所有EyeLink眼动仪出版物
以下按年份列出了截至2025年（包括2026年初）的所有14000篇经同行评审的EyeLink研究出版物。您可以使用视觉搜索、平滑追求、帕金森氏症等关键字搜索出版物库。您还可以搜索单个作者的姓名。按研究领域分组的眼动追踪研究可以在解决方案页面上找到。如果我们错过了任何EyeLink眼动追踪论文，请给我们发电子邮件！
2011 |
Dan J. Graham; Robert W. Jeffery Location, location, location: Eye-tracking evidence that consumers preferentially view prominently positioned nutrition information Journal Article In: Journal of the American Dietetic Association, vol. 111, no. 11, pp. 1704–1711, 2011. @article{Graham2011,Background: Nutrition Facts labels can keep consumers better informed about their diets' nutritional composition, however, consumers currently do not understand these labels well or use them often. Thus, modifying existing labels may benefit public health. Objective: The present study tracked the visual attention of individuals making simulated food-purchasing decisions to assess Nutrition Facts label viewing. Primary research questions were how self-reported viewing of Nutrition Facts labels and their components relates to measured viewing and whether locations of labels and specific label components relate to viewing. Design: The study involved a simulated grocery shopping exercise conducted on a computer equipped with an eye-tracking camera. A post-task survey assessed self-reported nutrition information viewing, health behaviors, and demographics. Subjects/setting: Individuals 18 years old and older and capable of reading English words on a computer (n=203) completed the 1-hour protocol at the University of Minnesota during Spring 2010. Statistical analyses: Primary analyses included X2, analysis of variance, and t tests comparing self-reported and measured viewing of label components in different presentation configurations. Results: Self-reported viewing of Nutrition Facts label components was higher than objectively measured viewing. Label components at the top of the label were viewed more than those at the bottom, and labels positioned in the center of the screen were viewed more than those located on the sides. Conclusions: Nutrition Facts label position within a viewing area and position of specific components on a label relate to viewing. Eye tracking is a valuable technology for evaluating consumers' attention to nutrition information, informing nutrition labeling policy (eg, front-of-pack labels), and designing labels that best support healthy dietary decisions. |
Hideyuki Matsumoto; Yasuo Terao; Toshiaki Furubayashi; Akihiro Yugeta; Hideki Fukuda; Masaki Emoto; Ritsuko Hanajima; Yoshikazu Ugawa Small saccades restrict visual scanning area in Parkinson's disease Journal Article In: Movement Disorders, vol. 26, no. 9, pp. 1619–1626, 2011. @article{Matsumoto2011,The purpose of this study wasto investigate abnormalities in visual scanning when Parkinson's disease patients view images of varying complexity. Eighteen nondemented Parkinson's disease patients and 18 normal subjects participated in the study. The ocular fixation position during viewing visual images was recorded using an eye-tracking device. The number of saccades, duration of fixation, amplitude of saccades, and scanned area in Parkinson's disease patients were compared with those in normal subjects. We also investigated whether the number of saccades, duration of fixation, or amplitude of saccades influenced the scanned area. While scanning images of varying complexity, Parkinson's disease patients made fewer saccades with smaller amplitude and longer fixation compared with normal subjects. As image complexity increased, the number of saccades and duration of fixation gradually approached those of normal subjects. Nevertheless, the scanned area in Parkinson's disease patients was consistently smaller than that in normal subjects. The scanned area significantly correlated with saccade amplitude in most images. Importantly, although Parkinson's disease patients cannot make frequent saccades when viewing simple figures, they can increase the saccade number and reduce their fixation duration when viewing more complex figures, making use of the abundant visual cues in such figures, suggesting the existence of ocular kinesie paradoxale. Nevertheless, both the saccade amplitude and the scanned area were consistently smaller than those of normal subjects for all levels of visual complexity. This indicates that small saccade amplitude is the main cause of impaired visual scanning in Parkinson's disease patients. |
Adrian Staub The effect of lexical predictability on distributions of eye fixation durations Journal Article In: Psychonomic Bulletin & Review, vol. 18, no. 2, pp. 371–376, 2011. @article{Staub2011,A word's predictability in context has a well-established effect on fixation durations in reading. To investigate how this effect is manifested in distributional terms, an experiment was carried out in which subjects read each of 50 target words twice, once in a high-predictability context and once in a low-predictability context. The ex-Gaussian distribution was fit to each subject's first-fixation durations and single-fixation durations. For both measures, the μ parameter increased when a word was unpredictable, while the τ parameter was not significantly affected, indicating that a predictability manipulation shifts the distribution of fixation durations but does not affect the degree of skew. Vincentile plots showed that the mean ex-Gaussian parameters described the typical distribution shapes extremely well. These results suggest that the predictability and frequency effects are functionally distinct, since a frequency manipulation has been shown to influence both μ and τ. The results may also be seen as consistent with the finding from single-word recognition paradigms that semantic priming affects only μ. |
Eun Ju Lee; Gusang Kwon; Aekyoung Lee; Jamshid Ghajar; Minah Suh Individual differences in working memory capacity determine the effects of oculomotor task load on concurrent word recall performance Journal Article In: Brain Research, vol. 1399, pp. 59–65, 2011. @article{Lee2011,In this study, the interaction between individual differences in working memory capacity, which were assessed by the Korean version of the California Verbal Learning Test (K-CVLT), and the effects of oculomotor task load on word recall performance are examined in a dual-task experiment. We hypothesized that varying levels of oculomotor task load should result in different demands on cognitive resources. The verbal working memory task used in this study involved a brief exposure to seven words to be remembered, followed by a 30-second delay during which the subject carried out an oculomotor task. Then, memory performance was assessed by having the subjects recall as many words as possible. Forty healthy normal subjects with no vision-related problems carried out four separate dual-tasks over four consecutive days of participation, wherein word recall performances were tested under unpredictable random SPEM (smooth pursuit eye movement), predictive SPEM, fixation, and eyes-closed conditions. The word recall performance of subjects with low K-CVLT scores was significantly enhanced under predictive SPEM conditions as opposed to the fixation and eyes-closed conditions, but performance was reduced under the random SPEM condition, thus reflecting an inverted-U relationship between the oculomotor task load and word recall performance. Subjects with high K-CVLT scores evidenced steady word recall performances, regardless of the type of oculomotor task performed. The concurrent oculomotor performance measured by velocity error did not differ significantly among the K-CVLT groups. However, the high-scoring subjects evidenced smaller phase errors under predictive SPEM conditions than did the low-scoring subjects; this suggests that different resource allocation strategies may be adopted, depending on individuals' working memory capacity. |
Hideyuki Matsumoto; Yasuo Terao; Akihiro Yugeta; Hideki Fukuda; Masaki Emoto; Toshiaki Furubayashi; Tomoko Okano; Ritsuko Hanajima; Yoshikazu Ugawa Where do neurologists look when viewing brain CT images? An eye-tracking study involving stroke cases Journal Article In: PLoS ONE, vol. 6, no. 12, pp. e28928, 2011. @article{Matsumoto2011a,The aim of this study was to investigate where neurologists look when they view brain computed tomography (CT) images and to evaluate how they deploy their visual attention by comparing their gaze distribution with saliency maps. Brain CT images showing cerebrovascular accidents were presented to 12 neurologists and 12 control subjects. The subjects' ocular fixation positions were recorded using an eye-tracking device (Eyelink 1000). Heat maps were created based on the eye-fixation patterns of each group and compared between the two groups. The heat maps revealed that the areas on which control subjects frequently fixated often coincided with areas identified as outstanding in saliency maps, while the areas on which neurologists frequently fixated often did not. Dwell time in regions of interest (ROI) was likewise compared between the two groups, revealing that, although dwell time on large lesions was not different between the two groups, dwell time in clinically important areas with low salience was longer in neurologists than in controls. Therefore it appears that neurologists intentionally scan clinically important areas when reading brain CT images showing cerebrovascular accidents. Both neurologists and control subjects used the "bottom-up salience" form of visual attention, although the neurologists more effectively used the "top-down instruction" form. |
Adrian Staub Word recognition and syntactic attachment in reading: Evidence for a staged architecture Journal Article In: Journal of Experimental Psychology: General, vol. 140, no. 3, pp. 407–433, 2011. @article{Staub2011a,In 3 experiments, the author examined how readers' eye movements are influenced by joint manipulations of a word's frequency and the syntactic fit of the word in its context. In the critical conditions of the first 2 experiments, a high- or low-frequency verb was used to disambiguate a garden-path sentence, while in the last experiment, a high- or low-frequency verb constituted a phrase structure violation. The frequency manipulation always influenced the early eye movement measures of first-fixation duration and gaze duration. The context manipulation had a delayed effect in Experiment 1, influencing only the probability of a regressive eye movement from later in the sentence. However, the context manipulation influenced the same early eye movement measures as the frequency effect in Experiments 2 and 3, though there was no statistical interaction between the effects of these variables. The context manipulation also influenced the probability of a regressive eye movement from the verb, though the frequency manipulation did not. These results are shown to confirm predictions emerging from the serial, staged architecture for lexical and integrative processing of the E-Z Reader 10 model of eye movement control in reading (Reichle, Warren, & McConnell, 2009). It is argued, more generally, that the results provide an important constraint on how the relationship between visual word recognition and syntactic attachment is treated in processing models. |
V. C. Huddy; Timothy L. Hodgson; M. A. Ron; Thomas R. E. Barnes; Eileen M. Joyce Abnormal negative feedback processing in first episode schizophrenia: Evidence from an oculomotor rule switching task Journal Article In: Psychological Medicine, vol. 41, no. 9, pp. 1805–1814, 2011. @article{Huddy2011,Background. Previous studies have shown that patients with schizophrenia are impaired on executive tasks, where positive and negative feedbacks are used to update task rules or switch attention. However, research to date using saccadic tasks has not revealed clear deficits in task switching in these patients. The present study used an oculomotor ‘ rule switching ' task to investigate the use of negative feedback when switching between task rules in people with schizophrenia. Method. A total of 50 patients with first episode schizophrenia and 25 healthy controls performed a task in which the association between a centrally presented visual cue and the direction of a saccade could change from trial to trial. Rule changes were heralded by an unexpected negative feedback, indicating that the cue-response mapping had reversed. Results. Schizophrenia patients were found to make increased errors following a rule switch, but these were almost entirely the result of executing saccades away from the location at which the negative feedback had been presented on the preceding trial. This impairment in negative feedback processing was independent of IQ. Conclusions. The results not only confirm the existence of a basic deficit in stimulus–response rule switching in schizophrenia, but also suggest that this arises from aberrant processing of response outcomes, resulting in a failure to appropriately update rules. The findings are discussed in the context of neurological and pharmacological abnormalities in the conditions that may disrupt prediction error signalling in schizophrenia. |
Peggy Gerardin; Valérie Gaveau; Denis Pélisson; Claude Prablanc Integration of visual information for saccade production Journal Article In: Human Movement Science, vol. 30, no. 6, pp. 1009–1021, 2011. @article{Gerardin2011,To foveate a visual target, subjects usually execute a primary hypometric saccade (S1) bringing the target in perifoveal vision, followed by a corrective saccade (S2) or by more than one S2. It is still debated to what extent these S2 are pre-programmed or dependent only on post-saccadic retinal error. To answer this question, we used a visually-triggered saccade task in which target position and target visibility were manipulated. In one-third of the trials, the target was slightly displaced at S1 onset (so-called double step paradigm) and was maintained until the end of S1, until the start of the first S2 or until the end of the trial. Experiments took place in two visual environments: in the dark and in a dimly lit room with a visible random square background. The results showed that S2 were less accurate for shortest target durations. The duration of post-saccadic visual integration thus appears as the main factor responsible for corrective saccade accuracy. We also found that the visual context modulates primary saccade accuracy, especially for the most hypometric subjects. These findings suggest that the saccadic system is sensitive to the visual properties of the environment and uses different strategies to maintain final gaze accuracy. |
Alan F. Dixson; Barnaby J. Dixson Venus figurines of the european paleolithic: Symbols of fertility or attractiveness? Journal Article In: Journal of Anthropology, vol. 2011, pp. 1–11, 2011. @article{Dixson2011,The earliest known representations of the human female form are the European Paleolithic “Venus figurines,” ranging in age from 23,000 to 25,000 years. We asked participants to rate images of Paleolithic figurines for their attractiveness, age grouping and reproductive status. Attractiveness was positively correlated with measures of the waist-to hip ratio (WHR) of figurines, consistent with the “sexually attractive symbolism” hypothesis. However, most figurines had high WHRs (>1.0) and received low attractiveness scores. Participants rated most figurines as representing middle-aged or young adult women, rather than being adolescent or older (postmenopausal). While some were considered to represent pregnant women, consistent with the “fertility symbol” hypothesis, most were judged as being non-pregnant. Some figurines depict obese, large-breasted women, who are in their mature reproductive years and usually regarded as being of lower attractiveness. At the time these figurines were made, Europe was in the grip of a severe ice age. Obesity and survival into middle age after multiple pregnancies may have been rare in the European Upper Paleolithic. We suggest that depictions of corpulent, middle-aged females were not “Venuses” in any conventional sense. They may, instead, have symbolized the hope for survival and longevity, within well-nourished and reproductively successful communities. |
Jonas Knöll; Paola Binda; M. Concetta Morrone; Frank Bremmer Spatiotemporal profile of peri-saccadic contrast sensitivity Journal Article In: Journal of Vision, vol. 11, no. 14, pp. 1–12, 2011. @article{Knoell2011,Sensitivity to luminance contrast is reduced just before and during saccades (saccadic suppression), whereas sensitivity to color contrast is unimpaired peri-saccadically and enhanced post-saccadically. The exact spatiotemporal map of these perceptual effects is as yet unknown. Here, we measured detection thresholds for briefly flashed Gaussian blobs modulated in either luminance or chromatic contrast, displayed at a range of eccentricities. Sensitivity to luminance contrast was reduced peri-saccadically by a scaling factor, which was almost constant across retinal space. Saccadic suppression followed a similar time course across all tested eccentricities and was maximal shortly after the saccade onset. Sensitivity to chromatic contrast was enhanced post-saccadically at all tested locations. The enhancement was not specifically linked to the execution of saccades, as it was also observed following a displacement of retinal images comparable to that caused by a saccade. We conclude that luminance and chromatic contrast sensitivities are subject to distinct modulations at the time of saccades, resulting from independent neural processes. |
Alexander Pollatsek; Raymond Bertram; Jukka Hyönä Processing novel and lexicalised Finnish compound words Journal Article In: Journal of Cognitive Psychology, vol. 23, no. 7, pp. 795–810, 2011. @article{Pollatsek2011,Participants read sentences in which novel and lexicalized two-constituent compound words appeared while their eye movements were measured. The frequency of the first constituent of the compounds was also varied factorially and the frequency of the lexicalized compounds was equated over the two conditions. The sentence frames prior to the target word were matched across conditions. Both lexicality and first constituent frequency had large and significant effects on gaze durations on the target word; moreover the constituent frequency effect was significantly larger for the novel words. These results indicate that first constituent frequency has an effect in two stages: in the initial encoding of the compound and in the construction of meaning for the novel compound. The difference between this pattern of results and those for English prefixed words (Pollatsek, Slattery, & Juhasz, 2008) is apparently due to differences in the construction of meaning stage. A general model of the relationship of the processing of polymorphemic words to how they are fixated is presented. |
Sarah Uzzaman; Steve Joordens The eyes know what you are thinking: Eye movements as an objective measure of mind wandering Journal Article In: Consciousness and Cognition, vol. 20, no. 4, pp. 1882–1886, 2011. @article{Uzzaman2011,Paralleling the recent work by Reichle, Reineberg, and Schooler (2010), we explore the use of eye movements as an objective measure of mind wandering while participants performed a reading task. Participants were placed in a self-classified probe-caught mind wandering paradigm while their eye movements were recorded. They were randomly probed every 2-3. min and were required to indicate whether their mind had been wandering. The results show that eye movements were generally less complex when participants reported mind wandering episodes, with both duration and frequency of within-word regressions, for example, becoming significantly reduced. This is consistent with the theoretical claim that the cognitive processes that normally influence eye movements to enhance semantic processing during reading exert less control during mind wandering episodes. |
