sensitivity to the more subtle changes to this spacing that frequently occur during normal reading. In the present study the eye movements of young and older adults were examined when reading texts for which interword spacing was normal, condensed to half its normal size or expanded to 1.5 times its normal size. Although these changes in interword spacing affected eye movement behaviour, this influence did not differ between young and older adults. Furthermore, a word frequency manipulation showed that these changes did not affect word identification for either group. The results indicate that older adults can adapt their eye moment behaviour to accommodate subtle changes in the spatial layout of text equally effectively as young adults. |
David B. T. McMahon; Brian E. Russ; Heba D. Elnaiem; Anastasia I. Kurnikova; David A. Leopold Single-unit activity during natural vision: Diversity, consistency, and spatial sensitivity among AF face patch neurons Journal Article In: Journal of Neuroscience, vol. 35, no. 14, pp. 5537–5548, 2015. @article{McMahon2015,Several visual areas within the STS of the macaque brain respond strongly to faces and other biological stimuli. Determining the principles that govern neural responses in this region has proven challenging, due in part to the inherently complex stimulus domain of dynamic biological stimuli that are not captured by an easily parameterized stimulus set. Here we investigated neural responses in one fMRI-defined face patch in the anterior fundus (AF) of the STS while macaques freely view complex videos rich with natural social content. Longitudinal single-unit recordings allowed for the accumulation of each neuron's responses to repeated video presentations across sessions. We found that individual neurons, while diverse in their response patterns, were consistently and deterministically driven by the video content. We used principal component analysis to compute a family of eigenneurons, which summarized 24% of the shared population activity in the first two components. We found that the most prominent component of AF activity reflected an interaction between visible body region and scene layout. Close-up shots of faces elicited the strongest neural responses, whereas far away shots of faces or close-up shots of hindquarters elicited weak or inhibitory responses. Sensitivity to the apparent proximity of faces was also observed in gamma band local field potential. This category-selective sensitivity to spatial scale, together with the known exchange of anatomical projections of this area with regions involved in visuospatial analysis, suggests that the AF face patch may be specialized in aspects of face perception that pertain to the layout of a social scene. |
Ishan Nigam; Mayank Vatsa; Richa Singh Ocular biometrics: A survey of modalities and fusion approaches Journal Article In: Information Fusion, vol. 26, pp. 1–35, 2015. @article{Nigam2015,Biometrics, an integral component of Identity Science, is widely used in several large-scale-county-wide projects to provide a meaningful way of recognizing individuals. Among existing modalities, ocular biometric traits such as iris, periocular, retina, and eye movement have received significant attention in the recent past. Iris recognition is used in Unique Identification Authority of India's Aadhaar Program and the United Arab Emirate's border security programs, whereas the periocular recognition is used to augment the performance of face or iris when only ocular region is present in the image. This paper reviews the research progression in these modalities. The paper discusses existing algorithms and the limitations of each of the biometric traits and information fusion approaches which combine ocular modalities with other modalities. We also propose a path forward to advance the research on ocular recognition by (i) improving the sensing technology, (ii) heterogeneous recognition for addressing interoperability, (iii) utilizing advanced machine learning algorithms for better representation and classification, (iv) developing algorithms for ocular recognition at a distance, (v) using multimodal ocular biometrics for recognition, and (vi) encouraging benchmarking standards and open-source software development. |
Taihei Ninomiya; Kacie Dougherty; David C. Godlove; Jeffrey D. Schall; Alexander Maier Microcircuitry of agranular frontal cortex: Contrasting laminar connectivity between occipital and frontal areas Journal Article In: Journal of Neurophysiology, vol. 113, no. 9, pp. 3242–3255, 2015. @article{Ninomiya2015,Neocortex is striking in its laminar architecture. Tracer studies have uncovered anatomical connectivity among laminae, but the functional connectivity between laminar compartments is still largely unknown. Such functional connectivity can be discerned through spontaneous neural correlations during rest. Previous work demonstrated a robust pattern of mesoscopic resting-state connectivity in macaque primary visual cortex (V1) through interlaminar cross-frequency coupling. Here we investigated whether this pattern generalizes to other cortical areas by comparing resting-state laminar connectivity between V1 and the supplementary eye field (SEF), a frontal area lacking a granular layer 4 (L4). Local field potentials (LFPs) were recorded with linear microelectrode arrays from all laminae of granular V1 and agranular SEF while monkeys rested in darkness. We found substantial differences in the relationship between the amplitude of gamma-band (>30 Hz) LFP and the phase of alpha-band (7-14 Hz) LFP between these areas. In V1, gamma amplitudes in L2/3 and L5 were coupled with alpha-band LFP phase in L5, as previously described. In contrast, in SEF phase-amplitude coupling was prominent within L3 and much weaker across layers. These results suggest that laminar interactions in agranular SEF are unlike those in granular V1. Thus the intrinsic functional connectivity of the cortical microcircuit does not seem to generalize across cortical areas. |
