EyeLink 认知出版物
All EyeLink cognitive and perception research publications up until 2023 (with some early 2024s) are listed below by year. You can search the publications using keywords such as Visual Search, Scene Perception, Face Processing, etc. You can also search for individual author names. If we missed any EyeLink cognitive or perception articles, please email us!
2013 |
Miguel P. Eckstein; Stephen C. Mack; Dorion B. Liston; Lisa Bogush; Randolf Menzel; Richard J. Krauzlis Rethinking human visual attention: Spatial cueing effects and optimality of decisions by honeybees, monkeys and humans Journal Article In: Vision Research, vol. 85, pp. 5–9, 2013. @article{Eckstein2013, Visual attention is commonly studied by using visuo-spatial cues indicating probable locations of a target and assessing the effect of the validity of the cue on perceptual performance and its neural correlates. Here, we adapt a cueing task to measure spatial cueing effects on the decisions of honeybees and compare their behavior to that of humans and monkeys in a similarly structured two-alternative forced-choice perceptual task. Unlike the typical cueing paradigm in which the stimulus strength remains unchanged within a block of trials, for the monkey and human studies we randomized the contrast of the signal to simulate more real world conditions in which the organism is uncertain about the strength of the signal. A Bayesian ideal observer that weights sensory evidence from cued and uncued locations based on the cue validity to maximize overall performance is used as a benchmark of comparison against the three animals and other suboptimal models: probability matching, ignore the cue, always follow the cue, and an additive bias/single decision threshold model. We find that the cueing effect is pervasive across all three species but is smaller in size than that shown by the Bayesian ideal observer. Humans show a larger cueing effect than monkeys and bees show the smallest effect. The cueing effect and overall performance of the honeybees allows rejection of the models in which the bees are ignoring the cue, following the cue and disregarding stimuli to be discriminated, or adopting a probability matching strategy. Stimulus strength uncertainty also reduces the theoretically predicted variation in cueing effect with stimulus strength of an optimal Bayesian observer and diminishes the size of the cueing effect when stimulus strength is low. A more biologically plausible model that includes an additive bias to the sensory response from the cued location, although not mathematically equivalent to the optimal observer for the case stimulus strength uncertainty, can approximate the benefits of the more computationally complex optimal Bayesian model. We discuss the implications of our findings on the field's common conceptualization of covert visual attention in the cueing task and what aspects, if any, might be unique to humans. |
James T. Enns; Sarah C. MacDonald The role of clarity and blur in guiding visual attention in photographs Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 39, no. 2, pp. 568–578, 2013. @article{Enns2013, Visual artists and photographers believe that a viewer's gaze can be guided by selective use of image clarity and blur, but there is little systematic research. In this study, participants performed several eye-tracking tasks with the same naturalistic photographs, including recognition memory for the entire photo, as well as recognition memory and personality ratings for individual people in the photos (Experiments 1-3). The results showed that fixations occurred more rapidly and frequently to a local region of clarity than to a comparable blurred region in all tasks, independent of the content of the photo in the local region, and even under instructions to look equally at both regions. However, this bias was reversed when the content of the photos was no longer task-relevant. In Experiment 4, participants located target regions defined by either clarity or blur. Fixations and manual responses were faster for blurred than for sharp targets. These findings imply that the saliency of both image clarity and image blur depends on viewers' goals. Focusing on photo content prioritizes regions of clarity whereas focusing on photo quality prioritizes attention to regions of blur. |
Andrés Fernández-Martín; Aida Gutiérrez-García; Manuel G. Calvo A smile radiates outwards and biases the eye expression Journal Article In: Spanish Journal of Psychology, vol. 16, pp. 1–11, 2013. @article{FernandezMartin2013, <p>This study investigated how extrafoveally seen smiles influence the viewers' perception of non-happy eyes in a face. A smiling mouth appeared in composite faces with incongruent (angry, fearful, neutral, etc.) eyes, thus producing blended expressions, or they appeared in intact faces with genuine expressions. Overt attention to the eye region was spatially cued, foveal vision of the mouth was blocked by gaze-contingent masking, and the distance between the eyes and the mouth was varied. Participants evaluated whether the eyes were happy or not. Results indicated that the same non-happy eyes were more likely to be judged as happy, and more slowly to be judged as not happy, in presence more than in absence of a smile. As (a) the smiling mouth was highly salient regardless of type of eyes, (b) the influence on the eyes increased gradually as a function of eye-mouth proximity, and (c) the effect occurred in the absence of fixations on the mouth, we conclude that a salient smile radiates outwards to other face regions through a projection mechanism, thus making the eye expression look happy.</p> |
Yariv Festman; Jos J. Adam; Jay Pratt; Martin H. Fischer Continuous hand movement induces a far-hand bias in attentional priority Journal Article In: Attention, Perception, and Psychophysics, vol. 75, no. 4, pp. 644–649, 2013. @article{Festman2013, Previous research on the interaction between manual action and visual perception has focused on discrete movements or static postures and discovered better performance near the hands (the near-hand effect). However, in everyday behaviors, the hands are usually moving continuously between possible targets. Therefore, the current study explored the effects of continuous hand motion on the allocation of visual attention. Eleven healthy adults performed a visual discrimination task during cyclical concealed hand movements underneath a display. Both the current hand position and its movement direction systematically contributed to participants' visual sensitivity. Discrimination performance increased substantially when the hand was distant from but moving toward the visual probe location (a far-hand effect). Implications of this novel observation are discussed. |
Heather Flowe; Lorraine Hope; Anne P. Hillstrom Oculomotor examination of the weapon focus effect: Does a gun automatically engage visual attention? Journal Article In: PLoS ONE, vol. 8, no. 12, pp. e81011, 2013. @article{Flowe2013, BACKGROUND: A person is less likely to be accurately remembered if they appear in a visual scene with a gun, a result that has been termed the weapon focus effect (WFE). Explanations of the WFE argue that weapons engage attention because they are unusual and/or threatening, which causes encoding deficits for the other items in the visual scene. Previous WFE research has always embedded the weapon and nonweapon objects within a larger context that provides information about an actor's intention to use the object. As such, it is currently unknown whether a gun automatically engages attention to a greater extent than other objects independent of the context in which it is presented. METHOD: Reflexive responding to a gun compared to other objects was examined in two experiments. Experiment 1 employed a prosaccade gap-overlap paradigm, whereby participants looked toward a peripheral target, and Experiment 2 employed an antisaccade gap-overlap paradigm, whereby participants looked away from a peripheral target. In both experiments, the peripheral target was a gun or a nonthreatening object (i.e., a tomato or pocket watch). We also controlled how unexpected the targets were and compared saccadic reaction times across types of objects. RESULTS: A gun was not found to differentially engage attention compared to the unexpected object (i.e., a pocket watch). Some evidence was found (Experiment 2) that both the gun and the unexpected object engaged attention to a greater extent compared the expected object (i.e., a tomato). CONCLUSION: An image of a gun did not engage attention to a larger extent than images of other types of objects (i.e., a pocket watch or tomato). The results suggest that context may be an important determinant of WFE. The extent to which an object is threatening may depend on the larger context in which it is presented. |
Tom Foulsham; James Farley; Alan Kingstone Mind wandering in sentence reading: Decoupling the link between mind and eye Journal Article In: Canadian Journal of Experimental Psychology, vol. 67, no. 1, pp. 51–59, 2013. @article{Foulsham2013, When people read, their thoughts sometimes drift away from the task at hand: They are "mind wandering." Recent research suggests that this change in task focus is reflected in eye movements and this was tested in an experiment using controlled stimuli. Participants were presented with a series of sentences containing high- and low-frequency words, which they read while being eye-tracked, and they were sometimes probed to indicate whether they were on task or mind wandering. The results showed multiple differences between reading prior to a mind-wandering response and reading when on task: Mind wandering led to slower reading times, longer average fixation duration, and an absence of the word frequency effect on gaze duration. Collectively, these findings confirm that task focus could be inferred from eye movements, and they indicate that the link between word identification and eye scanning is decoupled when the mind wanders. |
Tom Foulsham; Alexander Gray; Eleni Nasiopoulos; Alan Kingstone Leftward biases in picture scanning and line bisection: A gaze-contingent window study Journal Article In: Vision Research, vol. 78, pp. 14–25, 2013. @article{Foulsham2013d, A bias for humans to attend to the left side of space has been reported in a variety of experiments. While patients with hemispatial neglect mistakenly bisect horizontal lines to the right of centre, neurologically healthy individuals show a mean leftward error. Here, two experiments demonstrated a robust tendency for participants to saccade to the left when viewing photographs. We were able to manipulate this bias by using an asymmetrical gaze-contingent window, which revealed more of the scene on one side of fixation-causing participants to saccade more often in that direction. A second experiment demonstrated the same change in eye movements occurring rapidly from trial to trial, and investigated whether it would carry over and effect attention during a line bisection task. There was some carry-over from gaze-contingent scene viewing to the eye movements during line bisection. However, despite frequent initial eye movements and many errors to the left, manual responses were not affected by this change in orienting. We conclude that the mechanisms underlying asymmetrical attention in picture scanning and line bisection are flexible and can be separated, with saccades in scene perception driven more by a skewed perceptual span. |
Tom Foulsham; Alan Kingstone Fixation-dependent memory for natural scenes: An experimental test of scanpath theory Journal Article In: Journal of Experimental Psychology: General, vol. 142, no. 1, pp. 41–56, 2013. @article{Foulsham2013a, Many modern theories propose that perceptual information is represented by the sensorimotor activity elicited by the original stimulus. Scanpath theory (Noton & Stark, 1971) predicts that reinstating a sequence of eye fixations will help an observer recognize a previously seen image. However, the only studies to investigate this are correlational ones based on calculating scanpath similarity. We therefore describe a series of 5 experiments that constrain the fixations during encoding or recognition of images in order to manipulate scanpath similarity. Participants encoded a set of images and later had to recognize those that they had seen. They spontaneously selected regions that they had fixated during encoding (Experiment 1), and this was a predictor of recognition accuracy. Yoking the parts of the image available at recognition to the encoded scanpath led to better memory performance than randomly selected image regions (Experiment 2), and this could not be explained by the spatial distribution of locations (Experiment 3). However, there was no recognition advantage for re-viewing one's own fixations versus someone else's (Experiment 4) or for retaining their serial order (Experiment 5). Therefore, although it is beneficial to look at encoded regions, there is no evidence that scanpaths are stored or that scanpath recapitulation is functional in scene memory. This paradigm provides a controlled way of studying the integration of scene content, spatial structure, and oculomotor signals, with consequences for the perception, representation, and retrieval of visual information. |
Tom Foulsham; Alan Kingstone Optimal and preferred eye landing positions in objects and scenes Journal Article In: Quarterly Journal of Experimental Psychology, vol. 66, no. 9, pp. 1707–1728, 2013. @article{Foulsham2013b, Viewing position effects are commonly observed in reading, but they have only rarely been investigated in object perception or in the realistic context of a natural scene. In two experiments, we explored where people fixate within photorealistic objects and the effects of this landing position on recognition and subsequent eye movements. The results demonstrate an optimal viewing position-objects are processed more quickly when fixation is in the centre of the object. Viewers also prefer to saccade to the centre of objects within a natural scene, even when making a large saccade. A central landing position is associated with an increased likelihood of making a refixation, a result that differs from previous reports and suggests that multiple fixations within objects, within scenes, occur for a range of reasons. These results suggest that eye movements within scenes are systematic and are made with reference to an early parsing of the scene into constituent objects. |
Shai Gabay; Yoni Pertzov; Noga Cohen; Galia Avidan; Avishai Henik Remapping of the environment without corollary discharges: Evidence from scene-based IOR Journal Article In: Journal of vision, vol. 13, pp. 1–10, 2013. @article{Gabay2013, Previous studies suggested that in order to perceive a stable image of the visual world despite constant eye movements, an efference copy of the oculomotor command is used to remap the representation of the environment in the brain. In two experiments, an inhibitory attentional component (inhibition of return-IOR) was used to examine whether remapping can occur also in the absence of eye movements. Participants were asked to maintain fixation while an unpredictive, attention-grabbing cue appeared and was then followed by a movement of the background image which was artificial (random dots, Experiment 1) or composed of natural scenes (Experiment 2). The participants were then required to respond to a target stimulus that was presented either at the same location as the cue relative to fixation (retinotopic), or at a matching location relative to the background (scene based). In both experiments, an IOR effect was found in scene-based locations immediately after the movement of the background. We suggest that remapping of the inhibitory tagging, which might be a proxy for remapping of the visual scene, could be accomplished rapidly even without the use of an efference copy; the inhibitory tag seems to be anchored to the background image and to move together with it. |
Jason P. Gallivan; Craig S. Chapman; D. Adam Mclean; J. Randall Flanagan; Jody C. Culham Activity patterns in the category-selective occipitotemporal cortex predict upcoming motor actions Journal Article In: European Journal of Neuroscience, vol. 38, no. 3, pp. 2408–2424, 2013. @article{Gallivan2013a, Converging lines of evidence point to the occipitotemporal cortex (OTC) as a critical structure in visual perception. For instance, human functional magnetic resonance imaging (fMRI) has revealed a modular organisation of object-selective, face-selective, body-selective and scene-selective visual areas in the OTC, and disruptions to the processing within these regions, either in neuropsychological patients or through transcranial magnetic stimulation, can produce category-specific deficits in visual recognition. Here we show, using fMRI and pattern classification methods, that the activity in the OTC also represents how stimuli will be interacted with by the body–a level of processing more traditionally associated with the preparatory activity in sensorimotor circuits of the brain. Combining functional mapping of different OTC areas with a real object-directed delayed movement task, we found that the pre-movement spatial activity patterns across the OTC could be used to predict both the action of an upcoming hand movement (grasping vs. reaching) and the effector (left hand vs. right hand) to be used. Interestingly, we were able to extract this wide range of predictive movement information even though nearly all OTC areas showed either baseline-level or below baseline-level activity prior to action onset. Our characterisation of different OTC areas according to the features of upcoming movements that they could predict also revealed a general gradient of effector-to-action-dependent movement representations along the posterior-anterior OTC axis. These findings suggest that the ventral visual pathway, which is well known to be involved in object recognition and perceptual processing, plays a larger than previously expected role in preparing object-directed hand actions. |
Jason P. Gallivan; D. Adam McLean; J. Randall Flanagan; Jody C. Culham In: Journal of Neuroscience, vol. 33, no. 5, pp. 1991–2008, 2013. @article{Gallivan2013, Planning object-directed hand actions requires successful integration of the movement goal with the acting limb. Exactly where and how this sensorimotor integration occurs in the brain has been studied extensively with neurophysiological recordings in nonhuman primates, yet to date, because of limitations of non-invasive methodologies, the ability to examine the same types of planning-related signals in humans has been challenging. Here we show, using a multivoxel pattern analysis of functional MRI (fMRI) data, that the preparatory activity patterns in several frontoparietal brain regions can be used to predict both the limb used and hand action performed in an upcoming movement. Participants performed an event-related delayed movement task whereby they planned and executed grasp or reach actions with either their left or right hand toward a single target object. We found that, although the majority of frontoparietal areas represented hand actions (grasping vs reaching) for the contralateral limb, several areas additionally coded hand actions for the ipsilateral limb. Notable among these were subregions within the posterior parietal cortex (PPC), dorsal premotor cortex (PMd), ventral premotor cortex, dorsolateral prefrontal cortex, presupplementary motor area, and motor cortex, a region more traditionally implicated in contralateral movement generation. Additional analyses suggest that hand actions are represented independently of the intended limb in PPC and PMd. In addition to providing a unique mapping of limb-specific and action-dependent intention-related signals across the human cortical motor system, these findings uncover a much stronger representation of the ipsilateral limb than expected from previous fMRI findings. |