Barnaby J. Dixson; Gina M. Grimshaw; Wayne L. Linklater; Alan F. Dixson Eye-tracking of men's preferences for waist-to-hip ratio and breast size of women Journal Article In: Archives of Sexual Behavior, vol. 40, no. 1, pp. 43–50, 2011. @article{Dixson2011a,Studies of human physical traits and mate preferences often use questionnaires asking participants to rate the attractiveness of images. Female waist-to-hip ratio (WHR), breast size, and facial appearance have all been implicated in assessments by men of female attractiveness. However, very little is known about how men make fine-grained visual assessments of such images. We used eye-tracking techniques to measure the numbers of visual fixations, dwell times, and initial fixations made by men who viewed front-posed photographs of the same woman, computer-morphed so as to differ in her WHR (0.7 or 0.9) and breast size (small, medium, or large). Men also rated these images for attractiveness. Results showed that the initial visual fixation (occurring within 200 ms from the start of each 5 s test) involved either the breasts or the waist. Both these body areas received more first fixations than the face or the lower body (pubic area and legs). Men looked more often and for longer at the breasts, irrespective of the WHR of the images. However, men rated images with an hourglass shape and a slim waist (0.7 WHR) as most attractive, irrespective of breast size. These results provide quantitative data on eye movements that occur during male judgments of the attractiveness of female images, and indicate that assessments of the female hourglass figure probably occur very rapidly. |
Andi K. Winterboer; Martin I. Tietze; Maria K. Wolters; Johanna D. Moore The user model-based summarize and refine approach improves information presentation in spoken dialog systems Journal Article In: Computer Speech and Language, vol. 25, no. 2, pp. 175–191, 2011. @article{Winterboer2011,A common task for spoken dialog systems (SDS) is to help users select a suitable option (e.g., flight, hotel, and restaurant) from the set of options available. As the number of options increases, the system must have strategies for generating summaries that enable the user to browse the option space efficiently and successfully. In the user-model based summarize and refine approach (UMSR, Demberg and Moore, 2006), options are clustered to maximize utility with respect to a user model, and linguistic devices such as discourse cues and adverbials are used to highlight the trade-offs among the presented items. In a Wizard-of-Oz experiment, we show that the UMSR approach leads to improvements in task success, efficiency, and user satisfaction compared to an approach that clusters the available options to maximize coverage of the domain (Polifroni et al., 2003). In both a laboratory experiment and a web-based experimental paradigm employing the Amazon Mechanical Turk platform, we show that the discourse cues in UMSR summaries help users compare different options and choose between options, even though they do not improve verbatim recall. This effect was observed for both written and spoken stimuli. |
Barnaby J. Dixson; Gina M. Grimshaw; Wayne L. Linklater; Alan F. Dixson Eye tracking of men's preferences for female breast size and areola pigmentation Journal Article In: Archives of Sexual Behavior, vol. 40, no. 1, pp. 51–58, 2011. @article{Dixson2011b,Sexual selection via male mate choice has often been implicated in the evolution of permanently enlarged breasts in women. While questionnaire studies have shown that men find female breasts visually attractive, there is very little information about how they make such visual judgments. In this study, we used eye-tracking technology to test two hypotheses: (1) that larger breasts should receive the greatest number of visual fixations and longest dwell times, as well as being rated as most attractive; (2) that lightly pigmented areolae, indicative of youth and nubility, should receive most visual attention and be rated as most attractive. Results showed that men rated images with medium-sized or large breasts as significantly more attractive than small breasts. Images with dark and medium areolar pigmentation were rated as more attractive than images with light areolae. However, variations in breast size had no significant effect on eye-tracking measures (initial visual fixations, number of fixations, and dwell times). The majority of initial fixations during eye-tracking tests were on the areolae. However, areolar pigmentation did not affect measures of visual attention. While these results demonstrate that cues indicative of female sexual maturity (large breasts and dark areolae) are more attractive to men, patterns of eye movements did not differ based on breast size or areolar pigmentation. We conclude that areolar pigmentation, as well as breast size, plays a significant role in men's judgments of female attractiveness. However, fine-grained measures of men's visual attention to these morphological traits do not correlate, in a simplistic way, with their attractiveness judgments. |
Barbara J. Juhasz; Rachel N. Berkowitz Effects of morphological families on English compound word recognition: A multitask investigation Journal Article In: Language and Cognitive Processes, vol. 26, no. 4-6, pp. 653–682, 2011. @article{Juhasz2011,Three experiments examined the influence of first lexeme morphological family size on English compound word recognition. Concatenated compound words whose first lexemes were from large morphological families were responded to faster in word naming and lexical decision than compounds from small morphological families. In addition, an eye movement experiment showed that gaze durations were shorter on compounds from large morphological families during sentence reading. This was mainly due to more refixations on compounds from small morphological families. Posthoc analyses and re-analysis of past studies suggested that compounds with a larger number of higher frequency family members (HFFM) are read more slowly than compounds with fewer HFFM. Thus, while morphological family size is generally facilitative, the presence of HFFM has an inhibitory effect on eye movement behaviour. The time-course of these effects is discussed. |
Barbara J. Juhasz; Margaret M. Gullick; Leah W. Shesler The effects of age-of-Aacquisition on ambiguity resolution: Evidence from eye movements Journal Article In: Journal of Eye Movement Research, vol. 4, no. 1, pp. 1–14, 2011. @article{Juhasz2011a,Words that are rated as acquired earlier in life receive shorter fixation durations than later acquired words, even when word frequency is adequately controlled (Juhasz & Rayner, 2003; 2006). Some theories posit that age-of-acquisition (AoA) affects the semantic representation of words (e.g., Steyvers & Tenenbaum, 2005), while others suggest that AoA should have an influence at multiple levels in the mental lexicon (e.g. Ellis & Lambon Ralph, 2000). In past studies, early and late AoA words have differed from each other in orthography, phonology, and meaning, making it difficult to localize the influence of AoA. Two experiments are reported which examined the locus of AoA effects in reading. Both experiments used balanced ambiguous words which have two equally-frequent meanings acquired at different times (e.g. pot, tick). In Experiment 1, sentence context supporting either the early- or late-acquired meaning was presented prior to the ambiguous word; in Experiment 2, disambiguating context was presented after the ambiguous word. When prior context disambiguated the ambiguous word, meaning AoA influenced the processing of the target word. However, when disambiguating sentence context followed the ambiguous word, meaning frequency was the more important variable and no effect of meaning AoA was observed. These results, when combined with the past results of Juhasz and Rayner (2003; 2006) suggest that AoA influences access to multiple levels of representation in the mental lexicon. The results also have implications for theories of lexical ambiguity resolution, as they suggest that variables other than meaning frequency and context can influence resolution of noun-noun ambiguities. |
Timothy J. Slattery; Bernhard Angele; Keith Rayner Eye movements and display change detection during reading Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 37, no. 6, pp. 1924–1938, 2011. @article{sar11,In the boundary change paradigm (Rayner, 1975), when a reader's eyes cross an invisible boundary location, a preview word is replaced by a target word. Readers are generally unaware of such changes due to saccadic suppression. However, some readers detect changes on a few trials and a small percentage of them detect many changes. Two experiments are reported in which we combined eye movement data with signal detection analyses to investigate display change detection. On each trial, readers had to indicate if they saw a display change in addition to reading for meaning. On half the trials the display change occurred during the saccade (immediate condition); on the other half, it was slowed by 15-25 ms (delay condition) to increase the likelihood that a change would be detected. Sentences were presented in an alternating case fashion allowing us to investigate the influence of both letter identity and case. In the immediate condition, change detection was higher when letters changed than when case changed corroborating findings that word processing utilizes abstract (case independent) letter identities. However, in the delay condition (where d' was much higher than the immediate condition), detection was equal for letter and case changes. The results of both experiments indicate that sensitivity to display changes was related to how close the eyes were to the invalid preview on the fixation prior to the display change, as well as the timing of the completion of this change relative to the start of the post-change fixation. |
Daniel P. Kennedy; Ralph Adolphs Impaired fixation to eyes following amygdala damage arises from abnormal bottom-up attention Journal Article In: Neuropsychologia, vol. 49, no. 4, pp. 589–595, 2011. @article{Kennedy2011,SM is a patient with complete bilateral amygdala lesions who fails to fixate the eyes in faces and is consequently impaired in recognizing fear (Adolphs et al., 2005). Here we first replicated earlier findings in SM of reduced gaze to the eyes when seen in whole faces. Examination of the time course of fixations revealed that SM's reduced eye contact is particular pronounced in the first fixation to the face, and less abnormal in subsequent fixations. In a second set of experiments, we used a gaze-contingent presentation of faces with real time eye tracking, wherein only a small region of the face is made visible at the center of gaze. In essence, viewers explore the face by moving a small searchlight over the face with their gaze. Under such viewing conditions, SM's fixations to eye region of faces became entirely normalized. We suggest that this effect arises from the absence of bottom-up effects due to the facial features, allowing gaze location to be driven entirely by top-down control. Together with SM's failure to fixate the eyes in whole faces primarily at the very first saccade, the findings suggest that the saliency of the eyes normally attract our gaze in an amygdala-dependent manner. Impaired eye gaze is also a prominent feature of several psychiatric illnesses in which the amygdala has been hypothesized to be dysfunctional, and our findings and experimental manipulation may hold promise for interventions in such populations, including autism and fragile X syndrome. |
Huihui Zhou; Robert Desimone Feature-based attention in the Frontal Eye Field and area V4 during visual search Journal Article In: Neuron, vol. 70, no. 6, pp. 1205–1217, 2011. @article{Zhou2011,When we search for a target in a crowded visual scene, we often use the distinguishing features of the target, such as color or shape, to guide our attention and eye movements. To investigate the neural mechanisms of feature-based attention, we simultaneously recorded neural responses in the frontal eye field (FEF) and area V4 while monkeys performed a visual search task. The responses of cells in both areas were modulated by feature attention, independent of spatial attention, and the magnitude of response enhancement was inversely correlated with the number of saccades needed to find the target. However, an analysis of the latency of sensory and attentional influences on responses suggested that V4 provides bottom-up sensory information about stimulus features, whereas the FEF provides a top-down attentional bias toward target features that modulates sensory processing in V4 and that could be used to guide the eyes to a searched-for target. |
Manuel Perea; Chie Nakatani; Cees Leeuwen Transposition effects in reading Japanese Kana: Are they orthographic in nature? Journal Article In: Memory & Cognition, vol. 39, no. 4, pp. 700–707, 2011. @article{Perea2011,One critical question for the front end of models of visual-word recognition and reading is whether the stage of letter position coding is purely orthographic or whether phonology is (to some degree) involved. To explore this issue, we conducted a silent reading experiment in Japanese Kana–a script in which orthography and phonology can be easily separated–using a technique that is highly sensitive to phonological effects (i.e., Rayner's (1975) boundary technique). Results showed shorter fixation times on the target word when the parafoveal preview was a transposed-mora nonword (a.ri.me.ka [アリメカ]-a.me.ri.ka [アメリカ]) than when the preview was a replacement-mora nonword (a.ka.ho.ka [アカホカ] -a.me.ri.ka [アメリカ]). More critically, fixation times on the target word were remarkably similar when the parafoveal preview was a transposed-consonant nonword (a.re.mi.ka [アレミカ]-a.ri.me.ka [アリメカ]) and when the parafoveal preview was an orthographic control nonword (a.ke.hi.ka [アケヒカ]-a.me.ri.ka [アメリカ]). Thus, these findings offer strong support for the view that letter/mora position coding during silent reading is orthographic in nature. |
Timothy J. Slattery; Elizabeth R. Schotter; Raymond W. Berry; Keith Rayner Parafoveal and foveal processing of abbreviations during eye fixations in reading: Making a case for case Journal Article In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 37, no. 4, pp. 1022–1031, 2011. @article{ssbr11,The processing of abbreviations in reading was examined with an eye movement experiment. Abbreviations were of 2 distinct types: acronyms (abbreviations that can be read with the normal grapheme-phoneme correspondence [GPC] rules, such as NASA) and initialisms (abbreviations in which the GPCs are letter names, such as NCAA). Parafoveal and foveal processing of these abbreviations was assessed with the use of the boundary change paradigm (K. Rayner, 1975). Using this paradigm, previews of the abbreviations were either identical to the abbreviation (NASA or NCAA), orthographically legal (NUSO or NOBA), or illegal (NRSB or NRBA). The abbreviations were presented as capital letter strings within normal, predominantly lowercase sentences and also sentences in all capital letters such that the abbreviations would not be visually distinct. The results indicate that acronyms and initialisms undergo different processing during reading and that readers can modulate their processing based on low-level visual cues (distinct capitalization) in parafoveal vision. In particular, readers may be biased to process capitalized letter strings as initialisms in parafoveal vision when the rest of the sentence is normal, lowercase letters. |
Lynn Huestegge; Jos J. Adam Oculomotor interference during manual response preparation: Evidence from the response-cueing paradigm Journal Article In: Attention, Perception, & Psychophysics, vol. 73, no. 3, pp. 702–707, 2011. @article{Huestegge2011,Preparation provided by visual location cues is known to speed up behavior. However, the role of concurrent saccades in response to visual cues remains unclear. In this study, participants performed a spatial precueing task by pressing one of four response keys with one of four fingers (two of each hand) while eye movements were monitored. Prior to the stimulus, we presented a neutral cue (baseline), a hand cue (corresponding to left vs. right positions), or a finger cue (corresponding to inner vs. outer positions). Participants either remained fixated on a central fixation point or moved their eyes freely. The results demonstrated that saccades during the cueing interval altered the pattern of cueing effects. Finger cueing trials in which saccades were spatially incompatible (vs. compatible) with the subsequently required manual response exhibited slower manual RTs. We propose that interference between saccades and manual responses affects manual motor preparation. |
Debra Titone; Maya R. Libben; Julie Mercier; Veronica Whitford; Irina Pivneva Bilingual lexical access during L1 sentence reading: The effects of L2 knowledge, semantic constraint, and L1-L2 intermixing Journal Article In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 37, no. 6, pp. 1412–1431, 2011. @article{Titone2011,Libben and Titone (2009) recently observed that cognate facilitation and interlingual homograph interference were attenuated by increased semantic constraint during bilingual second language (L2) reading, using eye movement measures. We now investigate whether cross-language activation also occurs during first language (L1) reading as a function of age of L2 acquisition and task demands (i.e., inclusion of L2 sentences). In Experiment 1, participants read high and low constraint English (L1) sentences containing interlingual homographs, cognates, or control words. In Experiment 2, we included French (L2) filler sentences to increase salience of the L2 during L1 reading. The results suggest that bilinguals reading in their L1 show nonselective activation to the extent that they acquired their L2 early in life. Similar to our previous work on L2 reading, high contextual constraint attenuated cross-language activation for cognates. The inclusion of French filler items promoted greater cross-language activation, especially for late stage reading measures. Thus, L1 bilingual reading is modulated by L2 knowledge, semantic constraint, and task demands. |
Carsten N. Boehler; Jens-Max Hopf; Ruth M. Krebs; Christian M. Stoppel; Mircea A. Schoenfeld; Hans-Jochen Heinze; Toemme Noesselt Task-load-dependent activation of dopaminergic midbrain areas in the absence of reward Journal Article In: Journal of Neuroscience, vol. 31, no. 13, pp. 4955–4961, 2011. @article{Boehler2011,Dopamine release in cortical and subcortical structures plays a central role in reward-related neural processes. Within this context, dopaminergic inputs are commonly assumed to play an activating role, facilitating behavioral and cognitive operations necessary to obtain a prospective reward. Here, we provide evidence from human fMRI that this activating role can also be mediated by task-demand-related processes and thus extends beyond situations that only entail extrinsic motivating factors. Using a visual discrimination task in which varying levels of task demands were precued, we found enhanced hemodynamic activity in the substantia nigra (SN) for high task demands in the absence of reward or similar extrinsic motivating factors. This observation thus indicates that the SN can also be activated in an endogenous fashion. In parallel to its role in reward-related processes, reward-independent activation likely serves to recruit the processing resources needed to meet enhanced task demands. Simultaneously, activity in a wide network of cortical and subcortical control regions was enhanced in response to high task demands, whereas areas of the default-mode network were deactivated more strongly. The present observations suggest that the SN represents a core node within a broader neural network that adjusts the amount of available neural and behavioral resources to changing situational opportunities and task requirements, which is often driven by extrinsic factors but can also be controlled endogenously. |
