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2015 |
Naiman A. Khan; Carol L. Baym; Jim M. Monti; Lauren B. Raine; Eric S. Drollette; Mark R. Scudder; R. Davis Moore; Arthur F. Kramer; Charles H. Hillman; Neal J. Cohen Central adiposity is negatively associated with hippocampal-dependent relational memory among overweight and obese children Journal Article In: Journal of Pediatrics, vol. 166, no. 2, pp. 302–308, 2015. @article{Khan2015a, Objective—To assess associations between adiposity and hippocampal-dependent and hippocampal-independent memory forms among prepubertal children. Study design—Prepubertal children (7–9-year-olds |
Tim C. Kietzmann; P. König Effects of contextual information and stimulus ambiguity on overt visual sampling behavior Journal Article In: Vision Research, vol. 110, pp. 76–86, 2015. @article{Kietzmann2015, The sampling of our visual environment through saccadic eye movements is an essential function of the brain, allowing us to overcome the limits of peripheral vision. Understanding which parts of a scene attract overt visual attention is subject to intense research, and considerable progress has been made in unraveling the underlying cortical mechanisms. In contrast to spatial aspects, however, relatively little is understood about temporal aspects of overt visual sampling. At every fixation, the oculomotor system faces the decision whether to keep exploring different aspects of an object or scene or whether to remain fixated to allow for in-depth cortical processing - a situation that can be understood in terms of an exploration-exploitation dilemma. To improve our understanding of the factors involved in these decisions, we here investigate how the level of visual information, experimentally manipulated by scene context and stimulus ambiguity, changes the sampling behavior preceding the recognition of centrally presented ambiguous and disambiguated objects. Behaviorally, we find that context, although only presented until the first voluntary saccade, biases the perceptual outcome and significantly reduces reaction times. Importantly, we find that increased information about an object significantly alters its visual exploration, as evident through increased fixation durations and reduced saccade amplitudes. These results demonstrate that the initial sampling of an object, preceding its recognition, is subject to change based on the amount of information available in the system: increased evidence for its identity biases the exploration-exploitation strategy towards in-depth analyses. |
Tim C. Kietzmann; Sonia Poltoratski; Peter Konig; Randolph Blake; Frank Tong; Sam Ling The occipital face area is causally involved in facial viewpoint perception Journal Article In: Journal of Neuroscience, vol. 35, no. 50, pp. 16398–16403, 2015. @article{Kietzmann2015a, Humans reliably recognize faces across a range of viewpoints, but the neural substrates supporting this ability remain unclear. Recent work suggests that neural selectivity to mirror-symmetric viewpoints of faces, found across a large network of visual areas, may constitute a key computational step in achieving full viewpoint invariance. In this study, we used repetitive transcranial magnetic stimulation (rTMS) to test the hypothesis that the occipital face area (OFA), putatively a key node in the face network, plays a causal role in face viewpoint symmetry perception. Each participant underwent both offline rTMS to the right OFA and sham stimulation, preceding blocks of behavioral trials. After each stimulation period, the participant performed one of two behavioral tasks involving presentation of faces in the peripheral visual field: (1) judging the viewpoint symmetry; or (2) judging the angular rotation. rTMS applied to the right OFA significantly impaired performance in both tasks when stimuli were presented in the contralateral, left visual field. Interestingly, how-ever, rTMS had a differential effect on the two tasks performed ipsilaterally. Although viewpoint symmetry judgments were significantly disrupted, we observed no effect on the angle judgment task. This interaction, caused by ipsilateral rTMS, provides support for models emphasizing the role of interhemispheric crosstalk in the formation of viewpoint-invariant face perception. |
Eunah Kim; Silvina Montrul; James Yoon The on-line processing of binding principles in second language acquisition: Evidence from eye tracking Journal Article In: Applied Psycholinguistics, vol. 36, pp. 1317–1374, 2015. @article{Kim2015a, This study examined how adult L2 learners make use of grammatical and extragrammatical information to interpret reflexives and pronouns. Forty adult English native speakers and 32 intermediate–advanced Korean L2 learners participated in a visual world paradigm eye-tracking experiment. We investigated the interpretation of reflexives ( himself ) and pronouns ( him ) in contexts where there is a potential coargument antecedent and in the context of picture noun phrases ( a picture of him/himself ), where the distribution of reflexives and pronouns can overlap. The results indicated that the learners interpreted reflexives in a nativelike fashion in both contexts, whereas they interpreted pronouns differently from native speakers, even when learners had advanced English proficiency. Adopting the binding theory as developed in the reflexivity/primitives of binding framework (Reinhart & Reuland, 1993; Reuland, 2001, 2011), we interpret these results to mean that while adult L2 learners are able to apply syntactic binding principles to assign an interpretation to anaphoric expressions, they have difficulty in integrating syntactic information with contextual and discourse information. |
Kinam Kim; Minsung Kim; Jungyeop Shin; Jaemyong Ryu Eye-movement analysis of students' active examination strategy and its transfer in visuospatial representations Journal Article In: Journal of Geography, vol. 114, no. 4, pp. 133–145, 2015. @article{Kim2015b, This article examined the role of task demand and its effects on transfer in geographic learning. Student performance was measured through eye-movement analysis in two related experiments. In Experiment 1, the participants were told that they would travel through an area depicted in photographs either driving an automobile or observing the scenery. In Experiment 2, a map task was administered in which students were asked to find a target on a road map. The results showed that in the driving condition, the participants focused on structural information in the images, such as routes and connections. This cognitive process was transferred to the map task. |
Margit Hofler; Iain D. Gilchrist; Christof Korner Guidance toward and away from distractors in repeated visual search Journal Article In: Journal of Vision, vol. 15, no. 5, pp. 1–14, 2015. @article{Hofler2015, When searching for two targets consecutively in the same display, participants use memory of recently fixated distractors that become the target in the second search to find that target more quickly. Here we ask whether participants are also using memory for fixated distractors that do not become the target. In Experiment 1 we show that search is faster overall in the second search regardless of whether or not the second search target was fixated in the first search. We replicate this effect in Experiment 2 for different display sizes and further show that the effect is a result of the prioritization of locations that are more likely to contain the target. This suggests that representations of the fixated distractor items are retained across the two searches and that these representations can be used flexibly to optimize search performance. Furthermore, this suggests that the short-term memory processes that support search across consecutive searches not only facilitate guidance toward the target but also allow distractors to be excluded from the search process. |
Andrew Hollingworth Visual working memory modulates within‐object metrics of saccade landing position Journal Article In: Annals of the New York Academy of Sciences, vol. 1339, no. 1, pp. 11–19, 2015. @article{Hollingworth2015, In two experiments, we examined the influence of visual working memory (VWM) on oculomotor selection, testing whether the landing positions of rapidly generated saccades are biased toward the region of an object that matches a feature held in VWM. Participants executed a saccade to the center of a single saccade target, divided into two colored regions and presented on the horizontal midline. Concurrently, participants maintained a color in VWM for an unrelated memory task. This color either matched one of the two regions or neither of the regions. Relative to the no-match baseline, the landing positions of rapidly generated saccades (mean latency < 150 ms) were biased toward the region that matched the remembered color. The results support the hypothesis that VWM modulates early, spatially organized sensory representations to bias selection toward locations with features that match VWM content. In addition, the results demonstrate that saccades to spatially extended objects are sensitive to within-object differences in salience. |
Jörn M. Horschig; Wouter Oosterheert; Robert Oostenveld; Ole Jensen Modulation of posterior alpha activity by spatial attention allows for controlling a continuous brain–computer interface Journal Article In: Brain Topography, vol. 28, no. 6, pp. 852–864, 2015. @article{Horschig2015, Here we report that the modulation of alpha activity by covert attention can be used as a control signal in an online brain-computer interface, that it is reliable, and that it is robust. Subjects were instructed to orient covert visual attention to the left or right hemifield. We decoded the direction of attention from the magnetoencephalogram by a template matching classifier and provided the classification outcome to the subject in real-time using a novel graphical user interface. Training data for the templates were obtained from a Posner-cueing task conducted just before the BCI task. Eleven subjects participated in four sessions each. Eight of the subjects achieved classification rates significantly above chance level. Subjects were able to significantly increase their performance from the first to the second session. Individual patterns of posterior alpha power remained stable throughout the four sessions and did not change with increased performance. We conclude that posterior alpha power can successfully be used as a control signal in brain-computer interfaces. We also discuss several ideas for further improving the setup and propose future research based on solid hypotheses about behavioral consequences of modulating neuronal oscillations by brain computer interfacing. |
Gernot Horstmann; Arvid Herwig Surprise attracts the eyes and binds the gaze Journal Article In: Psychonomic Bulletin & Review, vol. 22, no. 3, pp. 743–749, 2015. @article{Horstmann2015, In recent years, researchers have become increasingly interested in the effects that deviations fromexpectations have on cognitive processing and, in particular, on the deployment of attention. Previous evidence for a surprise–attention link had been based on indirect measures of attention allocation. Here we used eyetracking to directly observe the impact of a novel color on its unannounced first presentation, which we regarded as a surprise condition. The results show that the novel color was quickly responded to with an eye movement, and that gaze was not turned away for a considerable amount of time. These results are direct evidence that deviations from expectations bias attentional priorities and lead to enhanced processing of the deviating stimulus. |
Michael C. Hout; Stephen D. Goldinger Target templates: The precision of mental representations affects attentional guidance and decision-making in visual search Journal Article In: Attention, Perception, and Psychophysics, vol. 77, no. 1, pp. 128–149, 2015. @article{Hout2015, When people look for things in the environment, they use target templates—mental representations of the objects they are attempting to locate—to guide attention and to assess incoming visual input as potential targets. However, unlike laboratory participants, searchers in the real world rarely have perfect knowledge regarding the potential appearance of targets. In seven experiments, we examined how the precision of target templates affects the ability to conduct visual search. Specifically, we degraded template precision in two ways: 1) by contaminating searchers' templateswith inaccurate features, and 2) by introducing extraneous features to the template that were unhelpful.We recorded eye movements to allow inferences regarding the relative extents to which attentional guidance and decision-making are hindered by template imprecision. Our findings support a dual-function theory of the target template and highlight the importance of examining template precision in visual search. |
Michael C. Hout; Stephen C. Walenchok; Stephen D. Goldinger; Jeremy M. Wolfe Failures of perception in the low-prevalence effect: Evidence from active and passive visual search Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 41, no. 4, pp. 977–994, 2015. @article{Hout2015a, In visual search, rare targets are missed disproportionately often. This low-prevalence effect (LPE) is a robust problem with demonstrable societal consequences. What is the source of the LPE? Is it a perceptual bias against rare targets or a later process, such as premature search termination or motor response errors? In 4 experiments, we examined the LPE using standard visual search (with eye tracking) and 2 variants of rapid serial visual presentation (RSVP) in which observers made present/absent decisions after sequences ended. In all experiments, observers looked for 2 target categories (teddy bear and butterfly) simultaneously. To minimize simple motor errors, caused by repetitive absent responses, we held overall target prevalence at 50%, with 1 low-prevalence and 1 high-prevalence target type. Across conditions, observers either searched for targets among other real-world objects or searched for specific bears or butterflies among within-category distractors. We report 4 main results: (a) In standard search, high-prevalence targets were found more quickly and accurately than low-prevalence targets. (b) The LPE persisted in RSVP search, even though observers never terminated search on their own. (c) Eye-tracking analyses showed that high-prevalence targets elicited better attentional guidance and faster perceptual decisions. And (d) even when observers looked directly at low-prevalence targets, they often (12%-34% of trials) failed to detect them. These results strongly argue that low-prevalence misses represent failures of perception when early search termination or motor errors are controlled. |
Tai-Hsiang Huang; Su-Ling Yeh; Yung-Hao Yang; Hsin-I Liao; Ya-Yeh Tsai; Pai-Ju Chang; Homer H. Chen Method and experiments of subliminal cueing for real-world images Journal Article In: Multimedia Tools and Applications, vol. 74, no. 22, pp. 10111–10135, 2015. @article{Huang2015, Unconscious attention shift triggered by a subliminal cue has been shown to be automatic; however, whether it can be brought into effect for images of real-world scenes remains to be investigated. We present a subliminal cueing method that flashes briefly a visual cue before presenting a real-world image to the viewer. The effectiveness of the method is verified by experiments using three types of cues (spatial cue, face cue, and object cue) of varied durations. Results show that depending on the cue type, the viewer's visual attention is directed to the cued visual hemifield or the cued location without engaging the viewer's awareness. The experiments demonstrate that a brief subliminal cue presented prior to the color image of a real-world complex scene can attract human visual attention. The method is useful for many applications that require efficient, unresisting attention shift to a target image area. |
Stefan Huber; Sonja Cornelsen; Korbinian Moeller; Hans-Christoph Nuerk Toward a model framework of generalized parallel componential processing of multi-symbol numbers Journal Article In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 41, no. 3, pp. 732–745, 2015. @article{Huber2015, In this article, we propose and evaluate a new model framework of parallel componential multi-symbol number processing, generalizing the idea of parallel componential processing of multi-digit numbers to the case of negative numbers by considering the polarity signs similar to single digits. In a first step, we evaluated this account by defining and investigating a sign-decade compatibility effect for the comparison of positive and negative numbers, which extends the unit-decade compatibility effect in 2-digit number processing. Then, we evaluated whether the model is capable of accounting for previous findings in negative number processing. In a magnitude comparison task, in which participants had to single out the larger of 2 integers, we observed a reliable sign-decade compatibility effect with prolonged reaction times for incompatible (e.g., −97 vs. +53; in which the number with the larger decade digit has the smaller, i.e., negative polarity sign) as compared with sign-decade compatible number pairs (e.g., −53 vs. +97). Moreover, an analysis of participants' eye fixation behavior corroborated our model of parallel componential processing of multi-symbol numbers. These results are discussed in light of concurrent theoretical notions about negative number processing. On the basis of the present results, we propose a generalized integrated model framework of parallel componential multi-symbol processing. |
Chia-Chun Hung; Cecil C. Yen; Jennifer L. Ciuchta; Daniel Papoti; Nicholas A. Bock; David A. Leopold; Afonso C. Silva Functional mapping of face-selective regions in the extrastriate visual cortex of the marmoset Journal Article In: Journal of Neuroscience, vol. 35, no. 3, pp. 1160–1172, 2015. @article{Hung2015a, The cerebral cortex of humans and macaques has specialized regions for processing faces and other visual stimulus categories. It is unknown whether a similar functional organization exists in New World monkeys, such as the common marmoset (Callithrix jacchus), a species of growing interest as a primate model in neuroscience. To address this question, we measured selective neural responses in the brain of four awake marmosets trained to fix their gaze upon images of faces, bodies, objects, and control patterns. In two of the subjects, we measured high gamma-range field potentials from electrocorticography arrays implanted over a large portion of the occipital and inferotemporal cortex. In the other two subjects, we measured BOLD fMRI responses across the entire brain. Both techniques revealed robust, regionally specific patterns of category-selective neural responses. We report that at least six face-selective patches mark the occipitotemporal pathway of the marmoset, with the most anterior patches showing the strongest preference for faces over other stimuli. The similar appearance of these patches to previous findings in macaques and humans, including their apparent arrangement in two parallel pathways, suggests that core elements of the face processing network were present in the common anthropoid primate ancestor living ∼35 million years ago. The findings also identify the marmoset as a viable animal model system for studying specialized neural mechanisms related to high-level social visual perception in humans. |