Hiroaki Gomi; Naotoshi Abekawa; Shinsuke Shimojo The hand sees visual periphery better than the eye: Motor-dependent visual motion analyses Journal Article In: Journal of Neuroscience, vol. 33, no. 42, pp. 16502–16509, 2013. @article{Gomi2013, Information pertaining to visual motion is used in the brain not only for conscious perception but also for various kinds of motor controls. In contrast to the increasing amount of evidence supporting the dissociation of visual processing for action versus perception, it is less clear whether the analysis of visual input is shared for characterizing various motor outputs, which require different kinds of interactions with environments. Here we show that, in human visuomotor control, motion analysis for quick hand control is distinct from that for quick eye control in terms of spatiotemporal analysis and spatial integration. The amplitudes of implicit and quick hand and eye responses induced by visual motion stimuli differently varied with stimulus size and pattern smoothness (e.g., spatial frequency). Surprisingly, the hand response did not decrease even when the visual motion with a coarse pattern was mostly occluded over the visual center, whereas the eye response markedly decreased. Since these contrasts cannot be ascribed to any difference in motor dynamics, they clearly indicate different spatial integration of visual motion for the individual motor systems. Going against the overly unified hierarchical view of visual analysis, our data suggest that visual motion analyses are separately tailored from early levels to individual motor modalities. Namely, the hand and eyes see the external world differently. |
Frauke Görges; Frank Oppermann; Jörg D. Jescheniak; Herbert Schriefers Activation of phonological competitors in visual search Journal Article In: Acta Psychologica, vol. 143, no. 2, pp. 168–175, 2013. @article{Goerges2013, Recently, Meyer, Belke, Telling and Humphreys (2007) reported that competitor objects with homophonous names (e.g., boy) interfere with identifying a target object (e.g., buoy) in a visual search task, suggesting that an object name's phonology becomes automatically activated even in situations in which participants do not have the intention to speak. The present study explored the generality of this finding by testing a different phonological relation (rhyming object names, e.g., cat-hat) and by varying details of the experimental procedure. Experiment 1 followed the procedure by Meyer et al. Participants were familiarized with target and competitor objects and their names at the beginning of the experiment and the picture of the target object was presented prior to the search display on each trial. In Experiment 2, the picture of the target object presented prior to the search display was replaced by its name. In Experiment 3, participants were not familiarized with target and competitor objects and their names at the beginning of the experiment. A small interference effect from phonologically related competitors was obtained in Experiments 1 and 2 but not in Experiment 3, suggesting that the way the relevant objects are introduced to participants affects the chances of observing an effect from phonologically related competitors. Implications for the information flow in the conceptual-lexical system are discussed. |
Davood G. Gozli; Amy Chow; Alison L. Chasteen; Jay Pratt Valence and vertical space: Saccade trajectory deviations reveal metaphorical spatial activation Journal Article In: Visual Cognition, vol. 21, no. 5, pp. 628–646, 2013. @article{Gozli2013, Concepts of positive and negative valence are metaphorically structured in space (e.g., happy is up,sad is down). In fact, coupling a conceptual task (e.g., evaluating words as positive or negative) with a visuospatial task (e.g., identifying stimuli above or below fixation) often gives rise to metaphorical congruency effects. For instance, after reading a positive concept, visual target processing is facilitated above fixation. However, it is possible that tasks requiring upwards and downwards attentional orienting artificially strengthen the link between vertical space and semantic valence. For this reason, in the present study the vertical axis was uncoupled from the response axis. Participants made eye movements along the horizontal axis after reading positive or negative affect words, while their saccade movement trajectories were recorded. Based on previous research on saccade trajectory deviation, we predicted that fast saccade trajectories curve towards the salient segment of space, whereas slow saccade trajectories would curve away from the salient segment. Examining saccadic trajectories revealed a pattern of deviations along the vertical axis consistent with the metaphorical congruency account, although this pattern was mainly driven by positive concepts. These results suggest that semantic processing of valence can automatically recruit spatial features along the vertical axis. |
Harold H. Greene; James M. Brown; Bryce A. Paradis Luminance contrast and the visual span during visual target localization Journal Article In: Displays, vol. 34, no. 1, pp. 27–32, 2013. @article{Greene2013, A concern for designers of monocular and binocular devices is the ability of users to search for, and localize target items embedded in noisy displays. Twenty-two participants searched (12 under monocular conditions) to localize a target embedded in random gray dot displays. The target was defined by a variation in pattern that did not differ in average contrast from the rest of each display. Displays were presented at.54 and.04 Michelson contrast. Across binocular and monocular viewings, fixation counts increased with decreasing contrast, but the gradient was steeper for monocular viewing. With decreasing contrast, fixations were longer, and the amplitudes of saccades used to localize the target decreased. The findings highlight for monocular vs. binocular target localization, the importance of considering separately, how many fixations are needed to localize the target, and how close to fixation the target must be for it to be noticed. |
Sarah J. Gervais; Arianne M. Holland; Michael D. Dodd My eyes are up here: The nature of the objectifying gaze toward women Journal Article In: Sex Roles, vol. 69, no. 11-12, pp. 557–570, 2013. @article{Gervais2013, Although objectification theory suggests that women frequently experience the objectifying gaze with many adverse consequences, there is scant research examining the nature and causes of the objectifying gaze for perceivers. The main purpose of this work was to examine the objectifying gaze toward women via eye tracking technology. A secondary purpose was to examine the impact of body shape on this objectifying gaze. To elicit the gaze, we asked participants (29 women, 36 men from a large Midwestern University in the U.S.), to focus on the appearance (vs. personality) of women and presented women with body shapes that fit cultural ideals of feminine attractiveness to varying degrees, including high ideal (i.e., hourglass-shaped women with large breasts and small waist-to-hip ratios), average ideal (with average breasts and average waist-to-hip ratios), and low ideal (i.e., with small breasts and large waist-to-hip ratios). Consistent with our main hypothesis, we found that participants focused on women's chests and waists more and faces less when they were appearance-focused (vs. personality-focused). Moreover, we found that this effect was particularly pronounced for women with high (vs. average and low) ideal body shapes in line with hypotheses. Finally, compared to female participants, male participants showed an increased tendency to initially exhibit the objectifying gaze and they regarded women with high (vs. average and low) ideal body shapes more positively, regardless of whether they were appearance-focused or personality-focused. Implications for objectification and person perception theories are discussed. |
Saeideh Ghahghaei; Karina J. Linnell; Martin H. Fischer; Amit Dubey; Robert Davis Effects of load on the time course of attentional engagement, disengagement, and orienting in reading Journal Article In: Quarterly Journal of Experimental Psychology, vol. 66, no. 3, pp. 453–470, 2013. @article{Ghahghaei2013, We examined how the frequency of the fixated word influences the spatiotemporal distribution of covert attention during reading. Participants discriminated gaze-contingent probes that occurred with different spatial and temporal offsets from randomly chosen fixation points during reading. We found that attention was initially focused at fixation and that subsequent defocusing was slower when the fixated word was lower in frequency. Later in a fixation, attention oriented more towards the next saccadic target for high- than for low-frequency words. These results constitute the first report of the time course of the effect of load on attentional engagement and orienting in reading. They are discussed in the context of serial and parallel models of reading. |
Aline Godfroid; Frank Boers; Alex Housen An eye for words: Gauging the role of attention in incidental L2 vocabulary acquisition by means of eye-tracking Journal Article In: Studies in Second Language Acquisition, vol. 35, no. 3, pp. 483–517, 2013. @article{Godfroid2013, This eye-tracking study tests the hypothesis that more attention leads to more learning, following claims that attention to new language elements in the input results in their initial representation in long-term memory (i.e., intake; Robinson, 2003; Schmidt, 1990, 2001). Twenty-eight advanced learners of English read English texts that contained 12 targets for incidental word learning. The target was a known word (control condition), a matched pseudoword, or that pseudoword preceded or followed by the known word (with the latter being a cue to the pseudoword's meaning). Participants' eye-fixation durations on the targets during reading served as a measure of the amount of attention paid (see Rayner, 2009). Results indicate that participants spent more time processing the unknown pseudowords than their matched controls. The longer participants looked at a pseudoword during reading, the more likely they were to recognize that word in an unannounced vocabulary posttest. Finally, the known, appositive cues were fixated longer when they followed the pseudowords than when they preceded them; however, their presence did not lead to higher retention of the pseudowords. We discuss how eye-tracking may add to existing methodologies for studying attention and noticing (Schmidt, 1990) in SLA. |
Ulrike Hochpöchler; Wolfgang Schnotz; Thorsten Rasch; Mark Ullrich; Holger Horz; Nele McElvany; Jürgen Baumert Dynamics of mental model construction from text and graphics Journal Article In: European Journal of Psychology of Education, vol. 28, no. 4, pp. 1105–1126, 2013. @article{Hochpoechler2013, When students read for learning, they frequently are required to integrate text and graphics information into coherent knowledge structures. The following study aimed at analyzing how students deal with texts and how they deal with graphics when they try to integrate the two sources of information. Furthermore, the study investigated differences between students from different school types and grades. Forty students from grades 5 and 8 from higher track and lower track of the German school system were asked to process and integrate texts and graphics in order to answer items from different levels of a text-picture integration taxonomy. Students' eye movements were recorded and analyzed. Results suggest fundamentally different functions of text and graphics, which are associated with different processing strategies. Texts are more likely to be used according to a coherence-formation strategy, whereas graphics are more likely to be used on demand as visual cognitive tools according to an information-selection strategy. Students from different tracks of schooling revealed different adaptivity with regard to the requirements of combining text and graphic information. |
Andrew Hollingworth; Michi Matsukura; Steven J. Luck Visual working memory modulates low-level saccade target selection: Evidence from rapidly generated saccades in the global effect paradigm Journal Article In: Journal of Vision, vol. 13, no. 13, pp. 1–8, 2013. @article{Hollingworth2013, In three experiments, we examined the influence of visual working memory (VWM) on the metrics of saccade landing position in a global effect paradigm. Participants executed a saccade to the more eccentric object in an object pair appearing on the horizontal midline, to the left or right of central fixation. While completing the saccade task, participants maintained a color in VWM for an unrelated memory task. Either the color of the saccade target matched the memory color (target match), the color of the distractor matched the memory color (distractor match), or the colors of neither object matched the memory color (no match). In the no-match condition, saccades tended to land at the midpoint between the two objects: the global, or averaging, effect. However, when one of the two objects matched VWM, the distribution of landing position shifted toward the matching object, both for target match and for distractor match. VWM modulation of landing position was observed even for the fastest quartile of saccades, with a mean latency as low as 112 ms. Effects of VWM on such rapidly generated saccades, with latencies in the express-saccade range, indicate that VWM interacts with the initial sweep of visual sensory processing, modulating perceptual input to oculomotor systems and thereby biasing oculomotor selection. As a result, differences in memory match produce effects on landing position similar to the effects generated by differences in physical salience. |
Andrew Hollingworth; Michi Matsukura; Steven J. Luck Visual working memory modulates rapid eye movements to simple onset targets Journal Article In: Psychological Science, vol. 24, no. 5, pp. 790–796, 2013. @article{Hollingworth2013a, Representations in visual working memory (VWM) influence attention and gaze control in complex tasks, such as visual search, that require top-down selection to resolve stimulus competition. VWM and visual attention clearly interact, but the mechanism of that interaction is not well understood. In the research reported here, we demonstrated that in the absence of stimulus competition or goal-level biases, VWM representations of object features influence the spatiotemporal dynamics of extremely simple eye movements. The influence of VWM therefore extends into the most basic operations of the oculomotor system. |
Junpeng Lao; Luca Vizioli; Roberto Caldara Culture modulates the temporal dynamics of global/local processing Journal Article In: Culture and Brain, vol. 1, no. 2-4, pp. 158–174, 2013. @article{Lao2013, Cultural differences in the way individuals from Western Caucasian (WC) and East Asian (EA) societies perceive and attend to visual information have been consistently reported in recent years. WC observers favor and perceive most efficiently the salient, local visual information by directing attention to focal objects. In contrast, EA observers show a bias towards global information, by preferentially attending elements in the background. However, the underlying neural mechanisms and the temporal dynamics of this striking cultural contrast have yet to be clarified. The combination of Navon figures, which contain both global and local features, and the measurement of neural adaptation constitute an ideal way to probe this issue. We recorded the electrophysiological signals of WC and EA observers while they actively matched culturally neutral geometric Navon shapes. In each trial, participants sequentially viewed and categorized an adapter shape followed by a target shape, as being either: identical; global congruent; local congruent; and different. We quantified the repetition suppression, a reduction in neural activity in stimulus sensitive regions following stimulus repetition, using a single-trial approach. A robust data-driven spatio-temporal analysis revealed at 80 ms a significant interaction between the culture of the observers and shape adaptation. EA observers showed sensitivity to global congruency on the attentional P1 component, whereas WC observers showed discrimination for global shapes at later stages. Our data revealed an early sensitivity to global and local shape cate- gorization, which is modulated by culture. This neural tuning could underlie more complex behavioral differences observed across human populations. |
Jochen Laubrock Laubrock; Anke Cajar Cajar; Ralf Engbert Control of fixation duration during scene viewing by interaction of foveal and peripheral processing Journal Article In: Journal of Vision, vol. 13, no. 12, pp. 1–20, 2013. @article{Laubrock2013, Processing in our visual system is functionally segregated, with the fovea specialized in processing fine detail (high spatial frequencies) for object identification, and the periphery in processing coarse information (low frequencies) for spatial orienting and saccade target selection. Here we investigate the consequences of this functional segregation for the control of fixation durations during scene viewing. Using gaze-contingent displays, we applied high-pass or low-pass filters to either the central or the peripheral visual field and compared eye-movement patterns with an unfiltered control condition. In contrast with predictions from functional segregation, fixation durations were unaffected when the critical information for vision was strongly attenuated (foveal low-pass and peripheral high-pass filtering); fixation durations increased, however, when useful information was left mostly intact by the filter (foveal high-pass and peripheral low-pass filtering). These patterns of results are difficult to explain under the assumption that fixation durations are controlled by foveal processing difficulty. As an alternative explanation, we developed the hypothesis that the interaction of foveal and peripheral processing controls fixation duration. To investigate the viability of this explanation, we implemented a computational model with two compartments, approximating spatial aspects of processing by foveal and peripheral activations that change according to a small set of dynamical rules. The model reproduced distributions of fixation durations from all experimental conditions by variation of few parameters that were affected by specific filtering conditions. |
Ada Le; Matthias Niemeier Left visual field preference for a bimanual grasping task with ecologically valid object sizes Journal Article In: Experimental Brain Research, vol. 230, pp. 187–196, 2013. @article{Le2013a, Grasping using two forelimbs in opposition to one another is evolutionary older than the hand with an opposable thumb (Whishaw and Coles in Behav Brain Res 77:135–148, 1996); yet, the mechanisms for bimanual grasps remain unclear. Similar to unimanual grasping, the localization of matching stable grasp points on an object is computationally expensive and so it makes sense for the signals to converge in a single cortical hemisphere. Indeed, bimanual grasps are faster and more accurate in the left visual field, and are disrupted if there is transcra- nial stimulation of the right hemisphere (Le and Niemeier in Exp Brain Res 224:263–273, 2013; Le et al. in Cereb Cortex. doi:10.1093/cercor/bht115, 2013). However, research so far has tested the right hemisphere dominance based on small objects only, which are usually grasped with one hand, whereas bimanual grasping is more com- monly used for objects that are too big for a single hand. Because grasping large objects might involve different neural circuits than grasping small objects (Grol et al. in J Neurosci 27:11877–11887, 2007), here we tested whether a left visual field/right hemisphere dominance for biman- ual grasping exists with large and thus more ecologically valid objects or whether the right hemisphere dominance is a function of object size. We asked participants to fixate to the left or right of an object and to grasp the object with the index and middle fingers of both hands. Consistent with previous observations, we found that for objects in the left visual field, the maximum grip apertures were scaled closer to the object width and were smaller and less variable, than for objects in the right visual field. Our results demonstrate that bimanual grasping is predominantly controlled by the right hemisphere, even in the context of grasping larger objects. |