Gustav Kuhn; Lauren Tewson; Lea Morpurgo; Susannah F. Freebody; Anna S. Musil; Susan R. Leekam Developmental changes in the control of saccadic eye movements in response to directional eye gaze and arrows Journal Article In: Quarterly Journal of Experimental Psychology, vol. 64, no. 10, pp. 1919–1929, 2011. @article{Kuhn2011a,We investigated developmental differences in oculomotor control between 10-year-old children and adults using a central interference task. In this task, the colour of a fixation point instructed participants to saccade either to the left or to the right. These saccade directions were either congruent or incongruent with two types of distractor cue: either the direction of eye gaze of a centrally presented schematic face, or the direction of arrows. Children had greater difficulties inhibiting the distractor cues than did adults, which revealed itself in longer saccade latencies for saccades that were incongruent with the distractor cues as well as more errors on these incongruent trials than on congruent trials. Counter to our prediction, in terms of saccade latencies, both children and adults had greater difficulties inhibiting the arrow than the eye gaze distractors. |
Joseph Schmidt; Gregory J. Zelinsky Visual search guidance is best after a short delay Journal Article In: Vision Research, vol. 51, no. 6, pp. 535–545, 2011. @article{sz11,Search displays are typically presented immediately after a target cue, but in the real-world, delays often exist between target designation and search. Experiments 1 and 2 asked how search guidance changes with delay. Targets were cued using a picture or text label, each for 3000ms, followed by a delay up to 9000ms before the search display. Search stimuli were realistic objects, and guidance was quantified using multiple eye movement measures. Text-based cues showed a non-significant trend towards greater guidance following any delay relative to a no-delay condition. However, guidance from a pictorial cue increased sharply 300-600ms after preview offset. Experiment 3 replicated this guidance enhancement using shorter preview durations while equating the time from cue onset to search onset, demonstrating that the guidance benefit is linked to preview offset rather than a more complete encoding of the target. Experiment 4 showed that enhanced guidance persists even with a mask flashed at preview offset, suggesting an explanation other than visual priming. We interpret our findings as evidence for the rapid consolidation of target information into a guiding representation, which attains its maximum effectiveness shortly after preview offset. |
Gustav Kuhn; Jason Tipples Increased gaze following for fearful faces. It depends on what you're looking for! Journal Article In: Psychonomic Bulletin & Review, vol. 18, no. 1, pp. 89–95, 2011. @article{Kuhn2011,An oculomotor visual search task was used to investigate how participants follow the gaze of a nonpredictive and task irrelevant distractor gaze, and the way in which this gaze following is influenced by the emotional expression (fearful vs. happy) as well as participants' goal. Previous research has suggested that fearful emotions should result in stronger cueing effects than happy faces. Our results demonstrated that the degree to which the emotional expression influenced this gaze following varied as a function of the search target. When searching for a threatening target, participants were more likely to look in the direction of eye gaze on a fearful compared to a happy face. However, when searching for a pleasant target, this stronger cueing effect for fearful faces disappeared. Therefore, gaze following is influenced by contextual factors such as the emotional expression, as well as the participant's goal. |
Seppo Vainio; Raymond Bertram; Anneli Pajunen; Jukka Hyönä Processing modifier-head agreement in long Finnish words: Evidence from eye movements Journal Article In: Acta Linguistica Hungarica, vol. 58, no. 1, pp. 134–156, 2011. @article{Vainio2011,The present study investigates whether processing of an inflected Finnish noun is facilitated when preceded by a modifier in the same case ending. In Finnish, modifiers agree with their head nouns both in case and in number and the agreement is expressed by means of suffixes (e.g., vanha/ssa talo/ssa 'old/in house/in' –> 'in the old house'). Vainio et al. (2003; 2008) showed processing benefits for this kind of modifier-head agreement, when the head nouns were relatively short. However, the effect showed up relatively late in the processing stream, such that word n + 1, the word following the target noun talo/ssa, was read faster when it was preceded by an agreeing modifier (vanha/ssa) than when no modifier was present. This led Vainio et al. to the conclusion that agreement exerts its effect at a later stage, namely at the level of syntactic integration and not at the level of lexical access. The current study investigates whether the same holds when head nouns are considerably longer (e.g., kaupungin/talo/ssa 'city house/in' –> 'in the city hall'). Our results show that the effect of agreement is facilitative in case of longer head nouns as well, but – in contrast to what was found for shorter words – the effect not only appeared late, but was also observed in earlier processing measures. It thus seems that, in processing long words, benefits related to modifier-head agreement are not confined to post-lexical syntactic integration processes, but extend to lexical identification of the head. Adapted from the source document |
Maria Staudte; Matthew W. Crocker Investigating joint attention mechanisms through spoken human-robot interaction Journal Article In: Cognition, vol. 120, no. 2, pp. 268–291, 2011. @article{Staudte2011,Referential gaze during situated language production and comprehension is tightly coupled with the unfolding speech stream (Griffin, 2001; Meyer, Sleiderink, & Levelt, 1998; Tanenhaus, Spivey-Knowlton, Eberhard, & Sedivy, 1995). In a shared environment, utterance comprehension may further be facilitated when the listener can exploit the speaker's focus of (visual) attention to anticipate, ground, and disambiguate spoken references. To investigate the dynamics of such gaze-following and its influence on utterance comprehension in a controlled manner, we use a human-robot interaction setting. Specifically, we hypothesize that referential gaze is interpreted as a cue to the speaker's referential intentions which facilitates or disrupts reference resolution. Moreover, the use of a dynamic and yet extremely controlled gaze cue enables us to shed light on the simultaneous and incremental integration of the unfolding speech and gaze movement.We report evidence from two eye-tracking experiments in which participants saw videos of a robot looking at and describing objects in a scene. The results reveal a quantified benefit-disruption spectrum of gaze on utterance comprehension and, further, show that gaze is used, even during the initial movement phase, to restrict the spatial domain of potential referents. These findings more broadly suggest that people treat artificial agents similar to human agents and, thus, validate such a setting for further explorations of joint attention mechanisms. |
Zheng Tai; Richard W. Hertle; Richard A. Bilonick; Dongsheng Yang A new algorithm for automated nystagmus acuity function analysis Journal Article In: British Journal of Ophthalmology, vol. 95, no. 6, pp. 832–836, 2011. @article{Tai2011,Aims: We developed a new data analysis algorithm called the automated nystagmus acuity function (ANAF) to automatically assess nystagmus acuity function. We compared results from the ANAF with those of the well-known expanded nystagmus acuity function (NAFX). Methods: Using the ANAF and NAFX, we analysed 60 segments of nystagmus data collected with a video-based eye tracking system (EyeLink 1000) from 30 patients with infantile or mal-development fusional nystagmus. The ANAF algorithm used the best-foveation positions (not true foveation positions) and all data points in each nystagmus cycle to calculate a nystagmus acuity function. Results: The ANAF automatically produced a nystagmus acuity function in a few seconds because manual identification of foveation eye positions is not required. A structural equation model was used to compare the ANAF and NAFX. Both ANAF and NAFX have similar measurement imprecision and relatively little bias. The estimated bias was not statistically significant for either methods or replicates. Conclusions: We conclude that the ANAF is a valid and efficient algorithm for determining a nystagmus acuity function. |
Bernhard Angele; Keith Rayner Parafoveal processing of word n + 2 during reading: Do the preceding words matter? Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 37, no. 4, pp. 1210–1220, 2011. @article{Angele2011,We used the boundary paradigm (Rayner, 1975) to test two hypotheses that might explain why no conclusive evidence has been found for the existence of n + 2 preprocessing effects. In Experiment 1, we tested whether parafoveal processing of the second word to the right of fixation (n + 2) takes place only when the preceding word (n + 1) is very short (Angele, Slattery, Yang, Kliegl, & Rayner, 2008); word n + 1 was always a three-letter word. Before crossing the boundary, preview for both words n + 1 and n + 2 was either incorrect or correct. In a third condition, only the preview for word n + 1 was incorrect. In Experiment 2, we tested whether word frequency of the preboundary word (n) had an influence on the presence of preview benefit and parafoveal-on-foveal effects. Additionally, Experiment 2 contained a condition in which only preview of n + 2 was incorrect. Our findings suggest that effects of parafoveal n + 2 preprocessing are not modulated by either n + 1 word length or n frequency. Furthermore, we did not observe any evidence of parafoveal lexical preprocessing of word n + 2 in either experiment. |
Jiyeon Lee; Cynthia K. Thompson Real-time production of unergative and unaccusative sentences in normal and agrammatic speakers: An eyetracking study Journal Article In: Aphasiology, vol. 25, no. 6-7, pp. 813–825, 2011. @article{Lee2011a,Background: Speakers with agrammatic aphasia have greater difficulty producing unaccusative (float) compared to unergative (bark) verbs (Kegl, 1995; Lee & Thompson, 2004; Thompson, 2003), putatively because the former involve movement of the theme to the subject position from the post-verbal position, and are therefore more complex than the latter (Burzio, 1986; Perlmutter, 1978). However, it is unclear if and how sentence production processes are affected by the linguistic distinction between these two types of verbs in normal and impaired speakers. Aims: This study examined real-time production of sentences with unergative (the black dog is barking) vs unaccusative (the black tube is floating) verbs in healthy young speakers and individuals with agrammatic aphasia, using eyetracking. Methods & Procedures: Participants' eye movements and speech were recorded while they produced a sentence using computer displayed written stimuli (e.g., black, dog, is barking). Outcomes & Results: Both groups of speakers produced numerically fewer unaccusative sentences than unergative sentences. However, the eye movement data revealed significant differences in fixations between the adjective (black) vs the noun (tube) when producing unaccusatives, but not when producing unergatives for both groups. Interestingly, whereas healthy speakers showed this difference during speech, speakers with agrammatism showed this difference prior to speech onset. Conclusions: These findings suggest that the human sentence production system differentially processes unaccusatives vs unergatives. This distinction is preserved in individuals with agrammatism; however, the time course of sentence planning appears to differ from healthy speakers (Lee & Thompson, 2010). |
Sven-Thomas Graupner; Sebastian Pannasch; Boris M. Velichkovsky In: International Journal of Psychophysiology, vol. 80, no. 1, pp. 54–62, 2011. @article{Graupner2011,Attention, visual information processing, and oculomotor control are integrated functions of closely related brain mechanisms. Recently, it was shown that the processing of visual distractors appearing during a fixation is modulated by the amplitude of its preceding saccade (Pannasch & Velichkovsky, 2009). So far, this was demonstrated only at the behavioral level in terms of saccadic inhibition. The present study investigated distractor-related brain activity with cortical eye fixation-related potentials (EFRPs). Moreover, the following saccade was included as an additional classification criterion. Eye movements and EFRPs were recorded during free visual exploration of paintings. During some of the fixations, a visual distractor was shown as an annulus around the fixation position, 100. ms after the fixation onset. The saccadic context of a fixation was classified by its preceding and following saccade amplitudes with the cut-off criterion set to 4° of visual angle. The prolongation of fixation duration induced by distractors was largest for fixations preceded and followed by short saccades. EFRP data revealed a difference in distractor-related P2 amplitude between the saccadic context conditions, following the same trend as in eye movements. Furthermore, influences of the following saccade amplitude on the latency of the saccadic inhibition and on the N1 amplitude were found. The EFRP results cannot be explained by the influence of saccades per se since this bias was removed by subtracting the baseline from the distractor EFRP. Rather, the data suggest that saccadic context indicates differences in how information is processed within single visual fixations. |
Stephanie Jainta The pupil reflects motor preparation for saccades – even before the eye starts to move Journal Article In: Frontiers in Human Neuroscience, vol. 5, pp. 97, 2011. @article{Jainta2011,The eye produces saccadic eye movements whose reaction times are perhaps the shortest in humans. Saccade latencies reflect ongoing cortical processing and, generally, shorter latencies are supposed to reflect advanced motor preparation. The dilation of the eye's pupil is reported to reflect cortical processing as well. Eight participants made saccades in a gap and overlap paradigm (in pure and mixed blocks), which we used in order to produce a variety of different saccade latencies. Saccades and pupil size were measured with the EyeLink II. The pattern in pupil dilation resembled that of a gap effect: for gap blocks, pupil dilations were larger compared to overlap blocks; mixing gap and overlap trials reduced the pupil dilation for gap trials thereby inducing a switching cost. Furthermore, saccade latencies across all tasks predicted the magnitude of pupil dilations post hoc: the longer the saccade latency the smaller the pupil dilation before the eye actually began to move. In accordance with observations for manual responses, we conclude that pupil dilations prior to saccade execution reflect advanced motor preparations and therefore provide valid indicator qualities for ongoing cortical processes. |
Stephanie Jainta; Anne Dehnert; Sven P. Heinrich; Wolfgang Jaschinski Binocular coordination during reading of blurred and nonblurred text Journal Article In: Investigative Ophthalmology & Visual Science, vol. 52, no. 13, pp. 9416–9424, 2011. @article{Jainta2011a,PURPOSE: Reading a text requires vergence angle adjustments, so that the images in the two eyes fall on corresponding retinal areas. Vergence adjustments bring the two retinal images into Panum's fusional area and therefore, small remaining errors or regulations do not lead to double vision. The present study evaluated dynamic and static aspects of the binocular coordination when upcoming text was blurred. METHODS: Binocular eye movements and accommodation responses were simultaneously measured for 20 participants while reading single, nonblurred sentences and while the text was blurred as if it were seen by a person in whom the combination of refraction and accommodation deviated from the stimulus plane by 0.5 D. RESULTS: Text comprehension did not change, even though fixation times increased for reading blurred sentences. The disconjugacy during saccades was also not affected by blurred text presentations, but the vergence adjustment during fixations was reduced. Further, for blurred text, the overall vergence angle shifted in the exo direction, and this shift correlated with the individual heterophoria. Accommodation measures showed that the lag of accommodation was slightly larger for reading blurred sentences and that the shift in vergence angle was larger when the individual lag of accommodation was also larger. CONCLUSIONS: The results suggest that reading comprehension is robust against changes in binocular coordination that result from moderate text degradation; nevertheless, these changes are likely to be linked to the development of fatigue and visual strain in near reading conditions. |
C. Witzel; Karl R. Gegenfurtner Is there a lateralized category effect for color? Journal Article In: Journal of Vision, vol. 11, no. 12, pp. 16–16, 2011. @article{Witzel2011,According to the lateralized category effect for color, the influence of color category borders on color perception in fast reaction time tasks is significantly stronger in the right visual field than in the left. This finding has directly related behavioral category effects to the hemispheric lateralization of language. Multiple succeeding articles have built on these findings. We ran ten different versions of the two original experiments with overall 230 naive observers. We carefully controlled the rendering of the stimulus colors and determined the genuine color categories with an appropriate naming method. Congruent with the classical pattern of a category effect, reaction times in the visual search task were lower when the two colors to be discriminated belonged to different color categories than when they belonged to the same category. However, these effects were not lateralized: They appeared to the same extent in both visual fields. |