Tom Hunt; David Clark-Carter; David Sheffield Exploring the relationship between mathematics anxiety and performance: The role of intrusive thoughts Journal Article In: Journal of Education, Psychology and Social Sciences, vol. 29, pp. 226–231, 2015. @article{Hunt2015, The mechanisms underpinning the relationship between math anxiety and arithmetic performance are not fully understood. This study used an eye-tracking approach to measure a range of eye movements of 78 undergraduate students in response to performance on an arithmetic verification task. Results demonstrated a significant positive relationship between self-reported math anxiety and response time, indicating reduced processing efficiency. Analysis of eye-movement data reinforced the utility of an eye-tracking approach in studying arithmetic performance; specificdigit fixations, dwell time, saccades, and regressions all significantly predicted response time. Furthermore, findings highlighted significant positive correlations between math anxiety and fixations, dwell time, and saccades. Despite there being little evidence that eye move- ments mediate the math anxiety-to-performance relationship, relationships observed between math anxiety and eye movements provide a useful starting point for research using an eye-tracking methodology in studying math anxiety and performance; the present findings suggest future work should focus on calculation strategy. |
David E. Irwin; Maria M. Robinson Detection of stimulus displacements across saccades is capacity-limited and biased in favor of the saccade target Journal Article In: Frontiers in Systems Neuroscience, vol. 9, pp. 161, 2015. @article{Irwin2015, Retinal image displacements caused by saccadic eye movements are generally unnoticed. Recent theories have proposed that perceptual stability across saccades depends on a local evaluation process centered on the saccade target object rather than on remapping and evaluating the positions of all objects in a display. In three experiments, we examined whether objects other than the saccade target also influence perceptual stability by measuring displacement detection thresholds across saccades for saccade targets and a variable number of non-saccade objects. We found that the positions of multiple objects are maintained across saccades, but with variable precision, with the saccade target object having priority in the perception of displacement, most likely because it is the focus of attention before the saccade and resides near the fovea after the saccade. The perception of displacement of objects that are not the saccade target is affected by acuity limitations, attentional limitations, and limitations on memory capacity. Unlike previous studies that have found that a postsaccadic blank improves the detection of displacement direction across saccades, we found that postsaccadic blanking hurt the detection of displacement per se by increasing false alarms. Overall, our results are consistent with the hypothesis that visual working memory underlies the perception of stability across saccades. |
Lena A. Jäger; Lena Benz; Jens Roeser; Brian W. Dillon; Shravan Vasishth Teasing apart retrieval and encoding interference in the processing of anaphors Journal Article In: Frontiers in Psychology, vol. 6, pp. 506, 2015. @article{Jaeger2015, Two classes of account have been proposed to explain the memory processes subserving the processing of reflexive-antecedent dependencies. Structure-based accounts assume that the retrieval of the antecedent is guided by syntactic tree-configurational information without considering other kinds of information such as gender marking in the case of English reflexives. By contrast, unconstrained cue-based retrieval assumes that all available information is used for retrieving the antecedent. Similarity-based interference effects from structurally illicit distractors which match a non-structural retrieval cue have been interpreted as evidence favoring the unconstrained cue-based retrieval account since cue-based retrieval interference from structurally illicit distractors is incompatible with the structure-based account. However, it has been argued that the observed effects do not necessarily reflect interference occurring at the moment of retrieval but might equally well be accounted for by interference occurring already at the stage of encoding or maintaining the antecedent in memory, in which case they cannot be taken as evidence against the structure-based account. We present three experiments (self-paced reading and eye-tracking) on German reflexives and Swedish reflexive and pronominal possessives in which we pit the predictions of encoding interference and cue-based retrieval interference against each other. We could not find any indication that encoding interference affects the processing ease of the reflexive-antecedent dependency formation. Thus, there is no evidence that encoding interference might be the explanation for the interference effects observed in previous work. We therefore conclude that invoking encoding interference may not be a plausible way to reconcile interference effects with a structure-based account of reflexive processing. |
Sharna D. Jamadar; Beth P. Johnson; Meaghan Clough; Gary F. Egan; Joanne Fielding Behavioral and neural plasticity of ocular motor control: Changes in performance and fMRI activity following antisaccade training Journal Article In: Frontiers in Human Neuroscience, vol. 9, no. 653, pp. 1–13, 2015. @article{Jamadar2015, The antisaccade task provides a model paradigm that sets the inhibition of a reflexively driven behavior against the volitional control of a goal-directed behavior. The stability and adaptability of antisaccade performance was investigated in 23 neurologically healthy individuals. Behavior and brain function were measured using functional magnetic resonance imaging (fMRI) prior to and immediately following 2 weeks of daily antisaccade training. Participants performed antisaccade trials faster with no change in directional error rate following 2 weeks of training; however this increased speed came at the cost of the spatial accuracy of the saccade (gain) which became more hypometric following training. Training on the antisaccade task resulted in increases in fMRI activity in the fronto-basal ganglia-parietal-cerebellar ocular motor network. Following training, antisaccade latency was positively associated with fMRI activity in the frontal and supplementary eye fields, anterior cingulate and intraparietal sulcus; antisaccade gain was negatively associated with fMRI activity in supplementary eye fields, anterior cingulate, intraparietal sulcus, and cerebellar vermis. In sum, the results suggest that following training, larger antisaccade latency is associated with larger activity in fronto-parietal-cerebellar ocular motor regions, and smaller antisaccade gain is associated with larger activity in fronto-parietal ocular motor regions. |
Yu-Cin Jian; Chao-Jung Wu Using eye tracking to investigate semantic and spatial representations of scientific diagrams during text-diagram integration Journal Article In: Journal of Science Education and Technology, vol. 24, no. 1, pp. 43–55, 2015. @article{Jian2015, We investigated strategies used by readers when reading a science article with a diagram and assessed whether semantic and spatial representations were constructed while reading the diagram. Seventy-one undergraduate participants read a scientific article while tracking their eye movements and then completed a reading comprehension test. Our results showed that the text-diagram referencing strategy was commonly used. However, some readers adopted other reading strategies, such as reading the diagram or text first. We found all readers who had referred to the diagram spent roughly the same amount of time reading and performed equally well. However, some participants who ignored the diagram performed more poorly on questions that tested understanding of basic facts. This result indicates that dual coding theory may be a possible theory to explain the phenomenon. Eye movement patterns indicated that at least some readers had extracted semantic information of the scientific terms when first looking at the diagram. Readers who read the scientific terms on the diagram first tended to spend less time looking at the same terms in the text, which they read after. Besides, presented clear diagrams can help readers process both semantic and spatial information, thereby facilitating an overall understanding of the article. In addition, although text-first and diagram-first readers spent similar total reading time on the text and diagram parts of the article, respectively, text-first readers had significantly less number of saccades of text and diagram than diagram-first readers. This result might be explained as text-directed reading. |
Yaoguang Jiang; Gopathy Purushothaman; Vivien A. Casagrande The functional asymmetry of ON and OFF channels in the perception of contrast Journal Article In: Journal of Neurophysiology, vol. 114, pp. 2816–2829, 2015. @article{Jiang2015a, To fully understand the relationship between perception and single neural responses, one should take into consideration the early stages of sensory processing. Few studies, however, have directly examined the neural underpinning of visual perception in the lateral geniculate nucleus (LGN), only one synapse away from the retina. In this study we recorded from LGN parvocellular (P) ON-center and OFF-center neurons while monkeys either passively viewed or actively detected a full range of contrasts. We found that OFF neurons were more sensitive in detecting negative contrasts than ON neurons were in detecting positive contrasts. Also, OFF neurons had higher spontaneous activities, higher peak response amplitudes, and were more sustained than ON neurons in their contrast responses. Puzzlingly, OFF neurons failed to show any significant correlations with the monkeys' perceptual choices, despite their greater contrast sensitivities. If, however, choice probabilities were calculated from interspike intervals instead of spike counts (thus taking into account the higher firing rates of OFF neurons), OFF neurons but not ON neurons were significantly correlated with behavioral choices. Taken together, these results demonstrate in awake, behaving animals that: 1) the ON and OFF pathways do not simply mirror each other in their functionality but instead carry qualitatively different types of information, and 2) the responses of ON and OFF neurons can be correlated with perceptual choices even in the absence of physical stimuli and interneuronal correlations. |
Helen E. Jones; Ian M. Andolina; Stewart D. Shipp; Daniel L. Adams; Javier Cudeiro; Thomas E. Salt; Adam M. Sillito Figure-ground modulation in awake primate thalamus Journal Article In: Proceedings of the National Academy of Sciences, vol. 112, no. 22, pp. 7085–7090, 2015. @article{Jones2015, Figure-ground discrimination refers to the perception of an object, the figure, against a nondescript background. Neural mechanisms of figure-ground detection have been associated with feedback interactions between higher centers and primary visual cortex and have been held to index the effect of global analysis on local feature encoding. Here, in recordings from visual thalamus of alert primates, we demonstrate a robust enhancement of neuronal firing when the figure, as opposed to the ground, component of a motion-defined figure-ground stimulus is located over the receptive field. In this paradigm, visual stimulation of the receptive field and its near environs is identical across both conditions, suggesting the response enhancement reflects higher integrative mechanisms. It thus appears that cortical activity generating the higher-order percept of the figure is simultaneously reentered into the lowest level that is anatomically possible (the thalamus), so that the signature of the evolving representation of the figure is imprinted on the input driving it in an iterative process. |
Suzanne R. Jongman; Antje S. Meyer; Ardi Roelofs The role of sustained attention in the production of conjoined noun phrases: An individual differences study Journal Article In: PLoS ONE, vol. 10, no. 9, pp. e0137557, 2015. @article{Jongman2015a, It has previously been shown that language production, performed simultaneously with a nonlinguistic task, involves sustained attention. Sustained attention concerns the ability to maintain alertness over time. Here, we aimed to replicate the previous finding by showing that individuals call upon sustained attention when they plan single noun phrases (e.g., "the carrot") and perform a manual arrow categorization task. In addition, we investigated whether speakers also recruit sustained attention when they produce conjoined noun phrases (e.g., "the carrot and the bucket") describing two pictures, that is, when both the first and second task are linguistic. We found that sustained attention correlated with the proportion of abnormally slow phrase-production responses. Individuals with poor sustained attention displayed a greater number of very slow responses than individuals with better sustained attention. Importantly, this relationship was obtained both for the production of single phrases while performing a nonlinguistic manual task, and the production of noun phrase conjunctions in referring to two spatially separated objects. Inhibition and updating abilities were also measured. These scores did not correlate with our measure of sustained attention, suggesting that sustained attention and executive control are distinct. Overall, the results suggest that planning conjoined noun phrases involves sustained attention, and that language production happens less automatically than has often been assumed. |
Suzanne R. Jongman; Ardi Roelofs; Antje S. Meyer Sustained attention in language production: An individual differences investigation Journal Article In: Quarterly Journal of Experimental Psychology, vol. 68, no. 4, pp. 710–730, 2015. @article{Jongman2015, Whereas it has long been assumed that most linguistic processes underlying language production happen automatically, accumulating evidence suggests that these processes do require some form of attention. Here we investigated the contribution of sustained attention: the ability to maintain alertness over time. In Experiment 1, participants' sustained attention ability was measured using auditory and visual continuous performance tasks. Subsequently, employing a dual-task procedure, participants described pictures using simple noun phrases and performed an arrow-discrimination task while their vocal and manual response times (RTs) and the durations of their gazes to the pictures were measured. Earlier research has demonstrated that gaze duration reflects language planning processes up to and including phonological encoding. The speakers' sustained attention ability correlated with the magnitude of the tail of the vocal RT distribution, reflecting the proportion of very slow responses, but not with individual differences in gaze duration. This suggests that sustained attention was most important after phonological encoding. Experiment 2 showed that the involvement of sustained attention was significantly stronger in a dual-task situation (picture naming and arrow discrimination) than in simple naming. Thus, individual differences in maintaining attention on the production processes become especially apparent when a simultaneous second task also requires attentional resources. |
Holly S. S. L. Joseph; Georgina Bremner; Simon P. Liversedge; Kate Nation Working memory, reading ability and the effects of distance and typicality on anaphor resolution in children Journal Article In: Journal of Cognitive Psychology, vol. 27, no. 5, pp. 622–639, 2015. @article{Joseph2015, We investigated the time course of anaphor resolution in children and whether this is modulated by individual differences in working memory and reading skill. The eye movements of 30 children (10–11 years) were monitored as they read short paragraphs in which (1) the semantic typicality of an antecedent and (2) its distance in relation to an anaphor were orthogonally manipulated. Children showed effects of distance and typicality on the anaphor itself and also on the word to the right of the anaphor, suggesting that anaphoric processing begins immediately but continues after the eyes have left the anaphor. Furthermore, children showed no evidence of resolving anaphors in the most difficult condition (distant atypical antecedent), suggesting that anaphoric processing that is demanding may not occur online in children of this age. Finally, working memory capacity and reading comprehension skill affect the magnitude and time course of typicality and distance effects during anaphoric processing. |
Christopher Kanan; Dina N. F. Bseiso; Nicholas A. Ray; Janet H. Hsiao; Garrison W. Cottrell Humans have idiosyncratic and task-specific scanpaths for judging faces Journal Article In: Vision Research, vol. 108, pp. 67–76, 2015. @article{Kanan2015, Since Yarbus's seminal work, vision scientists have argued that our eye movement patterns differ depending upon our task. This has recently motivated the creation of multi-fixation pattern analysis algorithms that try to infer a person's task (or mental state) from their eye movements alone. Here, we introduce new algorithms for multi-fixation pattern analysis, and we use them to argue that people have scanpath routines for judging faces. We tested our methods on the eye movements of subjects as they made six distinct judgments about faces. We found that our algorithms could detect whether a participant is trying to distinguish angriness, happiness, trustworthiness, tiredness, attractiveness, or age. However, our algorithms were more accurate at inferring a subject's task when only trained on data from that subject than when trained on data gathered from other subjects, and we were able to infer the identity of our subjects using the same algorithms. These results suggest that (1) individuals have scanpath routines for judging faces, and that (2) these are diagnostic of that subject, but that (3) at least for the tasks we used, subjects do not converge on the same "ideal" scanpath pattern. Whether universal scanpath patterns exist for a task, we suggest, depends on the task's constraints and the level of expertise of the subject. |
Christian H. Poth; Arvid Herwig; Werner X. Schneider Breaking object correspondence across saccadic eye movements deteriorates object recognition Journal Article In: Frontiers in Systems Neuroscience, vol. 9, pp. 176, 2015. @article{Poth2015, Visual perception is based on information processing during periods of eye fixations that are interrupted by fast saccadic eye movements. The ability to sample and relate information on task-relevant objects across fixations implies that correspondence between presaccadic and postsaccadic objects is established. Postsaccadic object information usually updates and overwrites information on the corresponding presaccadic object. The presaccadic object representation is then lost. In contrast, the presaccadic object is conserved when object correspondence is broken. This helps transsaccadic memory but it may impose attentional costs on object recognition. Therefore, we investigated how breaking object correspondence across the saccade affects postsaccadic object recognition. In Experiment 1, object correspondence was broken by a brief postsaccadic blank screen. Observers made a saccade to a peripheral object which was displaced during the saccade. This object reappeared either immediately after the saccade or after the blank screen. Within the postsaccadic object, a letter was briefly presented (terminated by a mask). Observers reported displacement direction and letter identity in different blocks. Breaking object correspondence by blanking improved displacement identification but deteriorated postsaccadic letter recognition. In Experiment 2, object correspondence was broken by changing the object's contrast-polarity. There were no object displacements and observers only reported letter identity. Again, breaking object correspondence deteriorated postsaccadic letter recognition. These findings identify transsaccadic object correspondence as a key determinant of object recognition across the saccade. This is in line with the recent hypothesis that breaking object correspondence results in separate representations of presaccadic and postsaccadic objects which then compete for limited attentional processing resources (Schneider, 2013). Postsaccadic object recognition is then deteriorated because less resources are available for processing postsaccadic objects. |