Babak Noory; Michael H. Herzog; Haluk Ogmen Retinotopy of visual masking and non-retinotopic perception during masking Journal Article In: Attention, Perception, & Psychophysics, vol. 77, no. 4, pp. 1263–1284, 2015. @article{Noory2015,Due to the movements of the observer and those of objects in the environment, retinotopic representations are highly unstable during ecological viewing conditions. The phenomenal stability of our perception suggests that retinotopic representations are transformed into non-retinotopic representations. It remains to show, however, which visual processes operate under retinotopic representations and which ones operate under non-retinotopic representations. Visual masking refers to the reduced visibility of one stimulus, called the target, due to the presence of a second stimulus, called the mask. Masking has been used extensively to study the dynamic aspects of visual perception. Previous studies using Saccadic Stimulus Presentation Paradigm (SSPP) suggested both retinotopic and non-retinotopic bases for visual masking. In order to understand how the visual system deals with retinotopic changes induced by moving targets, we investigated the retinotopy of visual masking and the fate of masked targets under conditions that do not involve eye movements. We have developed a series of experiments based on a radial Ternus-Pikler display. In this paradigm, the perceived Ternus-Pikler motion is used as a non-retinotopic reference frame to pit retinotopic against non-retinotopic visual masking hypothesis. Our results indicate that both metacontrast and structure masking are retinotopic. We also show that, under conditions that allow observers to read-out effectively non-retinotopic feature attribution, the target becomes visible at a destination different from its retinotopic/ spatiotopic location. We discuss the implications of our findings within the context of ecological vision and dynamic form perception. |
Antje Nuthmann; Wolfgang Einhäuser A new approach to modeling the influence of image features on fixation selection in scenes Journal Article In: Annals of the New York Academy of Sciences, vol. 1339, no. 1, pp. 82–96, 2015. @article{Nuthmann2015,Which image characteristics predict where people fixate when memorizing natural images? To answer this question, we introduce a new analysis approach that combines a novel scene-patch analysis with generalized linear mixed models (GLMMs). Our method allows for (1) directly describing the relationship between continuous feature value and fixation probability, and (2) assessing each feature's unique contribution to fixation selection. To demonstrate this method, we estimated the relative contribution of various image features to fixation selection: luminance and luminance contrast (low-level features); edge density (a mid-level feature); visual clutter and image segmentation to approximate local object density in the scene (higher-level features). An additional predictor captured the central bias of fixation. The GLMM results revealed that edge density, clutter, and the number of homogenous segments in a patch can independently predict whether image patches are fixated or not. Importantly, neither luminance nor contrast had an independent effect above and beyond what could be accounted for by the other predictors. Since the parcellation of the scene and the selection of features can be tailored to the specific research question, our approach allows for assessing the interplay of various factors relevant for fixation selection in scenes in a powerful and flexible manner. |
Thomas P. O'Connell; Dirk B. Walther Dissociation of salience-driven and content-driven spatial attention to scene category with predictive decoding of gaze patterns Journal Article In: Journal of Vision, vol. 15, no. 5, pp. 1–13, 2015. @article{OConnell2015,Scene content is thought to be processed quickly and efficiently to bias subsequent visual exploration. Does scene content bias spatial attention during task-free visual exploration of natural scenes? If so, is this bias driven by patterns of physical salience or content-driven biases formed through previous encounters with similar scenes? We conducted two eye-tracking experiments to address these questions. Using a novel gaze decoding method, we show that fixation patterns predict scene category during free exploration. Additionally, we isolate salience-driven contributions using computational salience maps and content-driven contributions using gaze-restricted fixation data. We find distinct time courses for salience-driven and content-driven effects. The influence of physical salience peaked initially but quickly fell off at 600 ms past stimulus onset. The influence of content effects started at chance and steadily increased over the 2000 ms after stimulus onset. The combination of these two components significantly explains the time course of gaze allocation during free exploration. |