Ada Le; Matthias Niemeier A right hemisphere dominance for bimanual grasps Journal Article In: Experimental Brain Research, vol. 224, no. 2, pp. 263–273, 2013. @article{Le2013, To find points on the surface of an object that ensure a stable grasp, it would be most effective to employ one area in one cortical hemisphere. But grasping the object with both hands requires control through both hemispheres. To better understand the control mechanisms underlying this "bimanual grasping", here we examined how the two hemispheres coordinate their control processes for bimanual grasping depending on visual field. We asked if bimanual grasping involves both visual fields equally or one more than the other. To test this, participants fixated either to the left or right of an object and then grasped or pushed it off a pedestal. We found that when participants grasped the object in the right visual field, maximum grip aperture (MGA) was larger and more variable, and participants were slower to react and to show MGA compared to when they grasped the object in the left visual field. In contrast, when participants pushed the object we observed no comparable visual field effects. These results suggest that grasping with both hands, specifically the computation of grasp points on the object, predominantly involves the right hemisphere. Our study provides new insights into the interactions of the two hemispheres for grasping. |
Alwine Lenzner; Wolfgang Schnotz; Andreas Müller The role of decorative pictures in learning Journal Article In: Instructional Science, vol. 41, no. 5, pp. 811–831, 2013. @article{Lenzner2013, Three experiments with students from 7th and 8th grade were performed to investigate the effects of decorative pictures in learning as compared to instructional pictures. Pictures were considered as instructional, when they were primarily informative, and as decorative, when they were primarily aesthetically appealing. The experiments investigated, whether and to what extent decorative pictures affect the learner's distribution of attention, whether they have an effect on the affective and motivational state and whether they affect the learning outcomes. The first experiment indicated with eye-tracking methodology that decorative pictures receive only a bit initial attention as part of the learner's initial orientation and are largely ignored afterwards, which suggests that they have only a minor distracting effect if any. The second experiment showed that despite the small amount of attention they receive, decorative pictures seem to induce better mood, alertness and calmness with learners. The third experiment indicated that decorative pictures did not intensify students' situational interest, but reduced perceived difficulty of the learning material. Regarding outcomes of learning, decorative pictures were altogether neither harmful nor beneficial for learning. However, they moderated the beneficial effect of instructional pictures–in essence: the multimedia effect. The moderating effect was especially pronounced when learners had lower prior knowledge. The findings are discussed from the perspective of cognitive, affective and motivational psychology. Perspectives of further research are pointed out. |
Carly J. Leonard; Benjamin M. Robinson; Samuel T. Kaiser; Britta Hahn; Clara McClenon; Alexander N. Harvey; Steven J. Luck; James M. Gold Testing sensory and cognitive explanations of the antisaccade deficit in schizophrenia Journal Article In: Journal of Abnormal Psychology, vol. 122, no. 4, pp. 1111–1120, 2013. @article{Leonard2013, Recent research has suggested that people with schizophrenia (PSZ) have sensory deficits, especially in the magnocellular pathway, and this has led to the proposal that dysfunctional sensory processing may underlie higher-order cognitive deficits. Here we test the hypothesis that the antisaccade deficit in PSZ reflects dysfunctional magnocellular processing rather than impaired cognitive processing, as indexed by working memory capacity. This is a plausible hypothesis because oculomotor regions have direct magnocellular inputs, and the stimuli used in most antisaccade tasks strongly activate the magnocellular visual pathway. In the current study, we examined both prosaccade and antisaccade performance in PSZ (N = 22) and matched healthy control subjects (HCS; N = 22) with Gabor stimuli designed to preferentially activate the magnocellular pathway, the parvocellular pathway, or both pathways. We also measured working memory capacity. PSZ exhibited impaired antisaccade performance relative to HCS across stimulus types, with impairment even for stimuli that minimized magnocellular activation. Although both sensory thresholds and working memory capacity were impaired in PSZ, only working memory capacity was correlated with antisaccade accuracy, consistent with a cognitive rather than sensory origin for the antisaccade deficit. |
Ute Leonards; Samantha Stone; Christine Mohr Line bisection by eye and by hand reveal opposite biases Journal Article In: Experimental Brain Research, vol. 228, no. 4, pp. 513–525, 2013. @article{Leonards2013, The vision-for-action literature favours the idea that the motor output of an action-whether manual or oculomotor-leads to similar results regarding object handling. Findings on line bisection performance challenge this idea: healthy individuals bisect lines manually to the left of centre and to the right of centre when using eye fixation. In case that these opposite biases for manual and oculomotor action reflect more universal compensatory mechanisms that cancel each other out to enhance overall accuracy, one would like to observe comparable opposite biases for other material. In the present study, we report on three independent experiments in which we tested line bisection (by hand, by eye fixation) not only for solid lines, but also for letter lines; the latter, when bisected manually, is known to result in a rightward bias. Accordingly, we expected a leftward bias for letter lines when bisected via eye fixation. Analysis of bisection biases provided evidence for this idea: manual bisection was more rightward for letter as compared to solid lines, while bisection by eye fixation was more leftward for letter as compared to solid lines. Support for the eye fixation observation was particularly obvious in two of the three studies, for which comparability between eye and hand action was increasingly adjusted (paper-pencil versus touch screen for manual action). These findings question the assumption that ocular motor and manual output are always inter-changeable, but rather suggest that at least for some situations ocular motor and manual output biases are orthogonal to each other, possibly balancing each other out. |
Benjamin D. Lester; Paul Dassonville Shifts of visuospatial attention do not cause the spatial distortions of the Roelofs effect Journal Article In: Journal of Vision, vol. 13, no. 12, pp. 4–4, 2013. @article{Lester2013, When a visible frame is offset left or right of an observer's objective midline, subjective midline is pulled toward the frame's center, resulting in an illusion of perceived space known as the Roelofs effect. However, a large frame is not necessary to generate the effect-even a small peripheral stimulus is sufficient, raising the possibility that the effect would be brought about by any stimulus that draws attention away from the midline. To assess the relationship between attention and distortions of perceived space, we adopted a paradigm that included a spatial cue that attracted the participant's attention, and an occasional probe whose location was to be reported. If shifts of attention cause the Roelofs effect, the probe's perceived location should vary with the locus of attention. Exogenous attentional cues caused a Roelofs-like effect, but these cues created an asymmetry in the visual display that may have driven the effect directly. In contrast, there was no mislocation after endogenous cues that contained no asymmetry in the visual display. A final experiment used color-contingent attentional cues to eliminate the confound between cue location and asymmetry in the visual display, and provided a clear demonstration that the Roelofs effect is caused by an asymmetric visual display, independent of any shift of attention. |
Joshua Levy; Tom Foulsham; Alan Kingstone Monsters are people too Journal Article In: Biology Letters, vol. 9, pp. 1–4, 2013. @article{Levy2013, Animals, including dogs, dolphins, monkeys and man, follow gaze. What mediates this bias towards the eyes? One hypothesis is that primates possess a distinct neural module that is uniquely tuned for the eyes of others. An alternative explanation is that configural face processing drives fixations to the middle of peoples' faces, which is where the eyes happen to be located. We distinguish between these two accounts. Observers were presented with images of people, non-human creatures with eyes in the middle of their faces (`humanoids') or creatures with eyes positioned elsewhere (`monsters'). There was a profound and significant bias towards looking early and often at the eyes of humans and humanoids and also, critically, at the eyes of monsters. These findings demonstrate that the eyes, and not the middle of the head, are being targeted by the oculomotor system. |
Li Jingling; Da-Lun Tang; Chia-huei Tseng Salient collinear grouping diminishes local salience in visual search: An eye movement study Journal Article In: Journal of Vision, vol. 13, no. 12, pp. 1–10, 2013. @article{Jingling2013, Our eyes and attention are easily attracted to salient items in search displays. When a target is spatially overlapped with a salient distractor (overlapping target), it is usually detected more easily than when it is not (nonoverlapping target). Jingling and Tseng (2013), however, found that a salient distractor impaired visual search when the distractor was comprised of more than nine bars collinearly aligned to each other. In this study, we examined whether this search impairment is due to reduction of salience on overlapping targets. We used the short-latency saccades as an index for perceptual salience. Results showed that a long collinear distractor decreases perceptual salience of local overlapping targets in comparison to nonoverlapping targets, reflected by a smaller proportion of the short-latency saccades. Meanwhile, a salient noncollinear distractor increases salience of overlapping targets. Our results led us to conclude that a long collinear distractor diminishes the perceptual salience of the target, a factor which poses a counter-intuitive condition in which a target on a salient region becomes less salient. We discuss the possible causes for our findings, including crowding, the global precedence effect, and the filling-in of a collinear contour. |
Jiri Lukavsky Eye movements in repeated multiple object tracking Journal Article In: Journal of vision, vol. 13, pp. 1–16, 2013. @article{JiriLukavsky2013, Contrary to other tasks (free viewing, recognition, visual search), participants often fail to recognize repetition of trials in multiple object tracking (MOT). This study examines the intra- and interindividual variability of eye movements in repeated MOT trials along with the adherence of eye movements to the previously described strategies. I collected eye movement data from 20 subjects during 64 MOT trials at slow speed (58/s). Half of the trials were repeated four times, and the remaining trials were unique. I measured the variability of eye- movement patterns during repeated trials using normalized scanpath saliency extended to the temporal domain. People tended to make similar eye movements during repeated presentations (with no or vague feeling of repetition) and the interindividual similarity remained at the same level over time. Several strategies (centroid strategy and its variants) were compared with data and they accounted for 48.8% to 54.3% of eye-movement variability, which was less then variability explained by other peoples' eye movements (68.6%). The results show that the observed intra- and interindividual similarity of eye movements is only partly explained by the current models. |
Donatas Jonikaitis; Martin Szinte; Martin Rolfs; Patrick Cavanagh Allocation of attention across saccades Journal Article In: Journal of Neurophysiology, vol. 109, no. 5, pp. 1425–1434, 2013. @article{Jonikaitis2013, Whenever the eyes move, spatial attention must keep track of the locations of targets as they shift on the retina. This study investigated transsaccadic updating of visual attention to cued targets. While observers prepared a saccade, we flashed an irrelevant, but salient, color cue in their visual periphery and measured the allocation of spatial attention before and after the saccade using a tilt discrimination task. We found that just before the saccade, attention was allocated to the cue's future retinal location, its predictively "remapped" location. Attention was sustained at the cue's location in the world across the saccade, despite the change of retinal position whereas it decayed quickly at the retinal location of the cue, after the eye landed. By extinguishing the color cue across the saccade, we further demonstrate that the visual system relies only on predictive allocation of spatial attention, as the presence of the cue after the saccade did not substantially affect attentional allocation. These behavioral results support and extend physiological evidence showing predictive activation of visual neurons when an attended stimulus will fall in their receptive field after a saccade. Our results show that tracking of spatial locations across saccades is a plausible consequence of physiological remapping. |
Donatas Jonikaitis; Jan Theeuwes Dissociating oculomotor contributions to spatial and feature-based selection Journal Article In: Journal of Neurophysiology, vol. 110, no. 7, pp. 1525–1534, 2013. @article{Jonikaitis2013a, Saccades not only deliver the high-resolution retinal image requisite for visual perception, but processing stages associated with saccade target selection affect visual perception even before the eye movement starts. These presaccadic effects are thought to arise from two visual selection mechanisms: spatial selection that enhances processing of the saccade target location and feature-based selection that enhances processing of the saccade target features. By measuring oculomotor performance and perceptual discrimination, we determined which selection mechanisms are associated with saccade preparation. We observed both feature-based and space-based selection during saccade preparation but found that feature-based selection was neither related to saccade initiation nor was it affected by simultaneously observed redistribution of spatial selection. We conclude that oculomotor selection biases visual selection only in a spatial, feature-unspecific manner. |
Mariska E. Kret; Karin Roelofs; Jeroen J. Stekelenburg; Beatrice Gelder Emotional signals from faces, bodies and scenes influence observers' face expressions, fixations and pupil-size Journal Article In: Frontiers in Human Neuroscience, vol. 7, pp. 810, 2013. @article{Kret2013, We receive emotional signals from different sources, including the face, the whole body, and the natural scene. Previous research has shown the importance of context provided by the whole body and the scene on the recognition of facial expressions. This study measured physiological responses to face-body-scene combinations. Participants freely viewed emotionally congruent and incongruent face-body and body-scene pairs whilst eye fixations, pupil-size, and electromyography (EMG) responses were recorded. Participants attended more to angry and fearful vs. happy or neutral cues, independent of the source and relatively independent from whether the face body and body scene combinations were emotionally congruent or not. Moreover, angry faces combined with angry bodies and angry bodies viewed in aggressive social scenes elicited greatest pupil dilation. Participants' face expressions matched the valence of the stimuli but when face-body compounds were shown, the observed facial expression influenced EMG responses more than the posture. Together, our results show that the perception of emotional signals from faces, bodies and scenes depends on the natural context, but when threatening cues are presented, these threats attract attention, induce arousal, and evoke congruent facial reactions. |
Mariska E. Kret; Jeroen J. Stekelenburg; Karin Roelofs; Beatrice Gelder Perception of face and body expressions using electromyography, pupillometry and gaze measures Journal Article In: Frontiers in Psychology, vol. 4, pp. 28, 2013. @article{Kret2013a, Traditional emotion theories stress the importance of the face in the expression of emotions but bodily expressions are becoming increasingly important as well. In these experiments we tested the hypothesis that similar physiological responses can be evoked by observing emotional face and body signals and that the reaction to angry signals is amplified in anxious individuals. We designed three experiments in which participants categorized emotional expressions from isolated facial and bodily expressions and emotionally congruent and incongruent face-body compounds. Participants' fixations were measured and their pupil size recorded with eye-tracking equipment and their facial reactions measured with electromyography. The results support our prediction that the recognition of a facial expression is improved in the context of a matching posture and importantly, vice versa as well. From their facial expressions, it appeared that observers acted with signs of negative emotionality (increased corrugator activity) to angry and fearful facial expressions and with positive emotionality (increased zygomaticus) to happy facial expressions. What we predicted and found, was that angry and fearful cues from the face or the body, attracted more attention than happy cues. We further observed that responses evoked by angry cues were amplified in individuals with high anxiety scores. In sum, we show that people process bodily expressions of emotion in a similar fashion as facial expressions and that the congruency between the emotional signals from the face and body facilitates the recognition of the emotion. |
Elke B. Lange; Ralf Engbert Differentiating between verbal and spatial encoding using eye-movement recordings Journal Article In: Quarterly Journal of Experimental Psychology, vol. 66, no. 9, pp. 1840–1857, 2013. @article{Lange2013, Visual information processing is guided by an active mechanism generating saccadic eye movements to salient stimuli. Here we investigate the specific contribution of saccades to memory encoding of verbal and spatial properties in a serial recall task. In the first experiment, participants moved their eyes freely without specific instruction. We demonstrate the existence of qualitative differences in eye-movement strategies during verbal and spatial memory encoding. While verbal memory encoding was characterized by shifting the gaze to the to-be-encoded stimuli, saccadic activity was suppressed during spatial encoding. In the second experiment, participants were required to suppress saccades by fixating centrally during encoding or to make precise saccades onto the memory items. Active suppression of saccades had no effect on memory performance, but tracking the upcoming stimuli decreased memory performance dramatically in both tasks, indicating a resource bottleneck between display-controlled saccadic control and memory encoding. We conclude that optimized encoding strategies for verbal and spatial features are underlying memory performance in serial recall, but such strategies work on an involuntary level only and do not support memory encoding when they are explicitly required by the task. |