Seema Gorur Prasad; Gouri Shanker Patil; Ramesh Kumar Mishra Effect of exogenous cues on covert spatial orienting in deaf and normal hearing individuals Journal Article In: PLoS ONE, vol. 10, no. 10, pp. e0141324, 2015. @article{Prasad2015, Deaf individuals have been known to process visual stimuli better at the periphery compared to the normal hearing population. However, very few studies have examined attention orienting in the oculomotor domain in the deaf, particularly when targets appear at variable eccentricity. In this study, we examined if the visual perceptual processing advantage reported in the deaf people also modulates spatial attentional orienting with eye movement responses. We used a spatial cueing task with cued and uncued targets that appeared at two different eccentricities and explored attentional facilitation and inhibition. We elicited both a saccadic and a manual response. The deaf showed a higher cueing effect for the ocular responses than the normal hearing participants. However, there was no group difference for the manual responses. There was also higher facilitation at the periphery for both saccadic and manual responses, irrespective of groups. These results suggest that, owing to their superior visual processing ability, the deaf may orient attention faster to targets. We discuss the results in terms of previous studies on cueing and attentional orienting in deaf. |
Mario Prsa; Danilo Jimenez-Rezende; Olaf Blanke Inference of perceptual priors from path dynamics of passive self-motion Journal Article In: Journal of Neurophysiology, vol. 113, no. 5, pp. 1400–1413, 2015. @article{Prsa2015, The monitoring of one's own spatial orientation depends on the ability to estimate successive self-motion cues accurately. This process has become to be known as path integration. A feature of sequential cue estimation, in general, is that the history of previously experienced stimuli, or priors, biases perception. Here, we investigate how during angular path integration, the prior imparted by the displacement path dynamics affects the translation of vestibular sensations into percep-tual estimates. Subjects received successive whole-body yaw rotations and were instructed to report their position within a virtual scene after each rotation. The overall movement trajectory either followed a parabolic path or was devoid of explicit dynamics. In the latter case, estimates were biased toward the average stimulus prior and were well captured by an optimal Bayesian estimator model fit to the data. However, the use of parabolic paths reduced perceptual uncertainty, and a decrease of the average size of bias and thus the weight of the average stimulus prior were observed over time. The produced esti-mates were, in fact, better accounted for by a model where a predic-tion of rotation magnitude is inferred from the underlying path dynamics on each trial. Therefore, when passively displaced, we seem to be able to build, over time, from sequential vestibular measure-ments an internal model of the vehicle's movement dynamics. Our findings suggest that in ecological conditions, vestibular afference can be internally predicted, even when self-motion is not actively gener-ated by the observer, thereby augmenting both the accuracy and precision of displacement perception. |
M. Victoria Puig; Earl K. Miller Neural substrates of dopamine D2 receptor modulated executive functions in the monkey prefrontal cortex Journal Article In: Cerebral Cortex, vol. 25, no. 9, pp. 2980–2987, 2015. @article{Puig2015, Dopamine D2 receptors (D2R) play a major role in cognition, mood and motor movements. Their blockade by antipsychotic drugs reduces hallucinatory and delusional behaviors in schizophrenia, but often fails to alleviate affective and cognitive dysfunctions. The prefrontal cortex (PFC) expresses D2R and is altered in schizophrenia. We investigated how D2R modulate behavior and PFC function in monkeys. Two monkeys learned new and performed highly familiar visuomotor associations, where each cue was associated with a saccade to a right or left target. We recorded neural spikes and local field potentials from multiple electrodes while injecting the D2R antagonist eticlopride in the lateral PFC. Blocking prefrontal D2R impaired associative learning and cognitive flexibility, reduced motivation, but left the performance of familiar associations intact. Eticlopride reduced saccade-direction selectivity of prefrontal neurons, leading to a decrease in neural information about the associations, and an increase in alpha oscillations. These results, together with our recent study using a D1R antagonist, suggest that D1R and D2R in the primate lateral PFC cooperate to modulate several executive functions. Our findings help to gain insight into why antipsychotic drugs, with strong antagonistic actions on D2R, fail to ameliorate cognitive and emotional deficits in schizophrenia. |
Michael Puntiroli; Dirk Kerzel; Sabine Born Perceptual enhancement prior to intended and involuntary saccades Journal Article In: Journal of Vision, vol. 15, no. 4, pp. 1–20, 2015. @article{Puntiroli2015, Prior to an eye movement, attention is gradually shifted toward the point where the saccade will land. Our goal was to better understand the allocation of attention in an oculomotor capture paradigm for saccades that go straight to the eye movement target and for saccades that go to a distractor and are followed by corrective saccades to the target (i.e., involuntary saccades). We also sought to test facilitation at the future retinotopic location of target and nontarget objects, with the principal aim of verifying whether the remapping process accounts for the retinal displacement caused by involuntary saccades. Two experiments were run employing a dual-task design, primarily requiring participants to perform saccades toward a target while discriminating an asymmetric cross presented briefly before saccade onset. The results clearly show perceptual facilitation at the target location for goal- directed saccades and at the distractor location when oculomotor capture occurred. Facilitation was observed at a location relating to the remapping of a future saccade landing point, in sequences of oculomotor capture. In contrast, performance remained unaffected at the remapped location of a salient distracting object, which was not looked at. The findings are taken as evidence that presaccadic enhancement occurs prior to involuntary and voluntary saccades alike and that the remapping process also indiscriminatingly accounts for the retinal displacement caused by either. |
Haoyue Qian; Xiangping Gao; Zhiguo Wang Faces distort eye movement trajectories, but the distortion is not stronger for your own face Journal Article In: Experimental Brain Research, vol. 233, no. 7, pp. 2155–2166, 2015. @article{Qian2015, It is currently unclear whether a person's own face has greater capacity in absorbing his/her attention than faces of others. With two visual distractor tasks, the present study assessed the extent to which a person's own face attracts his/her attention, by measuring face distractor elicited distortion of saccade trajectories. Experiment 1 showed that upright faces induced stronger distortion of saccade trajectories than inverted ones. This face inversion effect, however, was not stronger for the participant's own face than for unfamiliar other's faces. By manipulating fixation stimulus offset and using peripheral onset target, Experiment 2 further demonstrated that these observations were not contingent on saccade latency. Together, these findings suggest that a person's own face is not more salient or attention-absorbing than unfamiliar other's faces. |
Rishi Rajalingham; Kailyn Schmidt; James J. DiCarlo Comparison of object recognition behavior in human and monkey Journal Article In: Journal of Neuroscience, vol. 35, no. 35, pp. 12127–12136, 2015. @article{Rajalingham2015, Although the rhesus monkey is used widely as an animal model of human visual processing, it is not known whether invariant visual object recognition behavior is quantitatively comparable across monkeys and humans. To address this question, we systematically compared the core object recognition behavior of two monkeys with that of human subjects. To test true object recognition behavior (rather than image matching), we generated several thousand naturalistic synthetic images of 24 basic-level objects with high variation in viewing parameters and image background. Monkeys were trained to perform binary object recognition tasks on a match-to-sample paradigm. Data from 605 human subjects performing the same tasks on Mechanical Turk were aggregated to characterize "pooled human" object recognition behavior, as well as 33 separate Mechanical Turk subjects to characterize individual human subject behavior. Our results show that monkeys learn each new object in a few days, after which they not only match mean human performance but show a pattern of object confusion that is highly correlated with pooled human confusion patterns and is statistically indistinguishable from individual human subjects. Importantly, this shared human and monkey pattern of 3D object confusion is not shared with low-level visual representations (pixels, V1+; models of the retina and primary visual cortex) but is shared with a state-of-the-art computer vision feature representation. Together, these results are consistent with the hypothesis that rhesus monkeys and humans share a common neural shape representation that directly supports object perception. |
You Li; Lei Mo; Qi Chen Differential contribution of velocity and distance to time estimation during self-initiated time-to-collision judgment Journal Article In: Neuropsychologia, vol. 73, pp. 35–47, 2015. @article{Li2015c, To successfully intercept/avoid a moving object, human brain needs to precisely estimate the time-to-collision (TTC) of the object. In real life, time estimation is determined conjointly by the velocity and the distance of a moving object. However, surprisingly little is known concerning whether and how the velocity and the distance dimensions contribute differentially to time estimation. In this fMRI study, we demonstrated that variations of velocity evoked substantially different behavioral and neural responses than distance during self-initiated TTC judgments. Behaviorally, the velocity dimension induced a stronger time dilation effect than the distance dimension that participants' responses were significantly more delayed by increasing velocity than by decreasing distance, even with the theoretical TTC being equated between the two conditions. Neurally, activity in the dorsal fronto-parietal TTC network was parametrically modulated by variations in TTC irrespective of whether the variations in TTC were caused by velocity or distance. Importantly, even with spatial distance being equated, increasing velocity induced illusory perception of longer spatial trajectory in early visual cortex. Moreover, as velocity increased, the early visual cortex showed enhanced connectivity with the TTC network. Our results thus implied that with increasing velocity, TTC judgments depended increasingly on the velocity-induced illusory distance information from early visual cortex and was eventually tampered. |
Amy M. Lieberman; Arielle Borovsky; Marla Hatrak; Rachel I. Mayberry Real-time processing of ASL signs: Delayed first language acquisition affects organization of the mental lexicon Journal Article In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 41, no. 4, pp. 1130–1139, 2015. @article{Lieberman2015, Sign language comprehension requires visual attention to the linguistic signal and visual attention to referents in the surrounding world, whereas these processes are divided between the auditory and visual modalities for spoken language comprehension. Additionally, the age-onset of first language acquisition and the quality and quantity of linguistic input and for deaf individuals is highly heterogeneous, which is rarely the case for hearing learners of spoken languages. Little is known about how these modality and developmental factors affect real-time lexical processing. In this study, we ask how these factors impact real-time recognition of American Sign Language (ASL) signs using a novel adaptation of the visual world paradigm in deaf adults who learned sign from birth (Experiment 1), and in deaf individuals who were late-learners of ASL (Experiment 2). Results revealed that although both groups of signers demonstrated rapid, incremental processing of ASL signs, only native-signers demonstrated early and robust activation of sub-lexical features of signs during real-time recognition. Our findings suggest that the organization of the mental lexicon into units of both form and meaning is a product of infant language learning and not the sensory and motor modality through which the linguistic signal is sent and received. |
Yi Chun Lin; Tzu Chien Liu; John Sweller In: Computers and Education, vol. 88, pp. 280–291, 2015. @article{Lin2015, Computer simulations were used to teach students basic concepts associated with correlation. Half of the students were presented information in a sequential series of single frames in which each frame replaced the preceding frame while the other half were presented the information in simultaneous multiple frames in which each frame was added to the previous frames without replacement. It was hypothesized that if the isolated elements effect occurs, the single-frame condition should be superior. Alternatively, if the transient information effect dominates, the multiple-frame condition should be superior. Results confirmed the superiority of the single-frame presentation. Eye-tracking indicated that participants who learned with single frames paid more attention to the important representations than participants who learned with multiple frames. |
Sam Ling; Michael S. Pratte; Frank Tong Attention alters orientation processing in the human lateral geniculate nucleus Journal Article In: Nature Neuroscience, vol. 18, no. 4, pp. 496–498, 2015. @article{Ling2015, Orientation selectivity is a cornerstone property of vision, commonly believed to emerge in the primary visual cortex. We found that reliable orientation information could be detected even earlier, in the human lateral geniculate nucleus, and that attentional feedback selectively altered these orientation responses. This attentional modulation may allow the visual system to modify incoming feature-specific signals at the earliest possible processing site. |
Matteo Lisi; Patrick Cavanagh; Marco Zorzi Spatial constancy of attention across eye movements is mediated by the presence of visual objects Journal Article In: Attention, Perception, and Psychophysics, vol. 77, no. 4, pp. 1159–1169, 2015. @article{Lisi2015, Recent studies have shown that attentional facilitation lingers at the retinotopic coordinates of a previously attended position after an eye movement. These results are intriguing, because the retinotopic location becomes behaviorally irrelevant once the eyes have moved. Critically, in these studies participants were asked to maintain attention on a blank location of the screen. In the present study, we examined whether the continuing presence of a visual object at the cued location could affect the allocation of attention across eye movements. We used a trans-saccadic cueing paradigm in which the relevant positions could be defined or not by visual objects (simple square outlines). We find an attentional benefit at the spatiotopic location of the cue only when the object (the placeholder) has been continuously present at that location. We conclude that the presence of an object at the attended location is a critical factor for the maintenance of spatial constancy of attention across eye movements, a finding that helps to reconcile previous conflicting results. |
Zhiya Liu; Xiaohong Song; Carol A. Seger; Peter J. Hills An eye-tracking study of multiple feature value category structure learning: The role of unique features Journal Article In: PLoS ONE, vol. 10, no. 8, pp. e0135729, 2015. @article{Liu2015c, We examined whether the degree to which a feature is uniquely characteristic of a category can affect categorization above and beyond the typicality of the feature. We developed a multiple feature value category structure with different dimensions within which feature uniqueness and typicality could be manipulated independently. Using eye tracking, we found that the highest attentional weighting (operationalized as number of fixations, mean fixation time, and the first fixation of the trial) was given to a dimension that included a feature that was both unique and highly typical of the category. Dimensions that included features that were highly typical but not unique, or were unique but not highly typical, received less attention. A dimension with neither a unique nor a highly typical feature received least attention. On the basis of these results we hypothesized that subjects categorized via a rule learning procedure in which they performed an ordered evaluation of dimensions, beginning with unique and strongly typical dimensions, and in which earlier dimensions received higher weighting in the decision. This hypothesis accounted for performance on transfer stimuli better than simple implementations of two other common theories of category learning, exemplar models and prototype models, in which all dimensions were evaluated in parallel and received equal weighting. |
Francesc Llorens; Daniel Sanabria; Florentino Huertas; Enrique Molina; Simon J. Bennett Intense physical exercise reduces overt attentional capture Journal Article In: Journal of Sport and Exercise Psychology, vol. 37, no. 5, pp. 559–564, 2015. @article{Llorens2015, The abrupt onset of a visual stimulus typically results in overt attentional capture, which can be quantified by saccadic eye movements. Here, we tested whether attentional capture following onset of task-irrelevant visual stimuli (new object) is reduced after a bout of intense physical exercise. A group of participants performed a visual search task in two different activity conditions: rest, without any prior effort, and effort, immediately after an acute bout of intense exercise. The results showed that participants exhibited (1) slower reaction time of the first saccade toward the target when a new object was simultaneously presented in the visual field, but only in the rest activity condition, and (2) more saccades to the new object in the rest activity condition than in the effort activity condition. We suggest that immediately after an acute bout of effort, participants improved their ability to inhibit irrelevant (distracting) stimuli. |
