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！
2008 |
Bernhard Angele; Timothy J. Slattery; Jinmian Yang; Reinhold Kliegl; Keith Rayner Parafoveal processing in reading: Manipulating n+1 and n+2 previews simultaneously Journal Article In: Visual Cognition, vol. 16, no. 6, pp. 697–707, 2008. @article{Angele2008,The boundary paradigm (Rayner, 1975) with a novel preview manipulation was used to examine the extent of parafoveal processing of words to the right of fixation. Words n + 1 and n + 2 had either correct or incorrect previews prior to fixation (prior to crossing the boundary location). In addition, the manipulation utilized either a high or low frequency word in word n + 1 location on the assumption that it would be more likely that n + 2 preview effects could be obtained when word n + 1 was high frequency. The primary findings were that there was no evidence for a preview benefit for word n + 2 and no evidence for parafoveal-on-foveal effects when word n + 1 is at least four letters long. We discuss implications for models of eye-movement control in reading. |
Xiaochuan Pan; Kosuke Sawa; Ichiro Tsuda; Minoru Tsukada; Masamichi Sakagami Reward prediction based on stimulus categorization in primate lateral prefrontal cortex Journal Article In: Nature Neuroscience, vol. 11, no. 6, pp. 703–712, 2008. @article{Pan2008,To adapt to changeable or unfamiliar environments, it is important that animals develop strategies for goal-directed behaviors that meet the new challenges. We used a sequential paired-association task with asymmetric reward schedule to investigate how prefrontal neurons integrate multiple already-acquired associations to predict reward. Two types of reward-related neurons were observed in the lateral prefrontal cortex: one type predicted reward independent of physical properties of visual stimuli and the other encoded the reward value specific to a category of stimuli defined by the task requirements. Neurons of the latter type were able to predict reward on the basis of stimuli that had not yet been associated with reward, provided that another stimulus from the same category was paired with reward. The results suggest that prefrontal neurons can represent reward information on the basis of category and propagate this information to category members that have not been linked directly with any experience of reward. |
Rike Steenken; Hans Colonius; Adele Diederich; Stefan Rach Visual-auditory interaction in saccadic reaction time: Effects of auditory masker level Journal Article In: Brain Research, vol. 1220, pp. 150–156, 2008. @article{Steenken2008,Saccadic reaction time (SRT) to a visual target tends to be shorter when auditory stimuli are presented in close temporal and spatial proximity, even when subjects are instructed to ignore the auditory non-target (focused attention paradigm). Observed SRT reductions typically range between 10 and 50 ms and decrease as spatial disparity between the stimuli increases. Previous studies using pairs of visual and auditory stimuli differing in both azimuth and vertical position suggest that the amount of SRT facilitation decreases not with the physical but with the perceivable distance between visual target and auditory accessory. Here we probe this hypothesis by presenting an additional white-noise masker background of 3 s duration. Increasing the masker level had a diametrical effect on SRTs in spatially coincident vs. disparate stimulus configurations: saccadic responses to coincident visual-auditory stimuli are slowed down, whereas saccadic responses to disparate stimuli are speeded up. As verified in a separate auditory localization task, localizability of the auditory accessory decreases with masker level. The SRT results are accounted for by a conceptual model positing that increasing masker level enlarges the area of possible auditory stimulus locations: it implies that perceivable distances decrease for disparate stimulus configurations and increase for coincident stimulus pairs. |
Rike Steenken; Adele Diederich; Hans Colonius Time course of auditory masker effects: Tapping the locus of audiovisual integration? Journal Article In: Neuroscience Letters, vol. 435, no. 1, pp. 78–83, 2008. @article{Steenken2008a,In a focused attention paradigm, saccadic reaction time (SRT) to a visual target tends to be shorter when an auditory accessory stimulus is presented in close temporal and spatial proximity. Observed SRT reductions typically diminish as spatial disparity between the stimuli increases. Here a visual target LED (500 ms duration) was presented above or below the fixation point and a simultaneously presented auditory accessory (2 ms duration) could appear at the same or the opposite vertical position. SRT enhancement was about 35 ms in the coincident and 10 ms in the disparate condition. In order to further probe the audiovisual integration mechanism, in addition to the auditory non-target an auditory masker (200 ms duration) was presented before, simultaneous to, or after the accessory stimulus. In all interstimulus interval (ISI) conditions, SRT enhancement went down both in the coincident and disparate configuration, but this decrement was fairly stable across the ISI values. If multisensory integration solely relied on a feed-forward process, one would expect a monotonic decrease of the masker effect with increasing ISI in the backward masking condition. It is therefore conceivable that the relatively high-energetic masker causes a broad excitatory response of SC neurons. During this state, the spatial audio-visual information from multisensory association areas is fed back and merged with the spatially unspecific excitation pattern induced by the masker. Assuming that a certain threshold of activation has to be achieved in order to generate a saccade in the correct direction, the blurred joint output of noise and spatial audio-visual information needs more time to reach this threshold prolonging SRT to an audio-visual object. |
Dirk Kerzel; Angélique Gauch; Blandine Ulmann Local motion inside an object affects pointing less than smooth pursuit Journal Article In: Experimental Brain Research, vol. 191, no. 2, pp. 187–195, 2008. @article{Kerzel2008,During smooth pursuit eye movements, briefly presented objects are mislocalized in the direction of motion. It has been proposed that the localization error is the sum of the pursuit signal and the retinal motion signal in a ~200 ms interval after flash onset. To evaluate contributions of retinal motion signals produced by the entire object (global motion) and elements within the object (local motion), we asked observers to reach to flashed Gabor patches (Gaussian-windowed sine-wave gratings). Global motion was manipulated by varying the duration of a stationary flash, and local motion was manipulated by varying the motion of the sine-wave. Our results confirm that global retinal motion reduces the localization error. The effect of local retinal motion on object localization was far smaller, even though local and global motion had equal effects on eye velocity. Thus, local retinal motion has differential access to manual and oculomotor control circuits. Further, we observed moderate correlations between smooth pursuit gain and localization error. |
Kohske Takahashi; Katsumi Watanabe Persisting effect of prior experience of change blindness Journal Article In: Perception, vol. 37, no. 2, pp. 324–327, 2008. @article{Takahashi2008,Most cognitive scientists know that an airplane tends to lose its engine when the display is flickering. How does such prior experience influence visual search? We recorded eye movements made by vision researchers while they were actively performing a change-detection task. In selected trials, we presented Rensink's familiar 'airplane' display, but with changes occurring at locations other than the jet engine. The observers immediately noticed that there was no change in the location where the engine had changed in the previous change-blindness demonstration. Nevertheless, eye-movement analyses indicated that the observers were compelled to look at the location of the unchanged engine. These results demonstrate the powerful effect of prior experience on eye movements, even when the observers are aware of the futility of doing so. |
Johanna K. Kaakinen; Jukka Hyönä Perspective-driven text comprehension Journal Article In: Applied Cognitive Psychology, vol. 22, pp. 319–334, 2008. @article{Kaakinen2008,The present article reports results of an eye‐tracking experiment, which examines whether the perspective‐driven text comprehension framework applies to comprehension of narrative text. Sixty‐four participants were instructed to adopt either a burglar's or an interior designer's perspective. A pilot test showed that readers have more overlapping prior knowledge with the burglar‐relevant than with the interior designer‐relevant information of the experimental text. Participants read either a transparent text version where the (ir)relevance of text segments to the perspective was made apparent, or an opaque text version where no direct mention of the perspective was made. After reading participants wrote a free recall of the text. The results showed that perspective‐related prior knowledge modulates the perspective effects observed in on‐line text processing and that signalling of (ir)relevance helps in encoding relevant information to memory. It is concluded that the proposed framework generalizes to the on‐line comprehension of narrative texts. |
Gideon P. Caplovitz; Nora A. Paymer; Peter U. Tse The drifting edge illusion: A stationary edge abutting an oriented drifting grating appears to move because of the 'other aperture problem' Journal Article In: Vision Research, vol. 48, no. 22, pp. 2403–2414, 2008. @article{Caplovitz2008,We describe the Drifting Edge Illusion (DEI), in which a stationary edge appears to move when it abuts a drifting grating. Although a single edge is sufficient to perceive DEI, a particularly compelling version of DEI occurs when a drifting grating is viewed through an oriented and stationary aperture. The magnitude of the illusion depends crucially on the orientations of the grating and aperture. Using psychophysics, we describe the relationship between the magnitude of DEI and the relative angle between the grating and aperture. Results are discussed in the context of the roles of occlusion, component-motion, and contour relationships in the interpretation of motion information. In particular, we suggest that the visual system is posed with solving an ambiguity other than the traditionally acknowledged aperture problem of determining the direction of motion of the drifting grating. In this 'second aperture problem' or 'edge problem', a motion signal may belong to either the occluded or occluding contour. That is, the motion along the contour can arise either because the grating is drifting or because the edge is drifting over a stationary grating. DEI appears to result from a misattribution of motion information generated by the drifting grating to the stationary contours of the aperture, as if the edges are interpreted to travel over the grating, although they are in fact stationary. |
Melissa J. Green; Jennifer H. Waldron; Ian Simpson; Max Coltheart Visual processing of social context during mental state perception in schizophrenia Journal Article In: Journal of Psychiatry and Neuroscience, vol. 33, no. 1, pp. 34–42, 2008. @article{Green2008,OBJECTIVE: To examine schizophrenia patients' visual attention to social contextual information during a novel mental state perception task. METHOD: Groups of healthy participants (n = 26) and schizophrenia patients (n = 24) viewed 7 image pairs depicting target characters presented context-free and context-embedded (i.e., within an emotion-congruent social context). Gaze position was recorded with the EyeLink I Gaze Tracker while participants performed a mental state inference task. Mean eye movement variables were calculated for each image series (context-embedded v. context-free) to examine group differences in social context processing. RESULTS: The schizophrenia patients demonstrated significantly fewer saccadic eye movements when viewing context-free images and significantly longer eye-fixation durations when viewing context-embedded images. Healthy individuals significantly shortened eye-fixation durations when viewing context-embedded images, compared with context-free images, to enable rapid scanning and uptake of social contextual information; however, this pattern of visual attention was not pronounced in schizophrenia patients. In association with limited scanning and reduced visual attention to contextual information, schizophrenia patients' assessment of the mental state of characters embedded in social contexts was less accurate. CONCLUSION: In people with schizophrenia, inefficient integration of social contextual information in real-world situations may negatively affect the ability to infer mental and emotional states from facial expressions. |
Lillian Chen; Julie E. Boland Dominance and context effects on activation of alternative homophone meanings Journal Article In: Memory & Cognition, vol. 36, no. 7, pp. 1306–1323, 2008. @article{Chen2008,Two eyetracking-during-listening experiments showed frequency and context effects on fixation probability for pictures representing multiple meanings of homophones. Participants heard either an imperative sentence instructing them to look at a homophone referent (Experiment 1) or a declarative sentence that was either neutral or biased toward the homophone's subordinate meaning (Experiment 2). At homophone onset in both experiments, the participants viewed four pictures: (1) a referent of one homophone meaning, (2) a shape competitor for a nonpictured homophone meaning, and (3) two unrelated filler objects. In Experiment 1, meaning dominance affected looks to both the homophone referent and the shape competitor. In Experiment 2, as compared with neutral contexts, subordinatebiased contexts lowered the fixation probability for shape competitors of dominant meanings, but shape competitors still attracted more looks than would be expected by chance. We discuss the consistencies and discrepancies of these findings with the selective access and reordered access theories of lexical ambiguity resolution. |
Sofie Moresi; Jos J. Adam; Jons Rijcken; Pascal W. M. Van Gerven Cue validity effects in response preparation: A pupillometric study Journal Article In: Brain Research, vol. 1196, pp. 94–102, 2008. @article{Moresi2008,This study examined the effects of cue validity and cue difficulty on response preparation to provide a test of the Grouping Model [Adam, J.J., Hommel, B. and Umiltà, C., 2003. Preparing for perception and action (I): the role of grouping in the response-cuing paradigm. Cognit. Psychol. 46(3), 302-58, Adam, J.J., Hommel, B. and Umiltà, C., 2005. Preparing for perception and action (II) automatic and effortful processes in response cuing. Vis. Cogn. 12(8), 1444-1473.]. We used the pupillary response to index the cognitive processing load during and after the preparatory interval (2 s). Twenty-two participants performed the finger-cuing tasks with valid (75%) and invalid (25%) cues. Results showed longer reaction times, more errors, and larger pupil dilations for invalid than valid cues. During the preparation interval, pupil dilation varied systematically with cue difficulty, with easy cues (specifying 2 fingers on 1 hand) showing less pupil dilation than difficult cues (specifying 2 fingers on 2 hands). After the preparation interval, this pattern of differential pupil dilation as a function of cue difficulty reversed for invalid cues, suggesting that cues which incorrectly specified fingers on one hand required more effortful reprogramming operations than cues which incorrectly specified fingers on two hands. These outcomes were consistent with predictions derived from the Grouping Model. Finally, all participants exhibited two distinct pupil dilation strategies: an "early" strategy in which the onset of the main pupil dilation was tied to onset of the cue, and a "late" strategy in which the onset of the main pupil dilation was tied to the onset of the target. Thus, whereas the early pupil dilation strategy showed a strong dilation during the preparation interval, the late pupil strategy showed a strong constriction. Interestingly, only the late onset pupil dilation strategy revealed the above reported sensitivity to cue difficulty, showing for the first time that the well-known pupil's sensitivity to task difficulty can also emerge when the pupil is constricting instead of dilating. |
