Alexander C Schütz

Alexander C Schütz
Philipps University of Marburg | PUM · Faculty of Psychology

Dr. rer. nat. habil.

About

112
Publications
7,985
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1,511
Citations
Additional affiliations
June 2006 - present
Justus-Liebig-Universität Gießen

Publications

Publications (112)
Article
Multiple studies have shown that certain visual stimuli are perceived in accordance with strong biases that are both robust within individuals and highly variable from one individual to the next. These biases undergo small changes over time that demonstrate that they constitute latent states of the visual system. The literature to date indicates th...
Article
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Our environment contains an abundance of objects which humans interact with daily, gathering visual information using sequences of eye-movements to choose which object is best-suited for a particular task. This process is not trivial, and requires a complex strategy where task affordance defines the search strategy, and the estimated precision of t...
Article
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Expectations are probabilistic beliefs about the future that shape and influence our perception, affect, cognition, and behavior in many contexts. This makes expectations a highly relevant concept across basic and applied psychological disciplines. When expectations are confirmed or violated, individuals can respond by either updating or maintainin...
Article
Full-text available
Processing of visual information in the central (foveal) and peripheral visual field is vastly different. To achieve a homogeneous representation of the visual world across eye movements, the visual system needs to compensate for these differences. By introducing subtle changes between peripheral and foveal inputs across saccades, one can test this...
Article
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Neurons in visual cortex quickly adapt to constant input, which should lead to perceptual fading within few tens of milliseconds. However, perceptual fading is rarely observed in every day perception, possibly because eye movements refresh retinal input. Recently, it has been suggested that amplitudes of large saccadic eye movements are scaled to m...
Article
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Saccadic eye movements can drastically affect motion perception: during saccades, the stationary surround is swept rapidly across the retina and contrast sensitivity is suppressed. However, after saccades, contrast sensitivity is enhanced for color and high-spatial frequency stimuli and reflexive tracking movements known as ocular following respons...
Article
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During smooth pursuit eye movements, the visual system is faced with the task of telling apart reafferent retinal motion from motion in the world. While an efference copy signal can be used to predict the amount of reafference to subtract from the image, an image-based adaptive mechanism can ensure the continued accuracy of this computation. Indeed...
Article
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Saccadic eye movements modulate visual perception: they initiate and terminate high acuity vision at a certain location in space, but before and during their execution visual contrast sensitivity is strongly attenuated for 100 to 200 ms. Transient perisaccadic perceptual distortions are assumed to be an important mechanism to maintain visual stabil...
Article
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Motor adaptation maintains movement accuracy over the lifetime. Saccadic eye movements have been used successfully to study the mechanisms and neural basis of adaptation. Using behaviorally irrelevant targets, it has been shown that saccade adaptation is driven by errors only in a brief temporal interval after movement completion. However, under na...
Preprint
Expectations are probabilistic beliefs about the future that shape and influence our perception, affect, cognition, and behaviour in many contexts. This makes expectations a highly relevant concept across basic and applied psychological disciplines. When expectations are confirmed or violated, individuals can respond by either updating or maintaini...
Article
A major objective of perception is the reduction of uncertainty about the outside world. Eye-movement research has demonstrated that attention and oculomotor control can subserve the function of decreasing uncertainty in vision. Here, we ask whether a similar effect exists for awareness in binocular rivalry, when two distinct stimuli presented to t...
Article
Individuals are often confronted with events that violate their expectations, but disconfirming evidence does not always lead to expectation change. We review seven theoretical models on how individuals cope with disconfirming expectations: associative learning theories, the ViolEx Model, the model of coping with expectation disconfirmation (Roese...
Article
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In art schools and classes for art history students are trained to pay attention to different aspects of an artwork, such as art movement characteristics and painting techniques. Experts are better at processing style and visual features of an artwork than nonprofessionals. Here we tested the hypothesis that experts in art use different, task-depen...
Article
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Previous studies revealed that there are idiosyncratic preferences to perceive certain motion directions in front during motion transparency depth rivalry (Mamassian & Wallace, 2010; Schütz, 2014). Meanwhile, other studies reported idiosyncratic preferences in binocular rivalry during the onset stage (Carter & Cavanagh, 2007; Stanley, Carter, & For...
Article
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Visual processing varies dramatically across the visual field. These differences start in the retina and continue all the way to the visual cortex. Despite these differences in processing, the perceptual experience of humans is remarkably stable and continuous across the visual field. Research in the last decade has shown that processing in periphe...
Article
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Humans do not notice small displacements to objects that occur during saccades, termed saccadic suppression of displacement (SSD), and this effect is reduced when a blank is introduced between the pre-and postsaccadic stimulus (Bridgeman, Hendry, & Stark, 1975; Deubel, Schneider, & Bridgeman, 1996). While these effects have been studied extensively...
Chapter
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When a saccadic eye movement does not land accurately on its visual target, subsequent saccades to the same target are subject to a corrective adjustment, which has been called saccade adaptation. Saccade adaptation has emerged as a go-to model for sensorimotor learning. Because observers show limited awareness of image manipulations during saccade...
Article
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What we see is influenced by where we look. When confronted with multiple relevant targets, inaccurate saccade target selection can impair perceptual performance. Here we ask whether endpoint selection can be optimized by the mechanism maintaining saccade accuracy: saccade adaptation. Therefore, we introduce a double-target adaptation task, where a...
Article
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Humans constantly decide among multiple action plans. Carrying out one action usually implies that other plans are suppressed. Here we make use of inter-trial effects to determine whether suppression of non-chosen action plans is due to proactively preparing for upcoming decisions or due to retroactive influences from previous decisions. Participan...
Article