Davide Paoletti; Matthew David Weaver; Christoph Braun; Wieske Zoest Trading off stimulus salience for identity: A cueing approach to disentangle visual selection strategies Journal Article In: Vision Research, vol. 113, pp. 116–124, 2015. @article{Paoletti2015, Recent studies show that time plays a primary role in determining whether visual selection is influenced by stimulus salience or guided by observers' intentions. Accordingly, when a response is made seems critically important in defining the outcome of selection. The present study investigates whether observers are able to control the timing of selection and regulate the trade-off between stimulus- and goal-driven influences. One experiment was conducted in which participants were asked to make a saccade to the target, a tilted bar embedded in a matrix of vertical lines. An additional distractor, more or less salient than the target, was presented concurrently with the search display. To manipulate when in time the response was given we cued participants before each trial to be either fast or accurate. Participants received periodic feedback regarding performance speed and accuracy. The results showed participants were able to control the timing of selection: the distribution of responses was relatively fast or slow depending on the cue. Performance in the fast-cue condition appeared to be primarily driven by stimulus salience, while in the accurate-cue condition saccades were guided by the search template. Examining the distribution of responses that temporally overlapped between the two cue conditions revealed a main effect of cue. This suggests the cue had an additional benefit to performance independent of the effect of salience. These findings show that although early selection may be constrained by stimulus salience, observers are flexible in guiding the 'when' signal and consequently establishing a trade-off between saliency and identity. |
David Pascucci; Tommaso Mastropasqua; Massimo Turatto Monetary reward modulates task-irrelevant perceptual learning for invisible stimuli Journal Article In: PLoS ONE, vol. 10, no. 5, pp. e0124009, 2015. @article{Pascucci2015a, Task Irrelevant Perceptual Learning (TIPL) shows that the brain's discriminative capacity can improve also for invisible and unattended visual stimuli. It has been hypothesized that this form of “unconscious” neural plasticity is mediated by an endogenous reward mechanism triggered by the correct task performance. Although this result has challenged the mandatory role of attention in perceptual learning, no direct evidence exists of the hypothesized link between target recognition, reward and TIPL. Here, we manipulated the reward value associated with a target to demonstrate the involvement of reinforcement mechanisms in sensory plasticity for invisible inputs. Participants were trained in a central task associated with either high or low monetary incentives, provided only at the end of the experiment, while subliminal stimuli were presented peripherally. Our results showed that high incentive-value targets induced a greater degree of perceptual improvement for the subliminal stimuli, supporting the role of reinforcement mechanisms in TIPL. |
David Pascucci; Massimo Turatto The distracting impact of repeated visible and invisible onsets on focused attention Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 41, no. 3, pp. 879–892, 2015. @article{Pascucci2015, A sudden peripheral onset is a powerful attentional attractor. However, in real life potentially distracting events do not always occur as a single event, but rather they can occur in a repetitive fashion. Hence, one of the aims of the present study was to investigate how the attentional system reacts to multiple consecutive onsets within the same trial. The results, quite surprisingly, showed that repeated peripheral onsets do not have a negative impact on visual performance, while they confirmed that a single peripheral onset captures focused attention. We hypothesize the existence of a short-term habituation mechanism that prevents visual attention from being continuously distracted by the same task-irrelevant event when this is rapidly repeated. A further aim of the study was to test the proposal according to which subliminal visual transients can bypass the conscious inhibitory control, thus resulting more distracting than supraliminal transients. We did not find in any of the 8 experiments that we conducted that subliminal onsets, either single or repeated, can grab attention when fully focused at fixation. Hence, in the case of sudden onsets, the general claim that task-irrelevant invisible stimuli can be more disturbing than visible ones does not seem to be fully justified. |
Vivian C. Paulun; Alexander C. Schütz; Melchi M. Michel; Wilson S. Geisler; Karl R. Gegenfurtner Visual search under scotopic lighting conditions Journal Article In: Vision Research, vol. 113, pp. 155–168, 2015. @article{Paulun2015, When we search for visual targets in a cluttered background we systematically move our eyes around to bring different regions of the scene into foveal view. We explored how visual search behavior changes when the fovea is not functional, as is the case in scotopic vision. Scotopic contrast sensitivity is significantly lower overall, with a functional scotoma in the fovea. We found that in scotopic search, for a medium- and a low-spatial-frequency target, individuals made longer lasting fixations that were not broadly distributed across the entire search display but tended to peak in the upper center, especially for the medium-frequency target. The distributions of fixation locations are qualitatively similar to those of an ideal searcher that has human scotopic detectability across the visual field, and interestingly, these predicted distributions are different from those predicted by an ideal searcher with human photopic detectability. We conclude that although there are some qualitative differences between human and ideal search behavior, humans make principled adjustments in their search behavior as ambient light level decreases. |
Xiaofan Peng; Maoyang Zhang; Dajun Zhang; Deguang Xie; Yusheng Guan From anger to attribution: Could attention be a bridge? Journal Article In: Social Behavior and Personality, vol. 43, no. 3, pp. 505–518, 2015. @article{Peng2015, We explored whether or not anger increases attribution bias toward salient information by narrowing attention scope. In Experiment 1, participants made attributions about 6 daily events while experiencing anger or in a neutral state. The anger group was more biased toward the salient factor compared to the neutral group. Using eye-tracking methodology, in Experiment 2 we further demonstrated that attention scope that is narrowed due to anger is related to a polarized distribution of attention resources, particularly decreased eye fixation on the phrase containing nonsalient factors. Finally, in Experiment 3 we separated attention process from information salience and further confirmed that narrowing attention scope (polarizing attention resource) could bias the attribution. In sum, our results indicate that attention scope is the bridge by which anger increases attribution bias. |
Jairo Perez-Osorio; Hermann J. Müller; Eva Wiese; Agnieszka Wykowska Gaze following is modulated by expectations regarding others' action goals Journal Article In: PLoS ONE, vol. 10, no. 11, pp. e0143614, 2015. @article{PerezOsorio2015, Humans attend to social cues in order to understand and predict others' behavior. Facial expressions and gaze direction provide valuable information to infer others' mental states and intentions. The present study examined the mechanism of gaze following in the context of participants' expectations about successive action steps of an observed actor. We embedded a gaze-cueing manipulation within an action scenario consisting of a sequence of naturalistic photographs. Gaze-induced orienting of attention (gaze following) was analyzed with respect to whether the gaze behavior of the observed actor was in line or not with the action-related expectations of participants (i.e., whether the actor gazed at an object that was congruent or incongruent with an overarching action goal). In Experiment 1, participants followed the gaze of the observed agent, though the gaze-cueing effect was larger when the actor looked at an action-congruent object relative to an incongruent object. Experiment 2 examined whether the pattern of effects observed in Experiment 1 was due to covert, rather than overt, attentional orienting, by requiring participants to maintain eye fixation throughout the sequence of critical photographs (corroborated bymonitoring eye movements). The essential pattern of results of Experiment 1 was replicated, with the gaze- cueing effect being completely eliminated when the observed agent gazed at an action-incongruent object. Thus, our findings show that covert gaze following can be modulated by expectations that humans hold regarding successive steps of the action performed by an observed agent. |
Benjamin Peters; Jochen Kaiser; Benjamin Rahm; Christoph Bledowski Activity in human visual and parietal cortex reveals object-based attention in working memory Journal Article In: Journal of Neuroscience, vol. 35, no. 8, pp. 3360–3369, 2015. @article{Peters2015, Visual attention enables observers to select behaviorally relevant information based on spatial locations, features, or objects. Attentional selection is not limited to physically present visual information, but can also operate on internal representations maintained in working memory (WM) in service of higher-order cognition. However, only little is known about whether attention to WM contents follows the same principles as attention to sensory stimuli. To address this question, we investigated in humans whether the typically observed effects of object-based attention in perception are also evident for object-based attentional selection of internal object representations in WM. In full accordance with effects in visual perception, the key behavioral and neuronal characteristics of object-based attention were observed in WM. Specifically, we found that reaction times were shorter when shifting attention to memory positions located on the currently attended object compared with equidistant positions on a different object. Furthermore, functional magnetic resonance imaging and multivariate pattern analysis of visuotopic activity in visual (areas V1-V4) and parietal cortex revealed that directing attention to one position of an object held in WM also enhanced brain activation for other positions on the same object, suggesting that attentional selection in WM activates the entire object. This study demonstrated that all characteristic features of object-based attention are present in WM and thus follows the same principles as in perception. |
Patrick Loesche; Jennifer Wiley; Marcus Hasselhorn How knowing the rules affects solving the Raven Advanced Progressive Matrices Test Journal Article In: Intelligence, vol. 48, pp. 58–75, 2015. @article{Loesche2015, The solution process underlying the Raven Advanced Progressive Matrices (RAPM) has been conceptualized to consist of two subprocesses: rule induction and goal management. Past research has also found a strong relation between measures of working memory capacity and performance on RAPM. The present research attempted to test whether the goal management subprocess is responsible for the relation between working memory capacity and RAPM, using a paradigm where the rules necessary to solve the problems were given to subjects, assuming that it would render rule induction unnecessary. Three experiments revealed that working memory capacity was still strongly related to RAPM performance in the given-rules condition, while in two experiments the correlation in the given-rules condition was significantly higher than in the no-rules condition. Experiment 4 revealed that giving the rules affected problem solving behavior. Evidence from eye tracking protocols suggested that participants in the given-rules condition were more likely to approach the problems with a constructive matching strategy. Two possible mechanisms are discussed that could both explain why providing participants with the rules might increase the relation between working memory capacity and RAPM performance. |
Francisco López-Orozco; Luis D. Rodríguez-Vega Model of making decisions during an information search task Journal Article In: Research in Computing Science, vol. 105, pp. 157–166, 2015. @article{LopezOrozco2015, This paper presents a cognitive computational model of the way people read a paragraph with the task of quickly deciding whether it is related or not to a given goal. In particular, the model attempts to predict the time at which participants would decide to stop reading the paragraph because they have enough information to make their decision. Our model makes predictions at the level of words that are likely to be ?xated before the paragraph is abandoned. Human semantic judgments are mimicked by computing the semantic similarities between sets of words using Latent Semantic Analysis. A two-variable linear threshold is proposed to account for that decision, based on the rank of the ?xation and the semantic similarity between the paragraph and the goal. Model performance is compared to eyetracking data of 19 participants. |
Thomas Zhihao Luo; John H. R. Maunsell Neuronal modulations in visual cortex are associated with only one of multiple components of attention Journal Article In: Neuron, vol. 86, no. 5, pp. 1182–1188, 2015. @article{Luo2015, Neuronal signals related to visual attention are found in widespread brain regions, and these signals are generally assumed to participate in a common mechanism of attention. However, the behavioral effects of attention in detection can be separated into two distinct components: spatially selective shifts in either the criterion or sensitivity of the subject. Here we show that a paradigm used by many single-neuron studies of attention conflates behavioral changes in the subject's criterion and sensitivity. Then, using a task designed to dissociate these two components, we found that multiple aspects of attention-related neuronal modulations in area V4 of monkey visual cortex corresponded to behavioral shifts in sensitivity, but not criterion. This result suggests that separate components of attention are associated with signals in different brain regions and that attention is not a unitary process in the brain, but instead consists of distinct neurobiological mechanisms. Luo and Maunsell show that the neuronal modulations in visual cortex correspond to only one of multiple components of attention. This result suggests that different brain structures underlie separate mechanisms of attention and that attention is not a unitary process in the brain, but instead consists of distinct neurobiological mechanisms. |
W. Joseph MacInnes; Hannah M. Krüger; Amelia R. Hunt Just passing through? Inhibition of return in saccadic sequences Journal Article In: Quarterly Journal of Experimental Psychology, vol. 68, no. 2, pp. 402–416, 2015. @article{MacInnes2015, Responses tend to be slower to previously fixated spatial locations, an effect known as "inhibition of return" (IOR). Saccades cannot be assumed to be independent, however, and saccade sequences programmed in parallel differ from independent eye movements. We measured the speed of both saccadic and manual responses to probes appearing in previously fixated locations when those locations were fixated as part of either parallel or independent saccade sequences. Saccadic IOR was observed in independent but not parallel saccade sequences, while manual IOR was present in both parallel and independent sequence types. Saccadic IOR was also short-lived, and dissipated with delays of more than ∼1500 ms between the intermediate fixation and the probe onset. The results confirm that the characteristics of IOR depend critically on the response modality used for measuring it, with saccadic and manual responses giving rise to motor and attentional forms of IOR, respectively. Saccadic IOR is relatively short-lived and is not observed at intermediate locations of parallel saccade sequences, while attentional IOR is long-lasting and consistent for all sequence types. |
Gregory H. MacLean; Raymond M. Klein; Matthew D. Hilchey Does oculomotor readiness mediate exogenous capture of visual attention? Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 41, no. 5, pp. 1260–1270, 2015. @article{MacLean2015, The oculomotor readiness hypothesis makes 2 predictions: Shifts in covert attention are accompanied by preparedness to move one's eyes to the attended region, and preparedness to move one's eyes to a region in space is accompanied by a shift in covert attention to the prepared location. Both predictions have been disconfirmed using an endogenous attention task. In the 2 experiments presented here, the same 2 predictions were tested using an exogenous attention task. It was found that participants experienced covert capture without accompanying oculomotor activation and experienced oculomotor activation without accompanying covert capture. While under everyday conditions the overt and covert orienting systems may be strongly linked, apparently they can nonetheless operate with a high degree of independence from one another. |
Mary H. Maclean; Barry Giesbrecht Neural evidence reveals the rapid effects of reward history on selective attention Journal Article In: Brain Research, vol. 1606, pp. 86–94, 2015. @article{Maclean2015b, Selective attention is often framed as being primarily driven by two factors: task-relevance and physical salience. However, factors like selection and reward history, which are neither currently task-relevant nor physically salient, can reliably and persistently influence visual selective attention. The current study investigated the nature of the persistent effects of irrelevant, physically non-salient, reward-associated features. These features affected one of the earliest reliable neural indicators of visual selective attention in humans, the P1 event-related potential, measured one week after the reward associations were learned. However, the effects of reward history were moderated by current task demands. The modulation of visually evoked activity supports the hypothesis that reward history influences the innate salience of reward associated features, such that even when no longer relevant, nor physically salient, these features have a rapid, persistent, and robust effect on early visual selective attention. |
Najib J. Majaj; Ha Hong; Ethan A. Solomon; James J. DiCarlo Simple learned weighted sums of inferior temporal neuronal firing rates accurately predict human core object recognition performance Journal Article In: Journal of Neuroscience, vol. 35, no. 39, pp. 13402–13418, 2015. @article{Majaj2015, To go beyond qualitative models of the biological substrate of object recognition, we ask: can a single ventral stream neuronal linking hypothesis quantitatively account for core object recognition performance over a broad range of tasks? We measured human performance in 64 object recognition tests using thousands ofchallenging images that explore shape similarity and identity preserving object variation. We then used multielectrode arrays to measure neuronal population responses to those same images in visual areas V4 and inferior temporal (IT) cortex ofmonkeys and simulated V1 population responses. We tested leading candidate linking hypotheses and control hypotheses, each postulating how ventral stream neuronal responses underlie object recognition behavior. Specifically, for each hypothesis, we computed the predicted performance on the 64 tests and compared it with the measured pattern ofhuman performance. All tested hypotheses based on low- and mid-level visually evoked activity (pixels, V1, and V4) were very poor predictors ofthe human behavioral pattern. However, simple learned weighted sums of distributed average IT firing rates exactly predicted the behavioral pattern. More elaborate linking hypotheses relying on IT trial-by-trial correlational structure, finer IT temporal codes, or ones that strictly respect the known spatial substructures ofIT (“face patches”) did not improve predictive power. Although these results do not reject those more elaborate hypotheses, they suggest a simple, sufficient quantitative model: each object recognition task is learned from the spatially distributed mean firing rates (100 ms) of ~60,000 IT neurons and is executed as a simple weighted sum ofthose firing rates. |