Marc H. E. Lussanet; Luciano Fadiga; Lars Michels; Rüdiger J. Seitz; Raimund Kleiser; Markus Lappe Interaction of visual hemifield and body view in biological motion perception Journal Article In: European Journal of Neuroscience, vol. 27, no. 2, pp. 514–522, 2008. @article{Lussanet2008,The brain network for the recognition of biological motion includes visual areas and structures of the mirror-neuron system. The latter respond during action execution as well as during action recognition. As motor and somatosensory areas predominantly represent the contralateral side of the body and visual areas predominantly process stimuli from the contralateral hemifield, we were interested in interactions between visual hemifield and action recognition. In the present study, human participants detected the facing direction of profile views of biological motion stimuli presented in the visual periphery. They recognized a right-facing body view of human motion better in the right visual hemifield than in the left; and a left-facing body view better in the left visual hemifield than in the right. In a subsequent fMRI experiment, performed with a similar task, two cortical areas in the left and right hemispheres were significantly correlated with the behavioural facing effect: primary somatosensory cortex (BA 2) and inferior frontal gyrus (BA 44). These areas were activated specifically when point-light stimuli presented in the contralateral visual hemifield displayed the side view of their contralateral body side. Our results indicate that the hemispheric specialization of one's own body map extends to the visual representation of the bodies of others. |
Sofie Moresi; Jos J. Adam; Jons Rijcken; Pascal W. M. Van Gerven; Harm Kuipers; Jelle Jolles Pupil dilation in response preparation Journal Article In: International Journal of Psychophysiology, vol. 67, no. 2, pp. 124–130, 2008. @article{Moresi2008a,This study examined changes in pupil size during response preparation in a finger-cuing task. Based on the Grouping Model of finger preparation [Adam, J.J., Hommel, B. and Umiltà, C., 2003b. Preparing for perception and action (I): the role of grouping in the response-cuing paradigm. Cognitive Psychology. 46, (3), 302-358.; Adam, J.J., Hommel, B. and Umiltà, C., 2005. Preparing for perception and action (II) Automatic and effortfull Processes in Response cuing. Visual Cognition. 12, (8), 1444-1473.], it was hypothesized that the selection and preparation of more difficult response sets would be accompanied by larger pupillary dilations. The results supported this prediction, thereby extending the validity of pupil size as a measure of cognitive load to the domain of response preparation. |
Dirk Kerzel; David Souto; Nathalie E. Ziegler Effects of attention shifts to stationary objects during steady-state smooth pursuit eye movements Journal Article In: Vision Research, vol. 48, no. 7, pp. 958–969, 2008. @article{Kerzel2008a,A number of studies have shown that stationary backgrounds compromise smooth pursuit eye movements. It has been suggested that poor attentional selection of the pursuit target was responsible for reductions of pursuit gain. To quantify the detrimental effects of attention, we instructed observers to either pay attention to background objects or to ignore them. The to-be-attended object was indicated by peripheral or central cues. Strong reductions of pursuit gain occurred when the following conditions were met: (a) the subject payed attention to the object (b) a salient event was present, for instance the onset of the target or cue and (c) the attended target produced retinal motion. Removing any of the three conditions resulted in no or far smaller decreases of pursuit gain. Further, decreases in pursuit gain were present with perceptual discrimination and simple manual detection. |
John D. Koehn; Elizabeth Roy; Jason J. S. Barton The "diagonal effect": A systematic error in oblique antisaccades Journal Article In: Journal of Neurophysiology, vol. 100, no. 2, pp. 587–597, 2008. @article{Koehn2008,Antisaccades are known to show greater variable error and also a systematic hypometria in their amplitude compared with visually guided prosaccades. In this study, we examined whether their accuracy in direction (as opposed to amplitude) also showed a systematic error. We had human subjects perform prosaccades and antisaccades to goals located at a variety of polar angles. In the first experiment, subjects made prosaccades or antisaccades to one of eight equidistant locations in each block, whereas in the second, they made saccades to one of two equidistant locations per block. In the third, they made antisaccades to one of two locations at different distances but with the same polar angle in each block. Regardless of block design, the results consistently showed a saccadic systematic error, in that oblique antisaccades (but not prosaccades) requiring unequal vertical and horizontal vector components were deviated toward the 45 degrees diagonal meridians. This finding could not be attributed to range effects in either Cartesian or polar coordinates. A perceptual origin of the diagonal effect is suggested by similar systematic errors in other studies of memory-guided manual reaching or perceptual estimation of direction, and may indicate a common spatial bias when there is uncertain information about spatial location. |
Thomas Geyer; Hermann J. Müller; Joseph Krummenacher Expectancies modulate attentional capture by salient color singletons Journal Article In: Vision Research, vol. 48, no. 11, pp. 1315–1326, 2008. @article{Geyer2008,In singleton feature search for a form-defined target, the presentation of a task-irrelevant, but salient singleton color distractor is known to interfere with target detection [Theeuwes, J. (1991). Cross-dimensional perceptual selectivity. Perception & Psychophysics, 50, 184-193; Theeuwes, J. (1992). Perceptual selectivity for color and form. Perception & Psychophysics, 51, 599-606]. The present study was designed to re-examine this effect, by presenting observers with a singleton form target (on each trial) that could be accompanied by a salient) singleton color distractor, with the proportion of distractor to no-distractor trials systematically varying across blocks of trials. In addition to RTs, eye movements were recorded in order to examine the mechanisms underlying the distractor interference effect. The results showed that singleton distractors did interfere with target detection only when they were presented on a relatively small (but not on a large) proportion of trials. Overall, the findings suggest that cross-dimensional interference is a covert attention effect, arising from the competition of the target with the distractor for attentional selection [Kumada, T., & Humphreys, G. W. (2002). Cross-dimensional interference and cross-trial inhibition. Perception & Psychophysics, 64, 493-503], with the strength of the competition being modulated by observers' (top-down) incentive to suppress the distractor dimension. |
Lee Hogarth; Anthony Dickinson; Alison Austin; Craig Brown; Theodora Duka Attention and expectation in human predictive learning: The role of uncertainty Journal Article In: Quarterly Journal of Experimental Psychology, vol. 61, no. 11, pp. 1658–1668, 2008. @article{Hogarth2008,Three localized, visual pattern stimuli were trained as predictive signals of auditory outcomes. One signal partially predicted an aversive noise in Experiment 1 and a neutral tone in Experiment 2, whereas the other signals consistently predicted either the occurrence or absence of the noise. The expectation of the noise was measured during each signal presentation, and only participants for whom this expectation demonstrated contingency knowledge showed differential attention to the signals. Importantly, when attention was measured by visual fixations, the contingency-aware group attended more to the partially predictive signal than to the consistent predictors in both experiments. This profile of visual attention supports the Pearce and Hall (1980) theory of the role of attention in associative learning. |
Harold H. Greene Distance-from-target dynamics during visual search Journal Article In: Vision Research, vol. 48, no. 23-24, pp. 2476–2484, 2008. @article{Greene2008,Tseng, Y. C., & Li, C. S. (2004). Oculomotor correlates of context-guided learning in visual search. Perception & Psychophysics, 66, 1368-1378 noted that visual search with eye movements may be characterized by a search phase in which fixations do not move towards the target, followed by a phase in which fixations move steadily towards the target. They speculated that the phases are related to memory and recognition processes. Human visual search and Monte Carlo simulations are described towards an explanation. Distance-from-target dynamics were demonstrated to be sensitive to geometric constraints and therefore do not provide a solution to the question of memory in visual search. Finally, it is concluded that the specific distance-from-target dynamics noted by Tseng, Y. C., & Li, C. S. (2004). Oculomotor correlates of context-guided learning in visual search. Perception & Psychophysics, 66, 1368-1378 are parsimoniously explained by random walks that were initialized at the centre of their stimulus displays. |
Timo Stein; Ignacio Vallines; Werner X. Schneider Primary visual cortex repoundsects behavioral performance in the attentional blink Journal Article In: NeuroReport, vol. 19, no. 13, pp. 1277–1281, 2008. @article{Stein2008,When two masked targets are presented in a rapid sequence, attentional limitations are reflected in reduced identification accuracy for the second target (T2). We used functional magnetic resonance imaging to disentangle the distinct neural substrates of T2 processing during this attentional blink phenomenon. Spatially separating the two targets allows the retinotopic localization of the different stimuli's encoding sites in primary visual cortex (V1) and thus enables activation elicited by each target to be differentially measured in V1. The encoding location of the second target mirrored T2 identification accuracy in a retinotopically specific manner. These results are the first evidence for effects of behavioral performance on hemodynamic responses in V1 under conditions of the attentional blink. |
Matteo Valsecchi; Sven Saage; Brian J. White; Karl R. Gegenfurtner Advantage in reading lexical bundles is reduced in non-native speakers Journal Article In: Journal of Eye Movement Research, vol. 6, no. 5:2, pp. 1–15, 2008. @article{Valsecchi2008,Formulaic sequences such as idioms, collocations, and lexical bundles, which may be processed as holistic units, make up a large proportion of natural language. For language learners, however, formulaic patterns are a major barrier to achieving native like compe- tence. The present study investigated the processing of lexical bundles by native speakers and less advanced non-native English speakers using corpus analysis for the identification of lexical bundles and eye-tracking to measure the reading times. The participants read sentences containing 4-grams and control phrases which were matched for sub-string fre- quency. The results for native speakers demonstrate a processing advantage for formulaic sequences over the matched control units. We do not find any processing advantage for non-native speakers which suggests that native like processing of lexical bundles comes only late in the acquisition process |
Lee Hogarth; Anthony Dickinson; Molly Janowski; Aleksandra Nikitina; Theodora Duka The role of attentional bias in mediating human drug-seeking behaviour Journal Article In: Psychopharmacology, vol. 201, no. 1, pp. 29–41, 2008. @article{Hogarth2008a,RATIONALE: The attentional bias for drug cues is believed to be a causal cognitive process mediating human drug seeking and relapse. OBJECTIVES, METHODS AND RESULTS: To test this claim, we trained smokers on a tobacco conditioning procedure in which the conditioned stimulus (or S+) acquired parallel control of an attentional bias (measured with an eye tracker), tobacco expectancy and instrumental tobacco-seeking behaviour. Although this correlation between measures may be regarded as consistent with the claim that the attentional bias for the S+ mediated tobacco seeking, when a secondary task was added in the test phase, the attentional bias for the S+ was abolished, yet the control of tobacco expectancy and tobacco seeking remained intact. CONCLUSIONS: This dissociation suggests that the attentional bias for drug cues is not necessary for the control that drug cues exert over drug-seeking behaviour. The question raised by these data is what function does the attentional bias serve if it does not mediate drug seeking? |
Gregory J. Zelinsky A theory of eye movements during target acquisition Journal Article In: Psychological Review, vol. 115, pp. 787–835, 2008. @article{Zelinsky2008,The gaze movements accompanying target localization were examined via human observers and a computational model (Target Acquisition Model, TAM). Search contexts ranged from fully realistic scenes, to toys in a crib, to Os and Qs, and manipulations included set size, target eccentricity, and target-distractor similarity. Observers and the model always previewed the same targets and searched the identical displays. Behavioral and simulated eye movements were analyzed for acquisition accuracy, efficiency, and target guidance. TAM's behavior generally fell within the behavioral mean's 95% confidence interval for all measures in each experiment/condition. This agreement suggests that a fixed-parameter model using spatio-chromatic filters and a simulated retina, when driven by the correct visual routines, can be a good general purpose predictor of human target acquisition behavior. |
Jane L. Morgan; Gus Elswijk; Antje S. Meyer Extrafoveal processing of objects in a naming task: Evidence from word probe experiments Journal Article In: Psychonomic Bulletin & Review, vol. 15, no. 3, pp. 561–565, 2008. @article{Morgan2008,In two experiments, we investigated the processing of extrafoveal objects in a double-object naming task. On most trials, participants named two objects; but on some trials, the objects were replaced shortly after trial onset by a written word probe, which participants had to name instead of the objects. In Experiment 1, the word was presented in the same location as the left object either 150 or 350 msec after trial onset and was either phonologically related or unrelated to that object name. Phonological facilitation was observed at the later but not at the earlier SOA. In Experiment 2, the word was either phonologically related or unrelated to the right object and was presented 150 msec after the speaker had begun to inspect that object. In contrast with Experiment 1, phonological facilitation was found at this early SOA, demonstrating that the speakers had begun to process the right object prior to fixation. |
M. S. Baptista; C. Bohn; Reinhold Kliegl; Ralf Engbert; Jürgen Kurths Reconstruction of eye movements during blinks Journal Article In: Chaos, vol. 18, no. 1, pp. 1–15, 2008. @article{Baptista2008,In eye movement research in reading, the amount of data plays a crucial role for the validation of results. A methodological problem for the analysis of the eye movement in reading are blinks, when readers close their eyes. Blinking rate increases with increasing reading time, resulting in high data losses, especially for older adults or reading impaired subjects. We present a method, based on the symbolic sequence dynamics of the eye movements, that reconstructs the horizontal position of the eyes while the reader blinks. The method makes use of an observed fact that the movements of the eyes before closing or after opening contain information about the eyes movements during blinks. Test results indicate that our reconstruction method is superior to methods that use simpler interpolation approaches. In addition, analyses of the reconstructed data show no significant deviation from the usual behavior observed in readers. |
Gregory J. Zelinsky; Mark B. Neider An eye movement analysis of multiple object tracking in a realistic environment Journal Article In: Visual Cognition, vol. 16, no. 5, pp. 553–566, 2008. @article{Zelinsky2008a,To study multiple object tracking under naturalistic conditions, observers tracked 1–4 sharks (9 in total) swimming throughout an underwater scene. Accuracy was high in the Track 1–3 conditions (>92%), but declined when tracking 4 targets (78%). Gaze analyses revealed a dependency between tracking strategy and target number. Observers tracking 2 targets kept their gaze on the target centroid rather than individual objects; observers tracking 4 targets switched their gaze back-and-forth between sharks. Using an oculomotor method for identifying targets lost during tracking, we confirmed that this strategy shift was real and not an artifact of centroid definition. Moreover, we found that tracking errors increased with gaze time on targets, and decreased with time spent looking at the centroid. Depending on tracking load, both centroid and target-switching strategies are used, with accuracy improving with reliance on centroid tracking. An index juggling hypothesis is advanced to explain the suboptimal tendency to fixate tracked objects. |