Snigdha Banerjee; Adam C. Snyder; Sophie Molholm; John J. Foxe In: Journal of Neuroscience, vol. 31, no. 27, pp. 9923–9932, 2011. @article{Banerjee2011,Oscillatory alpha-band activity (8-15 Hz) over parieto-occipital cortex in humans plays an important role in suppression of processing for inputs at to-be-ignored regions of space, with increased alpha-band power observed over cortex contralateral to locations expected to contain distractors. It is unclear whether similar processes operate during deployment of spatial attention in other sensory modalities. Evidence from lesion patients suggests that parietal regions house supramodal representations of space. The parietal lobes are prominent generators of alpha oscillations, raising the possibility that alpha is a neural signature of supramodal spatial attention. Furthermore, when spatial attention is deployed within vision, processing of task-irrelevant auditory inputs at attended locations is also enhanced, pointing to automatic links between spatial deployments across senses. Here, we asked whether lateralized alpha-band activity is also evident in a purely auditory spatial-cueing task and whether it had the same underlying generator configuration as in a purely visuospatial task. If common to both sensory systems, this would provide strong support for "supramodal" attention theory. Alternately, alpha-band differences between auditory and visual tasks would support a sensory-specific account. Lateralized shifts in alpha-band activity were indeed observed during a purely auditory spatial task. Crucially, there were clear differences in scalp topographies of this alpha activity depending on the sensory system within which spatial attention was deployed. Findings suggest that parietally generated alpha-band mechanisms are central to attentional deployments across modalities but that they are invoked in a sensory-specific manner. The data support an "interactivity account," whereby a supramodal system interacts with sensory-specific control systems during deployment of spatial attention. |
Artem V. Belopolsky; Christel Devue; Jan Theeuwes Angry faces hold the eyes Journal Article In: Visual Cognition, vol. 19, no. 1, pp. 27–36, 2011. @article{Belopolsky2011a,Efficient processing of complex social and biological stimuli associated with threat is crucial for survival. Previous studies have suggested that threatening stimuli such as angry faces not only capture visual attention, but also delay the disengagement of attention from their location. However, in the previous studies disengagement of attention was measured indirectly and was inferred on the basis of delayed manual responses. The present study employed a novel paradigm that allows direct examination of the delayed disengagement hypothesis by measuring the time it takes to disengage the eyes from threatening stimuli. The results showed that participants were indeed slower to make an eye movement away from an angry face presented at fixation than from either a neutral or a happy face. This finding provides converging support that the delay in disengagement of attention is an important component of processing threatening information. |
Matthew C. Shake; Elizabeth A. L. Stine-Morrow Age differences in resolving anaphoric expressions during reading Journal Article In: Aging, Neuropsychology, and Cognition, vol. 18, no. 6, pp. 678–707, 2011. @article{shake2011age,One crucial component of reading comprehension is the ability to bind current information to earlier text, which is often accomplished via anaphoric expressions (e.g., pronouns referring to previous nouns). Processing time for anaphors that violate expectations (e.g., 'The firefighter burned herself while rescuing victims from the building') provide a window into how the semantic representation of the referent is instantiated and retained up to the anaphor. We present data from three eye-tracking experiments examining older and younger adults' reading patterns for passages containing such local expectancy violations. Younger adults quickly registered and resolved the expectancy violation at the point at which it first occurred (as measured by increased gaze duration on the anaphor), regardless of whether sentences were read in isolation or embedded in a discourse context. Older adults, however, immediately noticed the violation only when sentences were embedded in discourse context, suggesting that they relied more on situational grounding to instantiate the referent. For neither young nor old did prior disambiguation within the context (e.g., stating the firefighter was a woman) reduce the effect of the local violation on early processing. For older readers, however, prior disambiguation facilitated anaphor resolution by reducing reprocessing. These results suggest that (a) anaphor resolution unfolds serially, such that prior disambiguating context does not 'inoculate' against local activation of salient (but contextually inappropriate) features, and that (b) older readers use the situational grounding of discourse context to support earlier access to the antecedent, and are more likely to reprocess the context for anaphor resolution. |
Artem V. Belopolsky; Jan Theeuwes Selection within visual memory representations activates the oculomotor system Journal Article In: Neuropsychologia, vol. 49, no. 6, pp. 1605–1610, 2011. @article{Belopolsky2011,Humans tend to create and maintain internal representations of the environment that help guiding actions during the everyday activities. Previous studies have shown that the oculomotor system is involved in coding and maintenance of locations in visual-spatial working memory. In these studies selection of the relevant location for maintenance in working memory took place on the screen (selecting the location of a dot presented on the screen). The present study extended these findings by showing that the oculomotor system also codes selection of location from an internal memory representation. Participants first memorized two locations and after a retention interval selected one location for further maintenance. The results show that saccade trajectories deviated away from the ultimately remembered location. Furthermore, selection of the location from the memorized representation produced sustained oculomotor preparation to it. The results show that oculomotor system is very flexible and plays an active role for coding and maintaining information selected within internal memory representations. |
Lily Riggs; Douglas A. McQuiggan; Adam K. Anderson; Jennifer D. Ryan Evaluation of anti bacterial activity of fruit rind extract of Garcinia mangostana Linn on enteric pathogens-an in vitro study Journal Article In: Frontiers in Psychology, vol. 4, pp. 205, 2011. @article{rmar10,Research shows that memory for emotional aspects of an event may be enhanced at the cost of impaired memory for surrounding peripheral details. However, this has only been assessed directly via verbal reports which reveal the outcome of a long stream of processing but cannot shed light on how/when emotion may affect the retrieval process. In the present experiment, eye movement monitoring (EMM) was used as an indirect measure of memory as it can reveal aspects of online memory processing. For example, do emotions modulate the nature of memory representations or the speed with which such memories can be accessed? Participants viewed central negative and neutral scenes surrounded by three neutral objects and after a brief delay, memory was assessed indirectly via EMM and then directly via verbal reports. Consistent with the previous literature, emotion enhanced central and impaired peripheral memory as indexed by eye movement scanning and verbal reports. This suggests that eye movement scanning may contribute and/or is related to conscious access of memory. However, the central/peripheral tradeoff effect was not observed in an early measure of eye movement behavior, i.e., participants were faster to orient to a critical region of change in the periphery irrespective of whether it was previously studied in a negative or neutral context. These findings demonstrate emotion's differential influences on different aspects of retrieval. In particular, emotion appears to affect the detail within, and/or the evaluation of, stored memory representations, but it may not affect the initial access to those representations. |
Lynn Huestegge; Andrea M. Philipp Effects of spatial compatibility on integration processes in graph comprehension Journal Article In: Attention, Perception, & Psychophysics, vol. 73, no. 6, pp. 1903–1915, 2011. @article{Huestegge2011a,A precondition for efficiently understanding and memorizing graphs is the integration of all relevant graph elements and their meaning. In the present study, we analyzed integration processes by manipulating the spatial compatibility between elements in the data region and the legend. In Experiment 1, participants judged whether bar graphs depicting either statistical main effects or interactions correspond to previously presented statements. In Experiments 2 and 3, the same was tested with line graphs of varying complexity. In Experiment 4, participants memorized line graphs for a subsequent validation task. Throughout the experiments, eye movements were recorded. The results indicated that data-legend compatibility reduced the time needed to understand graphs, as well as the time needed to retrieve relevant graph information from memory. These advantages went hand in hand with a decrease of gaze transitions between the data region and the legend, indicating that data-legend compatibility decreases the difficulty of integration processes. |
Pierre Morel; Sophie Deneve; Pierre Baraduc Optimal and suboptimal use of postsaccadic vision in sequences of saccades Journal Article In: Journal of Neuroscience, vol. 31, no. 27, pp. 10039–10049, 2011. @article{Morel2011,Saccades are imprecise, due to sensory and motor noise. To avoid an accumulation of errors during sequences of saccades, a prediction derived from the efference copy can be combined with the reafferent visual feedback to adjust the following eye movement. By varying the information quantity of the visual feedback, we investigated how the reliability of the visual information affects the postsaccadic update in humans. Two elements of the visual scene were manipulated, the saccade target or the background, presented either together or in isolation. We determined the weight of the postsaccadic visual information by measuring the effect of intrasaccadic visual shifts on the following saccade. We confirmed that the weight of visual information evolves with information quantity as predicted for a statistically optimal system. In particular, we found that the visual background alone can guide the postsaccadic update, and that information from target and background are optimally combined. Moreover, these visual weights are adjusted dynamically and on a trial-to-trial basis to the level of visual noise determined by target eccentricity and reaction time. In contrast, we uncovered a dissociation between the visual signals used to update the next planned saccade (main saccade) and those used to generate an involuntary corrective saccade. The latter was exclusively based on visual information about the target, and discarded all information about the background: a suboptimal use of visual evidence. |
Lily Riggs; Douglas A. McQuiggan; Norman A. S. Farb; Adam K. Anderson; Jennifer D. Ryan The role of overt attention in emotion-modulated memory Journal Article In: Emotion, vol. 11, no. 4, pp. 776–785, 2011. @article{rmfar11,The presence of emotional stimuli results in a central/peripheral tradeoff effect in memory: memory for central details is enhanced at the cost of peripheral items. It has been assumed that emotion-modulated differences in memory are the result of differences in attention, but this has not been tested directly. The present experiment used eye movement monitoring as an index of overt attention allocation and mediation analysis to determine whether differences in attention were related to subsequent memory. Participants viewed negative and neutral scenes surrounded by three neutral objects and were then given a recognition memory test. The results revealed evidence in support of a central/peripheral tradeoff in both attention and memory. However, contrary with previous assumptions, whereas attention partially mediated emotion-enhanced memory for central pictures, it did not explain the entire relationship. Further, although centrally presented emotional stimuli led to decreased number of eye fixations toward the periphery, these differences in viewing did not contribute to emotion-impaired memory for specific details pertaining to the periphery. These findings suggest that the differential influence of negative emotion on central versus peripheral memory may result from other cognitive influences in addition to overt visual attention or on postencoding processes. |
Elke Smeets; Anita Jansen; Anne Roefs Bias for the (un)attractive self: On the role of attention in causing body (dis)satisfaction Journal Article In: Health Psychology, vol. 30, no. 3, pp. 360–367, 2011. @article{Smeets2011,Objective: Body dissatisfaction plays a key role in the maintenance of eating disorders, and selective attention might be crucial for the origin of body dissatisfaction. A. Jansen, C. Nederkoorn, and S. Mulkens (2005) showed that eating disorder patients attend relatively more to their own unattractive body parts, whereas healthy controls attend relatively more to their own attractive body parts. In 2 studies, we investigated whether this bias in selective attention is causal to body dissatisfaction and whether an experimentally induced bias for attractive body parts might lead to increased body satisfaction in women who are highly dissatisfied with their bodies. Design: We used a between-subjects design in which participants were trained to attend to either their self-defined unattractive body parts or their self-defined attractive body parts by use of an eye tracker. Main Outcome Measures: State body and weight satisfaction. Results: Inducing a temporary attentional bias for self-defined unattractive body parts led to a significant decrease in body satisfaction and teaching body-dissatisfied women to attend to their own attractive body parts led to a significant increase in body satisfaction. Conclusion: Selective attention for unattractive body parts can play a role in the development of body dissatisfaction, and changing the way one looks may be a new way for improving body dissatisfaction in women. |
Kohske Takahashi; Haruaki Fukuda; Hanako Ikeda; Hirokazu Doi; Katsumi Watanabe; Kazuhiro Ueda; Kazuyuki Shinohara Roles of the upper and lower bodies in direction discrimination of point-light walkers Journal Article In: Journal of Vision, vol. 11, no. 14, pp. 1–13, 2011. @article{Takahashi2011,We can easily recognize human movements from very limited visual information (biological motion perception). The present study investigated how upper and lower body areas contribute to direction discrimination of a point-light (PL) walker. Observers judged the direction that the PL walker was facing. The walker performed either normal walking or hakobi, a walking style used in traditional Japanese performing arts, in which the amount of the local motion of extremities is much smaller than that in normal walking. Either the upper, lower, or full body of the PL walker was presented. Discrimination performance was found to be better for the lower body than for the upper body. We also found that discrimination performance for the lower body was affected by walking style and/or the amount of local motion signals. Additional eye movement analyses indicated that the observers initially inspected the region corresponding to the upper body, and then the gaze shifted toward the lower body. This held true even when the upper body was absent. We conjectured that the upper body subserved to localize the PL walker and the lower body to discriminate walking direction. We concluded that the upper and lower bodies play different roles in direction discrimination of a PL walker. |
Jeremy Freeman; G. J. Brouwer; David J. Heeger; Elisha P. Merriam Orientation decoding depends on maps, not columns Journal Article In: Journal of Neuroscience, vol. 31, no. 13, pp. 4792–4804, 2011. @article{Freeman2011a,The representation of orientation in primary visual cortex (V1) has been examined at a fine spatial scale corresponding to the columnar architecture. We present functional magnetic resonance imaging (fMRI) measurements providing evidence for a topographic map of orientation preference in human V1 at a much coarser scale, in register with the angular-position component of the retinotopic map of V1. This coarse-scale orientation map provides a parsimonious explanation for why multivariate pattern analysis methods succeed in decoding stimulus orientation from fMRI measurements, challenging the widely held assumption that decoding results reflect sampling of spatial irregularities in the fine-scale columnar architecture. Decoding stimulus attributes and cognitive states from fMRI measurements has proven useful for a number of applications, but our results demonstrate that the interpretation cannot assume decoding reflects or exploits columnar organization. |
Sarah R. Heilbronner; Benjamin Y. Hayden; Michael L. Platt Decision salience signals in posterior cingulate cortex Journal Article In: Frontiers in Neuroscience, vol. 5, pp. 55, 2011. @article{Heilbronner2011,Despite its phylogenetic antiquity and clinical importance, the posterior cingulate cortex (CGp) remains an enigmatic nexus of attention, memory, motivation, and decision making. Here we show that CGp neurons track decision salience - the degree to which an option differs from a standard - but not the subjective value of a decision. To do this, we recorded the spiking activity of CGp neurons in monkeys choosing between options varying in reward-related risk, delay to reward, and social outcomes, each of which varied in level of decision salience. Firing rates were higher when monkeys chose the risky option, consistent with their risk-seeking preferences, but were also higher when monkeys chose the delayed and social options, contradicting their preferences. Thus, across decision contexts, neuronal activity was uncorrelated with how much monkeys valued a given option, as inferred from choice. Instead, neuronal activity signaled the deviation of the chosen option from the standard, independently of how it differed. The observed decision salience signals suggest a role for CGp in the flexible allocation of neural resources to motivationally significant information, akin to the role of attention in selective processing of sensory inputs. |
Margit Höfler; Iain D. Gilchrist; Christof Körner Inhibition of return functions within but not across searches Journal Article In: Attention, Perception, & Psychophysics, vol. 73, no. 5, pp. 1385–1397, 2011. @article{Hoefler2011,Inhibition of return (IOR) facilitates visual search by discouraging the reinspection of recently processed items. We investigated whether IOR operates across two consecutive searches of the same display for different targets. In Experiment 1, we demonstrated that IOR is present within each of the two searches. In Experiment 2, we found no evidence for IOR across searches. In Experiment 3, we showed that IOR is present across the two searches when the first search is interrupted, suggesting that the completion of the search is what causes the resetting of IOR. We concluded that IOR is a partially flexible process that can be reset when the task completes, but not necessarily when it changes. When resetting occurs, this flexibility ensures that the inhibition of previously visited locations does not interfere with the new search. |