Alex J. Major; Susheel Vijayraghavan; Stefan Everling Muscarinic attenuation of mnemonic rule representation in macaque dorsolateral prefrontal cortex during a pro-and anti-saccade task Journal Article In: Journal of Neuroscience, vol. 35, no. 49, pp. 16064–16076, 2015. @article{Major2015, Maintenance of context is necessary for execution of appropriate responses to diverse environmental stimuli. The dorsolateral prefrontal cortex (DLPFC) plays a pivotal role in executive function, including working memory and representation ofabstract rules. DLPFC activity is modulated by the ascending cholinergic system through nicotinic and muscarinic receptors. Although muscarinic receptors have been implicated in executive performance and gating ofsynaptic signals, their effect on local primate DLPFC neuronal activity in vivo during cognitive tasks remains poorly understood. Here, we examined the effects of muscarinic receptor blockade on rule-related activity in the macaque prefrontal cortex by combining iontophoretic application of the general muscarinic receptor antagonist scopolamine with single-cell recordings while monkeys performed a mnemonic rule-guided saccade task. We found that scopolamine reduced overall neuronal firing rate and impaired rule discriminability of task-selective cells. Saccade and visual direction selectivity measures were also reduced by muscarinic antagonism. These results demonstrate that blockade of muscarinic receptors in DLPFC creates deficits in working memory representation of rules in primates. |
George L. Malcolm; Sarah Shomstein Object-based attention in real-world scenes. Journal Article In: Journal of Experimental Psychology: General, vol. 144, no. 2, pp. 257–263, 2015. @article{Malcolm2015, We are continually confronted with more visual information than we can process in a given moment. In order to interact effectively with our environment, attentional mechanisms are used to select subsets of environmental properties for enhanced processing. Previous research demonstrated that spatial regions can be selected based on either their low-level feature or high-level semantic properties. However, the efficiency with which we interact with the world suggests that there must be an additional, midlevel, factor constraining effective attentional space. The present study investigates whether object-based attentional selection is one such midlevel factor that constrains visual attention in complex, real-world scenes. Participants viewed scene images while their eye movements were recorded. During viewing, a cue appeared on an object which participants were instructed to fixate. A target then appeared either on the same object as the cue, on a different object, or floating. Participants initiated saccades faster and had shorter response times to targets presented on the same object as the fixated cue. The results strongly suggest that when attending to a location on an object, the entire object benefits perceptually. This object-based effect on the distribution of spatial attention forms a critical link between low- and high-level factors that direct attention efficiently in complex real-world scenes. |
Pankhuri Malik; Joost C. Dessing; J. Douglas Crawford Role of early visual cortex in trans-saccadic memory of object features Journal Article In: Journal of Vision, vol. 15, no. 7, pp. 1–17, 2015. @article{Malik2015, Early visual cortex (EVC) participates in visual feature memory and the updating of remembered locations across saccades, but its role in the trans-saccadic integration of object features is unknown. We hypothesized that if EVC is involved in updating object features relative to gaze, feature memory should be disrupted when saccades remap an object representation into a simultaneously perturbed EVC site. To test this, we applied transcranial magnetic stimulation (TMS) over functional magnetic resonance imaging–localized EVC clusters corresponding to the bottom left/right visual quadrants (VQs). During experiments, these VQs were probed psychophysically by briefly presenting a central object (Gabor patch) while subjects fixated gaze to the right or left (and above). After a short memory interval, participants were required to detect the relative change in orientation of a re-presented test object at the same spatial location. Participants either sustained fixation during the memory interval (fixation task)ormade a horizontal saccade that either maintained or reversed the VQ of the object (saccade task). Three TMS pulses (coinciding with the pre-, peri-, and postsaccade intervals) were applied to the left or right EVC. This had no effect when (a) fixation was maintained, (b) saccades kept the object in the same VQ, or (c) the EVC quadrant corresponding to the first object was stimulated. However, as predicted, TMS reduced performance when saccades (especially larger saccades) crossed the remembered object location and brought it into the VQ corresponding to the TMS site. This suppression effect was statistically significant for leftward saccades and followed a weaker trend for rightward saccades. These causal results are consistent with the idea that EVC is involved in the gaze-centered updating of object features for trans-saccadic memory and perception. |
Ran Manor; Amir B. Geva Convolutional neural network for multi-category rapid serial visual presentation BCI Journal Article In: Frontiers in Computational Neuroscience, vol. 9, pp. 146, 2015. @article{Manor2015, Brain computer interfaces rely on machine learning (ML) algorithms to decode the brain's electrical activity into decisions. For example, in rapid serial visual presentation (RSVP) tasks, the subject is presented with a continuous stream of images containing rare target images among standard images, while the algorithm has to detect brain activity associated with target images. Here, we continue our previous work, presenting a deep neural network model for the use of single trial EEG classification in RSVP tasks. Deep neural networks have shown state of the art performance in computer vision and speech recognition and thus have great promise for other learning tasks, like classification of EEG samples. In our model, we introduce a novel spatio-temporal regularization for EEG data to reduce overfitting. We show improved classification performance compared to our earlier work on a five categories RSVP experiment. In addition, we compare performance on data from different sessions and validate the model on a public benchmark data set of a P300 speller task. Finally, we discuss the advantages of using neural network models compared to manually designing feature extraction algorithms. |
Barbara F. M. Marino; Giovanni Mirabella; Rossana Actis-Grosso; Emanuela Bricolo; Paola Ricciardelli Can we resist another person's gaze? Journal Article In: Frontiers in Behavioral Neuroscience, vol. 9, pp. 258, 2015. @article{Marino2015, Adaptive adjustments of strategies are needed to optimize behavior in a dynamic and uncertain world. A key function in implementing flexible behavior and exerting self- control is represented by the ability to stop the execution of an action when it is no longer appropriate for the environmental requests. Importantly, stimuli in our environment are not equally relevant and some are more valuable than others. One example is the gaze of other people, which is known to convey important social information about their direction of attention and their emotional and mental states. Indeed, gaze direction has a significant impact on the execution of voluntary saccades of an observer since it is capable of inducing in the observer an automatic gaze-following behavior: a phenomenon named social or joint attention. Nevertheless, people can exert volitional inhibitory control on saccadic eye movements during their planning. Little is known about the interaction between gaze direction signals and volitional inhibition of saccades. To fill this gap, we administered a countermanding task to 15 healthy participants in which they were asked to observe the eye region of a face with the eyes shut appearing at central fixation. In one condition, participants were required to suppress a saccade, that was previously instructed by a gaze shift toward one of two peripheral targets, when the eyes were suddenly shut down (social condition, SC). In a second condition, participants were asked to inhibit a saccade, that was previously instructed by a change in color of one of the two same targets, when a change of color of a central picture occurred (non- social condition, N-SC). We found that inhibitory control was more impaired in the SC, suggesting that actions initiated and stopped by social cues conveyed by the eyes are more difficult to withhold. This is probably due to the social value intrinsically linked to these cues and the many uses we make of them. |
Julie Markant; Michael S. Worden; Dima Amso Not all attention orienting is created equal: Recognition memory is enhanced when attention orienting involves distractor suppression Journal Article In: Neurobiology of Learning and Memory, vol. 120, pp. 28–40, 2015. @article{Markant2015, Learning through visual exploration often requires orienting of attention to meaningful information in a cluttered world. Previous work has shown that attention modulates visual cortex activity, with enhanced activity for attended targets and suppressed activity for competing inputs, thus enhancing the visual experience. Here we examined the idea that learning may be engaged differentially with variations in attention orienting mechanisms that drive eye movements during visual search and exploration. We hypothesized that attention orienting mechanisms that engaged suppression of a previously attended location would boost memory encoding of the currently attended target objects to a greater extent than those that involve target enhancement alone. To test this hypothesis we capitalized on the classic spatial cueing task and the inhibition of return (IOR) mechanism (. Posner, 1980; Posner, Rafal, & Choate, 1985) to demonstrate that object images encoded in the context of concurrent suppression at a previously attended location were encoded more effectively and remembered better than those encoded without concurrent suppression. Furthermore, fMRI analyses revealed that this memory benefit was driven by attention modulation of visual cortex activity, as increased suppression of the previously attended location in visual cortex during target object encoding predicted better subsequent recognition memory performance. These results suggest that not all attention orienting impacts learning and memory equally. |
Linda Marschner; Sebastian Pannasch; Johannes Schulz; Sven-Thomas Graupner Social communication with virtual agents: The effects of body and gaze direction on attention and emotional responding in human observers Journal Article In: International Journal of Psychophysiology, vol. 97, no. 2, pp. 85–92, 2015. @article{Marschner2015, In social communication, the gaze direction of other persons provides important information to perceive and interpret their emotional response. Previous research investigated the influence of gaze by manipulating mutual eye contact. Therefore, gaze and body direction have been changed as a whole, resulting in only congruent gaze and body directions (averted or directed) of another person. Here, we aimed to disentangle these effects by using short animated sequences of virtual agents posing with either direct or averted body or gaze. Attention allocation by means of eye movements, facial muscle response, and emotional experience to agents of different gender and facial expressions were investigated. Eye movement data revealed longer fixation durations, i.e., a stronger allocation of attention, when gaze and body direction were not congruent with each other or when both were directed towards the observer. This suggests that direct interaction as well as incongruous signals increase the demands of attentional resources in the observer. For the facial muscle response, only the reaction of muscle zygomaticus major revealed an effect of body direction, expressed by stronger activity in response to happy expressions for direct compared to averted gaze when the virtual character's body was directed towards the observer. Finally, body direction also influenced the emotional experience ratings towards happy expressions. While earlier findings suggested that mutual eye contact is the main source for increased emotional responding and attentional allocation, the present results indicate that direction of the virtual agent's body and head also plays a minor but significant role. |
Sébastien Marti; Laurie Bayet; Stanislas Dehaene Subjective report of eye fixations during serial search Journal Article In: Consciousness and Cognition, vol. 33, pp. 1–15, 2015. @article{Marti2015, Humans readily introspect upon their thoughts and their behavior, but how reliable are these subjective reports? In the present study, we explored the consistencies of and differences between the observer's subjective report and actual behavior within a single trial. On each trial of a serial search task, we recorded eye movements and the participants' beliefs of where their eyes moved. The comparison of reported versus real eye movements revealed that subjects successfully reported a subset of their eye movements. Limits in subjective reports stemmed from both the number and the type of eye movements. Furthermore, subjects sometimes reported eye movements they actually never made. A detailed examination of these reports suggests that they could reflect covert shifts of attention during overt serial search. Our data provide quantitative and qualitative measures of observers' subjective reports and reveal experimental effects of visual search that would otherwise be inaccessible. |
Svenja Marx; Gina Gruenhage; Daniel Walper; Ueli Rutishauser; Wolfgang Einhäuser Competition with and without priority control: Linking rivalry to attention through winner-take-all networks with memory Journal Article In: Annals of the New York Academy of Sciences, vol. 1339, no. 1, pp. 138–153, 2015. @article{Marx2015b, Competition is ubiquitous in perception. For example, items in the visual field compete for processing resources, and attention controls their priority (biased competition). The inevitable ambiguity in the interpretation of sensory signals yields another form of competition: distinct perceptual interpretations compete for access to awareness. Rivalry, where two equally likely percepts compete for dominance, explicates the latter form of competition. Building upon the similarity between attention and rivalry, we propose to model rivalry by a generic competitive circuit that is widely used in the attention literature-a winner-take-all (WTA) network. Specifically, we show that a network of two coupled WTA circuits replicates three common hallmarks of rivalry: the distribution of dominance durations, their dependence on input strength ("Levelt's propositions"), and the effects of stimulus removal (blanking). This model introduces a form of memory by forming discrete states and explains experimental data better than competitive models of rivalry without memory. This result supports the crucial role of memory in rivalry specifically and in competitive processes in general. Our approach unifies the seemingly distinct phenomena of rivalry, memory, and attention in a single model with competition as the common underlying principle. |
Tommaso Mastropasqua; Jessica Galliussi; David Pascucci; Massimo Turatto Location transfer of perceptual learning: Passive stimulation and double training Journal Article In: Vision Research, vol. 108, pp. 93–102, 2015. @article{Mastropasqua2015, Specificity has always been considered one of the hallmarks of perceptual learning, suggesting that performance improvement would reflect changes at early stages of visual analyses (e.g., V1). More recently, however, this view has been challenged by studies documenting complete transfer of learning among different spatial locations or stimulus orientations when a double-training procedure is adopted. Here, we further investigate the conditions under which transfer of visual perceptual learning takes place, confirming that the passive stimulation at the transfer location seems to be insufficient to overcome learning specificity. By contrast, learning transfer is complete when performing a secondary task at the transfer location. Interestingly, (i) transfer emerges when the primary and secondary tasks are intermingled on a trial-by-trial basis, and (ii) the effects of learning generalization appear to be reciprocal, namely the primary task also serves to enable transfer of the secondary task. However, if the secondary task is not performed for a sufficient number of trials, then transfer is not enabled. Overall, the results lend support to the recent view that task-relevant perceptual learning may involve high-level stages of visual analyses. |
Tommaso Mastropasqua; Peter U. Tse; Massimo Turatto Learning of monocular information facilitates breakthrough to awareness during interocular suppression Journal Article In: Attention, Perception, and Psychophysics, vol. 77, no. 3, pp. 790–803, 2015. @article{Mastropasqua2015a, Continuous flash suppression (CFS) is a potent method of inducing binocular rivalry, wherein a rapid succession of high-contrast images presented to one eye effectively blocks from awareness a low-contrast image presented to the other eye. Here we addressed whether the contents of the suppressed image can break through to awareness with extended CFS exposure. On 2/3 of the trials, we presented a faint bar (the target) to the nondominant eye while a high-contrast flickering Mondrian (the mask) was displayed to the dominant eye. Participants were first asked to report whether the target had broken through the CFS mask. Furthermore, on target-present trials, the participants were then asked to guess whether the target had appeared above or below the fixation point. In Experiment 1, the target was presented with a fixed orientation for four blocks of trials, whereas in the fifth block, the target could also have the orthogonal orientation. In Experiment 2, the target was always presented with a fixed orientation, but in the fifth block, unbeknownst to participants, the target and the mask were swapped across the eyes. We found that awareness of the target rapidly improved with training in both experiments. However, whereas Experiment 1 revealed that the improvement largely generalized across stimulus orientations, Experiment 2 showed that the effect of practice was eye-specific. The results suggest that increased breakthrough with training was due to a monocular form of learning. Finally, a control experiment was conducted to exclude the possibility that the monocular learning we reported could have been due to sensory adaptation caused by the masks. |