Mieke Donk; Wieske Zoest Effects of salience are short-lived Journal Article In: Psychological Science, vol. 19, no. 7, pp. 733–739, 2008. @article{Donk2008,A salient event in the visual field tends to attract attention and the eyes. To account for the effects of salience on visual selection, models generally assume that the human visual system continuously holds information concerning the relative salience of objects in the visual field. Here we show that salience in fact drives vision only during the short time interval immediately following the onset of a visual scene. In a saccadic target-selection task, human performance in making an eye movement to the most salient element in a display was accurate when response latencies were short, but was at chance when response latencies were long. In a manual discrimination task, performance in making a judgment of salience was more accurate with brief than with long display durations. These results suggest that salience is represented in the visual system only briefly after a visual image enters the brain. |
Ava Elahipanah; Bruce K. Christensen; Eyal M. Reingold Visual selective attention among persons with schizophrenia: The distractor ratio effect Journal Article In: Schizophrenia Research, vol. 105, pp. 61–67, 2008. @article{Elahipanah2008,The current study investigated whether impaired visual attention among patients with schizophrenia can be accounted for by poor perceptual organization and impaired search selectivity. Twenty-three patients with schizophrenia and 22 healthy control participants completed a conjunctive visual search task where the relative frequency of the two types of distractors was manipulated. It has been shown that, when the total number of items in a display is fixed, search performance depends on the relative frequency of the types of distractors (i.e., as the ratio becomes more discrepant search time decreases). This modulation of search efficiency reflects participants' ability to group items by their perceptual similarity and then search only the smaller group of items that share a feature with the target. Results show that patients modulate their response time normally as a function of the distractor ratio – that is, they benefit from the presence of a smaller distractor subset in the display. This suggests that patients with schizophrenia, group items according to their perceptual similarity and flexibly deploy their attention to the smaller subset of distractors on each trial. These results demonstrate that search selectivity as a function of the relative frequency of distractors is unimpaired among patients with schizophrenia. |
Falk Huettig; Robert J. Hartsuiker When you name the pizza you look at the coin and the bread: Eye movements reveal semantic activation during word production Journal Article In: Memory & Cognition, vol. 36, no. 2, pp. 341–360, 2008. @article{Huettig2008,Two eyetracking experiments tested for activation of category coordinate and perceptually related concepts when speakers prepare the name of an object. Speakers saw four visual objects in a 2 x 2 array and identified and named a target picture on the basis of either category (e.g., "What is the name of the musical instrument?") or visual-form (e.g., "What is the name of the circular object?") instructions. There were more fixations on visual-form competitors and category coordinate competitors than on unrelated objects during name preparation, but the increased overt attention did not affect naming latencies. The data demonstrate that eye movements are a sensitive measure of the overlap between the conceptual (including visual-form) information that is accessed in preparation for word production and the conceptual knowledge associated with visual objects. Furthermore, these results suggest that semantic activation of competitor concepts does not necessarily affect lexical selection, contrary to the predictions of lexical-selection-by-competition accounts (e.g., Levelt, Roelofs, & Meyer, 1999). |
Harold T. Nefs; J. M. Harris Induced motion in depth and the effects of vergence eye movements Journal Article In: Journal of Vision, vol. 8, no. 3, pp. 1–16, 2008. @article{Nefs2008,Induced motion is the false impression that physically stationary objects move when in the presence of other objects that really move. In this study, we investigated this motion illusion in the depth dimension. We raised three related questions, as follows: (1) What cues in the stimulus are responsible for this motion illusion in depth? (2) Is the size of this illusion affected by vergence eye movements? And (3) are the effects of eye movements different for motion in depth and for motion in the frontoparallel plane? To answer these questions, we measured the point of subjective stationarity. Observers viewed an inducer target that oscillated in depth and a test target that was located directly above it. The test target moved in phase or out of phase with the inducer, but with a smaller amplitude. Observers had to indicate whether the test target and the inducer target moved in phase or out of phase with one another. They were asked to keep their eyes either on the test target or on the inducer. For motion in depth, created by binocular disparity and retinal size change or by binocular disparity alone, we found that when the eyes followed the inducer, subjective stationarity occurred at approximately 40-45% of the inducer's amplitude. When the eyes were kept fixated on the test target, the bias decreased tenfold to around 4%. When size change was the only cue to motion in depth, there was no illusory motion. When the eyes were kept on an inducer moving in the frontoparallel plane, induced motion was of the same order as for induced motion in depth, namely, approximately 44%. When the induced motion was in the frontoparallel plane, we found that perceived stationarity occurred at approximately 23% of inducer's amplitude when the eyes were kept on the test target. |
Hans Peter Frey; Christian Honey; P. König; Peter Konig What's color got to do with it? The influence of color on visual attention in different categories Journal Article In: Journal of Vision, vol. 8, no. 14, pp. 1–17, 2008. @article{Frey2008,Certain locations attract human gaze in natural visual scenes. Are there measurable features, which distinguish these locations from others? While there has been extensive research on luminance-defined features, only few studies have examined the influence of color on overt attention. In this study, we addressed this question by presenting color-calibrated stimuli and analyzing color features that are known to be relevant for the responses of LGN neurons. We recorded eye movements of 15 human subjects freely viewing colored and grayscale images of seven different categories. All images were also analyzed by the saliency map model (L. Itti, C. Koch, & E. Niebur, 1998). We find that human fixation locations differ between colored and grayscale versions of the same image much more than predicted by the saliency map. Examining the influence of various color features on overt attention, we find two extreme categories: while in rainforest images all color features are salient, none is salient in fractals. In all other categories, color features are selectively salient. This shows that the influence of color on overt attention depends on the type of image. Also, it is crucial to analyze neurophysiologically relevant color features for quantifying the influence of color on attention. |
Fred H. Hamker; Marc Zirnsak; Markus Lappe About the influence of post-saccadic mechanisms for visual stability on peri-saccadic compression of object location Journal Article In: Journal of Vision, vol. 8, no. 14, pp. 1–13, 2008. @article{Hamker2008,Peri-saccadic perception experiments have revealed a multitude of mislocalization phenomena. For instance, a briefly flashed stimulus is perceived closer to the saccade target, whereas a displacement of the saccade target goes usually unnoticeable. This latter saccadic suppression of displacement has been explained by a built-in characteristic of the perceptual system: the assumption that during a saccade, the environment remains stable. We explored whether the mislocalization of a briefly flashed stimulus toward the saccade target also grounds in the built-in assumption of a stable environment. If the mislocalization of a peri-saccadically flashed stimulus originates from a post-saccadic alignment process, an additional location marker at the position of the upcoming flash should counteract compression. Alternatively, compression might be the result of peri-saccadic attentional phenomena. In this case, mislocalization should occur even if the position of the flashed stimulus is marked. When subjects were asked about their perceived location, they mislocalized the stimulus toward the saccade target, even though they were fully aware of the correct stimulus location. Thus, our results suggest that the uncertainty about the location of a flashed stimulus is not inherently relevant for compression. |
Sebastian Pannasch; Jens R. Helmert; Katharina Roth; Ann-Katrin Herbold; Henrik Walter Visual fixation durations and saccade amplitudes: Shifting relationship in a variety of conditions Journal Article In: Journal of Eye Movement Research, vol. 2, no. 2, pp. 1–19, 2008. @article{Pannasch2008,Is there any relationship between visual fixation durations and saccade amplitudes in free exploration of pictures and scenes? In four experiments with naturalistic stimuli, we compared eye movements during early and late phases of scene perception. Influences of repeated presentation of similar stimuli (Experiment 1), object density (Experiment 2), emotional stimuli (Experiment 3) and mood induction (Experiment 4) were examined. The results demonstrate a systematic increase in the durations of fixations and a decrease for saccadic amplitudes over the time course of scene perception. This relationship was very stable across the variety of studied conditions. It can be interpreted in terms of a shifting balance of the two modes of visual information processing. |
Victor Kuperman; Raymond Bertram; R. Harald Baayen Morphological dynamics in compound processing Journal Article In: Language and Cognitive Processes, vol. 23, no. 7-8, pp. 1089–1132, 2008. @article{Kuperman2008,This paper explores the time-course of morphological processing of trimorphemic Finnish compounds. We find evidence for the parallel access to full- forms and morphological constituents diagnosed by the early effects of compound frequency, as well as early effects of left constituent frequency and family size. We also observe an interaction between compound frequency and both the left and the right constituent family sizes. Furthermore, our data show that suffixes embedded in the derived left constituent of a compound are efficiently used for establishing the boundary between compounds' constituents. The success of segmentation of a compound is demonstrably modulated by the affixal salience of the embedded suffixes. We discuss implications of these findings for current models of morphological processing and propose a new model that views morphemes, combinations of morphemes and morphological paradigms as probabilistic sources of information that are interactively used in recognition of complex words. |
Jennifer J. Heisz; David I. Shore More efficient scanning for familiar faces Journal Article In: Journal of Vision, vol. 8, no. 1, pp. 1–10, 2008. @article{Heisz2008,The present study reveals changes in eye movement patterns as newly learned faces become more familiar. Observers received multiple exposures to newly learned faces over four consecutive days. Recall tasks were performed on all 4 days, and a recognition task was performed on the fourth day. Eye movement behavior was compared across facial exposure and task type. Overall, the eyes were viewed for longer and more often than any other facial region, regardless of face familiarity. As a face became more familiar, observers made fewer fixations during recall and recognition. With increased exposure, observers sampled more from the eyes and sampled less from the nose, mouth, forehead, chin, and cheek regions. Interestingly, this change in scanning behavior was only observed for recall tasks, but not for recognition. |
Jason S. McCarley; Christopher Grant State-trace analysis of the effects of a visual illusion on saccade amplitudes and perceptual judgments Journal Article In: Psychonomic Bulletin & Review, vol. 15, no. 5, pp. 1008–1014, 2008. @article{McCarley2008,Visual illusions often appear to have a larger influence on subjective judgments than on visuomotor behavior. Although this effect has been taken as evidence for multiple estimates of stimulus size in the visual brain, dissociations between subjective judgments and visuomotor measures can frequently be reconciled with a single-estimate model. To circumvent this difficulty, we used state-trace analysis in a pair of experiments to examine the effects of the Müller-Lyer illusion on subjective length estimates, voluntary saccade amplitudes, and reflexive saccade amplitudes. All dependent measures were affected by the illusion. However, state-trace analyses revealed nonmonotonic relationships among all three variables, a pattern inconsistent with the possibility of a single underlying estimate of stimulus size. |
Michael Schneider; Angela Heine; Verena Thaler; Joke Torbeyns; Bert De Smedt; Lieven Verschaffel; Arthur M. Jacobs; Elsbeth Stern A validation of eye movements as a measure of elementary school children's developing number sense Journal Article In: Cognitive Development, vol. 23, no. 3, pp. 409–422, 2008. @article{schneider2008validation,The number line estimation task captures central aspects of children's developing number sense, that is, their intuitions for numbers and their interrelations. Previous research used children's answer patterns and verbal reports as evidence of how they solve this task. In the present study we investigated to what extent eye movements recorded during task solution reflect children's use of the number line. By means of a cross-sectional design with 66 children from Grades 1, 2, and 3, we show that eye-tracking data (a) reflect grade-related increase in estimation competence, (b) are correlated with the accuracy of manual answers, (c) relate, in Grade 2, to children's addition competence, (d) are systematically distributed over the number line, and (e) replicate previous findings concerning children's use of counting strategies and orientation-point strategies. These findings demonstrate the validity and utility of eye-tracking data for investigating children's developing number sense and estimation competence. |
Werner X. Schneider; Ellen Matthias; Melissa L. -H. Võ In: Journal of Eye Movement Research, vol. 2, no. 2, pp. 1–13, 2008. @article{vsm08,The study presented here introduces a new approach to the investigation of transsaccadic memory for objects in naturalistic scenes. Participants were tested with a whole-report task from which — based on the theory of visual attention (TVA) — processing efficiency parameters were derived, namely visual short-term memory storage capacity and visual processing speed. By combining these processing efficiency parameters with transsaccadic memory data from a previous study, we were able to take a closer look at the contribution of visual short-term memory capacity and processing speed to the establishment of visual long-term memory representations during scene viewing. Results indicate that especially the VSTM storage capacity plays a major role in the generation of transsaccadic visual representations of naturalistic scenes. |
Peter Janssen; Siddharth Srivastava; Sien Ombelet; Guy A. Orban Coding of shape and position in macaque lateral Iintraparietal area Journal Article In: Journal of Neuroscience, vol. 28, no. 26, pp. 6679–6690, 2008. @article{Janssen2008,The analysis of object shape is critical for both object recognition and grasping. Areas in the intraparietal sulcus of the rhesus monkey are important for the visuomotor transformations underlying actions directed toward objects. The lateral intraparietal (LIP) area has strong anatomical connections with the anterior intraparietal area, which is known to control the shaping of the hand during grasping, and LIP neurons can respond selectively to simple two-dimensional shapes. Here we investigate the shape representation in area LIP of awake rhesus monkeys. Specifically, we determined to what extent LIP neurons are tuned to shape dimensions known to be relevant for grasping and assessed the invariance of their shape preferences with regard to changes in stimulus size and position in the receptive field. Most LIP neurons proved to be significantly tuned to multiple shape dimensions. The population of LIP neurons that were tested showed barely significant size invariance. Position invariance was present in a minority of the neurons tested. Many LIP neurons displayed spurious shape selectivity arising from accidental interactions between the stimulus and the receptive field. We observed pronounced differences in the receptive field profiles determined by presenting two different shapes. Almost all LIP neurons showed spatially selective saccadic activity, but the receptive field for saccades did not always correspond to the receptive field as determined using shapes. Our results demonstrate that a subpopulation of LIP neurons encodes stimulus shape. Furthermore, the shape representation in the dorsal visual stream appears to differ radically from the known representation of shape in the ventral visual stream. |