Nicole Naue; Daniel Strüber; Ingo Fründ; Jeanette Schadow; Daniel Lenz; Stefan Rach; Ursula Körner; Christoph S. Herrmann Gamma in motion: Pattern reversal elicits stronger gamma-band responses than motion Journal Article In: NeuroImage, vol. 55, no. 2, pp. 808–817, 2011. @article{Naue2011,Previous studies showed higher gamma-band responses (GBRs, ≈ 40. Hz) of the electroencephalogram (EEG) for moving compared to stationary stimuli. However, it is unclear whether this modulation by motion reflects a special responsiveness of the GBR to the stimulus feature ''motion,'' or whether GBR enhancements of similar magnitude can be elicited also by a salient change within a static stimulus that does not include motion.Therefore, we measured the EEG of healthy subjects watching stationary square wave gratings of high contrast that either started to move or reversed their black and white pattern shortly after their onset. The strong contrast change of the pattern reversal represented a salient but motionless change within the grating that was compared to the onset of the stationary grating and the motion onset. Induced and evoked GBRs were analyzed for all three display conditions. In order to assess the influenceof fixational eye movements on the induced GBRs, we also examined the time courses of microsaccade rates during the three display conditions. Amplitudes of both evoked and induced GBRs were stronger for pattern reversal than for motion onset. There was no significant amplitude difference between the onsets of the stationary and moving gratings. However, mean frequencies of the induced GBR were ~10. Hz higher in response to the onsets of moving compared to stationary gratings. Furthermore, the modulations of the induced GBR did not parallel the modulations of microsaccade rate, indicating that our induced GBRs reflect neuronal processes. These results suggest that, within the gamma-band range, the encoding of moving gratings in early visual cortex is primarily based on an upward frequency shift, whereas contrast changes within static gratings are reflected by amplitude enhancement. |
Joost Felius; Valeria L. N. Fu; Eileen E. Birch; Richard W. Hertle; Reed M. Jost; Vidhya Subramanian Quantifying nystagmus in infants and young children: Relation between foveation and visual acuity deficit Journal Article In: Investigative Ophthalmology & Visual Science, vol. 52, no. 12, pp. 8724–8731, 2011. @article{Felius2011,PURPOSE. Nystagmus eye movement data from infants and young children are often not suitable for advanced quantitative analysis. A method was developed to capture useful informa- tion from noisy data and validate the technique by showing meaningful relationships with visual functioning. METHODS. Horizontal eye movements from patients (age 5 months–8 years) with idiopathic infantile nystagmus syndrome (INS) were used to develop a quantitative outcome measure that allowed for head and body movement during the record- ing. The validity of this outcome was assessed by evaluating its relation to visual acuity deficit in 130 subjects, its relation to actual fixation as assessed under simultaneous fundus imaging, its correlation with the established expanded nystagmus acuity function (NAFX), and its test–retest variability. RESULTS. The nystagmus optimal fixation function (NOFF) was defined as the logit transform of the fraction of data points meeting position and velocity criteria within a moving win- dow. A decreasing exponential relationship was found be- tween visual acuity deficit and the NOFF, yielding a 0.75 logMAR deficit for the poorest NOFF and diminishing deficits with improving foveation. As much as 96% of the points iden- tified as foveation events fell within 0.25° of the actual target. Good correlation (r ⫽ 0.96) was found between NOFF and NAFX. Test–retest variability was 0.49 logit units. CONCLUSIONS. The NOFF is a feasible method to quantify noisy nystagmus eye movement data. Its validation makes it a prom- ising outcome measure for the progression and treatment of nystagmus during early childhood. |
Jeremy Freeman; Eero P. Simoncelli Metamers of the ventral stream Journal Article In: Nature Neuroscience, vol. 14, no. 9, pp. 1195–1204, 2011. @article{Freeman2011,The human capacity to recognize complex visual patterns emerges in a sequence of brain areas known as the ventral stream, beginning with primary visual cortex (V1). We developed a population model for mid-ventral processing, in which nonlinear combinations of V1 responses are averaged in receptive fields that grow with eccentricity. To test the model, we generated novel forms of visual metamers, stimuli that differ physically but look the same. We developed a behavioral protocol that uses metameric stimuli to estimate the receptive field sizes in which the model features are represented. Because receptive field sizes change along the ventral stream, our behavioral results can identify the visual area corresponding to the representation. Measurements in human observers implicate visual area V2, providing a new functional account of neurons in this area. The model also explains deficits of peripheral vision known as crowding, and provides a quantitative framework for assessing the capabilities and limitations of everyday vision. |
Ali Mazaheri; Nicholas E. DiQuattro; Jesse Bengson; Joy J. Geng Pre-stimulus activity predicts the winner of top-down vs. bottom-up attentional selection Journal Article In: PLoS ONE, vol. 6, no. 2, pp. e16243, 2011. @article{Mazaheri2011,Our ability to process visual information is fundamentally limited. This leads to competition between sensory information that is relevant for top-down goals and sensory information that is perceptually salient, but task-irrelevant. The aim of the present study was to identify, from EEG recordings, pre-stimulus and pre-saccadic neural activity that could predict whether top-down or bottom-up processes would win the competition for attention on a trial-by-trial basis. We employed a visual search paradigm in which a lateralized low contrast target appeared alone, or with a low (i.e., non-salient) or high contrast (i.e., salient) distractor. Trials with a salient distractor were of primary interest due to the strong competition between top-down knowledge and bottom-up attentional capture. Our results demonstrated that 1) in the 1-sec pre-stimulus interval, frontal alpha (8-12 Hz) activity was higher on trials where the salient distractor captured attention and the first saccade (bottom-up win); and 2) there was a transient pre-saccadic increase in posterior-parietal alpha (7-8 Hz) activity on trials where the first saccade went to the target (top-down win). We propose that the high frontal alpha reflects a disengagement of attentional control whereas the transient posterior alpha time-locked to the saccade indicates sensory inhibition of the salient distractor and suppression of bottom-up oculomotor capture. |
Sofie Moresi; Jos J. Adam; Jons Rijcken; Harm Kuipers; Marianne Severens; Pascal W. M. Van Gerven Response preparation with adjacent versus overlapped hands: A pupillometric study Journal Article In: International Journal of Psychophysiology, vol. 79, no. 2, pp. 280–286, 2011. @article{Moresi2011,Preparatory cues facilitate performance in speeded choice tasks. It is debated, however, whether the lateralized neuro-anatomical organization of the human motor system contributes to this facilitation. To investigate this issue, we examined response preparation in a finger-cuing task using two conditions. In the hands adjacent condition, the hands were placed adjacently to each other with index and middle fingers placed on four linearly arrayed response keys. In the overlapped hand placement condition, the fingers of different hands alternated, thus dissociating hand and spatial position factors. Preparatory cues specified a subset of two fingers. Left-right cues specified the two leftmost or two rightmost fingers. Inner-outer cues specified the two inner or outer fingers. Alternate cues specified the first and third, or the second and fourth finger in the response set. In addition to reaction time and response errors, we measured the pupillary response to assess the cognitive processing load associated with response preparation. Results showed stronger pupil dilations (and also longer RTs and more errors) for the overlapped than for the adjacent hand placement condition, reflecting an overall increase in cognitive processing load. Furthermore, the negative impact of overlapping the hands on pupil dilation interacted with cue type, indicating that left-right cues (associated with two fingers on one hand) suffered most from overlapping the hands. With the hands overlapped, alternate cues (now associated with two fingers on the same hand) produced the shortest RTs. These findings demonstrate the importance of motoric factors in response preparation. |
Sebastian J. Crutch; Manja Lehmann; Nikos Gorgoraptis; Diego Kaski; Natalie Ryan; Masud Husain; Elizabeth K. Warrington Abnormal visual phenomena in posterior cortical atrophy Journal Article In: Neurocase, vol. 17, no. 2, pp. 160–177, 2011. @article{Crutch2011,Individuals with posterior cortical atrophy (PCA) report a host of unusual and poorly explained visual disturbances. This preliminary report describes a single patient (CRO), and documents and investigates abnormally prolonged colour afterimages (concurrent and prolonged perception of colours complimentary to the colour of an observed stimulus), perceived motion of static stimuli, and better reading of small than large letters. We also evaluate CRO's visual and vestibular functions in an effort to understand the origin of her experience of room tilt illusion, a disturbing phenomenon not previously observed in individuals with cortical degenerative disease. These visual symptoms are set in the context of a 4-year longitudinal neuropsychological and neuroimaging investigation of CRO's visual and other cognitive skills. We hypothesise that prolonged colour after-images are attributable to relative sparing of V1 inhibitory interneurons; perceived motion of static stimuli reflects weak magnocellular function; better reading of small than large letters indicates a reduced effective field of vision; and room tilt illusion effects are caused by disordered integration of visual and vestibular information. This study contributes to the growing characterisation of PCA whose atypical early visual symptoms are often heterogeneous and frequently under-recognised. |
Anil Kumar; Irene Gottlob; Rebecca J. Mclean; Shery Thomas; Mervyn G. Thomas; Frank A. Proudlock Clinical and oculomotor characteristics of albinism compared to FRMD7 associated infantile nystagmus Journal Article In: Investigative Ophthalmology & Visual Science, vol. 52, no. 5, pp. 2306–2313, 2011. @article{Kumar2011,PURPOSE. Previous studies have found no difference between nystagmus characteristics associated with idiopathic infantile nystagmus (IIN) and that associated with albinism. The present aim is to compare the oculomotor characteristics and other associated clinical features of albinism and a genetically homogenous group of IIN volunteers where the nystagmus is associated with FRMD7 mutations. METHODS. Oculomotor characteristics and related clinical features between albinism (n ⫽ 52) and idiopathic nystag- mus associated with FRMD7 mutations (FRMD7-IIN |
Diego E. Shalom; Bruno Dagnino; Mariano Sigman Looking at Breakout: Urgency and predictability direct eye events Journal Article In: Vision Research, vol. 51, no. 11, pp. 1262–1272, 2011. @article{sds11,We investigated the organization of eye-movement classes in a natural and dynamical setup. To mimic the goals and objectives of the natural world in a controlled environment, we studied eye-movements while participants played Breakout, an old Atari game which remains surprisingly entertaining, often addictive, in spite of its graphic and structural simplicity. Our results show that eye-movement dynamics can be explained in terms of simple principles of moments of prediction and urgency of action. We observed a consistent anticipatory behavior (gaze was directed ahead of ball trajectory) except during the moment in which the ball bounced either in the walls, or in the paddle. At these moments, we observed a refractory period during which there are no blinks and saccades. Saccade delay caused the gaze to fall behind the ball. This pattern is consistent with a model by which participants postpone saccades at the bounces while predicting the ball trajectory and subsequently make a catch-up saccade directed to a position which anticipates ball trajectory. During bounces, trajectories were smooth and curved interpolating the V-shape function of the ball with minimal acceleration. These results pave the path to understand the taxonomy of eye-movements on natural configurations in which stimuli and goals switch dynamically in time. |
Johanna K. Kaakinen; Jukka Hyönä; Minna Viljanen Influence of a psychological perspective on scene viewing and memory for scenes Journal Article In: Quarterly Journal of Experimental Psychology, vol. 64, no. 7, pp. 1372–1387, 2011. @article{Kaakinen2011,In the study, 33 participants viewed photographs from either a potential homebuyer's or a burglar's perspective, or in preparation for a memory test, while their eye movements were recorded. A free recall and a picture recognition task were performed after viewing. The results showed that perspective had rapid effects, in that the second fixation after the scene onset was more likely to land on perspective-relevant than on perspective-irrelevant areas within the scene. Perspective-relevant areas also attracted longer total fixation time, more visits, and longer first-pass dwell times than did perspective-irrelevant areas. As for the effects of visual saliency, the first fixation was more likely to land on a salient than on a nonsalient area; salient areas also attracted more visits and longer total fixation time than did nonsalient areas. Recall and recognition performance reflected the eye fixation results: Both were overall higher for perspective-relevant than for perspective-irrelevant scene objects. The relatively low error rates in the recognition task suggest that participants had gained an accurate memory for scene objects. The findings suggest that the role of bottom-up versus top-down factors varies as a function of viewing task and the time-course of scene processing. |
Stephan Koenig; Harald Lachnit Curved saccade trajectories reveal conflicting predictions in associative learning Journal Article In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 37, no. 5, pp. 1164–1177, 2011. @article{Koenig2011,We report how the trajectories of saccadic eye movements are affected by memory interference acquired during associative learning. Human participants learned to perform saccadic choice responses based on the presentation of arbitrary central cues A, B, AC, BC, AX, BY, X, and Y that were trained to predict the appearance of a peripheral target stimulus at 1 of 3 possible locations, right (R), mid (M), or left (L), in the upper hemifield. We analyzed as measures of associative learning the frequency, latency, and curvature of saccades elicited by the cues and directed at the trained locations in anticipation of the targets. Participants were trained on two concurrent discrimination problems A+R, AC+R, AX+M, X+M and B+L, BC+L, BY+M, Y+M. From a connectionist perspective, cues were predicted to acquire associative links connecting the cues to the trained outcomes in memory. Model simulations based on the learning rule of the Rescorla and Wagner (1972) model revealed that for some cues, the prediction of the correct target location was challenged by the interfering prediction of an incorrect location. We observed that saccades directed at the correct location in anticipation of the target curved away from the location that was predicted by the interfering association. Furthermore, changes in curvature during training corresponded to predicted changes in associative memory. We propose that this curvature was caused by the inhibition of the incorrect prediction, as previously has been suggested with the concept of distractor inhibition (Sheliga, Riggio, & Rizzolatti, 1994; Tipper, Howard, & Houghton, 2000). The paradigm provides a new method to examine memory interference during associative learning. |
Alexander Maier; Christopher J. Aura; David A. Leopold Infragranular sources of sustained local field potential responses in macaque primary visual cortex Journal Article In: Journal of Neuroscience, vol. 31, no. 6, pp. 1971–1980, 2011. @article{Maier2011,A local field potential (LFP) response can be measured throughout the visual cortex in response to the abrupt appearance of a visual stimulus. Averaging LFP responses to many stimulus presentations isolates transient, phase-locked components of the response that are consistent from trial to trial. However, stimulus responses are also composed of sustained components, which differ in their phase from trial to trial and therefore must be evaluated using other methods, such as computing the power of the response of each trial before averaging. Here, we investigate the basis of phase-locked and non-phase-locked LFP responses in the primary visual cortex of the macaque monkey using a novel variant of current source density (CSD) analysis. We applied a linear array of electrode contacts spanning the thickness of the cortex to measure the LFP and compute band-limited CSD power to identify the laminar sites of persistent current exchange that may be the basis of sustained visual LFP responses. In agreement with previous studies, we found a short-latency phase-locked current sink, thought to correspond to thalamocortical input to layer 4C. In addition, we found a prominent non-phase-locked component of the CSD that persisted as long as the stimulus was physically present. The latter was relatively broadband, lasted throughout the stimulus presentation, and was centered ∼500 μm deeper than the initial current sink. These findings demonstrate a fundamental difference in the neural mechanisms underlying the initial and sustained processing of simple visual stimuli in the V1 microcircuit. |
Michael Zehetleitner; Michael Hegenloh; Hermann J. Muller Visually guided pointing movements are driven by the salience map Journal Article In: Journal of Vision, vol. 11, no. 1, pp. 24–24, 2011. @article{Zehetleitner2011,Visual salience maps are assumed to mediate target selection decisions in a motor-unspecific manner; accordingly, modulations of salience influence yes/no target detection or left/right localization responses in manual key-press search tasks, as well as ocular or skeletal movements to the target. Although widely accepted, this core assumption is based on little psychophysical evidence. At least four modulations of salience are known to influence the speed of visual search for feature singletons: (i) feature contrast, (ii) cross-trial dimension sequence and (iii) semantic pre-cueing of the target dimension, and (iv) dimensional target redundancy. If salience guides also manual pointing movements, their initiation latencies (and durations) should be affected by the same four manipulations of salience. Four experiments, each examining one of these manipulations, revealed this to be the case. Thus, these effects are seen independently of the motor response required to signal the perceptual decision (e.g., directed manual pointing as well as simple yes/no detection responses). This supports the notion of a motor-unspecific salience map, which guides covert attention as well as overt eye and hand movements. |