Sebastiaan Mathôt; Jean-Baptiste Melmi; Eric Castet Intrasaccadic perception triggers pupillary constriction Journal Article In: PeerJ, vol. 3, pp. 1–16, 2015. @article{Mathot2015, It is commonly believed that vision is impaired during saccadic eye movements. However, here we report that some visual stimuli are clearly visible during saccades, and trigger a constriction of the eye's pupil. Participants viewed sinusoid gratings that changed polarity 150 times per second (every 6.67 ms). At this rate of flicker, the gratings were perceived as homogeneous surfaces while participants fixated. However, the flickering gratings contained ambiguous motion: rightward and leftward motion for vertical gratings; upward and downward motion for horizontal gratings. When participants made a saccade perpendicular to the gratings' orientation (e.g., a leftward saccade for a vertical grating), the eye's peak velocity matched the gratings' motion. As a result, the retinal image was approximately stable for a brief moment during the saccade, and this gave rise to an intrasaccadic percept: A normally invisible stimulus became visible when eye velocity was maximal. Our results confirm and extend previous studies by demonstrating intrasaccadic perception using a reflexive measure (pupillometry) that does not rely on subjective report. Our results further show that intrasaccadic perception affects all stages of visual processing, from the pupillary response to visual awareness. |
Marianne E. F. Piano; Peter J. Bex; Anita J. Simmers Perceptual visual distortions in adult amblyopia and their relationship to clinical features Journal Article In: Investigative Ophthalmology & Visual Science, vol. 56, no. 9, pp. 5533–5542, 2015. @article{Piano2015, PURPOSE: Develop a paradigm to map binocular perceptual visual distortions in adult amblyopes and visually normal controls, measure their stability over time, and determine the relationship between strength of binocular single vision and distortion magnitude. METHODS: Perceptual visual distortions were measured in 24 strabismic, anisometropic, or microtropic amblyopes (interocular acuity difference ≥ 0.200 logMAR or history of amblyopia treatment) and 10 controls (mean age 27.13 ± 10.20 years). The task was mouse-based target alignment on a stereoscopic liquid crystal display monitor, measured binocularly five times during viewing dichoptically through active shutter glasses, amblyopic eye viewing cross-hairs, fellow eye viewing single target dots (16 locations within central 5°), and five times nondichoptically, with all stimuli visible to either eye. Measurements were repeated over time (1 week, 1 month) in eight amblyopic subjects, evaluating test-retest reliability. Measurements were also correlated against logMAR visual acuity, horizontal prism motor fusion range, Frisby/Preschool Randot stereoacuity, and heterophoria/heterotropia prism cover test measurement. RESULTS: Sixty-seven percent (16/24) of amblyopes had significant perceptual visual distortions under dichoptic viewing conditions compared to nondichoptic viewing conditions and dichoptic control group performance. Distortions correlated with the strength of motor fusion (r = -0.417 |
Jordan E. Pierce; J. Brett McCardel; Jennifer E. McDowell Trial-type probability and task-switching effects on behavioral response characteristics in a mixed saccade task Journal Article In: Experimental Brain Research, vol. 233, no. 3, pp. 959–969, 2015. @article{Pierce2015, Eye movement circuitry involved in saccade production offers a model for studying cognitive control: visually guided prosaccades are stimulus-directed responses, while goal-driven antisaccades rely upon more complex control processes to inhibit the prepotent tendency to look toward a cue, transform its spatial location, and generate a volitional saccade in the opposite direction. By manipulating the relative probability of these saccade types, we measured participants' behavioral responses to different levels of implicit trial-type probability and task-switching demands in conditions with relatively long inter-trial fixation and trial-type cue lengths. Results indicated that when prosaccades were less probable in a run, more prosaccade errors were generated; however, for antisaccades, trial-type probability had no effect on the percent of correct responses. For reaction times, specifically in runs with a larger probability of antisaccade trials, latencies increased for both anti- and pro-saccades. Furthermore, task switching resulted in a lower percentage of correct responses on switched trials, but a prior antisaccade trial led to slower reaction times for both trial types (i.e., a task switch cost for prosaccades and switch benefit for antisaccades). These findings indicate that cognitive control demands and residual inhibition from antisaccades alter performance relative to trial-type probability and task switching within a run, with the prosaccade task showing greater susceptibility to the influence of a large probability of cognitively complex antisaccades. |
Alessandro Piras; Milena Raffi; Ivan M. Lanzoni; Michela Persiani; Salvatore Squatrito Microsaccades and prediction of a motor act outcome in a dynamic sport situation Journal Article In: Investigative Ophthalmology & Visual Science, vol. 56, no. 8, pp. 4520–4530, 2015. @article{Piras2015, PURPOSE Microsaccades could indicate the place where our mind is unconsciously focusing, although our gaze is directed elsewhere. Many studies report the importance of microsaccades in visual scene perception, but none of them has addressed their relationship with the perception of a dynamic action and the prediction of its outcome. METHODS Expert and novice table tennis players were asked to fixate their gaze on a precise spot while viewing the launch of a ball whose final landing had to be predicted. Four separate epochs of the action were considered for their information content. The correctness of the prediction and microsaccade statistics were measured in order to estimate the relationship between covert attention and predictions. RESULTS Microsaccades rate showed a time course modulated by the different epochs, with a significant enhancement during the post-bounce. In this epoch, novices showed a significantly higher rate than experts when the responses were correct. Duration and amplitude were highest in the pre- and post-bounce periods and lowest in the other two. Mean microsaccades direction was toward the stimuli that most probably attracted the visual attention (ball or racket), whereas there was no relationship with the predicted side of the final bounce. CONCLUSIONS Distribution of microsaccades can be influenced by attentional cues in a task-specific situation, revealing links between visuomotor performance and covert attention shifts in fast visuomotor perception. Microsaccade orientation is conditioned by objects that attract visual attention and not by the direction in which action is expected to be performed. |
Luca Polonio; D. S. Guida; Giorgio Coricelli; Sibilla Di Guida; Giorgio Coricelli Strategic sophistication and attention in games: An eye-tracking study Journal Article In: Games and Economic Behavior, vol. 94, pp. 80–96, 2015. @article{Polonio2015, We used eye-tracking to measure the dynamic patterns of visual information acquisition in two-player normal-form games. Participants played one-shot games in which either, neither, or only one of the players had a dominant strategy. First, we performed a mixture models cluster analysis to group participants into types according to the pattern of visual information acquisition observed in a single class of games. Then, we predicted agents' choices in different classes of games and observed that patterns of visual information acquisition were game invariant. Our method allowed us to predict whether the decision process would lead to equilibrium choices or not, and to attribute out-of-equilibrium responses to limited cognitive capacities or social motives. Our results suggest the existence of individually heterogeneous-but-stable patterns of visual information acquisition based on subjective levels of strategic sophistication and social preferences. |
Kaewmart Pongakkasira; Markus Bindemann The shape of the face template: Geometric distortions of faces and their detection in natural scenes Journal Article In: Vision Research, vol. 109, pp. 99–106, 2015. @article{Pongakkasira2015, Human face detection might be driven by skin-coloured face-shaped templates. To explore this idea, this study compared the detection of faces for which the natural height-to-width ratios were preserved with distorted faces that were stretched vertically or horizontally. The impact of stretching on detection performance was not obvious when faces were equated to their unstretched counterparts in terms of their height or width dimension (Experiment 1). However, stretching impaired detection when the original and distorted faces were matched for their surface area (Experiment 2), and this was found with both vertically and horizontally stretched faces (Experiment 3). This effect was evident in accuracy, response times, and also observers' eye movements to faces. These findings demonstrate that height-to-width ratios are an important component of the cognitive template for face detection. The results also highlight important differences between face detection and face recognition. |
Avery Popien; Mallory Frayn; Kristin M. Ranson; Christopher R. Sears Eye gaze tracking reveals heightened attention to food in adults with binge eating when viewing images of real-world scenes Journal Article In: Appetite, vol. 91, pp. 233–240, 2015. @article{Popien2015, Individuals with eating disorders often exhibit food-related biases in attention tasks. To assess the engagement and maintenance of attention to food in adults with binge eating, in the present study, eye gaze tracking was used to compare fixations to food among non-clinical adults with versus without binge eating while they viewed images of real-world scenes. Fifty-seven participants' eye fixations were tracked and recorded throughout 8-second presentations of scenes containing high-calorie and/or low-caloriefood items in various settings (restaurants, social gatherings, etc.). Participants with binge eating fixated on both high-calorie and low-calorie food items significantly more than controls, and this was the case when the high- and low-calorie food items were presented in the same image and in different images. Participants with binge eating also fixated on food items significantly earlier in the presentations. A time course analysis that divided each 8-second presentation into 2-second intervals revealed that participants with binge eating attended to food items more than control participants throughout the 8-second presentation. These results have implications for theory regarding the initiation and maintenance of binge eating. |
Ivo D. Popivanov; Jan Jastorff; Wim Vanduffel; Rufin Vogels Tolerance of macaque middle STS body patch neurons to shape-preserving stimulus transformations Journal Article In: Journal of Cognitive Neuroscience, vol. 27, no. 5, pp. 1001–1016, 2015. @article{Popivanov2015, Functional imaging studies in human and nonhuman primates have demonstrated regions in the brain that show category selectivity for faces or (headless) bodies. Recent fMRI-guided single unit studies of the macaque face category-selective regions have increased our understanding of the response properties of single neurons in these face patches. However, much less is known about the response properties of neurons in the fMRI- defined body category-selective regions (“body patches”). Recently, we reported that the majority of single neurons in one fMRI-defined body patch, the mid-STS body patch, responded more strongly to bodies compared with other objects. Here we assessed the tolerance of these neurons' responses and stimulus preference for shape-preserving image transformations. After mapping the receptive field of the single neurons, we found that their stimulus preference showed a high degree of tolerance for changes in the position and size of the stimulus. However, their response strongly depended on the in-plane orientation of a body. The selectivity ofmost neurons was, to a large degree, preserved when silhouettes were presented instead of the original textured and shaded images, suggesting that mainly shape-based features are driving these neurons. In a human psychophysical study, we showed that the information present in silhouettes is largely sufficient for body versus nonbody categorization. These data suggest that mid-STS body patch neurons respond predominantly to oriented shape features that are prevalent in images of bodies. Their responses can inform position- and retinal size-invariant body categorization and discrimination based on shape. |
Carol McDonald Connor; Ralph Radach; Christian Vorstius; Stephanie L. Day; Leigh McLean; Frederick J. Morrison Individual differences in fifth graders' literacy and academic language predict comprehension monitoring development: An eye-movement study Journal Article In: Scientific Studies of Reading, vol. 19, no. 2, pp. 114–134, 2015. @article{McDonaldConnor2015, In this study, we investigated fifth graders' (n = 52) fall literacy, academic language, and motivation and how these skills predicted fall and spring comprehension monitoring on an eye movement task. Comprehension monitoring was defined as the identification and repair of misunderstandings when reading text. In the eye movement task, children read two sentences; the second included either a plausible or implausible word in the context of the first sentence. Stronger readers had shorter reading times overall suggesting faster processing of text. Generally fifth graders reacted to the implausible word (i.e., longer gaze duration on the implausible vs. the plausible word, which reflects lexical access). Students with stronger academic language, compared to those with weaker academic language, generally spent more time rereading the implausible target compared to the plausible target. This difference increased from fall to spring. Results support the centrality of academic language for meaning integration, setting standards of coherence, and utilizing comprehension repair strategies. |
Gerald P. McDonnell; Mark Mills; Leslie McCuller; Michael D. Dodd How does implicit learning of search regularities alter the manner in which you search? Journal Article In: Psychological Research, vol. 79, no. 2, pp. 183–193, 2015. @article{McDonnell2015, Individuals are highly sensitive to statistical regularities in their visual environment, even when these patterns do not reach conscious awareness. Here, we examine whether oculomotor behavior is systematically altered when distractor/target configurations rarely repeat, but target location on an initial trial predicts the location of a target on the subsequent trial. The purpose of the current study was to explore whether this temporal-spatial contextual cueing in a conjunction search task influences both reaction time to the target and participant's search strategy. Participants searched for a target through a gaze-contingent window in a display consisting of a large number of distractors, providing a target-present/absent response. Participants were faster to respond to the target on the predicted trial relative to the predictor trial in an implicit contextual cueing task but were no more likely to fixate first to the target quadrant on the predicted trial (Experiment 1). Furthermore, implicit learning was interrupted when instructing participants to vary their searching strategy across trials to eliminate visual scan similarity (Experiment 2). In Experiment 3, when participants were explicitly informed that a pattern was present at the start of the experiment, explicit learning was observed in both reaction time and eye movements. The present experiments provide evidence that implicit learning of sequential regularities regarding target locations is not based on learning more efficient scan paths, but is due to some other mechanism. |
David B. T. McMahon; Brian E. Russ; Heba D. Elnaiem; Anastasia I. Kurnikova; David A. Leopold Single-unit activity during natural vision: Diversity, consistency, and spatial sensitivity among AF face patch neurons Journal Article In: Journal of Neuroscience, vol. 35, no. 14, pp. 5537–5548, 2015. @article{McMahon2015, Several visual areas within the STS of the macaque brain respond strongly to faces and other biological stimuli. Determining the principles that govern neural responses in this region has proven challenging, due in part to the inherently complex stimulus domain of dynamic biological stimuli that are not captured by an easily parameterized stimulus set. Here we investigated neural responses in one fMRI-defined face patch in the anterior fundus (AF) of the STS while macaques freely view complex videos rich with natural social content. Longitudinal single-unit recordings allowed for the accumulation of each neuron's responses to repeated video presentations across sessions. We found that individual neurons, while diverse in their response patterns, were consistently and deterministically driven by the video content. We used principal component analysis to compute a family of eigenneurons, which summarized 24% of the shared population activity in the first two components. We found that the most prominent component of AF activity reflected an interaction between visible body region and scene layout. Close-up shots of faces elicited the strongest neural responses, whereas far away shots of faces or close-up shots of hindquarters elicited weak or inhibitory responses. Sensitivity to the apparent proximity of faces was also observed in gamma band local field potential. This category-selective sensitivity to spatial scale, together with the known exchange of anatomical projections of this area with regions involved in visuospatial analysis, suggests that the AF face patch may be specialized in aspects of face perception that pertain to the layout of a social scene. |
Radha Nila Meghanathan; Cees Leeuwen; Andrey R. Nikolaev Fixation duration surpasses pupil size as a measure of memory load in free viewing Journal Article In: Frontiers in Human Neuroscience, vol. 8, pp. 1063, 2015. @article{Meghanathan2015, Oculomotor behavior reveals, not only the acquisition of visual information at fixation, but also the accumulation of information in memory across subsequent fixations. Two candidate measures were considered as indicators of such dynamic visual memory load: fixation duration and pupil size. While recording these measures, we displayed an arrangement of 3, 4 or 5 targets among distractors. Both occurred in various orientations. Participants searched for targets and reported whether in a subsequent display one of them had changed orientation. We determined to what extent fixation duration and pupil size indicate dynamic memory load, as a function of the number of targets fixated during the search. We found that fixation duration reflects the number of targets, both when this number is within and above the limit of working memory capacity. Pupil size reflects the number of targets only when it exceeds the capacity limit. Moreover, the duration of fixations on successive targets but not on distractors increases whereas pupil size does not. The increase in fixation duration with number of targets both within and above working memory capacity suggests that in free viewing fixation duration is sensitive to actual memory load as well as to processing load, whereas pupil size is indicative of processing load only. Two alternative models relating visual attention and working memory are considered relevant to these results. We discuss the results as supportive of a model which involves a temporary buffer in the interaction of attention and working memory. |