Kai Kaspar; Teresa Maria Hloucal; Jürgen Kriz; Sonja Canzler; Ricardo Ramos Gameiro; Vanessa Krapp; Peter König Emotions' impact on viewing behavior under natural conditions Journal Article In: PLoS ONE, vol. 8, no. 1, pp. e52737, 2013. @article{Kaspar2013, Human overt attention under natural conditions is guided by stimulus features as well as by higher cognitive components, such as task and emotional context. In contrast to the considerable progress regarding the former, insight into the interaction of emotions and attention is limited. Here we investigate the influence of the current emotional context on viewing behavior under natural conditions.In two eye-tracking studies participants freely viewed complex scenes embedded in sequences of emotion-laden images. The latter primes constituted specific emotional contexts for neutral target images.Viewing behavior toward target images embedded into sets of primes was affected by the current emotional context, revealing the intensity of the emotional context as a significant moderator. The primes themselves were not scanned in different ways when presented within a block (Study 1), but when presented individually, negative primes were more actively scanned than positive primes (Study 2). These divergent results suggest an interaction between emotional priming and further context factors. Additionally, in most cases primes were scanned more actively than target images. Interestingly, the mere presence of emotion-laden stimuli in a set of images of different categories slowed down viewing activity overall, but the known effect of image category was not affected. Finally, viewing behavior remained largely constant on single images as well as across the targets' post-prime positions (Study 2).We conclude that the emotional context significantly influences the exploration of complex scenes and the emotional context has to be considered in predictions of eye-movement patterns. |
Dirk Kerzel; Josef G. Schönhammer Salient stimuli capture attention and action Journal Article In: Attention, Perception, and Psychophysics, vol. 75, no. 8, pp. 1633–1643, 2013. @article{Kerzel2013, Reaction times in a visual search task increase when an irrelevant but salient stimulus is presented. Recently, the hypothesis that the increase in reaction times was due to attentional capture by the salient distractor has been disputed. We devised a task in which a search display was shown after observers had initiated a reaching movement toward a touch screen. In a display of vertical bars, observers had to touch the oblique target while ignoring a salient color singleton. Because the hand was moving when the display appeared, reach trajectories revealed the current selection for action. We observed that salient but irrelevant stimuli changed the reach trajectory at the same time as the target was selected, about 270 ms after movement onset. The change in direction was corrected after another 160 ms. In a second experiment, we compared manual selection of color and orientation targets and observed that selection occurred earlier for color than for orientation targets. Salient stimuli support faster selection than do less salient stimuli. Under the assumption that attentional selection for action and perception are based on a common mechanism, our results suggest that attention is indeed captured by salient stimuli. |
Shah Khalid; Ulrich Ansorge The Simon effect of spatial words in eye movements: Comparison of vertical and horizontal effects and of eye and finger responses Journal Article In: Vision Research, vol. 86, pp. 6–14, 2013. @article{Khalid2013, Spatial stimulus location information impacts on saccades: Pro-saccades (saccades towards a stimulus location) are faster than anti-saccades (saccades away from the stimulus). This is true even when the spatial location is irrelevant for the choice of the correct response (Simon effect). The results are usually ascribed to spatial sensorimotor coupling. However, with finger responses Simon effects can be observed with irrelevant spatial word meaning, too. Here we tested whether a Simon effect of spatial word meaning in saccades could be observed for words with vertical ("above" or "below") and horizontal ("left" or "right") meanings. We asked our participants to make saccades towards one of the two saccade targets depending on the color of the centrally presented spatial word, while ignoring their spatial meaning (Experiment 1 and 2a). Results are compared to a condition in which finger responses instead of saccades were required (Experiment 2b). In addition to response latency we compared the time course of vertical and horizontal effects. We found the Simon effects due to irrelevant spatial meaning of the words in both saccades and finger responses. The time course investigations revealed different patterns for vertical and horizontal effects in saccades, indicating that distinct processes may be involved in the two types of Simon effects. |
Shah Khalid; Matthew Finkbeiner; Peter König; Ulrich Ansorge Subcortical human face processing? Evidence from masked priming Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 39, no. 4, pp. 989–1002, 2013. @article{Khalid2013a, Face processing without awareness might depend on subcortical structures (retino-collicular projection), cortical structures, or a combination of the two. The present study was designed to tease apart these possibilities. Because the retino-collicular projection is more sensitive to low spatial frequencies, we used masked (subliminal) face prime images that were spatially low-pass filtered, or high-pass filtered. The masked primes were presented in the periphery prior to clearly visible target faces. Participants had to discriminate between male and female target faces and we recorded prime-target congruence effects–that is, the difference in discrimination speed between congruent pairs (with prime and target of the same sex) and incongruent pairs (with prime and target of different sexes). In two experiments, we consistently find that masked low-pass filtered face primes produce a congruence effect and that masked high-pass filtered face primes do not. Together our results support the assumption that the retino-collicular route which carries the low spatial frequencies also conveys sex specific features of face images contributing to subliminal face processing. |
Rizwan Ahmed Khan; Alexandre Meyer; Hubert Konik; Saïda Bouakaz Framework for reliable, real-time facial expression recognition for low resolution images Journal Article In: Pattern Recognition Letters, vol. 34, no. 10, pp. 1159–1168, 2013. @article{Khan2013, Automatic recognition of facial expressions is a challenging problem specially for low spatial resolution facial images. It has many potential applications in human-computer interactions, social robots, deceit detection, interactive video and behavior monitoring. In this study we present a novel framework that can recognize facial expressions very efficiently and with high accuracy even for very low resolution facial images. The proposed framework is memory and time efficient as it extracts texture features in a pyramidal fashion only from the perceptual salient regions of the face. We tested the framework on different databases, which includes Cohn-Kanade (CK+) posed facial expression database, spontaneous expressions of MMI facial expression database and FG-NET facial expressions and emotions database (FEED) and obtained very good results. Moreover, our proposed framework exceeds state-of-the-art methods for expression recognition on low resolution images. |
Johann S. C. Kim; Gerhard Vossel; Matthias Gamer Effects of emotional context on memory for details: The role of attention Journal Article In: PLoS ONE, vol. 8, no. 10, pp. e77405, 2013. @article{Kim2013, It was repeatedly demonstrated that a negative emotional context enhances memory for central details while impairing memory for peripheral information. This trade-off effect is assumed to result from attentional processes: a negative context seems to narrow attention to central information at the expense of more peripheral details, thus causing the differential effects in memory. However, this explanation has rarely been tested and previous findings were partly inconclusive. For the present experiment 13 negative and 13 neutral naturalistic, thematically driven picture stories were constructed to test the trade-off effect in an ecologically more valid setting as compared to previous studies. During an incidental encoding phase, eye movements were recorded as an index of overt attention. In a subsequent recognition phase, memory for central and peripheral details occurring in the picture stories was tested. Explicit affective ratings and autonomic responses validated the induction of emotion during encoding. Consistent with the emotional trade-off effect on memory, encoding context differentially affected recognition of central and peripheral details. However, contrary to the common assumption, the emotional trade-off effect on memory was not mediated by attentional processes. By contrast, results suggest that the relevance of attentional processing for later recognition memory depends on the centrality of information and the emotional context but not their interaction. Thus, central information was remembered well even when fixated very briefly whereas memory for peripheral information depended more on overt attention at encoding. Moreover, the influence of overt attention on memory for central and peripheral details seems to be much lower for an arousing as compared to a neutral context. |
Pilyoung Kim; Joseph Arizpe; Brooke H. Rosen; Varun Razdan; Catherine T. Haring; Sarah E. Jenkins; Christen M. Deveney; Melissa A. Brotman; R. James R. Blair; Daniel S. Pine; Chris I. Baker; Ellen Leibenluft Impaired fixation to eyes during facial emotion labelling in children with bipolar disorder or severe mood dysregulation Journal Article In: Journal of Psychiatry and Neuroscience, vol. 38, no. 6, pp. 407–416, 2013. @article{Kim2013a, Background: Children with bipolar disorder (BD) or severe mood dysregulation (SMD) show behavioural and neural deficits during facial emotion processing. In those with other psychiatric disorders, such deficits have been associated with reduced attention to eye regions while looking at faces. Methods: We examined gaze fixation patterns during a facial emotion labelling task among children with pediatric BD and SMD and among healthy controls. Participants viewed facial expressions with varying emotions (anger, fear, sadness, happi- ness, neutral) and emotional levels (60%, 80%, 100%) and labelled emotional expressions. Results: Our study included 22 children with BD, 28 with SMD and 22 controls. Across all facial emotions, children with BD and SMD made more labelling errors than controls. Compared with controls, children with BD spent less time looking at eyes and made fewer eye fixations across emotional expressions. Gaze patterns in children with SMD tended to fall between those of children with BD and controls, although they did not differ significantly from either of these groups on most measures. Decreased fixations to eyes correlated with lower labelling accuracy in children with BD, but not in those with SMD or in controls. Limitations: Most children with BD were medicated, which precluded our ability to evaluate med- ication effects on gaze patterns. Conclusion: Facial emotion labelling deficits in children with BD are associated with impaired attention to eyes. Future research should examine whether impaired attention to eyes is associated with neural dysfunction. Eye gaze deficits in children with BD during facial emotion labelling may also have treatment implications. Finally, children with SMD exhibited decreased attention to eyes to a lesser extent than those with BD, and these equivocal findings are worthy of further study. |
Johannes Klackl; Michaela Pfundmair; Dmitrij Agroskin; Eva Jonas Who is to blame? Oxytocin promotes nonpersonalistic attributions in response to a trust betrayal Journal Article In: Biological Psychology, vol. 92, pp. 387–394, 2013. @article{Klackl2013, Recent research revealed that the neuropeptide Oxytocin (OT) increases and maintains trustful behavior, even towards interaction partners that have proven to be untrustworthy. However, the cognitive mechanisms behind this effect are unclear. In the present paper, we propose that OT might boost trust through the link between angry rumination and the use of nonpersonalistic and personalistic attributions. Nonpersonalistic attributions put the blame for the betrayal on the perpetrator's situation, whereas personalistic attributions blame his dispositions for the event. We predict that OT changes attribution processes in favor of nonpersonalistic ones and thereby boosts subsequent trust. Participants played a classic trust game in which the opponent systematically betrayed their trust. As predicted, OT strength- ened the relationship between angry rumination about the event and nonpersonalistic attribution of the opponents' behavior and weakened the link between angry rumination and personalistic attribution. Critically, nonpersonalistic attribution also mediated the interactive effect of OT and angry rumination on how strongly investments were reduced in the remaining rounds of the trust game. In summary, the present findings suggest that one underlying cognitive mechanism behind OT-induced trust might relate to how negative emotions evoked by a breach of trust influence the subsequent attributional analysis: OT seems to augment trust by fostering the interpretation of untrustworthy behavior as caused by non-personal factors. |
Jonas Knöll; M. Concetta Morrone; Frank Bremmer Spatio-temporal topography of saccadic overestimation of time Journal Article In: Vision Research, vol. 83, pp. 56–65, 2013. @article{Knoell2013, Rapid eye movements (saccades) induce visual misperceptions. A number of studies in recent years have investigated the spatio-temporal profiles of effects like saccadic suppression or perisaccadic mislocalization and revealed substantial functional similarities. Saccade induced chronostasis describes the subjective overestimation of stimulus duration when the stimulus onset falls within a saccade. In this study we aimed to functionally characterize saccade induced chronostasis in greater detail. Specifically we tested if chronostasis is influenced by or functionally related to saccadic suppression. In a first set of experiments, we measured the perceived duration of visual stimuli presented at different spatial positions as a function of presentation time relative to the saccade. We further compared perceived duration during saccades for isoluminant and luminant stimuli. Finally, we investigated whether or not saccade induced chronostasis is dependent on the execution of a saccade itself. We show that chronostasis occurs across the visual field with a clear spatio-temporal tuning. Furthermore, we report chronostasis during simulated saccades, indicating that spurious retinal motion induced by the saccade is a prime origin of the phenomenon. |
Stephanie Huette; Christopher T. Kello; Theo Rhodes; Michael J. Spivey Drawing from Memory: Hand-Eye Coordination at Multiple Scales Journal Article In: PLoS ONE, vol. 8, no. 3, pp. e58464, 2013. @article{Huette2013, Eyes move to gather visual information for the purpose of guiding behavior. This guidance takes the form of perceptual-motor interactions on short timescales for behaviors like locomotion and hand-eye coordination. More complex behaviors require perceptual-motor interactions on longer timescales mediated by memory, such as navigation, or designing and building artifacts. In the present study, the task of sketching images of natural scenes from memory was used to examine and compare perceptual-motor interactions on shorter and longer timescales. Eye and pen trajectories were found to be coordinated in time on shorter timescales during drawing, and also on longer timescales spanning study and drawing periods. The latter type of coordination was found by developing a purely spatial analysis that yielded measures of similarity between images, eye trajectories, and pen trajectories. These results challenge the notion that coordination only unfolds on short timescales. Rather, the task of drawing from memory evokes perceptual-motor encodings of visual images that preserve coarse-grained spatial information over relatively long timescales as well. |
Bipin Indurkhya; Amitash Ojha An empirical study on the role of perceptual similarity in visual metaphors and creativity Journal Article In: Metaphor and Symbol, vol. 28, no. 4, pp. 233–253, 2013. @article{Indurkhya2013, We investigate the role of perceptual similarity in visual metaphor comprehension process. In visual metaphors, perceptual features of the source and the target are objectively present as images. Moreover, to determine perceptual similarity, we use an image-based search system that computes similarity based on low-level perceptual features. We hypothesize that perceptual similarity at the level of color, shape, texture, orientation, and the like, between the source and the target image facilitates metaphorical comprehension and aids creative interpretation. We present three experiments, two of which are eye-movement studies, to demonstrate that in the interpretation and generation of visual metaphors, perceptual similarity between the two images is recognized at a subconscious level, and facilitates the search for creative conceptual associations in terms of emergent features. We argue that the capacity to recognize perceptual similarity-considered to be a hallmark of creativity-plays a major role in the creative understanding of metaphors. |
David E. Irwin; Glyn W. Humphreys Visual marking across eye blinks Journal Article In: Psychonomic Bulletin & Review, vol. 20, no. 1, pp. 128–134, 2013. @article{Irwin2013, Visual search for a conjunction target can be made efficient by presenting one initial set of distractors as a preview, prior to the onset of the other items in the search display Watson & Humphreys (Psychological Review 104:90-122, 1997). However, this "preview advantage" is lost if the initial items are offset for a brief period before onsetting again with the search display Kunar, Humphreys, & Smith (Psychological Science 14:181-185, 2003). Researchers have long disputed whether the preview advantage reflects a process of internally coding and suppressing the old items or of the onset of the new items capturing attention Donk & Theeuwes (Perception & Psychophysics 63:891-900, 2001). In this study, we assessed whether an internally driven blink (in which participants close their eyes) acts in the same manner as an external blink produced by offsetting and then onsetting the preview. In the novel blink conditions, participants searched feature, conjunction, and preview displays after being cued to blink their eyes. The search displays were presented during the eye blink, and so were immediately available once participants opened their eyes. Having participants make an eye blink generally slowed search but had no effect on the search slopes. In contrast, imposing an externally driven blink disrupted preview search. The data indicated that visual attention can compensate for internally driven blinks, and this does not lead to the loss of the representations of distractors across time. Moreover, efficient preview search occurred when the search items had no abrupt onsets, demonstrating that onsets of new search items are not critical for the preview benefit. |
Eve A. Isham; Joy J. Geng Looking time predicts choice but not aesthetic value Journal Article In: PLoS ONE, vol. 8, no. 8, pp. e71698, 2013. @article{Isham2013, Although visual fixations are commonly used to index stimulus-driven or internally-determined preference, recent evidence suggests that visual fixations can also be a source of decisional bias that moves selection toward the fixated object. These contrasting results raise the question of whether visual fixations always index comparative processes during choice-based tasks, or whether they might better reflect internal preferences when the decision does not carry any economic or corporeal consequences. In two experiments, participants chose which of two objects were more aesthetically pleasing (Exp.1) or appeared more organic (Exp.2), and provided independent aesthetic ratings of the stimuli. Our results demonstrated that fixation parameters were a better index of choice in both decisional domains than of aesthetic preference. The data support models in which visual fixations are specifically related to the evolution of decision processes even when the decision has no tangible consequences. |