Mark B. Neider; Gregory J. Zelinsky Exploring set size effects in scenes: Identifying the objects of search Journal Article In: Visual Cognition, vol. 16, no. 1, pp. 1–10, 2008. @article{Neider2008,Traditional search paradigms utilize simple displays, allowing a precise determination of set size. However, objects in realistic scenes are largely uncountable, and typically visually and semantically complex. Can traditional conceptions of set size be applied to search in realistic scenes? Observers searched quasirealistic scenes for a tank target hidden among tree distractors varying in number and density. Search efficiency improved as trees were added to the display, a reverse set size effect. Eye movement analyses revealed that observers fixated individual trees when the set size was small, and the open regions between trees when the set size was large. Rather than a set size consisting of objectively countable objects, we interpret these data as evidence for a restricted functional set size consisting of idiosyncratically defined objects of search. Observers exploit low-level perceptual grouping processes and high-level semantic scene constraints to dynamically create objects that are appropriate to a given search task. |
Tim J. Smith; John M. Henderson Edit Blindness: The relationship between attention and global change blindness in dynamic scenes Journal Article In: Journal of Eye Movement Research, vol. 2, no. 2, pp. 1–17, 2008. @article{sh08,Although we experience the visual world as a continuous, richly detailed space we often fail to notice large and significant changes. Such change blindness has been demonstrated for local object changes and changes to the visual form of whole images, however it is assumed that total changes from one image to another would be easily detected. Film editing presents such total changes several times a minute yet we rarely seem to be aware of them, a phenomenon we refer to here as edit blindness. This phenomenon has never been empirically demonstrated even though film editors believe they have at their disposal techniques that induce edit blindness, the Continuity Editing Rules. In the present study we tested the relationship between Continuity Editing Rules and edit blindness by instructing participants to detect edits while watching excerpts from feature films. Eye movements were recorded during the task. The results indicate that edits constructed according to the Continuity Editing Rules result in greater edit blindness than edits not adhering to the rules. A quarter of edits joining two viewpoints of the same scene were undetected and this increased to a third when the edit coincided with a sudden onset of motion. Some cuts may be missed due to suppression of the cut transients by coinciding with eyeblinks or saccadic eye movements but the majority seem to be due to inattentional blindness as viewers attend to the depicted narrative. In conclusion, this study presents the first empirical evidence of edit blindness and its relationship to natural attentional behaviour during dynamic scene viewing. |
Marine Vernet; Qing Yang; Gintautas Daunys; Christophe Orssaud; Thomas Eggert; Zoï Kapoula How the brain obeys Hering's law: A TMS study of the posterior parietal cortex Journal Article In: Investigative Ophthalmology & Visual Science, vol. 49, no. 1, pp. 230–237, 2008. @article{Vernet2008,PURPOSE: Human ocular saccades are not perfectly yoked; the origin of this disconjugacy (muscular versus central) remains controversial. The purpose of this study was to test a cortical influence on the binocular coordination of saccades. METHODS: The authors used a gap paradigm to elicit vertical or horizontal saccades of 10 degrees , randomly interleaved; transcranial magnetic stimulation (TMS) was applied on the posterior parietal cortex (PPC) 100 ms after the target onset. RESULTS: TMS of the left or right PPC increased (i) the misalignment of the eyes during the presaccadic fixation period; (ii) the size difference between the saccades of the eyes, called disconjugacy; the increase of disconjugacy was significant for rightward and downward saccades after TMS of the right PPC and for downward saccades after TMS of the left PPC. CONCLUSIONS: The authors conclude that the PPC is actively involved in maintaining eye alignment during fixation and in the control of binocular coordination of saccades. |
Gary D. Bond Deception detection expertise Journal Article In: Law and Human Behavior, vol. 32, no. 4, pp. 339–351, 2008. @article{Bond2008,A lively debate between Bond and Uysal (2007, Law and Human Behavior, 31, 109-115) and O'Sullivan (2007, Law and Human Behavior, 31, 117-123) concerns whether there are experts in deception detection. Two experiments sought to (a) identify expert(s) in detection and assess them twice with four tests, and (b) study their detection behavior using eye tracking. Paroled felons produced videotaped statements that were presented to students and law enforcement personnel. Two experts were identified, both female Native American BIA correctional officers. Experts were over 80% accurate in the first assessment, and scored at 90% accuracy in the second assessment. In Signal Detection analyses, experts showed high discrimination, and did not evidence biased responding. They exploited nonverbal cues to make fast, accurate decisions. These highly-accurate individuals can be characterized as experts in deception detection. |
Linus Holm; Johan Eriksson; Linus Andersson Looking as if you know: Systematic object inspection precedes object recognition Journal Article In: Journal of Vision, vol. 8, no. 4, pp. 1–7, 2008. @article{Holm2008,Sometimes we seem to look at the very object we are searching for, without consciously seeing it. How do we select object relevant information before we become aware of the object? We addressed this question in two recognition experiments involving pictures of fragmented objects. In Experiment 1, participants preferred to look at the target object rather than a control region 25 fixations prior to explicit recognition. Furthermore, participants inspected the target as if they had identified it around 9 fixations prior to explicit recognition. In Experiment 2, we investigated the influence of semantic knowledge in guiding object inspection prior to explicit recognition. Consistently, more specific knowledge about target identity made participants scan the fragmented stimulus more efficiently. For instance, non-target regions were rejected faster when participants knew the target object's name. Both experiments showed that participants were looking at the objects as if they knew them before they became aware of their identity. |
Marine Vernet; Qing Yang; Gintautas Daunys; Christophe Orssaud; Zoï Kapoula Divergence influences triggering of both vertical and horizontal saccades Journal Article In: Optometry and Vision Science, vol. 85, no. 3, pp. 187–195, 2008. @article{Vernet2008b,Purpose. In real life, divergence is frequently combined with vertical saccades. The purpose of this study was to examine the initiation of vertical and horizontal saccades, pure or combined with divergence. Methods. We used a gap paradigm to elicit vertical or horizontal saccades (10 degrees), pure or combined with a predictable divergence (10 degrees). Eye movements from 12 subjects were recorded with EyeLink II. Results. The major results were (i) when combined with divergence, the latency of horizontal saccades increased but not the latency of vertical saccades; (ii) for both vertical and horizontal saccades, a tight correlation between the latency of saccade and divergence was found; (iii) when the divergence was anticipated, the saccade was delayed. Conclusion. We conclude that the initiation of both components of combined movements is interdependent. |
Maria Nella Carminati; Roger P. G. Gompel; Christoph Scheepers; Manabu Arai Syntactic priming in comprehension: The role of argument order and animacy Journal Article In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 34, no. 5, pp. 1098–1110, 2008. @article{Carminati2008,Two visual-world eye-movement experiments investigated the nature of syntactic priming during comprehension–specifically, whether the priming effects in ditransitive prepositional object (PO) and double object (DO) structures (e.g., "The wizard will send the poison to the prince/the prince the poison?") are due to anticipation of structural properties following the verb (send) in the target sentence or to anticipation of animacy properties of the first postverbal noun. Shortly following the target verb onset, listeners looked at the recipient more (relative to the theme) following DO than PO primes, indicating that the structure of the prime affected listeners' eye gazes on the target scene. Crucially, this priming effect was the same irrespective of whether the postverbal nouns in the prime sentences did ("The monarch will send the painting to the president") or did not ("The monarch will send the envoy to the president") differ in animacy, suggesting that PO/DO priming in comprehension occurs because structural properties, rather than animacy features, are being primed when people process the ditransitive target verb. |
Ian Cunnings; Harald Clahsen The time-course of morphological constraints: A study of plurals inside derived words Journal Article In: The Mental Lexicon, vol. 3, no. 2, pp. 149–175, 2008. @article{Cunnings2008,The avoidance of regular but not irregular plurals inside compounds (e.g., *rats eater vs. mice eater) has been one of the most widely studied morphological phenomena in the psycholinguistics literature. To examine whether the constraints that are responsible for this contrast have any general significance beyond compounding, we investigated derived word forms containing regular and irregular plurals in two experiments. Experiment 1 was an offline acceptability judgment task, and Experiment 2 measured eye movements during reading derived words containing regular and irregular plurals and uninflected base nouns. The results from both experiments show that the constraint against regular plurals inside compounds generalizes to derived words. We argue that this constraint cannot be reduced to phonological properties, but is instead morphological in nature. The eye-movement data provide detailed information on the time-course of processing derived word forms indicating that early stages of processing are affected by a general constraint that disallows inflected words from feeding derivational processes, and that the more specific constraint against regular plurals comes in at a subsequent later stage of processing. We argue that these results are consistent with stage-based models of language processing. |
Marine Vernet; Qing Yang; Gintautas Daunys; Christophe Orssaud; Zoï Kapoula TMS of the posterior parietal cortex delays the latency of unpredictable saccades but not when they are combined with predictable divergence Journal Article In: Brain Research Bulletin, vol. 76, no. 1-2, pp. 50–56, 2008. @article{Vernet2008a,This study tests the influence of transcranial magnetic stimulation (TMS) of the posterior parietal cortex (PPC) on the initiation of horizontal and vertical saccades, alone or combined with a predictable divergence. A gap paradigm was used; TMS was applied 100 ms after target onset. TMS of the left PPC increased the latency of unpredictable rightward saccades, while TMS of the right PPC increased the latency of unpredictable downward saccades. Yet, when unpredictable saccades were combined with predictable divergence, neither component was affected. We suggest that in the latter case, the initiation of both components was taken in charge by another area, e.g. frontal. Thus, even when one component was predictable, a common mechanism controls the initiation of both components. The results confirm that TMS only modifies the latency when the cortical area stimulated is involved in the triggering of the eye movement. |
Linda Mortensen; Antje S. Meyer; Glyn W. Humphreys Speech planning during multiple-object naming: Effects of ageing Journal Article In: Quarterly Journal of Experimental Psychology, vol. 61, no. 8, pp. 1217–1238, 2008. @article{Mortensen2008,Two experiments were conducted with younger and older speakers. In Experiment 1, participants named single objects that were intact or visually degraded, while hearing distractor words that were phonologically related or unrelated to the object name. In both younger and older participants naming latencies were shorter for intact than for degraded objects and shorter when related than when unrelated distractors were presented. In Experiment 2, the single objects were replaced by object triplets, with the distractors being phonologically related to the first object's name. Naming latencies and gaze durations for the first object showed degradation and relatedness effects that were similar to those in single-object naming. Older participants were slower than younger participants when naming single objects and slower and less fluent on the second but not the first object when naming object triplets. The results of these experiments indicate that both younger and older speakers plan object names sequentially, but that older speakers use this planning strategy less efficiently. |
Roger Kalla; Neil G. Muggleton; Chi-Hung Juan; Alan Cowey; Vincent Walsh The timing of the involvement of the frontal eye fields and posterior parietal cortex in visual search Journal Article In: NeuroReport, vol. 19, no. 10, pp. 1069–1073, 2008. @article{Kalla2008,The frontal eye fields (FEFs) and posterior parietal cortex (PPC) are important for target detection in conjunction visual search but the relative timings of their contribution have not been compared directly. We addressed this using temporally specific double pulse transcranial magnetic stimulation delivered at different times over FEFs and PPC during performance of a visual search task. Disruption of performance was earlier (0/40 ms) with FEF stimulation than with PPC stimulation (120/160 ms), revealing a clear and substantial temporal dissociation of the involvement of these two areas in conjunction visual search. We discuss these timings with reference to the respective roles of FEF and PPC in the modulation of extrastriate visual areas and selection of responses. |
Julius Verrel; Harold Bekkering; Bert Steenbergen Eye-hand coordination during manual object transport with the affected and less affected hand in adolescents with hemiparetic cerebral palsy Journal Article In: Experimental Brain Research, vol. 187, no. 1, pp. 107–116, 2008. @article{Verrel2008,In the present study we investigated eye-hand coordination in adolescents with hemiparetic cerebral palsy (CP) and neurologically healthy controls. Using an object prehension and transport task, we addressed two hypotheses, motivated by the question whether early brain damage and the ensuing limitations of motor activity lead to general and/or effector-specific effects in visuomotor control of manual actions. We hypothesized that individuals with hemiparetic CP would more closely visually monitor actions with their affected hand, compared to both their less affected hand and to control participants without a sensorimotor impairment. A second, more speculative hypothesis was that, in relation to previously established deficits in prospective action control in individuals with hemiparetic CP, gaze patterns might be less anticipatory in general, also during actions performed with the less affected hand. Analysis of the gaze and hand movement data revealed the increased visual monitoring of participants with CP when using their affected hand at the beginning as well as during object transport. In contrast, no general deficit in anticipatory gaze control in the participants with hemiparetic CP could be observed. Collectively, these findings are the first to directly show that individuals with hemiparetic CP adapt eye-hand coordination to the specific constraints of the moving limb, presumably to compensate for sensorimotor deficits. |
Elizabeth Wonnacott; Elissa L. Newport; Michael K. Tanenhaus Acquiring and processing verb argument structure: Distributional learning in a miniature language Journal Article In: Cognitive Psychology, vol. 56, no. 3, pp. 165–209, 2008. @article{Wonnacott2008,Adult knowledge of a language involves correctly balancing lexically-based and more language-general patterns. For example, verb argument structures may sometimes readily generalize to new verbs, yet with particular verbs may resist generalization. From the perspective of acquisition, this creates significant learnability problems, with some researchers claiming a crucial role for verb semantics in the determination of when generalization may and may not occur. Similarly, there has been debate regarding how verb-specific and more generalized constraints interact in sentence processing and on the role of semantics in this process. The current work explores these issues using artificial language learning. In three experiments using languages without semantic cues to verb distribution, we demonstrate that learners can acquire both verb-specific and verb-general patterns, based on distributional information in the linguistic input regarding each of the verbs as well as across the language as a whole. As with natural languages, these factors are shown to affect production, judgments and real-time processing. We demonstrate that learners apply a rational procedure in determining their usage of these different input statistics and conclude by suggesting that a Bayesian perspective on statistical learning may be an appropriate framework for capturing our findings. |