Paul Metzner; Titus Malsburg; Shravan Vasishth; Frank Rösler Brain responses to world knowledge violations: A comparison of stimulus- and fixation-triggered event-related potentials and neural oscillations Journal Article In: Journal of Cognitive Neuroscience, vol. 27, no. 5, pp. 1017–1028, 2015. @article{Metzner2015,Recent research has shown that brain potentials time-locked to fixations in natural reading can be similar to brain potentials recorded during rapid serial visual presentation (RSVP). We attempted two replications of Hagoort, Hald, Bastiaansen, and Petersson [Hagoort, P., Hald, L., Bastiaansen, M., & Petersson, K. M. Integration of word meaning and world knowledge in language comprehension. Science, 304, 438-441, 2004] to determine whether this correspondence also holds for oscillatory brain responses. Hagoort et al. reported an N400 effect and synchronization in the theta and gamma range following world knowledge violations. Our first experiment (n = 32) used RSVP and replicated both the N400 effect in the ERPs and the power increase in the theta range in the time-frequency domain. In the second experiment (n = 49), participants read the same materials freely while their eye movements and their EEG were monitored. First fixation durations, gaze durations, and regression rates were increased, and the ERP showed an N400 effect. An analysis of time-frequency representations showed synchronization in the delta range (1-3 Hz) and desynchronization in the upper alpha range (11-13 Hz) but no theta or gamma effects. The results suggest that oscillatory EEG changes elicited by world knowledge violations are different in natural reading and RSVP. This may reflect differences in how representations are constructed and retrieved from memory in the two presentation modes. |
Inga Meyhöfer; Maria Steffens; Anna-Maria Kasparbauer; Phillip Grant; Bernd Weber; Ulrich Ettinger Neural mechanisms of smooth pursuit eye movements in schizotypy Journal Article In: Human Brain Mapping, vol. 36, pp. 340–353, 2015. @article{Meyhoefer2015,Patients with schizophrenia as well as individuals with high levels of schizotypy are known to have deficits in smooth pursuit eye movements (SPEM). Here, we investigated, for the first time, the neural mechanisms underlying SPEM performance in high schizotypy. Thirty-one healthy participants [N = 19 low schizotypes |
Elizabeth Michael; Vincent De Gardelle; Alejo Nevado-Holgado; Christopher Summerfield Unreliable evidence: 2 sources of uncertainty during perceptual choice Journal Article In: Cerebral Cortex, vol. 25, no. 4, pp. 937–947, 2015. @article{Michael2015,Perceptual decisions often involve integrating evidence from multiple concurrently available sources. Uncertainty arises when the integrated (mean) evidence fails to support one alternative over another. However, evidence heterogeneity (variability) also provokes uncertainty. Here, we asked whether these 2 sources of uncertainty have independent behavioral and neural effects during choice. Human observers undergoing functional neuroimaging judged the average color or shape of a multielement array. The mean and variance of the feature values exerted independent influences on behavior and brain activity. Surprisingly, BOLD signals in the dorsomedial prefrontal cortex (dmPFC) showed polar opposite responses to the 2 sources of uncertainty, with the strongest response to ambiguous tallies of evidence (high mean uncertainty) and to homogenous arrays (low variance uncertainty). These findings present a challenge for models that emphasize the role of the dmPFC in detecting conflict, errors, or surprise. We suggest an alternative explanation, whereby evidence is processed with increased gain near the category boundary. |
Cristiano Micheli; Daniel Kaping; Stephanie Westendorff; Taufik A. Valiante; Thilo Womelsdorf Inferior-frontal cortex phase synchronizes with the temporal-parietal junction prior to successful change detection Journal Article In: NeuroImage, vol. 119, pp. 417–431, 2015. @article{Micheli2015,The inferior frontal gyrus (IFG) and the temporo-parietal junction (TPJ) are believed to be core structures of human brain networks that activate when sensory top-down expectancies guide goal directed behavior and attentive perception. But it is unclear how activity in IFG and TPJ coordinates during attention demanding tasks and whether functional interactions between both structures are related to successful attentional performance.Here, we tested these questions in electrocorticographic (ECoG) recordings in human subjects using a visual detection task that required sustained attentional expectancy in order to detect non-salient, near-threshold visual events. We found that during sustained attention the successful visual detection was predicted by increased phase synchronization of band-limited 15-30. Hz beta band activity that was absent prior to misses. Increased beta-band phase alignment during attentional engagement early during the task was restricted to inferior and lateral prefrontal cortex, but with sustained attention it extended to long-range IFG-TPJ phase synchronization and included superior prefrontal areas. In addition to beta, a widely distributed network of brain areas comprising the occipital cortex showed enhanced and reduced alpha band phase synchronization before correct detections.These findings identify long-range phase synchrony in the 15-30. Hz beta band as the mesoscale brain signal that predicts the successful deployment of attentional expectancy of sensory events. We speculate that localized beta coherent states in prefrontal cortex index 'top-down' sensory expectancy whose coupling with TPJ subregions facilitates the gating of relevant visual information. |