Denise Nadine Stephan; Iring Koch; Jessica Hendler; Lynn Huestegge Task switching, modality compatibility, and the supra-modal function of eye movements Journal Article In: Experimental Psychology, vol. 60, no. 2, pp. 90–99, 2013. @article{Stephan2013, Previous research suggested that specific pairings of stimulus and response modalities (visual-manual and auditory-vocal tasks) lead to better dual-task performance than other pairings (visual-vocal and auditory-manual tasks). In the present task-switching study, we further examined this modality compatibility effect and investigated the role of response modality by additionally studying oculomotor responses as an alternative to manual responses. Interestingly, the switch cost pattern revealed a much stronger modality compatibility effect for groups in which vocal and manual responses were combined as compared to a group involving vocal and oculomotor responses, where the modality compatibility effect was largely abolished. We suggest that in the vocal-manual response groups the modality compatibility effect is based on cross-talk of central processing codes due to preferred stimulus-response modality processing pathways, whereas the oculomotor response modality may be shielded against cross-talk due to the supra-modal functional importance of visual orientation. |
Yin Su; Li-Lin Rao; Hong-Yue Sun; Xue-Lei Du; Xingshan Li; Shu Li Is making a risky choice based on a weighting and adding process? An eye-tracking investigation Journal Article In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 39, no. 6, pp. 1765–1780, 2013. @article{Su2013, The debate about whether making a risky choice is based on a weighting and adding process has a long history and is still unresolved. To address this long-standing controversy, we developed a comparative paradigm. Participants' eye movements in 2 risky choice tasks that required participants to choose between risky options in single-play and multiple-play conditions were separately compared with those in a baseline task in which participants naturally performed a deliberate calculation following a weighting and adding process. The results showed that, when participants performed the multiple-play risky choice task, their eye movements were similar to those in the baseline task, suggesting that participants may use a weighting and adding process to make risky choices in multiple-play conditions. In contrast, participants' eye movements were different in the single-play risky choice task versus the baseline task, suggesting that participants were not likely to use a weighting and adding process to make risky choices in single-play conditions and were more likely to use a heuristic process. We concluded that an expectation-based index for predicting risk preferences is applicable in multiple-play conditions but not in single-play conditions, implying the need to improve current theories that postulate the use of a heuristic process. |
Pei Sun; Justin L. Gardner; Mauro Costagli; Kenichi Ueno; R. Allen Waggoner; Keiji Tanaka; Kang Cheng In: Cerebral Cortex, vol. 23, no. 7, pp. 1618–1629, 2013. @article{Sun2013, Cells in the animal early visual cortex are sensitive to contour orientations and form repeated structures known as orientation columns. At the behavioral level, there exist 2 well-known global biases in orientation perception (oblique effect and radial bias) in both animals and humans. However, their neural bases are still under debate. To unveil how these behavioral biases are achieved in the early visual cortex, we conducted high-resolution functional magnetic resonance imaging experiments with a novel continuous and periodic stimulation paradigm. By inserting resting recovery periods between successive stimulation periods and introducing a pair of orthogonal stimulation conditions that differed by 90 degrees continuously, we focused on analyzing a blood oxygenation level-dependent response modulated by the change in stimulus orientation and reliably extracted orientation preferences of single voxels. We found that there are more voxels preferring horizontal and vertical orientations, a physiological substrate underlying the oblique effect, and that these over-representations of horizontal and vertical orientations are prevalent in the cortical regions near the horizontal- and vertical-meridian representations, a phenomenon related to the radial bias. Behaviorally, we also confirmed that there exists perceptual superiority for horizontal and vertical orientations around horizontal and vertical meridians, respectively. Our results, thus, refined the neural mechanisms of these 2 global biases in orientation perception. |
Megumi Suzuki; Jeremy M. Wolfe; Todd S. Horowitz; Yasuki Noguchi Apparent color-orientation bindings in the periphery can be influenced by feature binding in central vision Journal Article In: Vision Research, vol. 82, pp. 58–65, 2013. @article{Suzuki2013, A previous study reported the misbinding illusion in which visual features belonging to overlapping sets of items were erroneously integrated (Wu, Kanai, & Shimojo, 2004, Nature, 429, 262). In this illusion, central and peripheral portions of a transparent motion field combined color and motion in opposite fashions. When observers saw such stimuli, their perceptual color-motion bindings in the periphery were re-arranged in such a way as to accord with the bindings in the central region, resulting in erroneous color-motion pairings (misbinding) in peripheral vision. Here we show that this misbinding illusion is also seen in the binding of color and orientation. When the central field of a stimulus array was composed of objects that had coherent (regular) color-orientation pairings, subjective color-orientation bindings in the peripheral stimuli were automatically altered to match the coherent pairings of the central stimuli. Interestingly, the illusion was induced only when all items in the central field combined color and orientation in an orthogonal fashion (e.g. all red bars were horizontal and all green bars were vertical). If this orthogonality was disrupted (e.g. all red and green bars were horizontal), the central field lost its power to induce the misbinding illusion in the peripheral stimuli. The original misbinding illusion study proposed that the illusion stemmed from a perceptual extrapolation that resolved peripheral ambiguity with clear central vision. However, our present results indicate that visual analyses of the correlational structure between two features (color and orientation) are critical for the illusion to occur, suggesting a rapid integration of multiple featural cues in the human visual system. |
Bernard Marius Hart; Hannah Claudia Elfriede; Fanny Schmidt; Ingo Klein-Harmeyer; Wolfgang Einhäuser Attention in natural scenes: Contrast affects rapid visual processing and fixations alike Journal Article In: Philosophical Transactions of the Royal Society B: Biological Sciences, vol. 368, pp. 1–10, 2013. @article{tHart2013a, For natural scenes, attention is frequently quantified either by performance during rapid presentation or by gaze allocation during prolonged viewing. Both paradigms operate on different time scales, and tap into covert and overt attention, respectively. To compare these, we ask some observers to detect targets (animals/vehicles) in rapid sequences, and others to freely view the same target images for 3 s, while their gaze is tracked. In some stimuli, the target's contrast is modified (increased/decreased) and its back- ground modified either in the same or in the opposite way. We find that increasing target contrast relative to the background increases fixations and detection alike, whereas decreasing target contrast and simultaneously increasing background contrast has little effect. Contrast increase for the whole image (target þ background) improves detection, decrease worsens detection, whereas fixation probability remains unaffected by whole-image modifications. Object-unrelated local increase or decrease of contrast attracts gaze, but less than actual objects, supporting a precedence of objects over low-level features. Detection and fixation probability are correlated: the more likely a target is detected in one paradigm, the more likely it is fixated in the other. Hence, the link between overt and covert attention, which has been established in simple stimuli, transfers to more naturalistic scenarios. |
Bernard Marius Hart; Hannah C. E. F. Schmidt; Christine Roth; Wolfgang Einhäuser Fixations on objects in natural scenes: Dissociating importance from salience Journal Article In: Frontiers in Psychology, vol. 4, pp. 455, 2013. @article{tHart2013, The relation of selective attention to understanding of natural scenes has been subject to intense behavioral research and computational modeling, and gaze is often used as a proxy for such attention. The probability of an image region to be fixated typically correlates with its contrast. However, this relation does not imply a causal role of contrast. Rather, contrast may relate to an object's "importance" for a scene, which in turn drives attention. Here we operationalize importance by the probability that an observer names the object as characteristic for a scene. We modify luminance contrast of either a frequently named ("common"/"important") or a rarely named ("rare"/"unimportant") object, track the observers' eye movements during scene viewing and ask them to provide WABBLE describing the scene immediately after. When no object is modified relative to the background, important objects draw more fixations than unimportant ones. Increases of contrast make an object more likely to be fixated, irrespective of whether it was important for the original scene, while decreases in contrast have little effect on fixations. Any contrast modification makes originally unimportant objects more important for the scene. Finally, important objects are fixated more centrally than unimportant objects, irrespective of contrast. Our data suggest a dissociation between object importance (relevance for the scene) and salience (relevance for attention). If an object obeys natural scene statistics, important objects are also salient. However, when natural scene statistics are violated, importance and salience are differentially affected. Object salience is modulated by the expectation about object properties (e.g., formed by context or gist), and importance by the violation of such expectations. In addition, the dependence of fixated locations within an object on the object's importance suggests an analogy to the effects of word frequency on landing positions in reading. |
Clive R. Rosenthal; Tammy W. C. Ng; Christopher Kennard Generalisation of new sequence knowledge depends on response modality Journal Article In: PLoS ONE, vol. 8, no. 2, pp. e53990, 2013. @article{Rosenthal2013, New visuomotor skills can guide behaviour in novel situations. Prior studies indicate that learning a visuospatial sequence via responses based on manual key presses leads to effector- and response-independent knowledge. Little is known, however, about the extent to which new sequence knowledge can generalise, and, thereby guide behaviour, outside of the manual response modality. Here, we examined whether learning a visuospatial sequence either via manual (key presses, without eye movements), oculomotor (obligatory eye movements), or perceptual (covert reorienting of visuospatial attention) responses supported generalisation to direct and indirect tests administered either in the same (baseline conditions) or a novel response modality (transfer conditions) with respect to initial study. Direct tests measured the use of conscious knowledge about the studied sequence, whereas the indirect tests did not ostensibly draw on the study phase and measured response priming. Oculomotor learning supported the use of conscious knowledge on the manual direct tests, whereas manual learning supported generalisation to the oculomotor direct tests but did not support the conscious use of knowledge. Sequence knowledge acquired via perceptual responses did not generalise onto any of the manual tests. Manual, oculomotor, and perceptual sequence learning all supported generalisation in the baseline conditions. Notably, the manual baseline condition and the manual to oculomotor transfer condition differed in the magnitude of general skill acquired during the study phase; however, general skill did not predict performance on the post-study tests. The results demonstrated that generalisation was only affected by the responses used to initially code the visuospatial sequence when new knowledge was applied to a novel response modality. We interpret these results in terms of response-effect distinctiveness, the availability of integrated effector- and motor-plan based information, and discuss their implications for neurocognitive accounts of sequence learning. |
Nicholas M. Ross; Eileen Kowler Eye movements while viewing narrated, captioned, and silent videos Journal Article In: Journal of Vision, vol. 13, no. 4, pp. 1–19, 2013. @article{Ross2013, Videos are often accompanied by narration delivered either by an audio stream or by captions, yet little is known about saccadic patterns while viewing narrated video displays. Eye movements were recorded while viewing video clips with (a) audio narration, (b) captions, (c) no narration, or (d) concurrent captions and audio. A surprisingly large proportion of time (>40%) was spent reading captions even in the presence of a redundant audio stream. Redundant audio did not affect the saccadic reading patterns but did lead to skipping of some portions of the captions and to delays of saccades made into the caption region. In the absence of captions, fixations were drawn to regions with a high density of information, such as the central region of the display, and to regions with high levels of temporal change (actions and events), regardless of the presence of narration. The strong attraction to captions, with or without redundant audio, raises the question of what determines how time is apportioned between captions and video regions so as to minimize information loss. The strategies of apportioning time may be based on several factors, including the inherent attraction of the line of sight to any available text, the moment by moment impressions of the relative importance of the information in the caption and the video, and the drive to integrate visual text accompanied by audio into a single narrative stream. |
Paul Roux; Christine Passerieux; Franck Ramus Kinematics matters: A new eye-tracking investigation of animated triangles Journal Article In: Quarterly Journal of Experimental Psychology, vol. 66, no. 2, pp. 229–244, 2013. @article{Roux2013, Eye movements have been recently recorded in participants watching animated triangles in short movies that normally evoke mentalizing (Frith-Happé animations). Authors have found systematic differences in oculomotor behaviour according to the degree of mental state attribution to these triangles: Participants made longer fixations and looked longer at intentional triangles than at triangles moving randomly. However, no study has yet explored kinematic characteristics of Frith-Happé animations and their influence on eye movements. In a first experiment, we have run a quantitative kinematic analysis of Frith-Happé animations and found that the time triangles spent moving and the distance between them decreased with the mentalistic complexity of their movements. In a second experiment, we have recorded eye movements in 17 participants watching Frith-Happé animations and found that some differences in fixation durations and in the proportion of gaze allocated to triangles between the different kinds of animations were entirely explained by low-level kinematic confounds. We finally present a new eye-tracking measure of visual attention, triangle pursuit duration, which does differentiate the different types of animations even after taking into account kinematic cofounds. However, some idiosyncratic kinematic properties of the Frith-Happé animations prevent an entirely satisfactory interpretation of these results. The different eye-tracking measures are interpreted as implicit and line measures of the processing of animate movements. |
Donghyun Ryu; Bruce Abernethy; David L. Mann; Jamie M. Poolton; Adam D. Gorman The role of central and peripheral vision in expert decision making Journal Article In: Perception, vol. 42, no. 6, pp. 591–607, 2013. @article{Ryu2013, The purpose of this study was to investigate the role of central and peripheral vision in expert decision making. A gaze-contingent display was used to selectively present information to the central and peripheral areas of the visual field while participants performed a decision-making task. Eleven skilled and eleven less-skilled male basketball players watched video clips of basketball scenarios in three different viewing conditions: full-image control, moving window (central vision only), and moving mask (peripheral vision only). At the conclusion of each clip participants were required to decide whether it was more appropriate for the ball-carrier to pass the ball or to drive to the basket. The skilled players showed significantly higher response accuracy and faster response times compared with their lesser-skilled counterparts in all three viewing conditions, demonstrating superiority in information extraction that held irrespective of whether they were using central or peripheral vision. The gaze behaviour of the skilled players was less influenced by the gaze-contingent manipulations, suggesting they were better able to use the remaining information to sustain their normal gaze behaviour. The superior capacity of experts to interpret dynamic visual information is evident regardless of whether the visual information is presented across the whole visual field or selectively to either central or peripheral vision alone. |
Nuria Sagarra; Nick C. Ellis From seeing adverbs to seeing verbal morphology Journal Article In: Studies in Second Language Acquisition, vol. 35, no. 2, pp. 261–290, 2013. @article{Sagarra2013, Adult learners have persistent difficulty processing second language (L2) inflectional morphology. We investigate associative learning explanations that involve the blocking of later experienced cues by earlier learned ones in the first language (L1; i.e., transfer) and the L2 (i.e., proficiency). Sagarra (2008 ) and Ellis and Sagarra (2010b ) found that, unlike Spanish monolinguals, intermediate English-Spanish learners rely more on salient adverbs than on less salient verb inflections, but it is not clear whether this preference is a result of a default or a L1-based strategy. To address this question, 120 English (poor morphology) and Romanian (rich morphology) learners of Spanish (rich morphology) and 98 English, Romanian, and Spanish monolinguals read sentences in L2 Spanish (or their L1 in the case of the monolinguals) containing adverb-verb and verb-adverb congruencies or incongruencies and chose one of four pictures after each sentence (i.e., two that competed for meaning and two for form). Eye-tracking data revealed signifi cant effects for (a) sensitivity (all participants were sensitive to tense incongruencies), (b) cue location in the sentence (participants spent more time at their preferred cue, regardless of its position), (c) L1 experience (morphologically rich L1 learners and monolinguals looked longer at verbs than morphologically poor L1 learners and monolinguals), and (d) L2 experience (low-proficiency learners read more slowly and regressed longer than high-proficiency learners). We conclude that intermediate and advanced learners are sensitive to tense incongruencies and—like native speakers—tend to rely more heavily on verbs if their L1 is morphologically rich. These findings reinforce theories that support transfer effects such as the unifi ed competition model and the associative learning model but do not contradict Clahsen and Felser's ( 2006a ) shallow structure hypothesis because the target structure was morphological agreement rather than syntactic agreement. |