Isabel Dombrowe; Mieke Donk; Christian N. L. Olivers The costs of switching attentional sets Journal Article In: Attention, Perception, & Psychophysics, vol. 73, no. 8, pp. 2481–2488, 2011. @article{Dombrowe2011,People prioritize those aspects of the visual environment that match their attentional set. In the present study, we investigated whether switching from one attentional set to another is associated with a cost. We asked observers to sequentially saccade toward two color-defined targets, one on the left side of the display, the other on the right, each among a set of heterogeneously colored distractors. The targets were of the same color (no attentional set switch required) or of different colors (switch of attentional sets necessary), with each color consistently tied to a side, to allow observers to maximally prepare for the switch. We found that saccades were less accurate and slower in the switch condition than in the no-switch condition. Furthermore, whenever one of the distractors had the color associated with the other attentional set, a substantial proportion of saccades did not end on the target, but on this distractor. A time course analysis revealed that this distractor preference turned into a target preference after about 250-300 ms, suggesting that this is the time required to switch attentional sets. |
Boaz M. Ben-David; Craig G. Chambers; Meredyth Daneman; M. Kathleen Pichora-Fuller; Eyal M. Reingold; Bruce A. Schneider Effects of aging and noise on real-time spoken word recognition: Evidence from eye movements Journal Article In: Journal of Speech, Language, and Hearing Research, vol. 54, pp. 243–262, 2011. @article{BenDavid2011,PURPOSE: To use eye tracking to investigate age differences in real-time lexical processing in quiet and in noise in light of the fact that older adults find it more difficult than younger adults to understand conversations in noisy situations. METHOD: Twenty-four younger and 24 older adults followed spoken instructions referring to depicted objects, for example, "Look at the candle." Eye movements captured listeners' ability to differentiate the target noun (candle) from a similar-sounding phonological competitor (e.g., candy or sandal). Manipulations included the presence/absence of noise, the type of phonological overlap in target-competitor pairs, and the number of syllables. RESULTS: Having controlled for age-related differences in word recognition accuracy (by tailoring noise levels), similar online processing profiles were found for younger and older adults when targets were discriminated from competitors that shared onset sounds. Age-related differences were found when target words were differentiated from rhyming competitors and were more extensive in noise. CONCLUSIONS: Real-time spoken word recognition processes appear similar for younger and older adults in most conditions; however, age-related differences may be found in the discrimination of rhyming words (especially in noise), even when there are no age differences in word recognition accuracy. These results highlight the utility of eye movement methodologies for studying speech processing across the life span. |
Stephen J. Heinen; Z. Jin; Scott N. J. Watamaniuk Flexibility of foveal attention during ocular pursuit Journal Article In: Journal of Vision, vol. 11, no. 2, pp. 1–12, 2011. @article{Heinen2011,Smooth pursuit of natural objects requires flexible allocation of attention to inspect features. However, it has been reported that attention is focused at the fovea during pursuit. We ask here if foveal attention is obligatory during pursuit, or if it can be disengaged. Observers tracked a stimulus composed of a central dot surrounded by four others and identified one of the dots when it dimmed. Extinguishing the center dot before the dimming improved task performance, suggesting that attention was released from it. To determine if the center dot automatically usurped attention, we provided the pursuit system with an alternative sensory signal by adding peripheral motion that moved with the stimulus. This also improved identification performance, evidence that a central target does not necessarily require attention during pursuit. Identification performance at the central dot also improved, suggesting that the spatial extent of the background did not attract attention to the periphery; instead, peripheral motion freed pursuit attention from the central dot, affording better identification performance. The results show that attention can be flexibly allocated during pursuit and imply that attention resources for pursuit of small and large objects come from different sources. |
Jie Cui; Jorge Otero-Millan; Stephen L. Macknik; Mac King; Susana Martinez-Conde Social misdirection fails to enhance a magic illusion Journal Article In: Frontiers in Human Neuroscience, vol. 5, pp. 103, 2011. @article{Cui2011,Visual, multisensory and cognitive illusions in magic performances provide new windows into the psychological and neural principles of perception, attention, and cognition. We investigated a magic effect consisting of a coin “vanish” (i.e., the perceptual disappear- ance of a coin after a simulated toss from hand to hand). Previous research has shown that magicians can use joint attention cues such as their own gaze direction to strengthen the observers' perception of magic. Herewe presented naïve observers with videos including real and simulated coin tosses to determine if joint attention might enhance the illusory perception of simulated coin tosses. The observers' eye positions were measured, and their perceptual responses simultaneously recorded via button press. To control for the magician's use of joint attention cues, we occluded his head in half of the trials.We found that subjects did not direct their gaze at the magician's face at the time of the coin toss, whether the face was visible or occluded, and that the presence of the magician's face did not enhance the illusion. Thus, our results show that joint attention is not necessary for the perception of this effect.We conclude that social misdirection is redundant and possibly detracting to this very robust sleight-of-hand illusion.We further determined that subjects required multiple trials to effectively distinguish real from simulated tosses; thus the illusion was resilient to repeated viewing. |
Falk Huettig; Gerry T. M. Altmann In: Quarterly Journal of Experimental Psychology, vol. 64, no. 1, pp. 122–145, 2011. @article{Huettig2011,Three eye-tracking experiments investigated the influence of stored colour knowledge, perceived surface colour, and conceptual category of visual objects on language-mediated overt attention. Participants heard spoken target words whose concepts are associated with a diagnostic colour (e.g., "spinach"; spinach is typically green) while their eye movements were monitored to (a) objects associated with a diagnostic colour but presented in black and white (e.g., a black-and-white line drawing of a frog), (b) objects associated with a diagnostic colour but presented in an appropriate but atypical colour (e.g., a colour photograph of a yellow frog), and (c) objects not associated with a diagnostic colour but presented in the diagnostic colour of the target concept (e.g., a green blouse; blouses are not typically green). We observed that colour-mediated shifts in overt attention are primarily due to the perceived surface attributes of the visual objects rather than stored knowledge about the typical colour of the object. In addition our data reveal that conceptual category information is the primary determinant of overt attention if both conceptual category and surface colour competitors are copresent in the visual environment. |
Femke Maij; Eli Brenner; Jeroen B. J. Smeets Peri-saccadic mislocalization is not influenced by the predictability of the saccade target location Journal Article In: Vision Research, vol. 51, no. 1, pp. 154–159, 2011. @article{Maij2011,Flashes presented around the time of a saccade are often mislocalized. The precise pattern of mislocalization is influenced by many factors. Here we study one such factor: the predictability of the saccade target's location. The experiment examines two conditions. In the first the subject makes the same horizontal rightward saccade to the same target location over and over again. In the second the subject makes saccades to a target that is jumping in unpredictable radial directions. A dot is flashed in the vicinity of the saccade target near the time of saccade onset. Subjects are asked to localize the flash by touching its location on the screen. Although various saccade parameters differed, the errors that subjects made were very similar in both conditions. We conclude that the pattern of mislocalization does not depend on the predictability of the location of the saccade target. |
Ava Elahipanah; Bruce K. Christensen; Eyal M. Reingold What can eye movements tell us about Symbol Digit substitution by patients with schizophrenia? Journal Article In: Schizophrenia Research, vol. 127, no. 1-3, pp. 137–143, 2011. @article{Elahipanah2011,Substitution tests are sensitive to cognitive impairment and reliably discriminate patients with schizophrenia from healthy individuals better than most other neuropsychological instruments. However, due to their multifaceted nature, substitution test scores cannot pinpoint the specific cognitive deficits that lead to poor performance. The current study investigated eye movements during performance on a substitution test in order to better understand what aspect of substitution test performance underlies schizophrenia-related impairment. Twenty-five patients with schizophrenia and 25 healthy individuals performed a computerized version of the Symbol Digit Modalities Test while their eye movements were monitored. As expected, patients achieved lower overall performance scores. Moreover, analysis of participants' eye movements revealed that patients spent more time searching for the target symbol every time they visited the key area. Patients also made more visits to the key area for each response that they made. Regression analysis suggested that patients' impaired performance on substitution tasks is primarily related to a less efficient visual search and, secondarily, to impaired memory. |
Femke Maij; Eli Brenner; Jeroen B. J. Smeets Temporal uncertainty separates flashes from their background during saccades Journal Article In: Journal of Neuroscience, vol. 31, no. 10, pp. 3708–3711, 2011. @article{Maij2011a,It is known that spatial localization of flashed objects fails around the time of rapid eye movements (saccades). This mislocalization is often interpreted in terms of a combination of shifts and deformations of the brain's representation of space to account for the eye movement. Such temporary remapping of positions in space should affect all elements in a scene, leaving ordinal relationships between positions intact. We performed an experiment in which we presented flashes on a background with red and green regions to human subjects. We found that flashes that were presented on the green part of the background around the time of a saccade were readily reported to have been presented on the red part of the background and vice versa. This is inconsistent with the notion of a temporary shift and deformation of perceived space. To explain our results, we present a model that illustrates how temporal uncertainty could give rise to the observed spatial mislocalization. The model combines uncertainty about the time of the flash with a bias to localize targets where one is looking. It reproduced the pattern of mislocalization very accurately, showing that perisaccadic mislocalization can best be explained in terms of temporal uncertainty about the moment of the flash. |
Kathryn L. McCabe; Dominique Rich; Carmel M. Loughland; Ulrich Schall; Linda E. Campbell Visual scanpath abnormalities in 22q11.2 deletion syndrome: Is this a face specific deficit? Journal Article In: Psychiatry Research, vol. 189, no. 2, pp. 292–298, 2011. @article{McCabe2011,People with 22q11.2 deletion syndrome (22q11DS) have deficits in face emotion recognition. However, it is not known whether this is a deficit specific to faces, or represents maladaptive information processing strategies to complex stimuli in general. This study examined the specificity of face emotion processing deficits in 22q11DS by exploring recognition accuracy and visual scanpath performance to a Faces task compared to a Weather Scene task. Seventeen adolescents with 22q11DS (11. =females |
Swetha Shankar; Dino P. Massoglia; Dantong Zhu; M. Gabriela Costello; Terrence R. Stanford; Emilio Salinas Tracking the temporal evolution of a perceptual judgment using a compelled-response task Journal Article In: Journal of Neuroscience, vol. 31, no. 23, pp. 8406–8421, 2011. @article{shankar2011tracking,Choice behavior and its neural correlates have been intensely studied with tasks in which a subject makes a perceptual judgment and indicates the result with a motor action. Yet a question crucial for relating behavior to neural activity remains unresolved: what fraction of a subject's reaction time (RT) is devoted to the perceptual evaluation step, as opposed to executing the motor report? Making such timing measurements accurately is complicated because RTs reflect both sensory and motor processing, and because speed and accuracy may be traded. To overcome these problems, we designed the compelled-saccade task, a two-alternative forced-choice task in which the instruction to initiate a saccade precedes the appearance of the relevant sensory information. With this paradigm, it is possible to track perceptual performance as a function of the amount of time during which sensory information is available to influence a subject's choice. The result-the tachometric curve-directly reveals a subject's perceptual processing capacity independently of motor demands. Psychophysical data, together with modeling and computer-simulation results, reveal that task performance depends on three separable components: the timing of the motor responses, the speed of the perceptual evaluation, and additional cognitive factors. Each can vary quickly, from one trial to the next, or can show stable, longer-term changes. This novel dissociation between sensory and motor processes yields a precise metric of how perceptual capacity varies under various experimental conditions and serves to interpret choice-related neuronal activity as perceptual, motor, or both. |
Ava Elahipanah; Bruce K. Christensen; Eyal M. Reingold Attentional guidance during visual search among patients with schizophrenia Journal Article In: Schizophrenia Research, vol. 131, no. 1-3, pp. 224–230, 2011. @article{Elahipanah2011a,The current study investigated visual guidance and saccadic selectivity during visual search among patients with schizophrenia (SCZ). Data from a previous study (Elahipanah, A., Christensen, B.K., & Reingold, E.M., 2008. Visual selective attention among persons with schizophrenia: The distractor ratio effect. Schizophr. Res. 105, 61-67.) suggested that visual guidance for the less frequent distractors in a conjunction search display (i.e., the distractor ratio effect) is intact among SCZ patients. The current study investigated the distractor ratio effect among SCZ patients when: 1) search is more demanding, and 2) search involves motion perception. In addition, eye tracking was employed to directly study saccadic selectivity for the different types of distractors. Twenty-eight SCZ patients receiving a single antipsychotic medication and 26 healthy control participants performed two conjunction search tasks: a within-dimension (i.e., colour × colour) search task; and a cross-dimension (i.e., motion × colour) search task. In each task the relative frequency of distractors was manipulated across 5 levels. Despite slower search times, patients' eye movement data indicated unimpaired visual guidance in both tasks. However, in the motion × colour conjunction search task, patients displayed disproportionate difficulty detecting the moving target when the majority of distractors were also moving. Results demonstrate that bottom-up attentional guidance is unimpaired among patients with SCZ; however, patients' impairment in motion discrimination impedes their ability to detect a moving target against noisy backgrounds. |
Jens K. Apel; Gavin F. Revie; Angelo Cangelosi; Rob Ellis; Jeremy Goslin; Martin H. Fischer Attention deployment during memorizing and executing complex instructions Journal Article In: Experimental Brain Research, vol. 214, no. 2, pp. 249–259, 2011. @article{Apel2011,We investigated the mental rehearsal of complex action instructions by recording spontaneous eye movements of healthy adults as they looked at objects on a monitor. Participants heard consecutive instructions, each of the form "move [object] to [location]". Instructions were only to be executed after a go signal, by manipulating all objects successively with a mouse. Participants re-inspected previously mentioned objects already while listening to further instructions. This rehearsal behavior broke down after 4 instructions, coincident with participants' instruction span, as determined from subsequent execution accuracy. These results suggest that spontaneous eye movements while listening to instructions predict their successful execution. |
Minglei Chen; Hwawei Ko Exploring the eye-movement patterns as Chinese children read texts: A developmental perspective Journal Article In: Journal of Research in Reading, vol. 34, no. 2, pp. 232–246, 2011. @article{Chen2011,This study was to investigate Chinese children's eye patterns while reading different text genres from a developmental perspective. Eye movements were recorded while children in the second through sixth grades read two expository texts and two narrative texts. Across passages, overall word frequency was not significantly different between the two genres. Results showed that all children had longer fixation durations for low-frequency words. They also had longer fixation durations on content words. These results indicate that children adopted a word-based processing strategy like skilled readers do. However, only older children's rereading times were affected by genre. Overall, eye-movement patterns of older children reported in this study are in accordance with those of skilled Chinese readers, but younger children are more likely to be responsive to word characteristics than text level when reading a Chinese text. |
Genevieve Z. Steiner; Robert J. Barry Pupillary responses and event-related potentials as indices of the orienting reflex Journal Article In: Psychophysiology, vol. 48, no. 12, pp. 1648–1655, 2011. @article{Steiner2011,This study examined skin conductance responses, the late positive complex of the event-related potential, and pupillary dilation responses as autonomic and central correlates of the orienting reflex (OR) in the context of indifferent and significant stimuli. In particular, we aimed to clarify the inconsistencies surrounding the pupillary dilation response as an OR index. An auditory dishabituation paradigm was employed, and physiological measures were recorded from 24 participants. Response decrement to a repeated stimulus, response recovery to a change stimulus, and subsequent dishabituation were assessed. Findings confirmed expectations that the skin conductance response and the late positive complex are indices of the OR. The pupillary dilation response, however, demonstrated an unexpected sensitivity to stimulus novelty only, while the prestimulus measure of tonic pupil diameter showed the significance effect that was expected of the phasic measure. Together, these findings argue against the suggestion that the pupillary dilation response is an OR index. The diverse results obtained from this experiment contribute to our understanding of the OR, and provide impetus for further research with a variety of paradigm manipulations. |