Jonathan S. A. Carriere; Daniel Eaton; Michael G. Reynolds; Mike J. Dixon; Daniel Smilek Grapheme–color synesthesia influences overt visual attention Journal Article In: Journal of Cognitive Neuroscience, vol. 21, no. 2, pp. 246–258, 2008. @article{Carriere2008,For individuals with grapheme–color synesthesia, achromatic letters and digits elicit vivid perceptual experiences of color. We report two experiments that evaluate whether synesthesia influences overt visual attention. In these experiments, two grapheme–color synesthetes viewed colored letters while their eye movements were monitored. Letters were presented in colors that were either congruent or incongruent with the synesthetes' colors. Eye tracking analysis showed that synesthetes exhibited a color congruity bias—a propensity to fixate congruently colored letters more often and for longer durations than incongruently colored letters—in a naturalistic free-viewing task. In a more structured visual search task, this congruity bias caused synesthetes to rapidly fixate and identify congruently colored target letters, but led to problems in identifying incongruently colored target letters. The results are discussed in terms of their implications for perception in synesthesia. |
Verena S. Bonitz; Robert D. Gordon Attention to smoking-related and incongruous objects during scene viewing Journal Article In: Acta Psychologica, vol. 129, no. 2, pp. 255–263, 2008. @article{Bonitz2008,This study examined the influences of semantic characteristics of objects in real-world scenes on allocation of attention as reflected in eye movement measures. Stimuli consisted of full-color photographic scenes, and within each scene, the semantic salience of two target objects was manipulated while the objects' perceptual salience was kept constant. One of the target objects was either inconsistent or consistent with the scene category. In addition, the second target object was either smoking-related or neutral. Two groups of college students, namely current cigarette smokers (N = 18) and non-smokers (N = 19), viewed each scene for 10 s while their eye movements were recorded. While both groups showed preferential allocation of attention to inconsistent objects, smokers also selectively attended to smoking-related objects. Theoretical implications of the results are discussed. |
Jens R. Helmert; Sebastian Pannasch; Boris M. Velichkovsky Influences of dwell time and cursor control on the performance in gaze driven typing Journal Article In: Journal of Eye Movement Research, vol. 2, no. 1, pp. 1–8, 2008. @article{Helmert2008,In gaze controlled computer interfaces the dwell time is often used as selection criterion. But this solution comes along with several problems, especially in the temporal domain: Eye movement studies on scene perception could demonstrate that fixations of different durations serve different purposes and should therefore be differentiated. The use of dwell time for selection implies the need to distinguish intentional selections from merely per-ceptual processes, described as the Midas touch problem. Moreover, the feedback of the actual own eye position has not yet been addressed to systematic studies in the context of usability in gaze based computer interaction. We present research on the usability of a simple eye typing set up. Different dwell time and eye position feedback configurations were tested. Our results indicate that smoothing raw eye position and temporal delays in visual feedback enhance the system's functionality and usability. Best overall performance was obtained with a dwell time of 500 ms. |
Sarah Brown-Schmidt; Christine Gunlogson; Michael K. Tanenhaus Addressees distinguish shared from private information when interpreting questions during interactive conversation Journal Article In: Cognition, vol. 107, no. 3, pp. 1122–1134, 2008. @article{BrownSchmidt2008,Two experiments examined the role of common ground in the production and on-line interpretation of wh-questions such as What's above the cow with shoes? Experiment 1 examined unscripted conversation, and found that speakers consistently use wh-questions to inquire about information known only to the addressee. Addressees were sensitive to this tendency, and quickly directed attention toward private entities when interpreting these questions. A second experiment replicated the interpretation findings in a more constrained setting. These results add to previous evidence that the common ground influences initial language processes, and suggests that the strength and polarity of common ground effects may depend on contributions of sentence type as well as the interactivity of the situation. |
S. Moshel; Ari Z. Zivotofsky; L. Jin-Rong; Ralf Engbert; Jürgen Kurths; Reinhold Kliegl; Shlomo Havlin Persistence and phase synchronisation properties of fixational eye movements Journal Article In: The European Physical Journal Special Topics, vol. 161, pp. 207–223, 2008. @article{Moshel2008,When we fixate our gaze on a stable object, our eyes move continuously with extremely small involuntary and autonomic movements, that even we are unaware of during their occurrence. One of the roles of these fixational eye movements is to prevent the adaptation of the visual system to continuous illumination and inhibit fading of the image. These random, small movements are restricted at long time scales so as to keep the target at the centre of the field of view. In addition, the synchronisation properties between both eyes are related to binocular coordination in order to provide stereopsis. We investigated the roles of different time scale behaviours, especially how they are expressed in the different spatial directions (vertical versus horizontal). We also tested the synchronisation between both eyes. Results show different scaling behaviour between horizontal and vertical movements. When the small ballistic movements, i.e., microsaccades, are removed, the scaling behaviour in both axes becomes similar. Our findings suggest that microsaccades enhance the persistence at short time scales mostly in the horizontal component and much less in the vertical component. We also applied the phase synchronisation decay method to study the synchronisation between six combinations of binocular fixational eye movement components. We found that the vertical-vertical components of right and left eyes are significantly more synchronised than the horizontal-horizontal components. These differences may be due to the need for continuously moving the eyes in the horizontal plane in order to match the stereoscopic image for different viewing distances. |
George L. Malcolm; Linda J. Lanyon; Andrew J. B. Fugard; Jason J. S. Barton Scan patterns during the processing of facial expression versus identity: An exploration of task-driven and stimulus-driven effects Journal Article In: Journal of Vision, vol. 8, no. 8, pp. 1–9, 2008. @article{Malcolm2008,Perceptual studies suggest that processing facial identity emphasizes upper-face information, whereas processing expressions of anger or happiness emphasizes the lower-face. The two goals of the present study were to determine (a) if the distributions of eye fixations reflect these upper/lower-face biases, and (b) whether this bias is task- or stimulus-driven. We presented a target face followed by a probe pair of morphed faces, neither of which was identical to the target. Subjects judged which of the pair was more similar to the target face while eye movements were recorded. In Experiment 1 the probe pair always differed from each other in both identity and expression on each trial. In one block subjects judged which probe face was more similar to the target face in identity, and in a second block subjects judged which probe face was more similar to the target face in expression. In Experiment 2 the two probe faces differed in either expression or identity, but not both. Subjects were not informed which dimension differed, but simply asked to judge which probe face was more similar to the target face. We found that subjects scanned the upper-face more than the lower-face during the identity task but the lower-face more than the upper-face during the expression task in Experiment 1 (task-driven effects), with significantly less variation in bias in Experiment 2 (stimulus-driven effects). We conclude that fixations correlate with regional variations of diagnostic information in different processing tasks, but that these reflect top-down task-driven guidance of information acquisition more than stimulus-driven effects. |
Wolfgang Jaschinski; Stephanie Jainta; Jörg Hoormann Comparison of shutter glasses and mirror stereoscope for measuring dynamic and static vergence Journal Article In: Journal of Eye Movement Research, vol. 1, no. 2, pp. 1–7, 2008. @article{Jaschinski2008,Vergence eye movement recordings in response to disparity step stimuli require to present different stimuli to the two eyes. The traditional method is a mirror stereoscope. Shutter glasses are more convenient, but have disadvantages as limited repetition rate, residual cross task, and reduced luminance. Therefore, we compared both techniques measuring (1) dynamic disparity step responses for stimuli of 1 and 3 deg and (2) fixation disparity, the static vergence error. Shutter glasses and mirror stereoscope gave very similar dynamic responses with correlations of about 0.95 for the objectively measured vergence velocity and for the response amplitude reached 400 ms after the step stimulus (measured objectively with eye movement recordings and subjectively with dichoptic nonius lines). Both techniques also provided similar amounts of fixation disparity, tested with dichoptic nonius lines. |
Ronald Berg; Frans W. Cornelissen; Jos B. T. M. Roerdink Perceptual dependencies in information visualization assessed by complex visual search Journal Article In: ACM Transactions on Applied Perception, vol. 4, no. 4, pp. 1–21, 2008. @article{Berg2008,A common approach for visualizing data sets is to map them to images in which distinct data dimensions are mapped to distinct visual features, such as color, size and orientation. Here, we consider visualizations in which different data dimensions should receive equal weight and attention. Many of the end-user tasks performed on these images involve a form of visual search. Often, it is simply assumed that features can be judged independently of each other in such tasks. However, there is evidence for perceptual dependencies when simultaneously presenting multiple features. Such dependencies could potentially affect information visualizations that contain combinations of features for encoding information and, thereby, bias subjects into unequally weighting the relevance of different data dimensions. We experimentally assess (1) the presence of judgment dependencies in a visualization task (searching for a target node in a node-link diagram) and (2) how feature contrast relates to salience. From a visualization point of view, our most relevant findings are that (a) to equalize saliency (and thus bottom-up weighting) of size and color, color contrasts have to become very low. Moreover, orientation is less suitable for representing information that consists of a large range of data values, because it does not show a clear relationship between contrast and salience; (b) color and size are features that can be used independently to represent information, at least as far as the range of colors that were used in our study are concerned; (c) the concept of (static) feature salience hierarchies is wrong; how salient a feature is compared to another is not fixed, but a function of feature contrasts; (d) final decisions appear to be as good an indicator of perceptual performance as indicators based on measures obtained from individual fixations. Eye tracking, therefore, does not necessarily present a benefit for user studies that aim at evaluating performance in search tasks. |
L. Elliot Hong; Kathleen A. Turano; Hugh B. O'Neill; Lei Hao; Ikwunga Wonodi; Robert P. McMahon; Amie Elliott; Gunvant K. Thaker Refining the predictive pursuit endophenotype in schizophrenia. Journal Article In: Biological Psychiatry, vol. 63, no. 5, pp. 458–464, 2008. @article{Hong2008,Background: To utilize fully a schizophrenia endophenotype in gene search and subsequent neurobiological studies, it is critical that the precise underlying physiologic deficit is identified. Abnormality in smooth pursuit eye movements is one of the endophenotypes of schizophrenia. The precise nature of the abnormality is unknown. Previous work has shown a reduced predictive pursuit response to a briefly masked (i.e., invisible) moving object in schizophrenia. However, the overt awareness of target removal can confound the measurement. Methods: This study employed a novel method that covertly stabilized the moving target image onto the fovea. The foveal stabilization was implemented after the target on a monitor had oscillated at least for one cycle and near the change of direction when the eye velocity momentarily reached zero. Thus, the subsequent pursuit eye movements were completely predictive and internally driven. Eye velocity during this foveally stabilized smooth pursuit was compared among schizophrenia patients (n = 45), their unaffected first-degree relatives (n = 42), and healthy comparison subjects (n = 22). Results: Schizophrenia patients and their unaffected relatives performed similarly and both had substantially reduced predictive pursuit acceleration and velocity under the foveally stabilized condition. Conclusions: These findings show that inability to maintain internal representation of the target motion or integration of such information into a predictive response may be the specific brain deficit indexed by the smooth pursuit endophenotype in schizophrenia. Similar performance between patients and unaffected relatives suggests that the refined predictive pursuit measure may index a less complex genetic origin of the eye-tracking deficits in schizophrenia families. |
Thérèse Collins; Tobias Schicke; Brigitte Röder Action goal selection and motor planning can be dissociated by tool use Journal Article In: Cognition, vol. 109, no. 3, pp. 363–371, 2008. @article{Collins2008,The preparation of eye or hand movements enhances visual perception at the upcoming movement end position. The spatial location of this influence of action on perception could be determined either by goal selection or by motor planning. We employed a tool use task to dissociate these two alternatives. The instructed goal location was a visual target to which participants pointed with the tip of a triangular hand-held tool. The motor endpoint was defined by the final fingertip position necessary to bring the tool tip onto the goal. We tested perceptual performance at both locations (tool tip endpoint, motor endpoint) with a visual discrimination task. Discrimination performance was enhanced in parallel at both spatial locations, but not at nearby and intermediate locations, suggesting that both action goal selection and motor planning contribute to visual perception. In addition, our results challenge the widely held view that tools extend the body schema and suggest instead that tool use enhances perception at those precise locations which are most relevant during tool action: the body part used to manipulate the tool, and the active tool tip. |
Matthew S. Peterson; Melissa R. Beck; Jason H. Wong Were you paying attention to where you looked? The role of executive working memory in visual search Journal Article In: Psychonomic Bulletin & Review, vol. 15, no. 2, pp. 372–377, 2008. @article{Peterson2008,Recent evidence has indicated that performing a working memory task that loads executive working memory leads to less efficient visual search (Han & Kim, 2004). We explored the role that executive functioning plays in visual search by examining the pattern of eye movements while participants performed a search task with or without a secondary executive working memory task. Results indicate that executive functioning plays two roles in visual search: the identification of objects and the control of the disengagement of attention. |