Benjamin Reichelt; Sina Kühnel; Dennis E. Dal Mas The influence of explicit and implicit memory processes on experience-dependent eye movements Journal Article In: Procedia Social and Behavioral Sciences, vol. 82, pp. 455–460, 2013. @article{Reichelt2013, In some studies experience-dependent eye movements have been reported with as well as without conscious awareness. Thus, our study aims to clarify if experience-dependent eye movements are influenced by mainly implicit or explicit memory processes. Participants saw in experiment 1 photographed scenes that were novel, repeated or repeated with a manipulation (object added /removed). In experiment 2, participants viewed novel and repeated scenes distributed over three days. Participants subsequently had to recognize whether the scenes were novel, repeated or manipulated. In both experiments, experience-dependent eye movements were observed when participants were aware of the manipulation or repetition as well as when they were unaware. In contrast to previous studies, our results suggest that explicit as well as implicit memory processes have an influence on experience-dependent eye movements. |
Fabio Richlan; Benjamin Gagl; Sarah Schuster; Stefan Hawelka; Josef Humenberger; Florian Hutzler A new high-speed visual stimulation method for gaze-contingent eye movement and brain activity studies Journal Article In: Frontiers in Systems Neuroscience, vol. 7, pp. 24, 2013. @article{Richlan2013, Approaches using eye movements as markers of ongoing brain activity to investigate perceptual and cognitive processes were able to implement highly sophisticated paradigms driven by eye movement recordings. Crucially, these paradigms involve display changes that have to occur during the time of saccadic blindness, when the subject is unaware of the change. Therefore, a combination of high-speed eye tracking and high-speed visual stimulation is required in these paradigms. For combined eye movement and brain activity studies (e.g., fMRI, EEG, MEG), fast and exact timing of display changes is especially important, because of the high susceptibility of the brain to visual stimulation. Eye tracking systems already achieve sampling rates up to 2000 Hz, but recent LCD technologies for computer screens reduced the temporal resolution to mostly 60 Hz, which is too slow for gaze-contingent display changes. We developed a high-speed video projection system, which is capable of reliably delivering display changes within the time frame of < 5 ms. This could not be achieved even with the fastest cathode ray tube (CRT) monitors available (< 16 ms). The present video projection system facilitates the realization of cutting-edge eye movement research requiring reliable high-speed visual stimulation (e.g., gaze-contingent display changes, short-time presentation, masked priming). Moreover, this system can be used for fast visual presentation in order to assess brain activity using various methods, such as electroencephalography (EEG) and functional magnetic resonance imaging (fMRI). The latter technique was previously excluded from high-speed visual stimulation, because it is not possible to operate conventional CRT monitors in the strong magnetic field of an MRI scanner. Therefore, the present video projection system offers new possibilities for studying eye movement-related brain activity using a combination of eye tracking and fMRI. |
Gerulf Rieger; Allen M. Rosenthal; Brian M. Cash; Joan A. W. Linsenmeier; J. Michael Bailey; Ritch C. Savin-Williams Male bisexual arousal: A matter of curiosity? Journal Article In: Biological Psychology, vol. 94, no. 3, pp. 479–489, 2013. @article{Rieger2013, Conflicting evidence exists regarding whether bisexual-identified men are sexually aroused to both men and women. We hypothesized that a distinct characteristic, level of curiosity about sexually diverse acts, distinguishes bisexual-identified men with and without bisexual arousal. Study 1 assessed men's (n= 277) sexual arousal via pupil dilation to male and female sexual stimuli. Bisexual men were, on average, higher in their sexual curiosity than other men. Despite this general difference, only bisexual-identified men with elevated sexual curiosity showed bisexual arousal. Those lower in curiosity had responses resembling those of homosexual men. Study 2 assessed men's (n= 72) sexual arousal via genital responses and replicated findings of Study 1. Study 3 provided information on the validity on our measure of sexual curiosity by relating it to general curiosity and sexual sensation seeking (n= 83). Based on their sexual arousal and personality, at least two groups of men identify as bisexual. |
Hector Rieiro; Susana Martinez-Conde; Stephen L. Macknik Perceptual elements in Penn & Teller's “Cups and Balls” magic trick Journal Article In: PeerJ, vol. 1, pp. 1–12, 2013. @article{Rieiro2013, Magic illusions provide the perceptual and cognitive scientist with a toolbox of experimental manipulations and testable hypotheses about the building blocks of conscious experience. Here we studied several sleight-of-hand manipulations in the performance of the classic "Cups and Balls" magic trick (where balls appear and disappear inside upside-down opaque cups). We examined a version inspired by the entertainment duo Penn & Teller, conducted with three opaque and subsequently with three transparent cups. Magician Teller used his right hand to load (i.e. introduce surreptitiously) a small ball inside each of two upside-down cups, one at a time, while using his left hand to remove a different ball from the upside-down bottom of the cup. The sleight at the third cup involved one of six manipulations: (a) standard maneuver, (b) standard maneuver without a third ball, (c) ball placed on the table, (d) ball lifted, (e) ball dropped to the floor, and (f) ball stuck to the cup. Seven subjects watched the videos of the performances while reporting, via button press, whenever balls were removed from the cups/table (button "1") or placed inside the cups/on the table (button "2"). Subjects' perception was more accurate with transparent than with opaque cups. Perceptual performance was worse for the conditions where the ball was placed on the table, or stuck to the cup, than for the standard maneuver. The condition in which the ball was lifted displaced the subjects' gaze position the most, whereas the condition in which there was no ball caused the smallest gaze displacement. Training improved the subjects' perceptual performance. Occlusion of the magician's face did not affect the subjects' perception, suggesting that gaze misdirection does not play a strong role in the Cups and Balls illusion. Our results have implications for how to optimize the performance of this classic magic trick, and for the types of hand and object motion that maximize magic misdirection. |
James A. Roberts; Guy Wallis; Michael Breakspear Fixational eye movements during viewing of dynamic natural scenes Journal Article In: Frontiers in Psychology, vol. 4, pp. 797, 2013. @article{Roberts2013a, Even during periods of fixation our eyes undergo small amplitude movements. These movements are thought to be essential to the visual system because neural responses rapidly fade when images are stabilized on the retina. The considerable recent interest in fixational eye movements (FEMs) has thus far concentrated on idealized experimental conditions with artificial stimuli and restrained head movements, which are not necessarily a suitable model for natural vision. Natural dynamic stimuli, such as movies, offer the potential to move beyond restrictive experimental settings to probe the visual system with greater ecological validity. Here, we study FEMs recorded in humans during the unconstrained viewing of a dynamic and realistic visual environment, revealing that drift trajectories exhibit the properties of a random walk with memory. Drifts are correlated at short time scales such that the gaze position diverges from the initial fixation more quickly than would be expected for an uncorrelated random walk. We propose a simple model based on the premise that the eye tends to avoid retracing its recent steps to prevent photoreceptor adaptation. The model reproduces key features of the observed dynamics and enables estimation of parameters from data. Our findings show that FEM correlations thought to prevent perceptual fading exist even in highly dynamic real-world conditions. |
Alec Scharff; John Palmer; Cathleen M. Moore Divided attention limits perception of 3-D object shapes Journal Article In: Journal of Vision, vol. 13, no. 2, pp. 1–24, 2013. @article{Scharff2013, Can one perceive multiple object shapes at once? We tested two benchmark models of object shape perception under divided attention: an unlimited- capacity and a fixed-capacity model. Under unlimited- capacity models, shapes are analyzed independently and in parallel. Under fixed-capacity models, shapes are processed at a fixed rate (as in a serial model). To distinguish these models, we compared conditions in which observers were presented with simultaneous or sequential presentations of a fixed number of objects (The extended simultaneous-sequential method: Scharff, Palmer, & Moore, 2011a, 2011b). We used novel physical objects as stimuli, minimizing the role of semantic categorization in the task. Observers searched for a specific object among similar objects. We ensured that non-shape stimulus properties such as color and texture could not be used to complete the task. Unpredictable viewing angles were used to preclude image-matching strategies. The results rejected unlimited-capacity models for object shape perception and were consistent with the predictions of a fixed-capacity model. In contrast, a task that required observers to recognize 2-D shapes with predictable viewing angles yielded an unlimited capacity result. Further experiments ruled out alternative explanations for the capacity limit, leading us to conclude that there is a fixed-capacity limit on the ability to perceive 3-D object shapes. |
Anne Schmechtig; Jane Lees; Lois Grayson; Kevin J. Craig; Rukiya Dadhiwala; Gerard R. Dawson; J. F. William Deakin; Colin T. Dourish; Ivan Koychev; Katrina McMullen; Ellen M. Migo; Charlotte Perry; Lawrence Wilkinson; Robin Morris; Steve C. R. Williams; Ulrich Ettinger Effects of risperidone, amisulpride and nicotine on eye movement control and their modulation by schizotypy Journal Article In: Psychopharmacology, vol. 227, no. 2, pp. 331–345, 2013. @article{Schmechtig2013a, RATIONALE: The increasing demand to develop more efficient compounds to treat cognitive impairments in schizophrenia has led to the development of experimental model systems. One such model system combines the study of surrogate populations expressing high levels of schizotypy with oculomotor biomarkers. OBJECTIVES: We aimed (1) to replicate oculomotor deficits in a psychometric schizotypy sample and (2) to investigate whether the expected deficits can be remedied by compounds shown to ameliorate impairments in schizophrenia. METHODS: In this randomized double-blind, placebo-controlled study 233 healthy participants performed prosaccade (PS), antisaccade (AS) and smooth pursuit eye movement (SPEM) tasks after being randomly assigned to one of four drug groups (nicotine, risperidone, amisulpride, placebo). Participants were classified into medium- and high-schizotypy groups based on their scores on the Schizotypal Personality Questionnaire (SPQ, Raine (Schizophr Bull 17:555-564, 1991)). RESULTS: AS error rate showed a main effect of Drug (p < 0.01), with nicotine improving performance, and a Drug by Schizotypy interaction (p = 0.04), indicating higher error rates in medium schizotypes (p = 0.01) but not high schizotypes under risperidone compared to placebo. High schizotypes had higher error rates than medium schizotypes under placebo (p = 0.03). There was a main effect of Drug for saccadic peak velocity and SPEM velocity gain (both p </= 0.01) indicating impaired performance with risperidone. CONCLUSIONS: We replicate the observation of AS impairments in high schizotypy under placebo and show that nicotine enhances performance irrespective of group status. Caution should be exerted in applying this model as no beneficial effects of antipsychotics were seen in high schizotypes. |
Anne Schmechtig; Jane Lees; Adam M. Perkins; A. Altavilla; Kevin J. Craig; G. R. Dawson; J. F. William Deakin; Colin T. Dourish; L. H. Evans; Ivan Koychev; K. Weaver; R. Smallman; J. Walters; L. S. Wilkinson; R. Morris; Steve C. R. Williams; Ulrich Ettinger The effects of ketamine and risperidone on eye movement control in healthy volunteers Journal Article In: Translational Psychiatry, vol. 3, pp. e334, 2013. @article{Schmechtig2013, The non-competitive N-methyl-D-aspartate receptor antagonist ketamine leads to transient psychosis-like symptoms and impairments in oculomotor performance in healthy volunteers. This study examined whether the adverse effects of ketamine on oculomotor performance can be reversed by the atypical antipsychotic risperidone. In this randomized double-blind, placebo-controlled study, 72 healthy participants performed smooth pursuit eye movements (SPEM), prosaccades (PS) and antisaccades (AS) while being randomly assigned to one of four drug groups (intravenous 100 ng ml(-1) ketamine, 2 mg oral risperidone, 100 ng ml(-1) ketamine plus 2 mg oral risperidone, placebo). Drug administration did not lead to harmful adverse events. Ketamine increased saccadic frequency and decreased velocity gain of SPEM (all P < 0.01) but had no significant effects on PS or AS (all P > or = 0.07). An effect of risperidone was observed for amplitude gain and peak velocity of PS and AS, indicating hypometric gain and slower velocities compared with placebo (both P < or = 0.04). No ketamine by risperidone interactions were found (all P > or = 0.26). The results confirm that the administration of ketamine produces oculomotor performance deficits similar in part to those seen in schizophrenia. The atypical antipsychotic risperidone did not reverse ketamine-induced deteriorations. These findings do not support the cognitive enhancing potential of risperidone on oculomotor biomarkers in this model system of schizophrenia and point towards the importance of developing alternative performance-enhancing compounds to optimise pharmacological treatment of schizophrenia. |
Casey A. Schofield; Albrecht W. Inhoff; Meredith E. Coles Time-course of attention biases in social phobia Journal Article In: Journal of Anxiety Disorders, vol. 27, no. 7, pp. 661–669, 2013. @article{Schofield2013, Theoretical models of social phobia implicate preferential attention to social threat in the maintenance of anxiety symptoms, though there has been limited work characterizing the nature of these biases over time. The current study utilized eye-movement data to examine the time-course of visual attention over 1500. ms trials of a probe detection task. Nineteen participants with a primary diagnosis of social phobia based on DSM-IV criteria and 20 non-clinical controls completed this task with angry, fearful, and happy face trials. Overt visual attention to the emotional and neutral faces was measured in 50. ms segments across the trial. Over time, participants with social phobia attend less to emotional faces and specifically less to happy faces compared to controls. Further, attention to emotional relative to neutral expressions did not vary notably by emotion for participants with social phobia, but control participants showed a pattern after 1000. ms in which over time they preferentially attended to happy expressions and avoided negative expressions. Findings highlight the importance of considering attention biases to positive stimuli as well as the pattern of attention between groups. These results suggest that attention "bias" in social phobia may be driven by a relative lack of the biases seen in non-anxious participants. |
Jörg Schorer; Rebecca Rienhoff; Lennart Fischer; Joseph Baker Foveal and peripheral fields of vision influences perceptual skill in anticipating opponents' attacking position in volleyball Journal Article In: Applied Psychophysiology Biofeedback, vol. 38, no. 3, pp. 185–192, 2013. @article{Schorer2013, The importance of perceptual-cognitive expertise in sport has been repeatedly demonstrated. In this study we examined the role of different sources of visual information (i.e., foveal versus peripheral) in anticipating volleyball attack positions. Expert (n = 11), advanced (n = 13) and novice (n = 16) players completed an anticipation task that involved predicting the location of volleyball attacks. Video clips of volleyball attacks (n = 72) were spatially and temporally occluded to provide varying amounts of information to the participant. In addition, participants viewed the attacks under three visual conditions: full vision, foveal vision only, and peripheral vision only. Analysis of variance revealed significant between group differences in prediction accuracy with higher skilled players performing better than lower skilled players. Additionally, we found significant differences between temporal and spatial occlusion conditions. Both of those factors interacted separately, but not combined with expertise. Importantly, for experts the sum of both fields of vision was superior to either source in isolation. Our results suggest different sources of visual information work collectively to facilitate expert anticipation in time-constrained sports and reinforce the complexity of expert perception. |
Elizabeth R. Schotter; Victor S. Ferreira; Keith Rayner Parallel object activation and attentional gating of information: Evidence from eye movements in the multiple object naming paradigm Journal Article In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 39, no. 2, pp. 365–374, 2013. @article{Schotter2013, Do we access information from any object we can see, or do we access information only from objects that we intend to name? In 3 experiments using a modified multiple object naming paradigm, subjects were required to name several objects in succession when previews appeared briefly and simultaneously in the same location as the target as well as at another location. In Experiment 1, preview benefit-faster processing of the target when the preview was related (a mirror image of the target) compared to unrelated (semantically and phonologically)-was found for the preview in the target location but not a location that was never to be named. In Experiment 2, preview benefit was found if a related preview appeared in either the target location or the third-to-be-named location. Experiment 3 showed the difference between results from the first 2 experiments was not due to the number of objects on the screen. These data suggest that attention serves to gate visual input about objects based on the intention to name them and that information from one intended-to-be-named object can facilitate processing of an object in another location. |
Alexander C. Schutz; Felix Lossin; Dirk Kerzel Temporal stimulus properties that attract gaze to the periphery and repel gaze from fixation Journal Article In: Journal of Vision, vol. 13, no. 5, pp. 1–17, 2013. @article{Schutz2013, Humans use saccadic eye movements to fixate different parts of their visual environment. While stimulus features that determine the location of the next fixation in static images have been extensively studied, temporal stimulus features that determine the timing of the gaze shifts received less attention. It is also unclear if stimulus features at the present gaze location can trigger gaze shifts to another location. To investigate these questions, we asked observers to switch their gaze between two blobs. In three different conditions, either the fixated blob, the peripheral blob, or both blobs were flickering. A time-frequency analysis of the flickering noise values, time locked to the gaze shifts, revealed significant phase locking in a time window 300 to 100 ms before the gaze shift at temporal frequencies below 20 Hz. The average phase angles at these time-frequency points indicated that observer's gaze was repelled by decreasing contrast of the fixated blob and attracted by increasing contrast of the peripheral blob. These results show that temporal properties of both, fixated, and peripheral stimuli are capable of triggering gaze shifts. |