Gonçalo Padrão; Borja Rodriguez-Herreros; Laura Pérez Zapata; Antoni Rodriguez-Fornells Exogenous capture of medial-frontal oscillatory mechanisms by unattended conflicting information Journal Article In: Neuropsychologia, vol. 75, pp. 458–468, 2015. @article{Padrao2015, A long-standing debate in psychology and cognitive neuroscience concerns the way in which unattended information is processed and influences goal-directed behavior. Although selective attention allows us to filter out task-irrelevant information, there is a substantial number of unattended, yet relevant, events that must be evaluated in a flexible manner so that appropriate behaviors can succeed. Here we inspected the extent to which unattended conflicting visual information, which cannot be consciously identified, influences behavior and activates medial prefrontal cortex (mPFC) mechanisms of action-monitoring and regulation, traditionally associated with conscious control processes.To that end, we performed two experiments using a novel variant of the Eriksen flanker task in which spatial attention was manipulated, preventing the conscious identification of unattended visual events. The first behavioral experiment was conducted to validate the efficacy of the novel paradigm. In the second experiment, we evaluated electrophysiological correlates of mPFC activity (a frontocentral negative ERP component and medial-frontal theta oscillations) in response to attended and unattended conflicting events. The results of both experiments demonstrated that attended and unattended conflicting stimuli altered subjects' behavior in a similar fashion, i.e. slowing down their reaction times and increasing their error rates. Importantly, the results of the EEG experiment showed that unattended conflicting stimuli, similarly to attended conflicting stimuli, led to an increase in theta-related frontocentral ERP activity and medial-frontal theta power, irrespective of the degree of conscious representation of the sources of conflict. This study provides evidence that medial-frontal theta oscillations represent a neural mechanism through which the mPFC may suppress and regulate potentially inappropriate actions that are automatically triggered by conflicting environmental stimuli to which we are oblivious. |
David R. Painter; Paul E. Dux; Jason B. Mattingley Causal involvement of visual area MT in global feature-based enhancement but not contingent attentional capture Journal Article In: NeuroImage, vol. 118, pp. 90–102, 2015. @article{Painter2015, When visual attention is set for a particular target feature, such as color or shape, neural responses to that feature are enhanced across the visual field. This global feature-based enhancement is hypothesized to underlie the contingent attentional capture effect, in which task-irrelevant items with the target feature capture spatial attention. In humans, however, different cortical regions have been implicated in global feature-based enhancement and contingent capture. Here, we applied intermittent theta-burst stimulation (iTBS) to assess the causal roles of two regions of extrastriate cortex - right area MT and the right temporoparietal junction (TPJ) - in both global feature-based enhancement and contingent capture. We recorded cortical activity using EEG while participants monitored centrally for targets defined by color and ignored peripheral checkerboards that matched the distractor or target color. In central vision, targets were preceded by colored cues designed to capture attention. Stimuli flickered at unique frequencies, evoking distinct cortical oscillations. Analyses of these oscillations and behavioral performance revealed contingent capture in central vision and global feature-based enhancement in the periphery. Stimulation of right area MT selectively increased global feature-based enhancement, but did not influence contingent attentional capture. By contrast, stimulation of the right TPJ left both processes unaffected. Our results reveal a causal role for the right area MT in feature-based attention, and suggest that global feature-based enhancement does not underlie the contingent capture effect. |
Adam Palanica; Roxane J. Itier Eye gaze and head orientation modulate the inhibition of return for faces Journal Article In: Attention, Perception, and Psychophysics, vol. 77, no. 8, pp. 2589–2600, 2015. @article{Palanica2015, The present study used an inhibition of return (IOR) spatial cueing paradigm to examine how gaze direction and head orientation modulate attention capture for human faces. Target response time (RT) was measured after the presentation of a peripheral cue, which was either a face (with front-facing or averted gaze, in either frontal head view or averted head view) or a house (control). Participants fixated on a centered cross at all times and responded via button press to a peripheral target after a variable stimulus onset asynchrony (SOA) from the stimulus cue. At the shortest SOA (150 ms), RTs were shorter for faces than houses, independent of an IOR response, suggesting a cue-based RT advantage elicited by faces. At the longest SOA (2,400 ms), a larger IOR magnitude was found for faces compared to houses. Both the cue-based RT advantage and later IOR responses were modulated by gaze-head congruency; these effects were strongest for frontal gaze faces in frontal head view, and for averted gaze faces in averted head view. Importantly, participants were not given any specific information regarding the stimuli, nor were they told the true purpose of the study. These findings indicate that the congruent combination of head and gaze direction influence the exogenous attention capture of faces during inhibition of return. |
Lotje Linden; Sebastiaan Mathôt; Françoise Vitu The role of object affordances and center of gravity in eye movements toward isolated daily-life objects Journal Article In: Journal of Vision, vol. 15, no. 5, pp. 1–18, 2015. @article{Linden2015, The purpose of the current study was to investigate to what extent low-level versus high-level effects determine where the eyes land on isolated daily-life objects. We operationalized low-level effects as eye movements toward an object's center of gravity (CoG) or the absolute object center (OC) and high-level effects as visuomotor priming by object affordances. In two experiments, we asked participants to make saccades toward peripherally presented photographs of graspable objects (e.g., a hammer) and to either categorize them (Experiment 1) or to discriminate them from visually matched nonobjects (Experiment 2). Objects were rotated such that their graspable part (e.g., the hammer's handle) pointed toward either the left or the right whereas their action-performing part (e.g., the hammer's head) pointed toward the other side. We found that early-triggered saccades were neither biased toward the object's graspable part nor toward its action-performing part. Instead, participants' eyes landed near the CoG/OC. Only longer-latency initial saccades and refixations were subject to high-level influences, being significantly biased toward the object's action-performing part. Our comparison with eye movements toward visually matched nonobjects revealed that the latter was not merely the consequence of a low-level effect of shape, texture, asymmetry, or saliency. Instead, we interpret it as a higher-level, object-based affordance effect that requires time, and to some extent also foveation, in order to build up and to overcome default saccadic-programming mechanisms. |
Stefan Van der Stigchel; Jelmer P. De Vries There is no attentional global effect: Attentional shifts are independent of the saccade endpoint Journal Article In: Journal of Vision, vol. 15, no. 15, pp. 17, 2015. @article{VanderStigchel2015, Many studies have found a strong coupling between selective attention and eye movements. The premotor theory of attention suggests that saccade preparation is directly responsible for such attentional shifts. While it has already been shown that the attentional shift is not directly coupled to the final stages of motor execution, it is currently unknown to what aspect of the earlier stages of saccade preparation the attentional shift is coupled. An important step in this preparation process is resolving the landing point when multiple elements compete for the saccade. Here we ask how such a competition influences the presaccadic attentional locus and whether the presaccadic shift of attention is coupled to the saccade landing position or the possible saccade goals. To this end, we adopt a global effect paradigm where a target is accompanied by a salient distractor resulting in the majority of eye movements landing in between target and distractor. To determine the allocation of attention, participants are presented with a discrimination task shortly before the execution of the saccade. Despite a strong global effect obtained for saccade endpoints, we find little evidence for attentional facilitation at the location between target and distractor, but strong attentional facilitation at the location of the target and distractor.We argue that attention is coupled to active oculomotor programs, but not part of the resolution of these programs towards the execution of the saccade. |
Wieske Zoest; Dirk Kerzel The effects of saliency on manual reach trajectories and reach target selection Journal Article In: Vision Research, vol. 113, pp. 179–187, 2015. @article{Zoest2015, Reaching trajectories curve toward salient distractors, reflecting the competing activation of reach plans toward target and distractor stimuli. We investigated whether the relative saliency of target and distractor influenced the curvature of the movement and the selection of the final endpoint of the reach. Participants were asked to reach a bar tilted to the right in a context of gray vertical bars. A bar tilted to the left served as distractor. Relative stimulus saliency was varied via color: either the distractor was red and the target was gray, or vice versa. Throughout, we observed that reach trajectories deviated toward the distractor. Surprisingly, relative saliency had no effect on the curvature of reach trajectories. Moreover, when we increased time pressure in separate experiments and analyzed the curvature as a function of reaction time, no influence of relative stimulus saliency was found, not even for the fastest reaction times. If anything, curvature decreased with strong time pressure. In contrast, reach target selection under strong time pressure was influenced by relative saliency: reaches with short reaction times were likely to go to the red distractor. The time course of reach target selection was comparable to saccadic target selection. Implications for the neural basis of trajectory deviations and target selection in manual and eye movements are discussed. |
Bram-Ernst Verhoef; Pascal Michelet; Rufin Vogels; Peter Janssen Choice-related activity in the anterior intraparietal area during 3-D structure categorization Journal Article In: Journal of Cognitive Neuroscience, vol. 27, pp. 1104–1115, 2015. @article{Verhoef2015a, The anterior intraparietal area (AIP) of macaques contains neurons that signal the depth structure of disparity-defined 3-D shapes. Previous studies have suggested that AIP's depth information is used for sensorimotor transformations related to the efficient grasping of 3-D objects. We trained monkeys to categorize disparity-defined 3-D shapes and examined whether neuronal activity in AIP may also underlie pure per- ceptual categorization behavior. We first show that neurons with a similar 3-D shape preference cluster in AIP. We then demonstrate that the monkeys' 3-D shape discrimination perfor- mance depends on the position in depth of the stimulus and that this performance difference is reflected in the activity of AIP neurons. We further reveal correlations between the neuronal activity in AIP and the subject's subsequent choices and RTs during 3-D shape categorization. Our findings propose AIP as an important processing stage for 3-D shape perception. |
Petra Vetter; Marie-Hélène Grosbras; Lars Muckli TMS over V5 disrupts motion prediction Journal Article In: Cerebral Cortex, vol. 25, no. 4, pp. 1052–1059, 2015. @article{Vetter2015, Given the vast amount of sensory information the brain has to deal with, predicting some of this information based on the current context is a resource-efficient strategy. The framework of predictive coding states that higher-level brain areas generate a predictive model to be communicated via feedback connections to early sensory areas. Here, we directly tested the necessity of a higher-level visual area, V5, in this predictive processing in the context of an apparent motion paradigm. We flashed targets on the apparent motion trace in-time or out-of-time with the predicted illusory motion token. As in previous studies, we found that predictable in-time targets were better detected than unpredictable out-of-time targets. However, when we applied functional magnetic resonance imaging-guided, double-pulse transcranial magnetic stimulation (TMS) over left V5 at 13-53 ms before target onset, the detection advantage of in-time targets was eliminated; this was not the case when TMS was applied over the vertex. Our results are causal evidence that V5 is necessary for a prediction effect, which has been shown to modulate V1 activity (Alink et al. 2010). Thus, our findings suggest that information processing between V5 and V1 is crucial for visual motion prediction, providing experimental support for the predictive coding framework. |
Cyril Vienne; Laurent Blondé; Pascal Mamassian Depth-of-focus affects 3d perception in stereoscopic displays Journal Article In: Perception, vol. 44, no. 6, pp. 613–627, 2015. @article{Vienne2015, Stereoscopic systems present binocular images on planar surface at a fixed distance. They induce cues to flatness, indicating that images are presented on a unique surface and specifying the relative depth of that surface. The center of interest of this study is on a second problem, arising when a 3D object distance differs from the display distance. As binocular disparity must be scaled using an estimate of viewing distance, object depth can thus be affected through disparity scaling. Two previous experiments revealed that stereoscopic displays can affect depth perception due to conflicting accommodation and vergence cues at near distances. In this study, depth perception is evaluated for farther accommodation and vergence distances using a commercially available 3D TV. In Experiment 1, we evaluated depth perception of 3D stimuli at different vergence distances for a large pool of participants. We observed a strong effect of vergence distance that was bigger for younger than for older participants, suggesting that the effect of accommodation was reduced in participants with emerging presbyopia. In Experiment 2, we extended 3D estimations by varying both the accommodation and vergence distances. We also tested the hypothesis that setting accommodation open loop by constricting pupil size could decrease the contribution of focus cues to perceived distance. We found that the depth constancy was affected by accommodation and vergence distances and that the accommodation distance effect was reduced with a larger depth-of-focus. We discuss these results with regard to the effectiveness of focus cues as a distance signal. Overall, these results highlight the importance of appropriate focus cues in stereoscopic displays at intermediate viewing distances. |
Eckart Zimmermann; M. Concetta Morrone; David C. Burr Visual mislocalization during saccade sequences Journal Article In: Experimental Brain Research, vol. 233, no. 2, pp. 577–585, 2015. @article{Zimmermann2015a, Visual objects briefly presented around the time of saccadic eye movements are perceived compressed towards the saccade target. Here, we investigated perisaccadic mislocalization with a double-step saccade paradigm, measuring localization of small probe dots briefly flashed at various times around the sequence of the two saccades. At onset of the first saccade, probe dots were mislocalized towards the first and, to a lesser extent, also towards the second saccade target. However, there was very little mislocalization at the onset of the second saccade. When we increased the presentation duration of the saccade targets prior to onset of the saccade sequence, perisaccadic mislocalization did occur at the onset of the second saccade. |
Maryam Ziaei; William Hippel; Julie D. Henry; Stefanie I. Becker Are age effects in positivity influenced by the valence of distractors? Journal Article In: PLoS ONE, vol. 10, no. 9, pp. e0137604, 2015. @article{Ziaei2015, An age-related ‘positivity' effect has been identified, in which older adults show an information- processing bias towards positive emotional items in attention and memory. In the present study, we examined this positivity bias by using a novel paradigm in which emotional and neutral distractors were presented along with emotionally valenced targets. Thirty-five older and 37 younger adults were asked during encoding to attend to emotional targets paired with distractors that were either neutral or opposite in valence to the target. Pupillary responses were recorded during initial encoding as well as a later incidental recognition task. Memory and pupillary responses for negative items were not affected by the valence of distractors, suggesting that positive distractors did not automatically attract older adults' attention while they were encoding negative targets. Additionally, the pupil dilation to negative items mediated the relation between age and positivity in memory. Overall, memory and pupillary responses provide converging support for a cognitive control account of positivity effects in late adulthood and suggest a link between attentional processes and the memory positivity effect. |
Avinash R. Vaidya; Lesley K. Fellows Testing necessary regional frontal contributions to value assessment and fixation-based updating Journal Article In: Nature Communications, vol. 6, pp. 10120, 2015. @article{Vaidya2015, Value-based decisions are biased by the time people spend viewing each option: Options fixated longer are chosen more often, even when previously rated as less appealing. This bias is thought to reflect /`value updating/' as new evidence is accumulated. Prior work has shown that ventromedial prefrontal cortex (PFC) carries a fixation-dependent value comparison signal, while other studies implicate dorsomedial PFC in representing the value of alternative options. Here, we test whether these regions are necessary for fixation-related value updating in 33 people with frontal lobe damage and 27 healthy controls performing a simple choice task. We show that damage to dorsomedial PFC leads to an exaggerated influence of fixations on choice, while damage to ventromedial or lateral PFC has no effect on this bias. These findings suggest a critical role for dorsomedial, and not ventromedial PFC, in mediating the relative influence of current fixations and a priori value on choice. |