Steven Frisson; Brian McElree Complement coercion is not modulated by competition: Evidence from eye movements Journal Article In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 34, no. 1, pp. 1–11, 2008. @article{Frisson2008a,An eye-movement study examined the processing of expressions requiring complement coercion (J. Pustejovsky, 1995), in which a noun phrase that does not denote an event (e.g., the book) appears as the complement of an event-selecting verb (e.g., began the book). Previous studies demonstrated that these expressions are more costly to process than are control expressions that can be processed with basic compositional operations (L. Pylkka ̈nen & B. McElree, 2006). Complement coercion is thought to be costly because comprehenders need to construct an event sense of the complement to satisfy the semantic restrictions of the verb (e.g., began writing the book). The reported experiment tests the alternative hypotheses that the cost arises from the need to select 1 interpretation from several or from competition between alternative interpretations. Expressions with weakly constrained interpretations (no dominant interpretation and several alternative interpretations) were not more costly to process than expressions with a strongly constrained interpretation (1 dominant interpretation and few alternative interpretations). These results are consistent with the hypothesis that the cost reflects the on-line construction of an event sense for the complement. |
Amelia R. Hunt; Craig S. Chapman; Alan Kingstone Taking a long look at action and time perception Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 34, no. 1, pp. 125–136, 2008. @article{Hunt2008,Everyone has probably experienced chronostasis, an illusion of time that can cause a clock's second hand to appear to stand still during an eye movement. Though the illusion was initially thought to reflect a mechanism for preserving perceptual continuity during eye movements, an alternative hypothesis has been advanced that overestimation of time might be a general effect of any action. Contrary to both of these hypotheses, the experiments reported here suggest that distortions of time perception related to an eye movement are not distinct from temporal distortions for other kinds of responses. Moreover, voluntary action is neither necessary nor sufficient for overestimation effects. These results lead to a new interpretation of chronostasis based on the role of attention and memory in time estimation. |
Steven Frisson; Elizabeth Niswander-Klement; Alexander Pollatsek The role of semantic transparency in the processing of English compound words Journal Article In: British Journal of Psychology, vol. 99, no. 1, pp. 87–107, 2008. @article{Frisson2008,Experiment 1 examined whether the semantic transparency of an English unspaced compound word affected how long it took to process it in reading. Three types of opaque words were each compared with a matched set of transparent words (i.e. matched on the length and frequency of the constituents and the frequency of the word as a whole). Two sets of the opaque words were partially opaque: either the first constituent was not related to the meaning of the compound (opaque-transparent) or the second constituent was not related to the meaning of the compound (transparent-opaque). In the third set (opaque-opaque), neither constituent was related to the meaning of the compound. For all three sets, there was no significant difference between the opaque and the transparent words on any eye-movement measure. This replicates an earlier finding with Finnish compound words (Pollatsek & Hyönä, 2005) and indicates that, although there is now abundant evidence that the component constituents play a role in the encoding of compound words, the meaning of the compound word is not constructed from the parts, at least for compound words for which a lexical entry exists. Experiment 2 used the same compounds but with a space between the constituents. This presentation resulted in a transparency effect, indicating that when an assembly route is 'forced', transparency does play a role. |
Christoph Rasche; Karl R. Gegenfurtner Orienting during gaze guidance in a letter-identification task Journal Article In: Journal of Eye Movement Research, vol. 3, no. 4, pp. 1–10, 2008. @article{rg10b,The idea of gaze guidance is to lead a viewer's gaze through a visual display in order to facilitate the viewer's search for specific information in a least-obtrusive manner. This study investigates saccadic orienting when a viewer is guided in a fast-paced, low-contrast letter identification task. Despite the task's difficulty and although guiding cues were ad-justed to gaze eccentricity, observers preferred attentional over saccadic shifts to obtain a letter identification judgment; and if a saccade was carried out its saccadic constant error was 50%. From those results we derive a number of design recommendations for the process of gaze guidance. |
Areh Mikulić; Michael C. Dorris Temporal and spatial allocation of motor preparation during a mixed-strategy game Journal Article In: Journal of Neurophysiology, vol. 100, no. 4, pp. 2101–2108, 2008. @article{Mikulic2008,Adopting a mixed response strategy in competitive situations can prevent opponents from exploiting predictable play. What drives stochastic action selection is unclear given that choice patterns suggest that, on average, players are indifferent to available options during mixed-strategy equilibria. To gain insight into this stochastic selection process, we examined how motor preparation was allocated during a mixed-strategy game. If selection processes on each trial reflect a global indifference between options, then there should be no bias in motor preparation (unbiased preparation hypothesis). If, however, differences exist in the desirability of options on each trial then motor preparation should be biased toward the preferred option (biased preparation hypothesis). We tested between these alternatives by examining how saccade preparation was allocated as human subjects competed against an adaptive computer opponent in an oculomotor version of the game "matching pennies." Subjects were free to choose between two visual targets using a saccadic eye movement. Saccade preparation was probed by occasionally flashing a visual distractor at a range of times preceding target presentation. The probability that a distractor would evoke a saccade error, and when it failed to do so, the probability of choosing each of the subsequent targets quantified the temporal and spatial evolution of saccade preparation, respectively. Our results show that saccade preparation became increasingly biased as the time of target presentation approached. Specifically, the spatial locus to which saccade preparation was directed varied from trial to trial, and its time course depended on task timing. |
Andre Kaminiarz; Bart Krekelberg; Frank Bremmer Expansion of visual space during optokinetic afternystagmus (OKAN) Journal Article In: Journal of Neurophysiology, vol. 99, no. 5, pp. 2470–2478, 2008. @article{Kaminiarz2008,The mechanisms underlying visual perceptual stability are usually investigated using voluntary eye movements. In such studies, errors in perceptual stability during saccades and pursuit are commonly interpreted as mismatches between actual eye position and eye-position signals in the brain. The generality of this interpretation could in principle be tested by investigating spatial localization during reflexive eye movements whose kinematics are very similar to those of voluntary eye movements. Accordingly, in this study, we determined mislocalization of flashed visual targets during optokinetic afternystagmus (OKAN). These eye movements are quite unique in that they occur in complete darkness and are generated by subcortical control mechanisms. We found that during horizontal OKAN slow phases, subjects mislocalize targets away from the fovea in the horizontal direction. This corresponds to a perceived expansion of visual space and is unlike mislocalization found for any other voluntary or reflexive eye movement. Around the OKAN fast phases, we found a bias in the direction of the fast phase prior to its onset and opposite to the fast-phase direction thereafter. Such a biphasic modulation has also been reported in the temporal vicinity of saccades and during optokinetic nystagmus (OKN). A direct comparison, however, showed that the modulation during OKAN was much larger and occurred earlier relative to fast-phase onset than during OKN. A simple mismatch between the current eye position and the eye-position signal in the brain is unlikely to explain such disparate results across similar eye movements. Instead, these data support the view that mislocalization arises from errors in eye-centered position information. |
Leah Roberts; Marianne Gullberg; Peter Indefrey Online pronoun resolution in L2 discouse: L1 influence and general learner effects Journal Article In: Studies in Second Language Acquisition, vol. 30, pp. 333–357, 2008. @article{rgi08,This study investigates whether advanced second language (L2) learners of a nonnull subject language (Dutch) are influenced by their null subject first language (L1) (Turkish) in their offline and online resolution of subject pronouns in L2 discourse. To tease apart potential L1 effects from possible general L2 processing effects, we also tested a group of German L2 learners of Dutch who were predicted to perform like the native Dutch speakers. The two L2 groups differed in their offline interpretations of subject pronouns. The Turkish L2 learners exhibited a L1 influence, because approximately half the time they interpreted Dutch subject pronouns as they would overt pronouns in Turkish, whereas the German L2 learners performed like the Dutch controls, interpreting pronouns as coreferential with the current discourse topic. This L1 effect was not in evidence in eye-tracking data, however. Instead, the L2 learners patterned together, showing an online processing disadvantage when two potential antecedents for the pronoun were grammatically available in the discourse. This processing disadvantage was in evidence irrespective of the properties of the learners' L1 or their final interpretation of the pronoun. Therefore, the results of this study indicate both an effect of the L1 on the L2 in offline resolution and a general L2 processing effect in online subject pronoun resolution. |
Angelika Lingnau; Jens Schwarzbach; Dirk Vorberg Adaptive strategies for reading with a forced retinal location Journal Article In: Journal of Vision, vol. 8, no. 5, pp. 1–18, 2008. @article{Lingnau2008,Forcing normal-sighted participants to use a distinct parafoveal retinal location for reading, we studied which part of the visual field is best suited to take over functions of the fovea during early stages of macular degeneration (MD). A region to the right of fixation lead to best reading performance and most natural gaze behavior, whereas reading performance was severely impaired when a region to the left or below fixation had to be used. An analysis of the underlying oculomotor behavior revealed that practice effects were accompanied by a larger number of saccades in text direction and decreased fixation durations, whereas no adjustment of saccade amplitudes was observed. We provide an explanation for the observed performance differences at different retinal locations based on the interplay of attention and eye movements. Our findings have important implications for the development of training methods for MD patients targeted at reading, suggesting that it would be beneficial for MD patients to use a region to the right of their central scotoma. |
Brad C. Motter; Diglio A. Simoni Changes in the functional visual field during search with and without eye movements Journal Article In: Vision Research, vol. 48, pp. 2382–2393, 2008. @article{Motter2008,The size of the functional visual field (FVF) is dynamic, changing with the context and attentive demand that each fixation brings as we move our eyes and head to explore the visual scene. Using performance measures of the FVF we show that during search conditions with eye movements, the FVF is small compared to the size of the FVF measured during search without eye movements. In all cases the size of the FVF is constrained by the density of distracting items. During search without eye movements the FVF expands with time; subjects have idiosyncratic spatial biases suggesting covert shifts of attention. For search within the constraints imposed by item density, the rate of item inspection is the same across all search conditions. Array set size effects are not apparent once stimulus density is taken into account, a result that is consistent with a spatial constraint for the FVF based on the cortical separation hypothesis. |
J. F. Soechting; Martha Flanders Extrapolation of visual motion for manual interception Journal Article In: Journal of Neurophysiology, vol. 99, no. 6, pp. 2956–2967, 2008. @article{sf08,A frequent goal of hand movement is to touch a moving target or to make contact with a stationary object that is in motion relative to the moving head and body. This process requires a prediction of the target's motion, since the initial direction of the hand movement anticipates target motion. This experiment was designed to define the visual motion parameters that are incorporated in this prediction of target motion. On seeing a go signal (a change in target color), human subjects slid the right index finger along a touch-sensitive computer monitor to intercept a target moving along an unseen circular or oval path. The analysis focused on the initial direction of the interception movement, which was found to be influenced by the time required to intercept the target and the target's distance from the finger's starting location. Initial direction also depended on the curvature of the target's trajectory in a manner that suggested that this parameter was underestimated during the process of extrapolation. The pattern of smooth pursuit eye movements suggests that the extrapolation of visual target motion was based on local motion cues around the time of the onset of hand movement, rather than on a cognitive synthesis of the target's pattern of motion. |
Archana Pradeep; Shery Thomas; Eryl O. Roberts; Frank A. Proudlock; Irene Gottlob Reduction of congenital nystagmus in a patient after smoking cannabis Journal Article In: Strabismus, vol. 16, no. 1, pp. 29–32, 2008. @article{Pradeep2008,INTRODUCTION: Smoking cannabis has been described to reduce acquired pendular nystagmus in MS, but its effect on congenital nystagmus is not known. PURPOSE: To report the effect of smoking cannabis in a case of congenital nystagmus. METHODS: A 19-year-old male with congenital horizontal nystagmus presented to the clinic after smoking 10 mg of cannabis. He claimed that the main reason for smoking cannabis was to improve his vision. At the next clinic appointment, he had not smoked cannabis for 3weeks. Full ophthalmologic examination and eye movement recordings were performed at each visit. RESULTS: Visual acuity improved by 3 logMar lines in the left eye and by 2 logMar lines in the right eye after smoking cannabis. The nystagmus intensities were reduced by 30% in primary position and 44%, 11%, 10% and 40% at 20-degree eccentricity to the right, left, elevation and depression, respectively, after smoking cannabis. CONCLUSION: Cannabis may be beneficial in the treatment of congenital idiopathic nystagmus (CIN). Further research to clarify the safety and efficacy of cannabis in patients with CIN, administered for example by capsules or spray, would be important. |
Dale J. Barr Pragmatic expectations and linguistic evidence: Listeners anticipate but do not integrate common ground Journal Article In: Cognition, vol. 109, no. 1, pp. 18–40, 2008. @article{Barr2008,When listeners search for the referent of a speaker's expression, they experience interference from privileged knowledge, knowledge outside of their 'common ground' with the speaker. Evidence is presented that this interference reflects limitations in lexical processing. In three experiments, listeners' eye movements were monitored as they searched for the target of a speaker's referring expression in a display that also contained a phonological competitor (e.g., bucket/buckle). Listeners anticipated that the speaker would refer to something in common ground, but they did not experience less interference from a competitor in privileged ground than from a matched competitor in common ground. In contrast, interference from the competitor was eliminated when it was ruled out by a semantic constraint. These findings support a view of comprehension as relying on multiple systems with distinct access to information and present a challenge for constraint-based views of common ground. |
Jörg Hoormann; Stephanie Jainta; Wolfgang Jaschinski The effect of calibration errors on the accuracy of the eye movement recordings Journal Article In: Journal of Eye Movement Research, vol. 1, no. 2, pp. 1–7, 2008. @article{Hoormann2008,For calibrating eye movement recordings, a regression between spatially defined calibration points and corresponding measured raw data is performed. Based on this regression, a confidence interval (CI) of the actually measured eye position can be calculated in order to$backslash$nquantify the measurement error introduced by inaccurate calibration coefficients. For calculating this CI, a standard deviation (SD) - depending on the calibration quality and the$backslash$ndesign of the calibration procedure - is needed.$backslash$nExamples of binocular recordings with separate monocular calibrations illustrate that the SD is almost independent of the number and spatial separation between the calibration points – even though the later was expected from theoretical simulation. Our simulations and recordings demonstrate that the SD depends critically on residuals at certain calibration points, thus robust regressions are suggested. |