Immo Schütz; Denise Y. P. Henriques; K. Fiehler Gaze-centered spatial updating in delayed reaching even in the presence of landmarks Journal Article In: Vision Research, vol. 87, pp. 46–52, 2013. @article{Schuetz2013, Previous results suggest that the brain predominantly relies on a constantly updated gaze-centered target representation to guide reach movements when no other visual information is available. In the present study, we investigated whether the addition of reliable visual landmarks influences the use of spatial reference frames for immediate and delayed reaching. Subjects reached immediately or after a delay of 8 or 12. s to remembered target locations, either with or without landmarks. After target presentation and before reaching they shifted gaze to one of five different fixation points and held their gaze at this location until the end of the reach. With landmarks present, gaze-dependent reaching errors were smaller and more precise than when reaching without landmarks. Delay influenced neither reaching errors nor variability. These findings suggest that when landmarks are available, the brain seems to still use gaze-dependent representations but combine them with gaze-independent allocentric information to guide immediate or delayed reach movements to visual targets. |
Diego E. Shalom; Maximiliano G. Sousa Serro; Maximiliano Giaconia; Luis M. Martinez; Andres Rieznik; Mariano Sigman Choosing in freedom or forced to choose? Introspective blindness to psychological forcing in stage-magic Journal Article In: PLoS ONE, vol. 8, no. 3, pp. e58254, 2013. @article{Shalom2013, We investigated an individual ability to identify whether choices were made freely or forced by external parameters. We capitalized on magical setups where the notion of psychological forcing constitutes a well trodden path. In live stage magic, a magician guessed cards from spectators while inquiring how freely they thought they had made the choice. Our data showed a marked blindness in the introspection of free choice. Spectators assigned comparable ratings when choosing the card that the magician deliberately forced them compared to any other card, even in classical forcing, where the magician literally handles a card to the participant This observation was paralleled by a laboratory experiment where we observed modest changes in subjective reports by factors with drastic effect in choice. Pupil dilatation, which is known to tag slow cognitive events related to memory and attention, constitutes an efficient fingerprint to index subjective and objective aspects of choice. |
Diego E. Shalom; Mariano Sigman Freedom and rules in human sequential performance: A refractory period in eye-hand coordination Journal Article In: Journal of Vision, vol. 13, no. 3, pp. 1–13, 2013. @article{Shalom2013a, In action sequences, the eyes and hands ought to be coordinated in precise ways. The mechanisms governing the architecture of encoding and action of several effectors remain unknown. Here we study hand and eye movements in a sequential task in which letters have to be typed while they move down through the screen. We observe a strict refractory period of about 200 ms between the initiation of manual and eye movements. Subjects do not initiate a saccade just after typing and do not type just after making the saccade. This refractory period is observed ubiquitously in every subject and in each step of the sequential task, even when keystrokes and saccades correspond to different items of the sequence-for instance when a subject types a letter that has been gazed at in a preceding fixation. These results extend classic findings of dual-task paradigms, of a bottleneck tightly locked to the response selection process, to unbounded serial routines. Interestingly, while the bottleneck is seemingly inevitable, better performing subjects can adopt a strategy to minimize the cost of the bottleneck, overlapping the refractory period with the encoding of the next item in the sequence. |
Tracey A. Shaw; Melanie A. Porter Emotion recognition and visual-scan paths in fragile X syndrome Journal Article In: Journal of Autism and Developmental Disorders, vol. 43, no. 5, pp. 1119–1139, 2013. @article{Shaw2013, This study investigated emotion recognition abilities and visual scanning of emotional faces in 16 Fragile X syndrome (FXS) individuals compared to 16 chronological-age and 16 mental-age matched controls. The relationships between emotion recognition, visual scan-paths and symptoms of social anxiety, schizotypy and autism were also explored. Results indicated that, com- pared to both control groups, the FXS group displayed specific emotion recognition deficits for angry and neutral (but not happy or fearful) facial expressions. Despite these evident emotion recognition deficits, the visual scanning of emotional faces was found to be at developmentally appropriate levels in the FXS group. Significant relation- ships were also observed between visual scan-paths, emo- tion recognition performance and symptomology in the FXS group. |
Heather Sheridan; Eyal M. Reingold The mechanisms and boundary conditions of the Einstellung Effect in chess: Evidence from eye movements Journal Article In: PLoS ONE, vol. 8, no. 10, pp. e75796, 2013. @article{Sheridan2013a, In a wide range of problem-solving settings, the presence of a familiar solution can block the discovery of better solutions (i.e., the Einstellung effect). To investigate this effect, we monitored the eye movements of expert and novice chess players while they solved chess problems that contained a familiar move (i.e., the Einstellung move), as well as an optimal move that was located in a different region of the board. When the Einstellung move was an advantageous (but suboptimal) move, both the expert and novice chess players who chose the Einstellung move continued to look at this move throughout the trial, whereas the subset of expert players who chose the optimal move were able to gradually disengage their attention from the Einstellung move. However, when the Einstellung move was a blunder, all of the experts and the majority of the novices were able to avoid selecting the Einstellung move, and both the experts and novices gradually disengaged their attention from the Einstellung move. These findings shed light on the boundary conditions of the Einstellung effect, and provide convergent evidence for Bilalić, McLeod, & Gobet (2008)'s conclusion that the Einstellung effect operates by biasing attention towards problem features that are associated with the familiar solution rather than the optimal solution. |
Veronica Shi; Jie Cui; Xoana G. Troncoso; Stephen L. Macknik; Susana Martinez-Conde Effect of stimulus width on simultaneous contrast Journal Article In: PeerJ, vol. 1, pp. 1–13, 2013. @article{Shi2013, Perceived brightness of a stimulus depends on the background against which the stimulus is set, a phenomenon known as simultaneous contrast. For instance, the same gray stimulus can look light against a black background or dark against a white background. Here we quantified the perceptual strength of simultaneous contrast as a function of stimulus width. Previous studies have reported that wider stimuli result in weaker simultaneous contrast, whereas narrower stimuli result in stronger simultaneous contrast. However, no previous research has quantified this relationship. Our results show a logarithmic relationship between stimulus width and perceived brightness. This relationship is well matched by the normalized output of a Difference-of-Gaussians (DOG) filter applied to stimuli of varied widths. |
Masanori Shimono; Kazuhisa Niki Global mapping of the whole-brain network underlining binocular rivalry Journal Article In: Brain Connectivity, vol. 3, no. 2, pp. 212–221, 2013. @article{Shimono2013, We investigated how the structure of the brain network relates to the stability of perceptual alternation in binocular rivalry. Historically, binocular rivalry has provided important new insights to our understandings in neuroscience. Although various relationships between the local regions of the human brain structure and perceptual switching phenomena have been shown in previous researches, the global organization of the human brain structural network relating to this phenomenon has not yet been addressed. To approach this issue, we reconstructed fiber-tract bundles using diffusion tensor imaging and then evaluated the correlations between the speeds of perceptual alternation and fractional anisotropy (FA) values in each fiber-tract bundle integrating among 84 brain regions. The resulting comparison revealed that the distribution of the global organization of the structural brain network showed positive or negative correlations between the speeds of perceptual alternation and the FA values. First, the connections between the subcortical regions stably were negatively correlated. Second, the connections between the cortical regions mainly showed positive correlations. Third, almost all other cortical connections that showed negative correlations were located in one central cluster of the subcortical connections. This contrast between the contribution of the cortical regions to destabilization and the contribution of the subcortical regions to stabilization of perceptual alternation provides important information as to how the global architecture of the brain structural network supports the phenomenon of binocular rivalry. |
Alisha Siebold; Wieske Zoest; Martijn Meeter; Mieke Donk In defense of the salience map: Salience rather than visibility determines selection Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 39, no. 6, pp. 1516–1524, 2013. @article{Siebold2013, The aim of the present study was to investigate whether time-dependent biases of oculomotor selection as typically observed during visual search are better accounted for by an absolute-processing-speed account (J. P. de Vries, I. T. C. Hooge, M. A. Wiering, & F. A. J. Verstraten, 2011, How longer saccade latencies lead to a competition for salience. Psychological Science, 22, 916-923) or a relative-salience account (e.g., M. Donk, & W. van Zoest, 2008, Effects of salience are short-lived. Psychological Science, 19, 733-739; M. Donk & W. van Zoest, 2011, No control in orientation search: The effects of instruction on oculomotor selection in visual search. Vision Research, 51, 2156-2166). In order to test these two models, we performed an experiment in which participants were instructed to make a speeded eye movement to any of two orientation singletons presented among a homogeneous set of vertically oriented background lines. One singleton, the fixed singleton, remained identical across conditions, whereas the other singleton, the variable singleton, varied such that its orientation contrast relative to the background lines was either smaller or larger than that of the fixed singleton. The results showed that the proportion of eye movements directed toward the fixed singleton varied substantially depending on the orientation contrast of the variable singleton. A model assuming selection behavior to be determined by relative salience provided a better fit to the individual data than the absolute processing speed model. These findings suggest that relative salience rather than the visibility of an element is crucial in determining temporal variations in oculomotor selection behavior and that an explanation of visual selection behavior is insufficient without the concept of a salience map. |
Massimo Silvetti; Ruth Seurinck; Marlies E. Bochove; Tom Verguts The influence of the noradrenergic system on optimal control of neural plasticity Journal Article In: Frontiers in Behavioral Neuroscience, vol. 7, pp. 160, 2013. @article{Silvetti2013, Decision making under uncertainty is challenging for any autonomous agent. The challenge increases when the environment's stochastic properties change over time, i.e., when the environment is volatile. In order to efficiently adapt to volatile environments, agentsmust primarily rely on recent outcomes to quickly change their decision strategies; in otherwords, they need to increase their knowledge plasticity. On the contrary, in stable environments, knowledge stability must be preferred to preserve useful information against noise. Here we propose that in mammalian brain, the locus coeruleus (LC) is one of the nuclei involved in volatility estimation and in the subsequent control of neural plasticity. During a reinforcement learning task, LC activation, measured bymeans of pupil diameter, coded both for environmental volatility and learning rate. We hypothesize that LC could be responsible, through norepinephrinic modulation, for adaptations to optimize decisionmaking in volatile environments.We also suggest a computational model on the interaction between the anterior cingulate cortex (ACC) and LC for volatility estimation. |
Benjamin W. Tatler; Yoriko Hirose; Sarah K. Finnegan; Riina Pievilainen; Clare Kirtley; Alan Kennedy Priorities for selection and representation in natural tasks Journal Article In: Philosophical Transactions of the Royal Society B: Biological Sciences, vol. 368, pp. 1–10, 2013. @article{Tatler2013, Selecting and remembering visual information is an active and competitive process. In natural environments, representations are tightly coupled to task. Objects that are task-relevant are remembered better due to a combination of increased selection for fixation and strategic control of encoding and/or retaining viewed information. However, it is not understood how physically manipulating objects when performing a natural task influences priorities for selection and memory. In this study, we compare priorities for selection and memory when actively engaged in a natural task with first-person observation of the same object manipulations. Results suggest that active manipulation of a task-relevant object results in a specific prioritization for object position information compared with other properties and compared with action observation of the same manipulations. Experiment 2 confirms that this spatial prioritization is likely to arise from manipulation rather than differences in spatial representation in real environments and the movies used for action observation. Thus, our findings imply that physical manipulation of task relevant objects results in a specific prioritization of spatial information about task-relevant objects, possibly coupled with strategic de-prioritization of colour memory for irrelevant objects. |
Laura E. Thomas Spatial working memory is necessary for actions to guide thought Journal Article In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 39, no. 6, pp. 1974–1981, 2013. @article{Thomas2013a, Directed actions can play a causal role in cognition, shaping thought processes. What drives this cross-talk between action and thought? I investigated the hypothesis that representations in spatial working memory mediate interactions between directed actions and problem solving. Participants attempted to solve an insight problem while occasionally either moving their eyes in a pattern embodying the problem's solution or maintaining fixation. They simultaneously held either a spatial or verbal stimulus in working memory. Participants who moved their eyes in a pattern that embodied the solution were more likely to solve the problem, but only while also performing a verbal working memory task. Embodied guidance of insight was eliminated when participants were instead engaged in a spatial working memory task while moving their eyes, implying that loading spatial working memory prevented movement representations from influencing problem solving. These results point to spatial working memory as a mechanism driving embodied guidance of insight, suggesting that actions do not automatically influence problem solving. Instead, cross-talk between action and higher order cognition requires representations in spatial working memory. |
Guanghan Song; Denis Pellerin; Lionel Granjon Different types of sounds influence gaze differently in videos Journal Article In: Journal of Eye Movement Research, vol. 6, no. 4, pp. 1–13, 2013. @article{Song2013, This paper presents an analysis of the effect of different types of sounds on visual gaze when a person is looking freely at videos, which would be helpful to predict eye position. In order to test the effect of sound, an audio-visual experiment was designed with two groups of participants, with audio-visual (AV) and visual (V) conditions. By using statisti- cal tools, we analyzed the difference between eye position of participants with AV and V conditions. We observed that the effect of sound is different depending on the kind of sound, and that the classes with human voice (i.e. speech, singer, human noise and singers) have the greatest effect. Furthermore, the results of the distance between sound source and eye position of the group with AV condition, suggested that only particular types of sound attract human eye position to the sound source. Finally, an analysis of the fixation duration between AV and V conditions showed that participants with AV condition move eyes more frequently than those with V condition. |
Joo-Hyun Song; Patrick Bédard Allocation of attention for dissociated visual and motor goals Journal Article In: Experimental Brain Research, vol. 226, no. 2, pp. 209–219, 2013. @article{Song2013a, In daily life, selecting an object visually is closely intertwined with processing that object as a potential goal for action. Since visual and motor goals are typically identical, it remains unknown whether attention is primarily allocated to a visual target, a motor goal, or both. Here, we dissociated visual and motor goals using a visuomotor adaptation paradigm, in which participants reached toward a visual target using a computer mouse or a stylus pen, while the direction of the cursor was rotated 45° counter-clockwise from the direction of the hand movement. Thus, as visuomotor adaptation was accomplished, the visual target was dissociated from the movement goal. Then, we measured the locus of attention using an attention-demanding rapid serial visual presentation (RSVP) task, in which participants detected a pre-defined visual stimulus among the successive visual stimuli presented on either the visual target, the motor goal, or a neutral control location. We demonstrated that before visuomotor adaptation, participants performed better when the RSVP stream was presented at the visual target than at other locations. However, once visual and motor goals were dissociated following visuomotor adaptation, performance at the visual and motor goals was equated and better than performance at the control location. Therefore, we concluded that attentional resources are allocated both to visual target and motor goals during goal-directed reaching movements. |
Mingli Song; Dapeng Tao; Chun Chen; Jiajun Bu; Yezhou Yang Color-to-gray based on chance of happening preservation Journal Article In: Neurocomputing, vol. 119, pp. 222–231, 2013. @article{Song2013b, It is important to convert color images into grayscale ones for both commercial and scientific applications, such as reducing the publication cost and making the color blind people capture the visual content and semantics from color images. Recently, a dozen of algorithms have been developed for color-to-gray conversion. However, none of them considers the visual attention consistency between the color image and the converted grayscale one. Therefore, these methods may fail to convey important visual information from the original color image to the converted grayscale image. Inspired by the Helmholtz principle (Desolneux et al. 2008 [16]) that "we immediately perceive whatever could not happen by chance", we propose a new algorithm for color-to-gray to solve this problem. In particular, we first define the Chance of Happening (CoH) to measure the attentional level of each pixel in a color image. Afterward, natural image statistics are introduced to estimate the CoH of each pixel. In order to preserve the CoH of the color image in the converted grayscale image, we finally cast the color-to-gray to a supervised dimension reduction problem and present locally sliced inverse regression that can be efficiently solved by singular value decomposition. Experiments on both natural images and artificial pictures suggest (1) that the proposed approach makes the CoH of the color image and that of the converted grayscale image consistent and (2) the effectiveness and the efficiency of the proposed approach by comparing with representative baseline algorithms. In addition, it requires no human-computer interactions. |