Patrick A. Bolger; Gabriela Zapata Semantic categories and context in L2 vocabulary learning Journal Article In: Language Learning, vol. 61, no. 2, pp. 614–646, 2011. @article{Bolger2011,This article extends recent findings that presenting semantically related vocabulary simultaneously inhibits learning. It does so by adding story contexts. Participants learned 32 new labels for known concepts from four different semantic categories in stories that were either semantically related (one category per story) or semantically unrelated (four categories per story). They then completed a semantic-categorization task, followed by a stimulus-match verification task in an eye-tracker. Results suggest that there may be a slight learning advantage in the semantically unrelated condition. However, our findings are better interpreted in terms of how learning occurred and how vocabulary was processed afterward. Additionally, our results suggest that contextual support from the stories may have surmounted much of the disadvantage attributed to semantic relatedness. |
Ava Elahipanah; Bruce K. Christensen; Eyal M. Reingold Controlling the spotlight of attention: Visual span size and flexibility in schizophrenia Journal Article In: Neuropsychologia, vol. 49, no. 12, pp. 3370–3376, 2011. @article{Elahipanah2011b,The current study investigated the size and flexible control of visual span among patients with schizophrenia during visual search performance. Visual span is the region of the visual field from which one extracts information during a single eye fixation, and a larger visual span size is linked to more efficient search performance. Therefore, a reduced visual span may explain patients' impaired performance on search tasks. The gaze-contingent moving window paradigm was used to estimate the visual span size of patients and healthy participants while they performed two different search tasks. In addition, changes in visual span size were measured as a function of two manipulations of task difficulty: target-distractor similarity and stimulus familiarity. Patients with schizophrenia searched more slowly across both tasks and conditions. Patients also demonstrated smaller visual span sizes on the easier search condition in each task. Moreover, healthy controls' visual span size increased as target discriminability or distractor familiarity increased. This modulation of visual span size, however, was reduced or not observed among patients. The implications of the present findings, with regard to previously reported visual search deficits, and other functional and structural abnormalities associated with schizophrenia, are discussed. |
Keith S. Apfelbaum; Sheila E. Blumstein; Bob Mcmurray Semantic priming is affected by real-time phonological competition: Evidence for continuous cascading systems Journal Article In: Psychonomic Bulletin & Review, vol. 18, no. 1, pp. 141–149, 2011. @article{Apfelbaum2011,Lexical-semantic access is affected by the phonological structure of the lexicon. What is less clear is whether such effects are the result of continuous activation between lexical form and semantic processing or whether they arise from a more modular system in which the timing of accessing lexical form determines the timing of semantic activation. This study examined this issue using the visual world paradigm by investigating the time course of semantic priming as a function of the number of phonological competitors. Critical trials consisted of high or low density auditory targets (e.g., horse) and a visual display containing a target, a semantically related object (e.g., saddle), and two phonologically and semantically unrelated objects (e.g., chimney, bikini). Results showed greater magnitude of priming for semantically related objects of low than of high density words, and no differences for high and low density word targets in the time course of looks to the word semantically related to the target. This pattern of results is consistent with models of cascading activation, which predict that lexical activation has continuous effects on the level of semantic activation, with no delays in the onset of semantic activation for phonologically competing words. |
B. -E. Verhoef; Rufin Vogels; Peter Janssen Synchronization between the end stages of the dorsal and the ventral visual stream Journal Article In: Journal of Neurophysiology, vol. 105, no. 5, pp. 2030–2042, 2011. @article{Verhoef2011,The end stage areas of the ventral (IT) and the dorsal (AIP) visual streams encode the shape of disparity-defined three-dimensional (3D) surfaces. Recent anatomical tracer studies have found direct reciprocal connections between the 3D-shape selective areas in IT and AIP. Whether these anatomical connections are used to facilitate 3D-shape perception is still unknown. We simultaneously recorded multi-unit activity (MUA) and local field potentials in IT and AIP while monkeys discriminated between concave and convex 3D shapes and measured the degree to which the activity in IT and AIP synchronized during the task. We observed strong beta-band synchronization between IT and AIP preceding stimulus onset that decreased shortly after stimulus onset and became modulated by stereo-signal strength and stimulus contrast during the later portion of the stimulus period. The beta-coherence modulation was unrelated to task-difficulty, regionally specific, and dependent on the MUA selectivity of the pairs of sites under study. The beta-spike-field coherence in AIP predicted the upcoming choice of the monkey. Several convergent lines of evidence suggested AIP as the primary source of the AIP-IT synchronized activity. The synchronized beta activity seemed to occur during perceptual anticipation and when the system has stabilized to a particular perceptual state but not during active visual processing. Our findings demonstrate for the first time that synchronized activity exists between the end stages of the dorsal and ventral stream during 3D-shape discrimination. |
Mieke Donk; Wieske Zoest No control in orientation search: The effects of instruction on oculomotor selection in visual search Journal Article In: Vision Research, vol. 51, no. 19, pp. 2156–2166, 2011. @article{Donk2011,The present study aimed to investigate whether people can selectively use salience information in search for a target. Observers were presented with a display consisting of multiple homogeneously oriented background lines and two orientation singletons. The orientation singletons differed in salience, where salience was defined by their orientation contrast relative to the background lines. Observers had the task to make a speeded eye movement towards a target, which was either the most or the least salient element of the two orientation singletons. The specific orientation of the target was either constant or variable over a block of trials such that observers had varying knowledge concerning the target identity. The results demonstrated that instruction - whether people were instructed to move to the most or the least salient item - only minimally affected the results. Short-latency eye movements were completely salience driven; here it did not matter whether people were searching for the most or least salient element. Long-latency eye movements were marginally affected by instruction, in particular when observers knew the target identity. These results suggest that even though people use salience information in oculomotor selection, they cannot use this information in a goal-driven manner. The results are discussed in terms of current models on visual selection. |
Nicholas D. Smith; David P. Crabb; David F. Garway-Heath An exploratory study of visual search performance in glaucoma Journal Article In: Ophthalmic and Physiological Optics, vol. 31, no. 3, pp. 225–232, 2011. @article{Smith2011,PURPOSE: Visual search plays an integral role in many daily activities. This study aimed to determine whether patients with glaucoma are slower than visually healthy age-matched individuals when searching for items in computer displayed images. METHODS: Forty participants were recruited for the study: 20 patients with a clinical diagnosis of glaucoma and 20 age-similar visually healthy control subjects. All participants had visual acuity of 6/12 or better. Participants were presented with 20 images with Landolt C symbols and 15 photographic images of everyday scenes on a computer. The time taken by each participant to locate a specified item in each image was recorded. Average search times were calculated across participants and compared between groups. RESULTS: All the patients had visual field defects in both eyes. On average, the patients also differed from control subjects by binocular contrast sensitivity measurements (p = 0.01) and visual acuity (p = 0.003). The patients (mean age = 67 years, S.D.: 10 years) and controls (mean age: 67 years, S.D.: 11 years) were age similar (p = 0.40). The median search time for patients finding target items in photographs of everyday scenes was 15.2 s (interquartile range 9.4-20.6 s) and this was significantly slower than the median time (10.0 s; interquartile range 7.2-10.3 s) taken by the controls (p = 0.007). There was no statistical evidence for a difference in median search times between groups in the Landolt C search task (p = 0.24). CONCLUSION: Some individuals with glaucomatous visual field defects in both eyes find it especially difficult to locate objects in photographs of everyday scenes when compared to visually healthy individuals of a similar age. |
Eva Van Assche; Denis Drieghe; Wouter Duyck; Marijke Welvaert; Robert J. Hartsuiker The influence of semantic constraints on bilingual word recognition during sentence reading Journal Article In: Journal of Memory and Language, vol. 64, no. 1, pp. 88–107, 2011. @article{VanAssche2011,The present study investigates how semantic constraint of a sentence context modulates language-non-selective activation in bilingual visual word recognition. We recorded Dutch-English bilinguals' eye movements while they read cognates and controls in low and high semantically constraining sentences in their second language. Early and late eye-movement measures yielded cognate facilitation, both for low- and high-constraint sentences. Facilitation increased gradually as a function of cross-lingual overlap between translation equivalents. A control experiment showed that the same stimuli did not yield cognate effects in English monolingual controls, ensuring that these effects were not due to any uncontrolled stimulus characteristics. The present study supports models of bilingual word recognition with a limited role for top-down influences of semantic constraints on lexical access in both early and later stages of bilingual word recognition. |
Jennifer J. Heisz; Jennifer D. Ryan The effects of prior exposure on face processing in younger and older adults Journal Article In: Frontiers in Aging Neuroscience, vol. 3, pp. 15, 2011. @article{Heisz2011,Older adults differ from their younger counterparts in the way they view faces. We assessed whether older adults can use past experience to mitigate these typical face-processing differences; that is, we examined whether there are age-related differences in the use of memory to support current processing. Eye movements of older and younger adults were monitored as they viewed faces that varied in the type/amount of prior exposure. Prior exposure was manipulated by including famous and novel faces, and by presenting faces up to five times. We expected that older adults may have difficulty quickly establishing new representations to aid in the processing of recently presented faces, but would be able to invoke face representations that have been stored in memory long ago to aid in the processing of famous faces. Indeed, younger adults displayed effects of recent exposure with a decrease in the total fixations to the faces and a gradual increase in the proportion of fixations to the eyes. These effects of recent exposure were largely absent in older adults. In contrast, the effect of fame, revealed by a subtle increase in fixations to the inner features of famous compared to non-famous faces, was similar for younger and older adults. Our results suggest that older adults' current processing can benefit from lifetime experience, however the full benefit of recent experience on face processing is not realized in older adults. |
Sebastian Pannasch; Johannes Schulz; Boris M. Velichkovsky On the control of visual fixation durations in free viewing of complex images Journal Article In: Attention, Perception, & Psychophysics, vol. 73, no. 4, pp. 1120–1132, 2011. @article{Pannasch2011,The mechanisms for the substantial variation in the durations of visual fixations in scene perception are not yet well understood. During free viewing of paintings, gaze-contingent irrelevant distractors (Exp. 1) and non-gaze-related time-locked display changes (Exp. 2) were presented. We demonstrated that any visual change-its onset and offset-prolongs the ongoing fixation (i.e., delays the following saccade), strongly suggesting that fixation durations are under the direct control of the stimulus information. The strongest influence of distraction was observed for fixations preceded by saccades within the parafoveal range (<5° of visual angle). We assume that these fixations contribute to the focal in contrast to the ambient mode of attention (Pannasch & Velichkovsky, Visual Cognition, 17, 1109-1131, 2009; Velichkovsky, Memory, 10, 405-419, 2002). Recent findings about two distinct "subpopulations of fixations," one under the direct and another under the indirect control of stimulation (e.g., Henderson & Smith, Visual Cognition, 17, 1055-1082, 2009), are reconsidered in view of these results. |
Falk Huettig; James M. Mcqueen The nature of the visual environment induces implicit biases during language-mediated visual search Journal Article In: Memory & Cognition, vol. 39, no. 6, pp. 1068–1084, 2011. @article{Huettig2011a,Four eyetracking experiments examined whether semantic and visual-shape representations are routinely retrieved from printed word displays and used during language-mediated visual search. Participants listened to sentences containing target words that were similar semantically or in shape to concepts invoked by concurrently displayed printed words. In Experiment 1, the displays contained semantic and shape competitors of the targets along with two unrelated words. There were significant shifts in eye gaze as targets were heard toward semantic but not toward shape competitors. In Experiments 2-4, semantic competitors were replaced with unrelated words, semantically richer sentences were presented to encourage visual imagery, or participants rated the shape similarity of the stimuli before doing the eyetracking task. In all cases, there were no immediate shifts in eye gaze to shape competitors, even though, in response to the Experiment 1 spoken materials, participants looked to these competitors when they were presented as pictures (Huettig & McQueen, 2007). There was a late shape-competitor bias (more than 2,500 ms after target onset) in all experiments. These data show that shape information is not used in online search of printed word displays (whereas it is used with picture displays). The nature of the visual environment appears to induce implicit biases toward particular modes of processing during language-mediated visual search. |
Olufunmilola Ogun; Jayalakshmi Viswanathan; Jason J. S. Barton The effect of central (macula) sparing of contralateral line bisection bias: A study with virtual hemianopia Journal Article In: Neuropsychologia, vol. 49, no. 12, pp. 3377–3382, 2011. @article{Ogun2011,Hemianopic patients show a contralesional bisection bias, but it is unclear whether this is a consequence of their field loss or related to extrastriate damage. One observation cited against the former is that hemianopic bisection bias does not vary with the degree of central (macular) sparing; however, it is unclear to what extent central sparing should affect this bias. Our goal was to determine the effect of central sparing on line bisection biases from field loss alone, with two approaches. First, we studied 12 healthy subjects viewing lines under conditions of virtual hemianopia, created by a gaze-contingent technique. Second, we calculated the effect predicted by a visuospatial model of the effect of central magnification on line representations in the visual system. Our results first replicated the contralateral line bisection bias with hemianopia, confirming that this can be generated by visual hemifield loss in the absence of extrastriate damage. Central sparing had only a modest effect on hemianopic bisection bias, with only slightly less bias with 10° compared to 2° of central sparing. In accordance with these empiric data, computing the center of mass for line representations in our model showed only a shallow decline in bisection bias as central sparing increased from 0 to 10°. We conclude that contralateral bisection bias only decreases slightly with central sparing, and that the absence of a statistically significant effect of central sparing in patients cannot be taken as evidence against a visual origin of contralateral hemianopic line bisection bias. |
Jelmer P. Vries; Ignace T. C. Hooge; Marco A. Wiering; Frans A. J. Verstraten How longer saccade latencies lead to a competition for salience Journal Article In: Psychological Science, vol. 22, no. 7, pp. 916–923, 2011. @article{Vries2011,It has been suggested that independent bottom-up and top-down processes govern saccadic selection. However, recent findings are hard to explain in such terms. We hypothesized that differences in visual-processing time can explain these findings, and we tested this using search displays containing two deviating elements, one requiring a short processing time and one requiring a long processing time. Following short saccade latencies, the deviation requiring less processing time was selected most frequently. This bias disappeared following long saccade latencies. Our results suggest that an element that attracts eye movements following short saccade latencies does so because it is the only element processed at that time. The temporal constraints of processing visual information therefore seem to be a determining factor in saccadic selection. Thus, relative saliency is a time-dependent phenomenon. |
Hans Peter Frey; Kerstin Wirz; Verena Willenbockel; Torsten Betz; Cornell Schreiber; Tom Troscianko; Peter König Beyond correlation: Do color features influence attention in rainforest? Journal Article In: Frontiers in Human Neuroscience, vol. 5, pp. 36, 2011. @article{Frey2011a,Recent research indicates a direct relationship between low-level color features and visual attention under natural conditions. However, the design of these studies allows only correlational observations and no inference about mechanisms. Here we go a step further to examine the nature of the influence of color features on overt attention in an environment in which trichromatic color vision is advantageous. We recorded eye-movements of color-normal and deuteranope human participants freely viewing original and modified rainforest images. Eliminating red-green color information dramatically alters fixation behavior in color-normal participants. Changes in feature correlations and variability over subjects and conditions provide evidence for a causal effect of red-green color-contrast. The effects of blue-yellow contrast are much smaller. However, globally rotating hue in color space in these images reveals a mechanism analyzing color-contrast invariant of a specific axis in color space. Surprisingly, in deuteranope participants we find significantly elevated red-green contrast at fixation points, comparable to color-normal participants. Temporal analysis indicates that this is due to compensatory mechanisms acting on a slower time scale. Taken together, our results suggest that under natural conditions red-green color information contributes to overt attention at a low-level (bottom-up). Nevertheless, the results of the image modifications and deuteranope participants indicate that evaluation of color information is done in a hue-invariant fashion. |