Mark Mills; Edwin S. Dalmaijer; Stefan Van der Stigchel; Michael D. Dodd Effects of task and task-switching on temporal inhibition of return, facilitation of return, and saccadic momentum during scene viewing Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 41, no. 5, pp. 1300–1314, 2015. @article{Mills2015,During scene viewing, saccades directed toward a recently fixated location tend to be delayed relative to saccades in other directions (“delay effect”), an effect attributable to inhibition of return (IOR) and/or saccadic momentum (SM). Previous work indicates this effect may be task-specific, suggesting that gaze control parameters are task-relevant and potentially affected by task-switching. Accordingly, the present study investigated task-set control of gaze behavior using the delay effect as a measure of task performance. The delay effect was measured as the effect of relative saccade direction on preceding fixation duration. Participants were cued on each trial to perform either a search, memory, or rating task. Tasks were performed either in pure-task or mixed-task blocks. This design allowed separation of switch-cost and mixing-cost. The critical result was that expression of the delay effect at 2-back locations was reversed on switch versus repeat trials such that return was delayed in repeat trials but speeded in switch trials. This difference between repeat and switch trials suggests that gaze-relevant parameters may be represented and switched as part of a task-set. Existing and new tests for dissociating IOR and SM accounts of the delay effect converged on the conclusion that the delay at 2-back locations was due to SM, and that task-switching affects SM. Additionally, the new test simultaneously replicated noncor- roborating results in the literature regarding facilitation-of-return (FOR), which confirmed its existence and showed that FOR is “reversed” SM that occurs when preceding and current saccades are both directed toward the 2-back location. |
Mark Mills; Kevin B. Smith; John R. Hibbing; Michael D. Dodd Obama cares about visuo-spatial attention: Perception of political figures moves attention and determines gaze direction Journal Article In: Behavioural Brain Research, vol. 278, pp. 221–225, 2015. @article{Mills2015a,Processing an abstract concept such as political ideology by itself is difficult but becomes easier when a background situation contextualizes it. Political ideology within American politics, for example, is commonly processed using space metaphorically, i.e., the political "left" and "right" (referring to Democrat and Republican views, respectively), presumably to provide a common metric to which abstract features of ideology can be grounded and understood. Commonplace use of space as metaphor raises the question of whether an inherently non-spatial stimulus (e.g., picture of the political "left" leader, Barack Obama) can trigger a spatially-specific response (e.g., attentional bias toward "left" regions of the visual field). Accordingly, pictures of well-known Democrats and Republicans were presented as central cues in peripheral target detection (Experiment 1) and saccadic free-choice (Experiment 2) tasks to determine whether perception of stimuli lacking a direct association with physical space nonetheless induce attentional and oculomotor biases in the direction compatible with the ideological category of the cue (i.e., Democrat/left and Republican/right). In Experiment 1, target detection following presentation of a Democrat (Republican) was facilitated for targets appearing to the left (right). In Experiment 2, participants were more likely to look left (right) following presentation of a Democrat (Republican). Thus, activating an internal representation of political ideology induced a shift of attention and biased choice of gaze direction in a spatially-specific manner. These findings demonstrate that the link between conceptual processing and spatial attention can be totally arbitrary, with no reference to physical or symbolic spatial information. |
Holger Mitterer; Eva Reinisch Letters don't matter: No effect of orthography on the perception of conversational speech Journal Article In: Journal of Memory and Language, vol. 85, pp. 116–134, 2015. @article{Mitterer2015,It has been claimed that learning to read changes the way we perceive speech, with detrimental effects for words with sound-spelling inconsistencies. Because conversational speech is peppered with segment deletions and alterations that lead to sound-spelling inconsistencies, such an influence would seriously hinder the perception of conversational speech. We hence tested whether the orthographic coding of a segment influences its deletion costs in perception. German glottal stop, a segment that is canonically present but not orthographically coded, allows such a test. The effects of glottal-stop deletion in German were compared to deletion of /h/ in German (grapheme: h) and deletion of glottal stop in Maltese (grapheme: q) in an implicit task with conversational speech and explicit task with careful speech. All segment deletions led to similar reduction costs in the implicit task, while an orthographic effect, with larger effects for orthographically coded segments, emerged in the explicit task. These results suggest that learning to read does not influence how we process speech but mainly how we think about it. |