Casimir J. H. Ludwig; Adam Ranson; Iain D. Gilchrist Oculomotor capture by transient events: A comparison of abrupt onsets, offsets, motion, and flicker Journal Article In: Journal of Vision, vol. 8, no. 14, pp. 1–16, 2008. @article{Ludwig2008,Attentional and oculomotor capture by some salient visual event gives insight into what types of dynamic signals the human orienting system is sensitive to. We examined the sensitivity of the saccadic eye movement system to 4 types of dynamic, but task-irrelevant, visual events: abrupt onset, abrupt offset, motion onset and flicker onset. We varied (1) the primary task (contrast vs. motion discrimination) and (2) the amount of prior knowledge of the location of the dynamic event. Interference from the irrelevant events was quantified using a discrimination threshold metric. When the primary task involved contrast discrimination, all four events disrupted performance approximately equally, including the sudden disappearance of an old object. However, when motion was the task-relevant dimension, abrupt onsets and offsets did not disrupt performance at all, but motion onset had a strong effect. Providing more spatial certainty to observers decreased the amount of direct oculomotor capture but nevertheless impaired performance. We conclude that oculomotor capture is predominantly contingent upon the channel the observer monitors in order to perform the primary visual task. |
Ralf Engbert; Antje Nuthmann Self-consistent estimation of mislocated fixations during reading Journal Article In: PLoS ONE, vol. 3, no. 2, pp. e1534, 2008. @article{Engbert2008,During reading, we generate saccadic eye movements to move words into the center of the visual field for word processing. However, due to systematic and random errors in the oculomotor system, distributions of within-word landing positions are rather broad and show overlapping tails, which suggests that a fraction of fixations is mislocated and falls on words to the left or right of the selected target word. Here we propose a new procedure for the self-consistent estimation of the likelihood of mislocated fixations in normal reading. Our approach is based on iterative computation of the proportions of several types of oculomotor errors, the underlying probabilities for word-targeting, and corrected distributions of landing positions. We found that the average fraction of mislocated fixations ranges from about 10% to more than 30% depending on word length. These results show that fixation probabilities are strongly affected by oculomotor errors. |
John M. Henderson; Graham L. Pierce Eye movements during scene viewing: Evidence for mixed control of fixation durations Journal Article In: Psychonomic Bulletin & Review, vol. 15, no. 3, pp. 566–573, 2008. @article{Henderson2008,Recent behavioral and computational research on eye movement control during scene viewing has focused on where the eyes move. However, fixations also differ in their durations, and when the eyes move may be another important indicator of perceptual and cognitive activity. Here we used a scene onset delay paradigm to investigate the degree to which individual fixation durations are under direct moment-to-moment control of the viewer's current visual scene. During saccades just prior to critical fixations, the scene was removed from view so that when the eyes landed, no scene was present. Following a manipulated delay period, the scene was restored to view. We found that one population of fixations was under the direct control of the current scene, increasing in duration as delay increased. A second population of fixations was relatively constant across delay. The pattern of data did not change whether delay duration was random or blocked, suggesting that the effects were not under the strategic control of the viewer. The results support a mixed control model in which the durations of some fixations proceed regardless of scene presence, whereas others are under the direct moment-to-moment control of ongoing scene analysis. |
Denis Drieghe Foveal processing and word skipping during reading Journal Article In: Psychonomic Bulletin & Review, vol. 15, no. 4, pp. 856–860, 2008. @article{Drieghe2008,An eyetracking experiment is reported examining the assumption that a word is skipped during sentence reading because parafoveal processing during preceding fixations has reached an advanced level in recognizing that word. Word n was presented with reduced contrast, with case alternation, or normally. Reingold and Rayner (2006) reported that, in comparison to the normal condition, reduced contrast increased viewing times on word n but not on word n+1, whereas case alternation increased viewing times on both words. These patterns were reflected in the fixation times of the present experiment, but a striking dissociation was observed in the skipping of word n+1: The reduced contrast of word n decreased skipping of word n+1, whereas case alternation did not. Apart from the amount of parafoveal processing, the decision to skip word n+1 is also influenced by the ease of processing word n: Difficulties in processing word n lead to a more conservative strategy in the decision to skip word n+1. |
Menno Van Der Schoot; Alain L. Vasbinder; Tako M. Horsley; Ernest C. D. M. Van Lieshout The role of two reading strategies in text comprehension: An eye fixation study in primary school children Journal Article In: Journal of Research in Reading, vol. 31, no. 2, pp. 203–223, 2008. @article{VanDerSchoot2008,This study examined whether 1012-year-old children use two reading strategies to aid their text comprehension: (1) distinguishing between important and unimportant words; and (2) resolving anaphoric references. Of interest was the question to what extent use of these reading strategies was predictive of reading comprehension skill over and above decoding skill and vocabulary. Reading strategy use was examined by the recording of eye fixations on specific target words. In contrast to less successful comprehenders, more successful comprehenders invested more processing time in important than in unimportant words. On the other hand, they needed less time to determine the antecedent of an anaphor. The results suggest that more successful comprehenders build a more effective mental model of the text than less successful comprehenders in at least two ways. First, they allocate more attention to the incorporation of goal-relevant than goal-irrelevant information into the model. Second, they ascertain that the text model is coherent and richly connected. |
Denise H. Wu; Anne Morganti; Anjan Chatterjee Neural substrates of processing path and manner information of a moving event Journal Article In: Neuropsychologia, vol. 46, no. 2, pp. 704–713, 2008. @article{Wu2008,Languages consistently distinguish the path and the manner of a moving event in different constituents, even if the specific constituents themselves vary across languages. Children also learn to categorize moving events according to their path and manner at different ages. Motivated by these linguistic and developmental observations, we employed fMRI to test the hypothesis that perception of and attention to path and manner of motion is segregated neurally. Moreover, we hypothesize that such segregation respects the "dorsal-where and ventral-what" organizational principle of vision. Consistent with this proposal, we found that attention to the path of a moving event was associated with greater activity within bilateral inferior/superior parietal lobules and the frontal eye-field, while attention to manner was associated with greater activity within bilateral postero-lateral inferior/middle temporal regions. Our data provide evidence that motion perception, traditionally considered as a dorsal "where" visual attribute, further segregates into dorsal path and ventral manner attributes. This neural segregation of the components of motion, which are linguistically tagged, points to a perceptual counterpart of the functional organization of concepts and language. |
Jennifer E. Arnold THE BACON not the bacon: How children and adults understand accented and unaccented noun phrases Journal Article In: Cognition, vol. 108, no. 1, pp. 69–99, 2008. @article{Arnold2008,Two eye-tracking experiments examine whether adults and 4- and 5-year-old children use the presence or absence of accenting to guide their interpretation of noun phrases (e.g., the bacon) with respect to the discourse context. Unaccented nouns tend to refer to contextually accessible referents, while accented variants tend to be used for less accessible entities. Experiment 1 confirms that accenting is informative for adults, who show a bias toward previously-mentioned objects beginning 300 ms after the onset of unaccented nouns and pronouns. But contrary to findings in the literature, accented words produced no observable bias. In Experiment 2, 4 and 5 year olds were also biased toward previously-mentioned objects with unaccented nouns and pronouns. This builds on findings of limits on children's on-line reference comprehension [Arnold, J. E., Brown-Schmidt, S., & Trueswell, J. C. (2007). Children's use of gender and order-of-mention during pronoun comprehension. Language and Cognitive Processes], showing that children's interpretation of unaccented nouns and pronouns is constrained in contexts with one single highly accessible object. |
Luke Barrington; Tim K. Marks; Janet Hui-wen Hsiao; Garrison W. Cottrell NIMBLE: A kernel density model of saccade-based visual memory Journal Article In: Journal of Vision, vol. 8, no. 14, pp. 17–17, 2008. @article{Barrington2008,We present a Bayesian version of J. Lacroix, J. Murre, and E. Postma's (2006) Natural Input Memory (NIM) model of saccadic visual memory. Our model, which we call NIMBLE (NIM with Bayesian Likelihood Estimation), uses a cognitively plausible image sampling technique that provides a foveated representation of image patches. We conceive of these memorized image fragments as samples from image class distributions and model the memory of these fragments using kernel density estimation. Using these models, we derive class-conditional probabilities of new image fragments and combine individual fragment probabilities to classify images. Our Bayesian formulation of the model extends easily to handle multi-class problems. We validate our model by demonstrating human levels of performance on a face recognition memory task and high accuracy on multi-category face and object identification. We also use NIMBLE to examine the change in beliefs as more fixations are taken from an image. Using fixation data collected from human subjects, we directly compare the performance of NIMBLE's memory component to human performance, demonstrating that using human fixation locations allows NIMBLE to recognize familiar faces with only a single fixation. |
William L. Miller; Vincenzo Maffei; Gianfranco Bosco; Marco Iosa; Myrka Zago; Emiliano Macaluso; Francesco Lacquaniti Vestibular nuclei and cerebellum put visual gravitational motion in context Journal Article In: Journal of Neurophysiology, vol. 99, no. 4, pp. 1969–1982, 2008. @article{Miller2008,Animal survival in the forest, and human success on the sports field, often depend on the ability to seize a target on the fly. All bodies fall at the same rate in the gravitational field, but the corresponding retinal motion varies with apparent viewing distance. How then does the brain predict time-to-collision under gravity? A perspective context from natural or pictorial settings might afford accurate predictions of gravity's effects via the recovery of an environmental reference from the scene structure. We report that embedding motion in a pictorial scene facilitates interception of gravitational acceleration over unnatural acceleration, whereas a blank scene eliminates such bias. Functional magnetic resonance imaging (fMRI) revealed blood-oxygen-level-dependent correlates of these visual context effects on gravitational motion processing in the vestibular nuclei and posterior cerebellar vermis. Our results suggest an early stage of integration of high-level visual analysis with gravity-related motion information, which may represent the substrate for perceptual constancy of ubiquitous gravitational motion. |
Alexandra Soliman; Gillian A. O'Driscoll; Jens Pruessner; Anne Lise V. Holahan; Isabelle Boileau; Danny Gagnon; Alain Dagher Stress-induced dopamine release in humans at risk of psychosis: A [ "C] raclopride PET study Journal Article In: Neuropsychopharmacology, vol. 33, no. 8, pp. 2033–2041, 2008. @article{Soliman2008,Drugs that increase dopamine levels in the brain can cause psychotic symptoms in healthy individuals and worsen them in schizophrenic patients. Psychological stress also increases dopamine release and is thought to play a role in susceptibility to psychotic illness. We hypothesized that healthy individuals at elevated risk of developing psychosis would show greater striatal dopamine release than controls in response to stress. Using positron emission tomography and [(11)C]raclopride, we measured changes in synaptic dopamine concentrations in 10 controls and 16 psychometric schizotypes; 9 with perceptual aberrations (PerAb, ie positive schizotypy) and 7 with physical anhedonia (PhysAn, ie negative schizotypy). [(11)C]Raclopride binding potential was measured during a psychological stress task and a sensory-motor control. All three groups showed significant increases in self-reported stress and cortisol levels between the stress and control conditions. However, only the PhysAn group showed significant stress-induced dopamine release. Dopamine release in the entire sample was significantly negatively correlated with smooth pursuit gain, an endophenotype linked to frontal lobe function. Our findings suggest the presence of abnormalities in the dopamine response to stress in negative symptom schizotypy, and provide indirect evidence of a link to frontal function. |
Julie N. Buchan; Martin Paré; Kevin G. Munhall The effect of varying talker identity and listening conditions on gaze behavior during audiovisual speech perception Journal Article In: Brain Research, vol. 1242, pp. 162–171, 2008. @article{Buchan2008,During face-to-face conversation the face provides auditory and visual linguistic information, and also conveys information about the identity of the speaker. This study investigated behavioral strategies involved in gathering visual information while watching talking faces. The effects of varying talker identity and varying the intelligibility of speech (by adding acoustic noise) on gaze behavior were measured with an eyetracker. Varying the intelligibility of the speech by adding noise had a noticeable effect on the location and duration of fixations. When noise was present subjects adopted a vantage point that was more centralized on the face by reducing the frequency of the fixations on the eyes and mouth and lengthening the duration of their gaze fixations on the nose and mouth. Varying talker identity resulted in a more modest change in gaze behavior that was modulated by the intelligibility of the speech. Although subjects generally used similar strategies to extract visual information in both talker variability conditions, when noise was absent there were more fixations on the mouth when viewing a different talker every trial as opposed to the same talker every trial. These findings provide a useful baseline for studies examining gaze behavior during audiovisual speech perception and perception of dynamic faces. |
Jennifer E. Arnold; Shin-Yi C. Lao Put in last position something previously unmentioned: Word order effects on referential expectancy and reference comprehension Journal Article In: Language and Cognitive Processes, vol. 23, no. 2, pp. 282–295, 2008. @article{Arnold2008a,Research has shown that the comprehension of definite referring expressions (e.g., "the triangle") tends to be faster for "given" (previously mentioned) referents, compared with new referents. This has been attributed to the presence of given information in the consciousness of discourse participants (e.g., Chafe, 1994) suggesting that given is always more accessible. By contrast, we find a bias toward new referents during the on-line comprehension of the direct object in heavy-NP-shifted word orders, e.g., "Put on the star the...." This order tends to be used for new direct objects; canonical unshifted orders are more common with given direct objects. Thus, word order provides probabilistic information about the givenness or newness of the direct object. Results from eyetracking and gating experiments show that the traditional given bias only occurs with unshifted orders; with heavy-NP-shifted orders, comprehenders expect the object to be new, and comprehension for new referents is facilitated. (Contains 2 figures and 3 tables.) |