Matthew J. Stainer; Kenneth C. Scott-Brown; Benjamin W. Tatler Behavioral biases when viewing multiplexed scenes: Scene structure and frames of reference for inspection Journal Article In: Frontiers in Psychology, vol. 4, pp. 624, 2013. @article{Stainer2013, Where people look when viewing a scene has been a much explored avenue of vision research (e.g., see Tatler, 2009). Current understanding of eye guidance suggests that a combination of high and low-level factors influence fixation selection (e.g., Torralba et al., 2006), but that there are also strong biases toward the center of an image (Tatler, 2007). However, situations where we view multiplexed scenes are becoming increasingly common, and it is unclear how visual inspection might be arranged when content lacks normal semantic or spatial structure. Here we use the central bias to examine how gaze behavior is organized in scenes that are presented in their normal format, or disrupted by scrambling the quadrants and separating them by space. In Experiment 1, scrambling scenes had the strongest influence on gaze allocation. Observers were highly biased by the quadrant center, although physical space did not enhance this bias. However, the center of the display still contributed to fixation selection above chance, and was most influential early in scene viewing. When the top left quadrant was held constant across all conditions in Experiment 2, fixation behavior was significantly influenced by the overall arrangement of the display, with fixations being biased toward the quadrant center when the other three quadrants were scrambled (despite the visual information in this quadrant being identical in all conditions). When scenes are scrambled into four quadrants and semantic contiguity is disrupted, observers no longer appear to view the content as a single scene (despite it consisting of the same visual information overall), but rather anchor visual inspection around the four separate "sub-scenes." Moreover, the frame of reference that observers use when viewing the multiplex seems to change across viewing time: from an early bias toward the display center to a later bias toward quadrant centers. |
Buyun Xu; James W. Tanaka Does face inversion qualitatively change face processing: An eye movement study using a face change detection task Journal Article In: Journal of Vision, vol. 13, no. 2, pp. 1–16, 2013. @article{Xu2013, Understanding the Face Inversion Effect is important for the study of face processing. Some researchers believe that the processing of inverted faces is qualitatively different from the processing of upright faces because inversion leads to a disproportionate performance decrement on the processing of different kinds of face information. Other researchers believe that the difference is quantitative because the processing of all kinds of facial information is less efficient due to the change in orientation and thus, the performance decrement is not disproportionate. To address the Qualitative and Quantitative debate, the current study employed a response-contingent, change detection paradigm to study eye movement during the processing of upright and inverted faces. In this study, configural and featural information were parametrically and independently manipulated in the eye and mouth region of the face. The manipulations for configural information involved changing the interocular distance between the eyes or the distance between the mouth and the nose. The manipulations for featural information involved changing the size of the eyes or the size of the mouth. The main results showed that change detection was more difficult in inverted than upright faces. Specifically, performance declined when the manipulated change occurred in the mouth region, despite the greater efforts allocated to the mouth region. Moreover, compared to upright faces where fixations were concentrated on the eyes and nose regions, inversion produced a higher concentration of fixations on the nose and mouth regions. Finally, change detection performance was better when the last fixation prior to response was located on the region of change, and the relationship between last fixation location and accuracy was stronger for inverted than upright faces. These findings reinforce the connection between eye movements and face processing strategies, and suggest that face inversion produces a qualitative disruption of looking behavior in the mouth region. |
Hongsheng Yang; Fang Wang; Nianjun Gu; Xiao Gao; Guang Zhao The cognitive advantage for one's own name is not simply familiarity: An eye-tracking study Journal Article In: Psychonomic Bulletin & Review, vol. 20, no. 6, pp. 1176–1180, 2013. @article{Yang2013, Eye-tracking technique and visual search task were employed to examine the cognitive advantage for one's own name and the possible effect of familiarity on this advantage. The results showed that fewer saccades and an earlier start time of first fixations on the target were associated with trials in which participants were asked to search for their own name, as compared to search for personally familiar or famous names. In addition, the results also demonstrated faster response times and higher accuracy in the former kind of trials. Taken together, these findings provide important evidence that one's own name has the potential to capture attention and that familiarity cannot account for this advantage. |
Zhou Yang; Todd Jackson; Hong Chen Effects of chronic pain and pain-related fear on orienting and maintenance of attention: An eye movement study Journal Article In: Journal of Pain, vol. 14, no. 10, pp. 1148–1157, 2013. @article{Yang2013b, Abstract In this study, effects of chronic pain and pain-related fear on orienting and maintenance of attention toward pain stimuli were evaluated by tracking eye movements within a dot-probe paradigm. The sample comprised matched chronic pain (n = 24) and pain-free (n = 24) groups, each of which included lower and higher fear of pain subgroups. Participants completed a dot-probe task wherein eye movements were assessed during the presentation of sensory pain-neutral, health catastrophe-neutral, and neutral-neutral word pairs. Higher fear of pain levels were associated with biases in 1) directing initial gaze toward health catastrophe words and, among participants with chronic pain, 2) subsequent avoidance of threat as reflected by shorter first fixation durations on health catastrophe words compared to pain-free cohorts. As stimulus word pairs persisted for 2,000 ms, no group differences were observed for overall gaze durations or reaction times to probes that followed. In sum, this research identified specific biases in visual attention related to fear of pain and chronic pain during early stages of information processing that were not evident on the basis of later behavior responses to probes. Perspective Effects of chronic pain and fear of pain on attention were examined by tracking eye movements within a dot-probe paradigm. Heightened fear of pain corresponded to biases in initial gaze toward health catastrophe words and, among participants with chronic pain, subsequent gaze shifts away from these words. No reaction time differences emerged. |
Chun Po Yin; Feng-Yang Kuo A study of how information system professionals comprehend indirect and direct speech acts in project communication Journal Article In: IEEE Transactions on Professional Communication, vol. 56, no. 3, pp. 226–241, 2013. @article{Yin2013, Research problem: Indirect communication is prevalent in business communication practices. For information systems (IS) projects that require professionals from multiple disciplines to work together, the use of indirect communication may hinder successful design, implementation, and maintenance of these systems. Drawing on the Speech Act Theory (SAT), this study investigates how direct and indirect speech acts may influence language comprehension in the setting of communication problems inherent in IS projects. Research questions: (1) Do participating subjects, who are IS professionals, differ in their comprehension of indirect and direct speech acts? (2) Do participants display different attention processes in their comprehension of indirect and direct speech acts? (3) Do participants' attention processes influence their comprehension of indirect and direct speech acts? Literature review: We review two relevant areas of theory—polite speech acts in professional communication and SAT. First, a broad review that focuses on literature related to the use of polite speech acts in the workplace and in information system (IS) projects suggests the importance of investigating speech acts by professionals. In addition, the SAT provides the theoretical framework guiding this study and the development of hypotheses. Methodology: The current study uses a quantitative approach. A between-groups experiment design was employed to test how direct and indirect speech acts influence the language comprehension of participants. Forty-three IS professionals participated in the experiment. In addition, through the use of eye-tracking technology, this study captured the attention process and analyzed the relationship between attention and comprehension. Results and discussion: The results show that the directness of speech acts significantly influences participants' attention process, which, in turn, significantly affects their comprehension. In addition, the findings indicate that indirect speech acts, if employed by IS professionals to communicate with others, may easily be distorted or misunderstood. Professionals and managers of organizations should be aware that effective communication in interdisciplinary projects, such as IS development, is not easy, and that reliance on polite or indirect communication may inhibit the generation of valid information. |
Angela H. Young; Johan Hulleman Eye movements reveal how task difficulty moulds visual search Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 39, no. 1, pp. 168–190, 2013. @article{Young2013, In two experiments we investigated the relationship between eye movements and performance in visual search tasks of varying difficulty. Experiment 1 provided evidence that a single process is used for search among static and moving items. Moreover, we estimated the functional visual field (FVF) from the gaze coordinates and found that its size during visual search shrinks with increasing task difficulty. In Experiment 2, we used a gaze-contingent window and confirmed the validity of the size estimates. The experiment also revealed that breakdown in robustness against item motion is related to item-by-item search, rather than search difficulty per se. We argue that visual search is an eye-movement-based process that works on a continuum, from almost parallel (where many items can be processed within a fixation) to completely serial (where only one item can be processed within a fixation). |
Stefan Van der Stigchel; Richard A. I. Bethlehem; Barrie P. Klein; Tos T. J. M. Berendschot; Tanja C. W. Nijboer; Serge O. Dumoulin Macular degeneration affects eye movement behavior during visual search Journal Article In: Frontiers in Psychology, vol. 4, pp. 579, 2013. @article{VanderStigchel2013, Patients with a scotoma in their central vision (e.g., due to macular degeneration, MD) commonly adopt a strategy to direct the eyes such that the image falls onto a peripheral location on the retina. This location is referred to as the preferred retinal locus (PRL). Although previous research has investigated the characteristics of this PRL, it is unclear whether eye movement metrics are modulated by peripheral viewing with a PRL as measured during a visual search paradigm. To this end, we tested four MD patients in a visual search paradigm and contrasted their performance with a healthy control group and a healthy control group performing the same experiment with a simulated scotoma. The experiment contained two conditions. In the first condition the target was an unfilled circle hidden among c-shaped distractors (serial condition) and in the second condition the target was a filled circle (pop-out condition). Saccadic search latencies for the MD group were significantly longer in both conditions compared to both control groups. Results of a subsequent experiment indicated that this difference between the MD and the control groups could not be explained by a difference in target selection sensitivity. Furthermore, search behavior of MD patients was associated with saccades with smaller amplitudes toward the scotoma, an increased intersaccadic interval and an increased number of eye movements necessary to locate the target. Some of these characteristics, such as the increased intersaccadic interval, were also observed in the simulation group, which indicate that these characteristics are related to the peripheral viewing itself. We suggest that the combination of the central scotoma and peripheral viewing can explain the altered search behavior and no behavioral evidence was found for a possible reorganization of the visual system associated with the use of a PRL. Thus the switch from a fovea-based to a PRL-based reference frame impairs search efficiency. |
Nathalie Van Humbeeck; Nadine Schmitt; Frouke Hermens; Johan Wagemans; Udo A. Ernst The role of eye movements in a contour detection task Journal Article In: Journal of Vision, vol. 13, no. 14, pp. 5, 2013. @article{VanHumbeeck2013, Vision combines local feature integration with active viewing processes, such as eye movements, to perceive complex visual scenes. However, it is still unclear how these processes interact and support each other. Here, we investigated how the dynamics of saccadic eye movements interact with contour integration, focusing on situations in which contours are difficult to find or even absent. We recorded observers' eye movements while they searched for a contour embedded in a background of randomly oriented elements. Task difficulty was manipulated by varying the contour's path angle. An association field model of contour integration was employed to predict potential saccade targets by identifying stimulus locations with high contour salience. We found that the number and duration of fixations increased with the increasing path angle of the contour. In addition, fixation duration increased over the course of a trial, and the time course of saccade amplitude depended on the percept of observers. Model fitting revealed that saccades fully compensate for the reduced saliency of peripheral contour targets. Importantly, our model predicted fixation locations to a considerable degree, indicating that observers fixated collinear elements. These results show that contour integration actively guides eye movements and determines their spatial and temporal parameters. |
Anouk Mariette Loon; Tomas Knapen; H. Steven Scholte; Elexa St. John-Saaltink; Tobias H. Donner; Victor A. F. Lamme GABA shapes the dynamics of bistable perception Journal Article In: Current Biology, vol. 23, no. 9, pp. 823–827, 2013. @article{Loon2013, Sometimes, perception fluctuates spontaneously between two distinct interpretations of a constant sensory input. These bistable perceptual phenomena provide a unique window into the neural mechanisms that create the contents of conscious perception [1]. Models of bistable perception posit that mutual inhibition between stimulus-selective neural populations in visual cortex plays a key role in these spontaneous perceptual fluctuations [2, 3]. However, a direct link between neural inhibition and bistable perception has not yet been established experimentally. Here, we link perceptual dynamics in three distinct bistable visual illusions (binocular rivalry, motion-induced blindness, and structure from motion) to measurements of gamma-aminobutyric acid (GABA) concentrations in human visual cortex (as measured with magnetic resonance spectroscopy) and to pharmacological stimulation of the GABAAreceptor by means of lorazepam. As predicted by a model of neural interactions underlying bistability, both higher GABA concentrations in visual cortex and lorazepam administration induced slower perceptual dynamics, as reflected in a reduced number of perceptual switches and a lengthening of percept durations. Thus, we show that GABA, the main inhibitory neurotransmitter, shapes the dynamics of bistable perception. These results pave the way for future studies into the competitive neural interactions across the visual cortical hierarchy that elicit conscious perception. |
Kathleen Vancleef; Johan Wagemans; Glyn W. Humphreys Impaired texture segregation but spared contour integration following damage to right posterior parietal cortex Journal Article In: Experimental Brain Research, vol. 230, no. 1, pp. 41–57, 2013. @article{Vancleef2013, We examined the relations between texture segregation and contour integration in patients with deficits in spatial attention leading to left or right hemisphere extinction. Patients and control participants were presented with texture and contour stimuli consisting of oriented elements. We induced regularity in the stimuli by manipulating the element orientations resulting in an implicit texture border or explicit contour. Participants had to discriminate curved from straight shapes without making eye movements, while the stimulus presentation time was varied using a QUEST procedure. The results showed that only patients with right hemisphere extinction had a spatial bias, needing a longer presentation time to determine the shape of the border or contour on the contralesional side, especially for borders defined by texture. These results indicate that texture segregation is modulated by attention-related brain areas in the right posterior parietal cortex. |
Signe Vangkilde; Anders Petersen; Claus Bundesen Temporal expectancy in the context of a theory of visual attention Journal Article In: Philosophical Transactions of the Royal Society B: Biological Sciences, vol. 368, pp. 1–11, 2013. @article{Vangkilde2013, Temporal expectation is expectation with respect to the timing of an event such as the appearance of a certain stimulus. In this paper, temporal expectancy is investigated in the context of the theory of visual attention (TVA), and we begin by summarizing the foundations of this theoretical framework. Next, we present a parametric experiment exploring the effects of temporal expectation on perceptual processing speed in cued single-stimulus letter recognition with unspeeded motor responses. The length of the cue-stimulus foreperiod was exponentially distributed with one of six hazard rates varying between blocks. We hypothesized that this manipulation would result in a distinct temporal expectation in each hazard rate condition. Stimulus exposures were varied such that both the temporal threshold of conscious perception (t0 ms) and the perceptual processing speed (v letters s(-1)) could be estimated using TVA. We found that the temporal threshold t0 was unaffected by temporal expectation, but the perceptual processing speed v was a strikingly linear function of the logarithm of the hazard rate of the stimulus presentation. We argue that the effects on the v values were generated by changes in perceptual biases, suggesting that our perceptual biases are directly related to our temporal expectations. |
Ronaldo Vigo; Derek E. Zeigler; Phillip A. Halsey Gaze and informativeness during category learning: Evidence for an inverse relation Journal Article In: Visual Cognition, vol. 21, no. 4, pp. 446–476, 2013. @article{Vigo2013, In what follows, we explore the general relationship between eye gaze during a category learning task and the information conveyed by each member of the learned category. To understand the nature of this relationship empirically, we used eye tracking during a novel object classification paradigm. Results suggest that the average fixation time per object during learning is inversely proportional to the amount of information that object conveys about its category. This inverse relationship may seem counterintuitive; however, objects that have a high-information value are inherently more representative of their category. Therefore, their generality captures the essence of the category structure relative to less representative objects. As such, it takes relatively less time to process these objects than their less informative companions. We use a general information measure referred to as representational information theory (Vigo, 2011a, 2013a) to articulate and interpret the results from our experiment and compare its predictions to those of three models of prototypicality. |