Kentaro Miyamoto; Ikuya Murakami Pupillary light reflex to light inside the natural blind spot Journal Article In: Scientific Reports, vol. 5, pp. 11862, 2015. @article{Miyamoto2015,When a light stimulus covers the human natural blind spot (BS), perceptual filling-in corrects for the missing information inside the BS. Here, we examined whether a filled-in surface of light perceived inside the BS affects the size of the short-latency pupillary light reflex (PLR), a pupil response mediated by a subcortical pathway for unconscious vision. The PLR was not induced by a red surface that was physically absent but perceptually filled-in inside the BS in the presence of a red ring surrounding it. However, a white large disk covering the BS unexpectedly induced a larger PLR than a white ring surrounding the BS border did, even though these two stimuli must be equivalent for the visual system, and trial-by-trial percepts did not predict PLR size. These results suggest that some physiological mechanism, presumably the retinal cells containing the photopigment melanopsin, receives the light projected inside the BS and enhances PLR. |
Tobias Moehler; Katja Fiehler The influence of spatial congruency and movement preparation time on saccade curvature in simultaneous and sequential dual-tasks Journal Article In: Vision Research, vol. 116, pp. 25–35, 2015. @article{Moehler2015,Saccade curvature represents a sensitive measure of oculomotor inhibition with saccades curving away from covertly attended locations. Here we investigated whether and how saccade curvature depends on movement preparation time when a perceptual task is performed during or before saccade preparation. Participants performed a dual-task including a visual discrimination task at a cued location and a saccade task to the same location (congruent) or to a different location (incongruent). Additionally, we varied saccade preparation time (time between saccade cue and Go-signal) and the occurrence of the discrimination task (during saccade preparation = simultaneous vs. before saccade preparation = sequential). We found deteriorated perceptual performance in incongruent trials during simultaneous task performance while perceptual performance was unaffected during sequential task performance. Saccade accuracy and precision were deteriorated in incongruent trials during simultaneous and, to a lesser extent, also during sequential task performance. Saccades consistently curved away from covertly attended non-saccade locations. Saccade curvature was unaffected by movement preparation time during simultaneous task performance but decreased and finally vanished with increasing movement preparation time during sequential task performance. Our results indicate that the competing saccade plan to the covertly attended non-saccade location is maintained during simultaneous task performance until the perceptual task is solved while in the sequential condition, in which the discrimination task is solved prior to the saccade task, oculomotor inhibition decays gradually with movement preparation time. |
Hassan Zanganeh Momtaz; Mohammad Reza Daliri Differences of eye movement pattern in natural and man-made scenes and image categorization with the help of these patterns Journal Article In: Journal of Integrative Neuroscience, vol. 14, no. 3, pp. 1–18, 2015. @article{Momtaz2015,In this paper, we investigated the parameters related to eye movement patterns of individuals while viewing images that consist of natural and man-made scenes. These parameters are as follows: number of fixations and saccades, fixation duration, saccade amplitude and distribution of fixation locations. We explored the way in which individuals look at images of different semantic categories, and used this information for automatic image classifcation. We showed that the eye movements and the contents of eye fixation locations of observers differ for images of different semantic categories. These differences were used effectively in automatic image categorization. Another goal of this study was to find the answer of this question that "whether the image patches of fixation points have sufficient information for image categorization?" To achieve this goal, a number of patches with different sizes from two different image categories was extracted. These patches, which were selected at the location of eye fixation points, were used to form a feature vector based on K-means clustering algorithm. Then, different statistical classiers were trained for categorization purpose. The results showed that it is possible to predict the image category by using the feature vectors derived from the image patches. We found significant differences in parameters of eye movement pattern between the two image categories (average across subjects). We could categorize images by using these parameters as features. The results also showed that it is possible to predict the image category by using image patches around the subjects' fixation points. |