Mark Wexler; Nizar Ouarti Depth affects where we look Journal Article In: Current Biology, vol. 18, no. 23, pp. 1872–1876, 2008. @article{Wexler2008,Understanding how we spontaneously scan the visual world through eye movements is crucial for characterizing both the strategies and inputs of vision [1-27]. Despite the importance of the third or depth dimension for perception and action, little is known about how the specifically three-dimensional aspects of scenes affect looking behavior. Here we show that three-dimensional surface orientation has a surprisingly large effect on spontaneous exploration, and we demonstrate that a simple rule predicts eye movements given surface orientation in three dimensions: saccades tend to follow surface depth gradients. The rule proves to be quite robust: it generalizes across depth cues, holds in the presence or absence of a task, and applies to more complex three-dimensional objects. These results not only lead to a more accurate understanding of visuo-motor strategies, but also suggest a possible new oculomotor technique for studying three-dimensional vision from a variety of depth cues in subjects-such as animals or human infants-that cannot explicitly report their perceptions. |
Monica S. Castelhano; Alexander Pollatsek; Kyle R. Cave Typicality aids search for an unspecified target, but only in identification and not in attentional guidance Journal Article In: Psychonomic Bulletin & Review, vol. 15, no. 4, pp. 795–801, 2008. @article{Castelhano2008,Participants searched for a picture of an object, and the object was either a typical or an atypical category member. The object was cued by either the picture or its basic-level category name. Of greatest interest was whether it would be easier to search for typical objects than to search for atypical objects. The answer was"yes," but only in a qualified sense: There was a large typicality effect on response time only for name cues, and almost none of the effect was found in the time to locate (i.e., first fixate) the target. Instead, typicality influenced verification time-the time to respond to the target once it was fixated. Typicality is thus apparently irrelevant when the target is well specified by a picture cue; even when the target is underspecified (as with a name cue), it does not aid attentional guidance, but only facilitates categorization. |
Delphine Dahan; Sarah J. Drucker; Rebecca A. Scarborough Talker adaptation in speech perception: Adjusting the signal or the representations? Journal Article In: Cognition, vol. 108, no. 3, pp. 710–718, 2008. @article{Dahan2008,Past research has established that listeners can accommodate a wide range of talkers in understanding language. How this adjustment operates, however, is a matter of debate. Here, listeners were exposed to spoken words from a speaker of an American English dialect in which the vowel /æ/ is raised before /g/, but not before /k/. Results from two experiments showed that listeners' identification of /k/-final words like back (which are unaffected by the dialect) was facilitated by prior exposure to their dialect-affected /g/-final counterparts, e.g., bag. This facilitation occurred because the competition between interpretations, e.g., bag or back, while hearing the initial portion of the input [bæ], was mitigated by the reduced probability for the input to correspond to bag as produced by this talker. Thus, adaptation to an accent is not just a matter of adjusting the speech signal as it is being heard; adaptation involves dynamic adjustment of the representations stored in the lexicon, according to the characteristics of the speaker or the context. |
Benjamin W. Tatler; Benjamin T. Vincent Systematic tendencies in scene viewing Journal Article In: Journal of Eye Movement Research, vol. 2, no. 2, pp. 1–18, 2008. @article{Tatler2008,While many current models of scene perception debate the relative roles of low- and high- level factors in eye guidance, systematic tendencies in how the eyes move may be infor- mative. We consider how each saccade and fixation is influenced by that which preceded or followed it, during free inspection of images of natural scenes. We find evidence to suggest periods of localized scanning separated by ‘global' relocations to new regions of the scene. We also find evidence to support the existence of small amplitude ‘corrective' saccades in natural image viewing. Our data reveal statistical dependencies between suc- cessive eye movements, which may be informative in furthering our understanding of eye guidance. |
Vaia Lestou; Frank E. Pollick; Zoe Kourtzi Neural substrates for action understanding at different description levels in the human brain Journal Article In: Journal of Cognitive Neuroscience, vol. 20, no. 2, pp. 324–341, 2008. @article{Lestou2008,Understanding complex movements and abstract action goals is an important skill for our social interactions. Successful social interactions entail understanding of actions at different levels of action description, ranging from detailed movement trajectories that support learning of complex motor skills through imitation to distinct features of actions that allow us to discriminate between action goals and different action styles. Previous studies have implicated premotor, parietal, and superior temporal areas in action understanding. However, the role of these different cortical areas in action understanding at different levels of action description remains largely unknown. We addressed this question using advanced animation and stimulus generation techniques in combination with sensitive functional magnetic resonance imaging adaptation or repetition suppression methods. We tested the neural sensitivity of fronto-parietal and visual areas to differences in the kinematics and goals of actions using kinematic morphs of arm movements. Our findings provide novel evidence for differential involvement of ventral premotor, parietal, and temporal regions in action understanding. We show that the ventral premotor cortex encodes the physical similarity between movement trajectories and action goals that are important for exact copying of actions and the acquisition of complex motor skills. In contrast, whereas parietal regions and the superior temporal sulcus process the perceptual similarity between movements and may support the perception and imitation of abstract action goals and movement styles. Thus, our findings propose that fronto-parietal and visual areas involved in action understanding mediate a cascade of visual-motor processes at different levels of action description from exact movement copies to abstract action goals achieved with different movement styles. |
Tobias Pflugshaupt; Thomas Nyffeler; Roman Von Wartburg; Christian W. Hess; René M. Müri Loss of exploratory vertical saccades after unilateral frontal eye field damage Journal Article In: Journal of Neurology, Neurosurgery and Psychiatry, vol. 79, no. 4, pp. 474–477, 2008. @article{Pflugshaupt2008,Despite their relevance for locomotion and social interaction in everyday situations, little is known about the cortical control of vertical saccades in humans. Results from microstimulation studies indicate that both frontal eye fields (FEFs) contribute to these eye movements. Here, we present a patient with a damaged right FEF, who hardly made vertical saccades during visual exploration. This finding suggests that, for the cortical control of exploratory vertical saccades, integrity of both FEFs is indeed important. |
Anne Roefs; Anita Jansen; Sofie Moresi; Paul Willems; Sarah Grootel; Anouk Borgh Looking good: BMI, attractiveness bias and visual attention. Journal Article In: Appetite, vol. 51, pp. 552–555, 2008. @article{rjmwvv08,The aim of this study was to study attentional bias when viewing one's own and a control body, and to relate this bias to body-weight and attractiveness ratings. Participants were 51 normal-weight female students with an unrestrained eating style. They were successively shown pictures of their own and a control body for 30s each, while their eye movements (overt attention) were being measured. Afterwards, participants were asked to identify the most attractive and most unattractive body part of both their own and a control body. The results show that with increasing BMI and where an individual has given a relatively low rating of attractiveness to their own body, participants attended relatively more to their self-identified most unattractive body part and the control body's most attractive body part. This increasingly negative bias in visual attention for bodies may maintain and/or exacerbate body dissatisfaction. |
Benjamin W. Tatler; Nicholas J. Wade; Kathrin Kaulard Examining art: Dissociating pattern and perceptual influences on oculomotor behaviour Journal Article In: Spatial Vision, vol. 21, no. 1, pp. 165–184, 2008. @article{Tatler2008a,When observing art the viewer's understanding results from the interplay between the marks made on the surface by the artist and the viewer's perception and knowledge of it. Here we use a novel set of stimuli to dissociate the influences of the marks on the surface and the viewer's perceptual experience upon the manner in which the viewer inspects art. Our stimuli provide the opportunity to study situations in which (1) the same visual stimulus can give rise to two different perceptual experiences in the viewer, and (2) the visual stimuli differ but give rise to the same perceptual experience in the viewer. We find that oculomotor behaviour changes when the perceptual experience changes. Oculomotor behaviour also differs when the viewer's perceptual experience is the same but the visual stimulus is different. The methodology used and insights gained from this study offer a first step toward an experimental exploration of the relative influences of the artist's creation and viewer's perception when viewing art and also toward a better understanding of the principles of composition in portraiture. |
N. Alahyane; V. Fonteille; C. Urquizar; Roméo Salemme; Norbert Nighoghossian; Denis Pelisson; C. Tilikete Separate neural substrates in the human cerebellum for sensory-motor adaptation of reactive and of scanning voluntary saccades Journal Article In: Cerebellum, vol. 7, no. 4, pp. 595–601, 2008. @article{Alahyane2008,Sensory-motor adaptation processes are critically involved in maintaining accurate motor behavior throughout life. Yet their underlying neural substrates and task-dependency bases are still poorly understood. We address these issues here by studying adaptation of saccadic eye movements, a well-established model of sensory-motor plasticity. The cerebellum plays a major role in saccadic adaptation but it has not yet been investigated whether this role can account for the known specificity of adaptation to the saccade type (e.g., reactive versus voluntary). Two patients with focal lesions in different parts of the cerebellum were tested using the double-step target paradigm. Each patient was submitted to two separate sessions: one for reactive saccades (RS) triggered by the sudden appearance of a visual target and the second for scanning voluntary saccades (SVS) performed when exploring a more complex scene. We found that a medial cerebellar lesion impaired adaptation of reactive-but not of voluntary-saccades, whereas a lateral lesion affected adaptation of scanning voluntary saccades, but not of reactive saccades. These findings provide the first evidence of an involvement of the lateral cerebellum in saccadic adaptation, and extend the demonstrated role of the cerebellum in RS adaptation to adaptation of SVS. The double dissociation of adaptive abilities is also consistent with our previous hypothesis of the involvement in saccadic adaptation of partially separated cerebellar areas specific to the reactive or voluntary task (Alahyane et al. Brain Res 1135:107-121 (2007)). |
Nadia Alahyane; Anne-Dominique Devauchelle; Roméo Salemme; Denis Pélisson Spatial transfer of adaptation of scanning voluntary saccades in humans Journal Article In: Neuroreport, vol. 19, no. 1, pp. 37–41, 2008. @article{Alahyane2008a,The properties and neural substrates of the adaptive mechanisms that maintain over time the accuracy of voluntary, internally triggered saccades are still poorly understood. Here, we used transfer tests to evaluate the spatial properties of adaptation of scanning voluntary saccades. We found that an adaptive reduction of the size of a horizontal rightward 7 degrees saccade transferred to other saccades of a wide range of amplitudes and directions. This transfer decreased as tested saccades increasingly differed in amplitude or direction from the trained saccade, being null for vertical and leftward saccades. Voluntary saccade adaptation thus presents bounded, but large adaptation fields, suggesting that at least part of the underlying neural substrate encodes saccades as vectors. |
D. A. Mills; Teresa C. Frohman; Scott L. Davis; A. R. Salter; Samuel M. McClure; I. Beatty; A. Shah; S. Galetta; E. Eggenberger; D. S. Zee; Elliot M. Frohman Break in binocular fusion during head turning in MS patients with INO Journal Article In: Neurology, vol. 71, pp. 457–460, 2008. @article{Mills2008,Internuclear ophthalmoparesis (INO) is the most common eye movement abnormality observed in pa- tients with multiple sclerosis (MS).1 While most MS patients with INO have no or little misalignment in the straight ahead position, significant disconjugacy occurs during horizontal saccades or with horizontal (yaw axis) head turning.2 A break in binocular fusion can produce a loss of stereopsis and depth percep- tion, transient diplopia (perceived as a double image or visual blur), oscillopsia, and disorientation.2 The purpose of this investigation was to confirm the hy- pothesis that a break in binocular fusion occurs in MS patients with INO during head or body turning, and that the magnitude of disconjugacy will be di- rectly correlated with the severity of this eye move- ment syndrome. |
Ardi Roelofs Attention, gaze shifting, and dual-task interference from phonological encoding in spoken word planning Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 34, no. 6, pp. 1580–1598, 2008. @article{r08,Controversy exists about whether dual-task interference from word planning reflects structural bottleneck or attentional control factors. Here, participants named pictures whose names could or could not be phonologically prepared, and they manually responded to arrows presented away from (Experiment 1), or superimposed onto, the pictures (Experiments 2 and 3); or they responded to tones (Experiment 4). Pictures and arrows/tones were presented at stimulus onset asynchronies of 0, 300, and 1,000 ms. Earlier research showed that vocal responding hampers auditory perception, which predicts earlier shifts of attention to the tones than to the arrows. Word planning yielded dual-task interference. Phonological preparation reduced the latencies of picture naming and gaze shifting. The preparation benefit was propagated into the latencies of the manual responses to the arrows but not to the tones. The malleability of the interference supports the attentional control account. This conclusion was corroborated by computer simulations showing that an extension of WEAVER++ (A. Roelofs, 2003) with assumptions about the attentional control of tasks quantitatively accounts for the latencies of vocal responding, gaze shifting, and manual responding. |
Christof Körner; Iain D. Gilchrist Memory processes in multiple-target visual search Journal Article In: Psychological Research, vol. 72, no. 1, pp. 99–105, 2008. @article{Koerner2008,Gibson, Li, Skow, Brown, and Cooke (Psychological Science, 11, 324–327, 2000) had participants carry out a search task in which they were required to detect the presence of one or two targets. In order to successfully perform such a multiple-target visual search task, participants had to remember the location of the Wrst target while searching for the second target. In two experiments we investigated the cost of remembering this target location. In Experiment 1, we compared performance on the Gibson et al. task with performance on a more conventional present–absent search task. The comparison suggests a substantial performance cost as measured by reaction time, number of Wxations and slope of the search functions. In Experment 2, we looked in detail at reWxations of distractors, which are a direct measure of attentional deployment. We demonstrated that the cost in this multiple-target visual search task was due to an increased number of reWxations on previously visited distractors. Such reWxations were present right from the start of the search. This change in search behaviour may be caused by the necessity of having to remember a target-allocating memory for the upcoming target may consume memory capacity that may otherwise be available for the tagging of distractors. These results support the notion of limited capacity memory processes in search. Introduction |