Marije Beilen; Remco J. Renken; Erik S. Groenewold; Frans W. Cornelissen Attentional window set by expected relevance of environmental signals Journal Article In: PLoS ONE, vol. 6, no. 6, pp. e21262, 2011. @article{Beilen2011,The existence of an attentional window–a limited region in visual space at which attention is directed–has been invoked to explain why sudden visual onsets may or may not capture overt or covert attention. Here, we test the hypothesis that observers voluntarily control the size of this attentional window to regulate whether or not environmental signals can capture attention. We have used a novel approach to test this: participants eye-movements were tracked while they performed a search task that required dynamic gaze-shifts. During the search task, abrupt onsets were presented that cued the target positions at different levels of congruency. The participant knew these levels. We determined oculomotor capture efficiency for onsets that appeared at different viewing eccentricities. From these, we could derive the participant's attentional window size as a function of onset congruency. We find that the window was small during the presentation of low-congruency onsets, but increased monotonically in size with an increase in the expected congruency of the onsets. This indicates that the attentional window is under voluntary control and is set according to the expected relevance of environmental signals for the observer's momentary behavioral goals. Moreover, our approach provides a new and exciting method to directly measure the size of the attentional window. |
Jelmer P. De Vries; Ignace T. C. Hooge; Marco A. Wiering; Frans A. J. Verstraten Saccadic selection and crowding in visual search: Stronger lateral masking leads to shorter search times Journal Article In: Experimental Brain Research, vol. 211, no. 1, pp. 119–131, 2011. @article{DeVries2011,We investigated the role of crowding in saccadic selection during visual search. To guide eye movements, often information from the visual periphery is used. Crowding is known to deteriorate the quality of peripheral information. In four search experiments, we studied the role of crowding, by accompanying individual search elements by flankers. Varying the difference between target and flankers allowed us to manipulate crowding strength throughout the stimulus. We found that eye movements are biased toward areas with little crowding for conditions where a target could be discriminated peripherally. Interestingly, for conditions in which the target could not be discriminated peripherally, this bias reversed to areas with strong crowding. This led to shorter search times for a target presented in areas with stronger crowding, compared to a target presented in areas with less crowding. These findings suggest a dual role for crowding in visual search. The presence of flankers similar to the target deteriorates the quality of the peripheral target signal but can also attract eye movements, as more potential targets are present over the area. |
Jared Frey; Dario L. Ringach Binocular eye movements evoked by self-induced motion parallax Journal Article In: Journal of Neuroscience, vol. 31, no. 47, pp. 17069–17073, 2011. @article{Frey2011,Perception often triggers actions, but actions may sometimes be necessary to evoke percepts. This is most evident in the recovery of depth by self-induced motion parallax. Here we show that depth information derived from one's movement through a stationary environment evokes binocular eye movements consistent with the perception of three-dimensional shape. Human subjects stood in front of a display and viewed a simulated random-dot sphere presented monocularly or binocularly. Eye movements were recorded by a head-mounted eye tracker, while head movements were monitored by a motion capture system. The display was continuously updated to simulate the perspective projection of a stationary, transparent random dot sphere viewed from the subject's vantage point. Observers were asked to keep their gaze on a red target dot on the surface of the sphere as they moved relative to the display. The movement of the target dot simulated jumps in depth between the front and back surfaces of the sphere along the line of sight. We found the subjects' eyes converged and diverged concomitantly with changes in the perceived depth of the target. Surprisingly, even under binocular viewing conditions, when binocular disparity signals conflict with depth information from motion parallax, transient vergence responses were observed. These results provide the first demonstration that self-induced motion parallax is sufficient to drive vergence eye movements under both monocular and binocular viewing conditions. |
Elsi Kaiser Focusing on pronouns: Consequences of subjecthood, pronominalisation, and contrastive focus Journal Article In: Language and Cognitive Processes, vol. 26, no. 10, pp. 1625–1666, 2011. @article{Kaiser2011,We report two visual-world eye-tracking experiments that investigated the effects of subjecthood, pronominalisation, and contrastive focus on the interpretation of pronouns in subsequent discourse. By probing the effects of these factors on real-time pronoun interpretation, we aim to contribute to our understanding of how topicality-related factors (subjecthood, givenness) interact with contrastive focus effects, and to investigate whether the seemingly mixed results obtained in prior work on topicality and focusing could be related to effects of subjecthood. Our results indicate that structural and semantic prominence (specifically, agentive subjects) influence pronoun interpretation even when separated from information-structural notions, and thus need to be taken into account when investigating topicality and focusing. We discuss how our results allow us to reconcile the distinct findings of prior studies. More generally, this research contributes to our understanding of how the language comprehension system integrates different kinds of information during real-time reference resolution.$backslash$nWe report two visual-world eye-tracking experiments that investigated the effects of subjecthood, pronominalisation, and contrastive focus on the interpretation of pronouns in subsequent discourse. By probing the effects of these factors on real-time pronoun interpretation, we aim to contribute to our understanding of how topicality-related factors (subjecthood, givenness) interact with contrastive focus effects, and to investigate whether the seemingly mixed results obtained in prior work on topicality and focusing could be related to effects of subjecthood. Our results indicate that structural and semantic prominence (specifically, agentive subjects) influence pronoun interpretation even when separated from information-structural notions, and thus need to be taken into account when investigating topicality and focusing. We discuss how our results allow us to reconcile the distinct findings of prior studies. More generally, this research contributes to our understanding of how the language comprehension system integrates different kinds of information during real-time reference resolution. |
Sven Ohl; Stephan A. Brandt; Reinhold Kliegl Secondary (micro-)saccades: The influence of primary saccade end point and target eccentricity on the process of postsaccadic fixation Journal Article In: Vision Research, vol. 51, no. 23-24, pp. 2340–2347, 2011. @article{Ohl2011,We examine how the size of saccadic under-/overshoot and target eccentricity influence the latency, amplitude and orientation of secondary (micro-)saccades. In our experiment, a target appeared at an eccentricity of either 6° or 14° of visual angle. Subjects were instructed to direct their gaze as quickly as possible to the target and hold fixation at the new location until the end of the trial. Typically, increasing saccadic error is associated with faster and larger secondary saccades. We show that secondary saccades at distant in contrast to close targets have in a specific error range a shorter latency, larger amplitude, and follow more often the direction of the primary saccade. Finally, we demonstrate that an undershooting primary saccade is followed almost exclusively by secondary saccades into the same direction while overshooting primary saccades are followed by secondary saccades into both directions. This supports the notion that under- and overshooting imply different consequences for postsaccadic oculomotor processing. Results are discussed using a model, introduced by Rolfs, Kliegl, and Engbert (2008), to account for the generation of microsaccades. We argue that the dynamic interplay of target eccentricity and the magnitude of the saccadic under-/overshoot can be explained by a different strength of activation in the two hemispheres of the saccadic motor map in this model. |
Goedele Van Belle; Thomas Busigny; Philippe Lefèvre; Sven Joubert; Olivier Felician; Francesco Gentile; Bruno Rossion; Philippe Lefèvre; Sven Joubert; Olivier Felician; Francesco Gentile; Bruno Rossion Impairment of holistic face perception following right occipito-temporal damage in prosopagnosia: Converging evidence from gaze-contingency Journal Article In: Neuropsychologia, vol. 49, no. 11, pp. 3145–3150, 2011. @article{VanBelle2011,Gaze-contingency is a method traditionally used to investigate the perceptual span in reading by selectively revealing/masking a portion of the visual field in real time. Introducing this approach in face perception research showed that the performance pattern of a brain-damaged patient with acquired prosopagnosia (PS) in a face matching task was reversed, as compared to normal observers: the patient showed almost no further decrease of performance when only one facial part (eye, mouth, nose, etc.) was available at a time (foveal window condition, forcing part-based analysis), but a very large impairment when the fixated part was selectively masked (mask condition, promoting holistic perception) (Van Belle, De Graef, Verfaillie, Busigny, & Rossion, 2010a; Van Belle, De Graef, Verfaillie, Rossion, & Lefèvre, 2010b). Here we tested the same manipulation in a recently reported case of pure prosopagnosia (GG) with unilateral right hemisphere damage (Busigny, Joubert, Felician, Ceccaldi, & Rossion, 2010). Contrary to normal observers, GG was also significantly more impaired with a mask than with a window, demonstrating impairment with holistic face perception. Together with our previous study, these observations support a generalized account of acquired prosopagnosia as a critical impairment of holistic (individual) face perception, implying that this function is a key element of normal human face recognition. Furthermore, the similar behavioral pattern of the two patients despite different lesion localizations supports a distributed network view of the neural face processing structures, suggesting that the key function of human face processing, namely holistic perception of individual faces, requires the activity of several brain areas of the right hemisphere and their mutual connectivity. |
Aarlenne Zein Khan; Joo-Hyun Song; Robert M. McPeek The eye dominates in guiding attention during simultaneous eye and hand movements. Journal Article In: Journal of Vision, vol. 11, no. 1, pp. 1–14, 2011. @article{Khan2011a,Prior to the onset of a saccade or a reach, attention is directed to the goal of the upcoming movement. However, it remains unknown whether attentional resources are shared across effectors for simultaneous eye and hand movements. Using a 4-AFC shape discrimination task, we investigated attentional allocation during the planning of a saccade alone, reach alone, or combined saccade and reach to one of five peripheral locations. Target discrimination was better when the probe appeared at the goal of the impending movement than when it appeared elsewhere. However, discrimination performance at the movement goal was not better for combined eye-hand movements compared to either effector alone, suggesting a shared limited attentional resource rather than separate pools of effector-specific attention. To test which effector dominates in guiding attention, we then separated eye and hand movement goals in two conditions: (1) cued reach/fixed saccade–subjects made saccades to the same peripheral location throughout the block, while the reach goal was cued and (2) cued saccade/fixed reach–subjects made reaches to the same location, while the saccade goal was cued. For both conditions, discrimination performance was consistently better at the eye goal than the hand goal. This indicates that shared attentional resources are guided predominantly by the eye during the planning of eye and hand movements. |
Sarah Risse; Reinhold Kliegl Adult age differences in the perceptual span during reading Journal Article In: Psychology and Aging, vol. 26, no. 2, pp. 451–460, 2011. @article{rk11,Following up on research suggesting an age-related reduction in the rightward extent of the perceptual span during reading (Rayner, Castelhano, & Yang, 2009), we compared old and young adults in an N + 2-boundary paradigm in which a nonword preview of word N + 2 or word N + 2 itself is replaced by the target word once the eyes cross an invisible boundary located after word N. The intermediate word N + 1 was always three letters long. Gaze durations on word N + 2 were significantly shorter for identical than nonword N + 2 preview both for young and for old adults, with no significant difference in this preview benefit. Young adults, however, did modulate their gaze duration on word N more strongly than old adults in response to the difficulty of the parafoveal word N + 1. Taken together, the results suggest a dissociation of preview benefit and parafoveal-on-foveal effect. Results are discussed in terms of age-related decline in resilience towards distributed processing while simultaneously preserving the ability to integrate parafoveal information into foveal processing. As such, the present results relate to proposals of regulatory compensation strategies older adults use to secure an overall reading speed very similar to that of young adults. |
K. Torab; T. S. Davis; D. J. Warren; Paul A. House; R. A. Normann; Bradley Greger In: Journal of Neural Engineering, vol. 8, no. 3, pp. 1–13, 2011. @article{Torab2011,We hypothesize that a visual prosthesis capable of evoking high-resolution visual perceptions can be produced using high-electrode-count arrays of penetrating microelectrodes implanted into the primary visual cortex of a blind human subject. To explore this hypothesis, and as a prelude to human psychophysical experiments, we have conducted a set of experiments in primary visual cortex (V1) of non-human primates using chronically implanted Utah Electrode Arrays (UEAs). The electrical and recording properties of implanted electrodes, the high-resolution visuotopic organization of V1, and the stimulation levels required to evoke behavioural responses were measured. The impedances of stimulated electrodes were found to drop significantly immediately following stimulation sessions, but these post-stimulation impedances returned to pre-stimulation values by the next experimental session. Two months of periodic microstimulation at currents of up to 96 µA did not impair the mapping of receptive fields from local field potentials or multi-unit activity, or impact behavioural visual thresholds of light stimuli that excited regions of V1 that were implanted with UEAs. These results demonstrate that microstimulation at the levels used did not cause functional impairment of the electrode array or the neural tissue. However, microstimulation with current levels ranging from 18 to 76 µA (46 ± 19 µA, mean ± std) was able to elicit behavioural responses on eight out of 82 systematically stimulated electrodes. We suggest that the ability of microstimulation to evoke phosphenes and elicit a subsequent behavioural response may depend on several factors: the location of the electrode tips within the cortical layers of V1, distance of the electrode tips to neuronal somata, and the inability of nonhuman primates to recognize and respond to a generalized set of evoked percepts. |
Alice K. Welham; Andy J. Wills Unitization, similarity, and overt attention in categorization and exposure Journal Article In: Memory & Cognition, vol. 39, no. 8, pp. 1518–1533, 2011. @article{Welham2011,Unitization, the creation of new stimulus features by the fusion of preexisting features, is one of the hypothesized processes of perceptual learning (Goldstone Annual Review of Psychology, 49:585-612, 1998). Some argue that unitization occurs to the extent that it is required for successful task performance (e.g., Shiffrin & Lightfoot, 1997), while others argue that unitization is largely independent of functionality (e.g., McLaren & Mackintosh Animal Learning & Behavior, 30:177-200, 2000). Across three experiments, employing supervised category learning and unsupervised exposure, we investigated three predictions of the McLaren and Mackintosh (Animal Learning & Behavior, 30:177-200, 2000) model: (1) Unitization is accompanied by an initial increase in the subjective similarity of stimuli sharing a unitized component; (2) unitization of a configuration occurs through exposure to its components, even when the task does not require it; (3) as unitization approaches completion, salience of the unitized component may be reduced. Our data supported these predictions. We also found that unitization is associated with increases in overt attention to the unitized component, as measured through eye tracking. |
Lynsey Wolter; Kristen Skovbroten Gorman; Michael K. Tanenhaus Scalar reference, contrast and discourse: Separating effects of linguistic discourse from availability of the referent Journal Article In: Journal of Memory and Language, vol. 65, no. 3, pp. 299–317, 2011. @article{Wolter2011,Listeners expect that a definite noun phrase with a pre-nominal scalar adjective (e.g., the big ...) will refer to an entity that is part of a set of objects contrasting on the scalar dimension, e.g., size (Sedivy, Tanenhaus, Chambers, & Carlson, 1999). Two visual world experiments demonstrate that uttering a referring expression with a scalar adjective makes all members of the relevant contrast set more salient in the discourse model, facilitating subsequent reference to other members of that contrast set. Moreover, this discourse effect is caused primarily by linguistic mention of a scalar adjective and not by the listener's prior visual or perceptual experience. These experiments demonstrate that language processing is sensitive to which information was introduced by linguistic mention, and that the visual world paradigm can be use to tease apart the separate contributions of visual and linguistic information to reference resolution. |