Mariah Moore; Peter C. Gordon Reading ability and print exposure: item response theory analysis of the author recognition test Journal Article In: Behavior Research Methods, vol. 47, no. 4, pp. 1095–1109, 2015. @article{Moore2015,In the author recognition test (ART), participants are presented with a series of names and foils and are asked to indicate which ones they recognize as authors. The test is a strong predictor of reading skill, and this predictive ability is generally explained as occurring because author knowledge is likely acquired through reading or other forms of print exposure. In this large-scale study (1,012 college student participants), we used item response theory (IRT) to analyze item (author) characteristics in order to facilitate identification of the determinants of item difficulty, provide a basis for further test development, and optimize scoring of the ART. Factor analysis suggested a potential two-factor structure of the ART, differentiating between literary and popular authors. Effective and ineffective author names were identified so as to facilitate future revisions of the ART. Analyses showed that the ART is a highly significant predictor of the time spent encoding words, as measured using eyetracking during reading. The relationship between the ART and time spent reading provided a basis for implementing a higher penalty for selecting foils, rather than the standard method of ART scoring (names selected minus foils selected). The findings provide novel support for the view that the ART is a valid indicator of reading volume. Furthermore, they show that frequency data can be used to select items of appropriate difficulty, and that frequency data from corpora based on particular time periods and types of texts may allow adaptations of the test for different populations. |
Pieter Moors; Filip Germeys; Iwona Pomianowska; Karl Verfaillie Perceiving where another person is looking: The integration of head and body information in estimating another person's gaze Journal Article In: Frontiers in Psychology, vol. 6, pp. 909, 2015. @article{Moors2015,The process through which an observer allocates his/her attention based on the attention of another person is known as joint attention. To be able to do this, the observer effectively has to compute where the other person is looking. It has been shown that observers integrate information from the head and the eyes to determine the gaze of another person. Most studies have documented that observers show a bias called the overshoot effect when eyes and head are misaligned. That is, when the head is not oriented straight to the observer, perceived gaze direction is sometimes shifted in the direction opposite to the head turn. The present study addresses whether body information is also used as a cue to compute perceived gaze direction. In Experiment 1, we observed a similar overshoot effect in both behavioral and saccadic responses when manipulating body orientation. In Experiment 2, we explored whether the overshoot effect was due to observers assuming that the eyes are oriented further than the head when head and body orientation are misaligned. We removed horizontal eye information by presenting the stimulus from a side view. Head orientation was now manipulated in a vertical direction and the overshoot effect was replicated. In summary, this study shows that body orientation is indeed used as a cue to determine where another person is looking. |
Candice C. Morey; Yongqi Cong; Yixia Zheng; Mindi Price; Richard D. Morey The color-sharing bonus: Roles of perceptual organization and attentive processes in visual working memory. Journal Article In: Archives of Scientific Psychology, vol. 3, no. 1, pp. 18–29, 2015. @article{Morey2015,Color repetitions in a visual scene boost memory for its elements, a phenomenon known as the color-sharing effect. This may occur because improved perceptual organization reduces information load or because the repetitions capture attention. The implications of these explanations differ drastically for both the theoretical meaning of this effect and its potential value for applications in design of visual materials. If repetitions capture attention to the exclusion of other details, then use of repetition in visual displays should be confined to emphasized details, but if repetitions reduce the load of the display, designers can assume that the nonrepeated information is also more likely to be attended and remembered. We manipulated the availability of general attention during a visual memory task by comparing groups of participants engaged in meaningless speech or attention-demanding continuous arithmetic. We also tracked eye movements as an implicit indicator of selective attention. Estimated memory capacity was always higher when color duplicates were tested, and under full attention conditions this bonus spilled over to the unique colors too. Analyses of gazes showed that with full attention, participants tended to glance earlier at duplicate colors during stimulus presentation but looked more at unique colors during the retention interval. This pattern of results suggests that the color-sharing bonus reflects efficient perceptual organization of the display based on the presence of repetitions, and possibly strategic attention allocation when attention is available. |