Matteo Valsecchi; Karl R. Gegenfurtner Control of binocular gaze in a high-precision manual task Journal Article In: Vision Research, vol. 110, no. PB, pp. 203–214, 2015. @article{Valsecchi2015, We investigated the precision of binocular gaze control while observers performed a high-precision manual movement, which involved hitting a target hole in a plate with a hand-held needle. Binocular eye movements and the 3D-position of the needle tip were tracked. In general the observers oriented their gaze to the target before they reached it with the needle. The amplitude of microsaccades scaled with the distance of the needle tip. We did not find evidence for the coordination of version and vergence during microsaccades which could be expected if those movements displaced gaze between the needle and the target hole. In a control experiment observers executed small saccades between marks on a slanted plane. Even when the observers executed saccades as small as the microsaccades in the needle experiment, we observed a coordinated displacement of the point of gaze on the horizontal and depth axis. Our results show that the characteristics of eye movements such as the frequency and amplitude of microsaccades are adapted online to the task demands. However, a coordinated control of version and vergence in small saccades is only observed if a movement of gaze on a slanted trajectory is explicitly instructed. |
Christian Valuch; Ulrich Ansorge The influence of color during continuity cuts in edited movies: An eye-tracking study Journal Article In: Multimedia Tools and Applications, vol. 74, no. 22, pp. 10161–10176, 2015. @article{Valuch2015a, Professionally edited videos entail frequent editorial cuts – that is, abrupt image changes from one frame to another. The impact of these cuts on human eye movements is currently not well understood. In the present eye-tracking study, we experimentally gauged the degree to which color and visual continuity contributed to viewers' eye movements following cinematic cuts. In our experiment, viewers were presented with two edited action sports movies on the same screen but they were instructed to watch and keep their gaze on only one of these movies. Crucially, the movies were frequently interrupted and continued after a short break either at the same or at switched locations. Hence, viewers needed to rapidly recognize the continuation of the relevant movie and re-orient their gaze toward it. Properties of saccadic eye movements following each interruption probed the recognition of the relevant movie after a cut. Two key findings were that (i) memory co-determines attention after cuts in edited videos, resulting in faster re-orientation toward scene continuations when visual continuity across the interruption is high than when it is low, and (ii) color contributes to the guidance of attention after cuts, but its benefit largely rests upon enhanced discrimination of relevant from irrelevant visual information rather than memory. Results are discussed with regard to previous research on eye movements in movies and recognition processes. Possible future directions of research are outlined. |
Christian Valuch; Lena S. Pfluger; Bernard Wallner; Bruno Laeng; Ulrich Ansorge Using eye tracking to test for individual differences in attention to attractive faces Journal Article In: Frontiers in Psychology, vol. 6, pp. 42, 2015. @article{Valuch2015, We assessed individual differences in visual attention toward faces in relation to their attractiveness via saccadic reaction times (SRTs). Motivated by the aim to understand individual differences in attention to faces, we tested three hypotheses: (a) Attractive faces hold or capture attention more effectively than less attractive faces; (b) men show a stronger bias toward attractive opposite-sex faces than women; and (c) blue-eyed men show a stronger bias toward blue-eyed than brown-eyed feminine faces. The latter test was included because prior research suggested a high effect size. Our data supported hypotheses (a) and (b) but not (c). By conducting separate tests for disengagement of attention and attention capture, we found that individual differences exist at distinct stages of attentional processing but these differences are of varying robustness and importance. In our conclusion, we also advocate the use of linear mixed effects models as the most appropriate statistical approach toward studying inter-individual differences in visual attention with naturalistic stimuli. |
Goedele Van Belle; Philippe Lefèvre; Bruno Rossion Face inversion and acquired prosopagnosia reduce the size of the perceptual field of view Journal Article In: Cognition, vol. 136, no. 1, pp. 403–408, 2015. @article{VanBelle2015, Using a gaze-contingent morphing approach, we asked human observers to choose one of two faces that best matched the identity of a target face: one face corresponded to the reference face's fixated part only (e.g., one eye), the other corresponded to the unfixated area of the reference face. The face corresponding to the fixated part was selected significantly more frequently in the inverted than in the upright orientation. This observation provides evidence that face inversion reduces an observer's perceptual field of view, even when both upright and inverted faces are displayed at full view and there is no performance difference between these conditions. It rules out an account of the drop of performance for inverted faces - one of the most robust effects in experimental psychology - in terms of a mere difference in local processing efficiency. A brain-damaged patient with pure prosopagnosia, viewing only upright faces, systematically selected the face corresponding to the fixated part, as if her perceptual field was reduced relative to normal observers. Altogether, these observations indicate that the absence of visual knowledge reduces the perceptual field of view, supporting an indirect view of visual perception. |
Steffi Zander; Maria Reichelt; Stefanie Wetzel; Frauke Kämmerer; Sven Bertel Does personalisation promote learners' attention? An eye-tracking study Journal Article In: Frontline Learning Research, vol. 3, no. 4, pp. 1–13, 2015. @article{Zander2015, The personalisation principle is a design recommendation and states that multimedia presentations using personalised language promote learning better than those using formal language (e.g., using ‘your' instead of ‘the'). It is often assumed that this design recommendation affects motivation and therefore allocation of attention. To gain further insight into the processes underlying personalisation effects we conducted an eye tracking experiment with 37 German university students who were presented with either personalised or formal learning materials. We examined group differences in attention allocation parameters (fixation count, fixation duration, transition count). The eye-tracking data was combined with self-reports concerning motivation, cognitive load, and learning outcomes. Eye-tracking data revealed a significantly higher reading depth for the main picture areas of interest in the personalised condition. Additionally, participants found the personalised version more appealing and inviting. For learning outcomes, there was a significant positive effect of personalisation for retention, not for transfer. We discuss additional explanatory variables as well as methodological and practical implications for instructional design. |
Xuelian Zang; Lina Jia; Hermann J. Müller; Zhuanghua Shi Invariant spatial context is learned but not retrieved in gaze-contingent limited-viewing search Journal Article In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 41, no. 3, pp. 807–819, 2015. @article{Zang2015, Our visual brain is remarkable in extracting invariant properties from the noisy environment, guiding selection of where to look and what to identify. However, how the brain achieves this is still poorly understood. Here we explore interactions of local context and global structure in the long-term learning and retrieval of invariant display properties. Participants searched for a target among distractors, without knowing that some “old” configurations were presented repeatedly (randomly inserted among “new” configurations). We simulated tunnel vision, limiting the visible region around fixation. Robust facilitation of performance for old versus new contexts was observed when the visible region was large but not when it was small. However, once the display was made fully visible during the subsequent transfer phase, facilitation did become manifest. Furthermore, when participants were given a brief preview of the total display layout prior to tunnel view search with 2 items visible, facilitation was already obtained during the learning phase. The eye movement results revealed contextual facilitation to be coupled with changes of saccadic planning, characterized by slightly extended gaze durations but a reduced number of fixations and shortened scan paths for old displays. Taken together, our findings show that invariant spatial display properties can be acquired based on scarce, para-/foveal information, while their effective retrieval for search guidance requires the availability (even if brief) of a certain extent of peripheral information. |
Alexandre Zenon; Mariam Sidibe; Etienne Olivier Disrupting the supplementary motor area makes physical effort appear less effortful Journal Article In: Journal of Neuroscience, vol. 35, no. 23, pp. 8737–8744, 2015. @article{Zenon2015, The perception of physical effort is relatively unaffected by the suppression of sensory afferences, indicating that this function relies mostly on the processing of the central motor command. Neural signals in the supplementary motor area (SMA) correlate with the intensity of effort, suggesting that the motor signal involved in effort perception could originate from this area, but experimental evidence supporting this view is still lacking. Here, we tested this hypothesis by disrupting neural activity in SMA, in primary motor cortex (M1), or in a control site by means of continuous theta-burst transcranial magnetic stimulation, while measuring effort perception during grip forces of different intensities. After each grip force exertion, participants had the opportunity to either accept or refuse to replicate the same effort for varying amounts of reward. In addition to the subjective rating of perceived exertion, effort perception was estimated on the basis of the acceptance rate, the effort replication accuracy, the influence of the effort exerted in trial t on trial t+1, and pupil dilation. We found that disruption of SMA activity, but not of M1, led to a consistent decrease in effort perception, whatever the measure used to assess it. Accordingly, we modeled effort perception in a structural equation model and found that only SMA disruption led to a significant alteration of effort perception. These findings indicate that effort perception relies on the processing of a signal originating from motor-related neural circuits upstream of M1 and that SMA is a key node of this network. |
Jiedong Zhang; Jia Liu; Yaoda Xu Neural decoding reveals impaired face configural processing in the right fusiform face area of individuals with developmental prosopagnosia Journal Article In: Journal of Neuroscience, vol. 35, no. 4, pp. 1539–1548, 2015. @article{Zhang2015, Most of human daily social interactions rely on the ability to successfully recognize faces. Yet ∼2% of the human population suffers from face blindness without any acquired brain damage [this is also known as developmental prosopagnosia (DP) or congenital prosopagnosia]). Despite the presence of severe behavioral face recognition deficits, surprisingly, a majority of DP individuals exhibit normal face selectivity in the right fusiform face area (FFA), a key brain region involved in face configural processing. This finding, together with evidence showing impairments downstream from the right FFA in DP individuals, has led some to argue that perhaps the right FFA is largely intact in DP individuals. Using fMRI multivoxel pattern analysis, here we report the discovery of a neural impairment in the right FFA of DP individuals that may play a critical role in mediating their face-processing deficits. In seven individuals with DP, we discovered that, despite the right FFA's preference for faces and it showing decoding for the different face parts, it exhibited impaired face configural decoding and did not contain distinct neural response patterns for the intact and the scrambled face configurations. This abnormality was not present throughout the ventral visual cortex, as normal neural decoding was found in an adjacent object-processing region. To our knowledge, this is the first direct neural evidence showing impaired face configural processing in the right FFA in individuals with DP. The discovery of this neural impairment provides a new clue to our understanding of the neural basis of DP. |
Jingjing Zhao; Yonghui Wang; Donglai Liu; Liang Zhao; Peng Liu In: Attention, Perception, and Psychophysics, vol. 77, no. 7, pp. 2284–2292, 2015. @article{Zhao2015, It was found in previous studies that two types of objects (rectangles formed according to the Gestalt principle and Chinese words formed in a top-down fashion) can both induce an object-based effect. The aim of the present study was to investigate how the strength of an object representation affects the result of the competition between these two types of objects based on research carried out by Liu, Wang and Zhou [(2011) Acta Psychologica, 138(3), 397-404]. In Experiment 1, the rectangles were filled with two different colors to increase the strength of Gestalt object representation, and we found that the object effect changed significantly for the different stimulus types. Experiment 2 used Chinese words with various familiarities to manipulate the strength of the top-down object representation. As a result, the object-based effect induced by rectangles was observed only when the Chinese word familiarity was low. These results suggest that the strength of object representation determines the result of competition between different types of objects. |
Thomas D. W. Wilcockson; E. M. Pothos Measuring inhibitory processes for alcohol-related attentional biases: Introducing a novel attentional bias measure Journal Article In: Addictive Behaviors, vol. 44, pp. 88–93, 2015. @article{Wilcockson2015, Introduction: Attentional biases for alcohol related information (AB) have often been reported for heavy drinkers. These attentional biases have been found to have predictive value regarding relapse in abstaining alcoholics. Similarly impaired inhibitory processes have also been found to be associated with heavy drinkers. This paper describes a new experimental paradigm that can be utilised to investigate attentional bias towards alcohol-related visual stimuli, specifically the ability to inhibit the orientation of initial and sustained attention, towards peripherally appearing stimuli. In this way we hope to study a novel aspect of attentional biases and how they relate to substance abuse. Methods: We used a novel eye-tracking task which aims to measure inhibitory processes for AB. The experiment utilised a gaze contingency paradigm to measure the compulsion to process or attend to alcohol stimuli. 86 undergraduate participants were recruited (31 males; 55 females), aged 18-49. years (m. =. 20.88; sd. =. 4.52). A 'break frequency' variable was computed for each participant. This was the number of times that participants tried to look at peripheral stimuli. We argue that this variable is a direct measure of how distracting peripheral stimuli were. Results: It was found that reported alcohol use was associated with the eye-tracking break frequency measure of inhibitory control. Thus, heavy drinking may be associated with decreased inhibitory control and increased attentional bias. Conclusions: Results suggest that attentional bias is not just a process of stimuli becoming prioritised, but also stimuli becoming compulsory to attend and process. |
Charlotte Willems; Atser Damsma; Stefan M. Wierda; Niels A. Taatgen; Sander Martens Training-induced changes in the dynamics of attention as reflected in pupil dilation Journal Article In: Journal of Cognitive Neuroscience, vol. 27, no. 6, pp. 1161–1171, 2015. @article{Willems2015, One of the major topics in attention literature is the atten- tional blink (AB), which demonstrates a limited ability to iden- tify the second of two targets (T1 and T2) when presented in close temporal succession (200–500 msec). Given that the effect has been thought of as robust and resistant to training for over 2 decades, one of the most remarkable findings in recent years is that the AB can be eliminated after a 1-hr training with a color-salient T2. However, the underlying mechanism of the training effect as well as the AB itself is as of yet still poorly understood. To elucidate this training effect, we employed a refined version of our recently developed pupil dilation deconvolution method to track any training-induced changes in the amount and onset of attentional processing in response to target stimuli. Behaviorally, we replicated the orig- inal training effect with a color-salient T2. However, we showed that training without a salient target, but with a consistent short target interval, is already sufficient to attenuate the AB. Pupil deconvolution did not reveal any posttraining changes in T2- related dilation but instead an earlier onset of dilation around T1. Moreover, normalized pupil dilation was enhanced post- training compared with pretraining. We conclude that the AB can be eliminated by training without a salient cue. Further- more, our data point to the existence of temporal expectations at the time points of the trained targets posttraining. Therefore, we tentatively conclude that temporal expectations arise as a result of training. |
Charlotte Willems; Johannes Herdzin; Sander Martens Individual differences in temporal selective attention as reflected in pupil dilation Journal Article In: PLoS ONE, vol. 10, no. 12, pp. e0145056, 2015. @article{Willems2015a, Background Attention is restricted for the second of two targets when it is presented within 200–500 ms of the first target. This attentional blink (AB) phenomenon allows one to study the dynamics of temporal selective attention by varying the interval between the two targets (T1 and T2). Whereas the AB has long been considered as a robust and universal cognitive limitation, several studies have demonstrated that AB task performance greatly differs between individuals, with some individuals showing no AB whatsoever. Methodology/Principal Findings Here, we studied these individual differences in AB task performance in relation to differences in attentional timing. Furthermore, we investigated whether AB magnitude is predictive for the amount of attention allocated to T1. For both these purposes pupil dilation was measured, and analyzed with our recently developed deconvolution method. We found that the dynamics of temporal attention in small versus large blinkers differ in a number of ways. Individuals with a relatively small AB magnitude seem better able to preserve temporal order information. In addition, they are quicker to allocate attention to both T1 and T2 than large blinkers. Although a popular explanation of the AB is that it is caused by an unnecessary overinvestment of attention allocated to T1, a more complex picture emerged from our data, suggesting that this may depend on whether one is a small or a large blinker. Conclusion The use of pupil dilation deconvolution seems to be a powerful approach to study the temporal dynamics of attention, bringing us a step closer to understanding the elusive nature of the AB. We conclude that the timing of attention to targets may be more important than the amount of allocated attention in accounting for individual differences. |