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Across saccades, humans can integrate the low-resolution presaccadic information of an upcoming saccade target with the high-resolution postsaccadic information. There is converging evidence to suggest that transsaccadic integration occurs at the saccade target. However, given divergent evidence on the spatial specificity of related mechanisms such...
Article
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Humans are able to integrate pre- and postsaccadic percepts of an object across saccades to maintain perceptual stability. Previous studies have used Maximum Likelihood Estimation (MLE) to determine that integration occurs in a near-optimal manner. Here, we compared three different models to investigate the mechanism of integration in more detail:...
Article
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When making decisions, humans can maximize the positive outcome of their actions by choosing the option associated with the highest reward. We have recently shown that choices modulate effects of reward via a bias in spatial attention: Locations associated with a lower reward are anticipatorily suppressed, as indicated by delayed responses to low-r...
Article
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Two types of photoreceptors in the human retina support vision across a wide range of luminances: cones are active under bright daylight illumination (photopic viewing) and rods under dim illumination at night (scotopic viewing). These photoreceptors are distributed inhomogeneously across the retina [1]: cone receptor density peaks at the center of...
Article
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Saccadic eye movements alter the visual processing of objects of interest by bringing them from the periphery, where there is only low-resolution vision, to the high-resolution fovea. Evidence suggests that people are able to achieve trans-saccadic integration in a near-optimal manner; however the mechanisms underlying integration are still unclear...
Article
The visual system needs to solve the correspondence problem (i.e., which elements belong together across space and time) to allow stable representations of objects. It has been shown that spatiotemporal and feature information can influence this correspondence process, but it is unclear how these factors interact with each other, especially when th...
Article
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Due to the foveal organization of our visual system we have to constantly move our eyes to gain precise information about our environment. Doing so massively alters the retinal input. This is problematic for the perception of moving objects, because physical motion and retinal motion become decoupled and the brain has to discount the eye movements...
Article
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When humans have to choose between different options, they can maximize their payoff by choosing the option that yields the highest reward. Information about reward is not only used to optimize decisions but also for movement preparation to minimize reaction times to rewarded targets. Here, we show that this is especially true in contexts in which...
Article
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With every saccade, humans must reconcile the low resolution peripheral information available before a saccade, with the high resolution foveal information acquired after the saccade. While research has shown that we are able to integrate peripheral and foveal vision in a near-optimal manner, it is still unclear which mechanisms may underpin this i...
Article
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Humans achieve a stable and homogeneous representation of their visual environment, although visual processing varies across the visual field. Here we investigated the circumstances under which peripheral and foveal information is integrated for numerosity estimation across saccades. We asked our participants to judge the number of black and white...
Article
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Positive outcome of actions can be maximized by choosing the option with the highest reward. For saccades, it has recently been suggested that the necessity to choose is, in fact, an important factor mediating reward effects: latencies to single low-reward targets increased with an increasing proportion of interleaved choice-trials, in which partic...
Article
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Saccades bring objects of interest onto the fovea for high-acuity processing. Saccades to rewarded targets show shorter latencies that correlate negatively with expected motivational value. Shorter latencies are also observed when the saccade target is relevant for a perceptual discrimination task. Here we tested whether saccade preparation is equa...
Article
Smooth pursuit and motion perception have mainly been investigated with stimuli moving along linear trajectories. Here we studied the quality of pursuit movements to curved motion trajectories in human observers and examined whether the pursuit responses would be sensitive enough to discriminate various degrees of curvature. In a two interval force...
Article
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Saccadic eye movements provide an opportunity to study closely interwoven perceptual, motor, and cognitive changes during aging. Here, we investigated age effects on different mechanisms of saccadic plasticity. We compared age effects in two different adaptation paradigms that tap into low- and high-level adaptation processes. A total of 27 senior...
Article
Visual sensitivity is dynamically modulated by eye movements. During saccadic eye movements, sensitivity is reduced selectively for low-spatial frequency luminance stimuli and largely unaffected for high-spatial frequency luminance and chromatic stimuli (Nature 371 (1994), 511-513). During smooth pursuit eye movements, sensitivity for low-spatial f...
Article
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Motion perception can be distorted (Filehne, 1922) or enhanced (Spering, Schütz, Braun, & Gegenfurtner, 2011) by smooth pursuit. Here we investigated the role of smooth pursuit in discriminating curvature of motion trajectories. Subjects viewed a white 0.5 deg diameter Gaussian blob on a black background in total darkness as it moved along an arc o...
Article
How does the visual system maintain an accurate perception of motion in the world during smooth pursuit eye movements? Previous research suggests there is a recalibration mechanism that shifts the point of subjective stationarity (PSS) to correspond to the predominant background motion experienced during previous eye movement episodes. This recalib...
Article
Superposition of two dot clouds moving in different directions results in the perception of two transparent layers. Despite the ambiguous depth order of the layers, there are consistent preferences to perceive the layer, which is moving either rightward or downward in front of the other layer. Here we investigated the origin of these depth order bi...
Article
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We use eye movements to gain information about our visual environment; this information can indirectly be used to affect the environment. Whereas eye movements are affected by explicit rewards such as points or money, it is not clear whether the information gained by finding a hidden target has a similar reward value. Here we tested whether finding...
Article
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Visual uncertainty may affect saccade adaptation in two complementary ways. First, an ideal adaptor should take into account the reliability of visual information for determining the amount of correction, predicting that increasing visual uncertainty should decrease adaptation rates. We tested this by comparing observers’ direction discrimination a...
Article
Full-text available
Due to the inhomogenous visual representation across the visual field, humans use peripheral vision to select objects of interest and foveate them by saccadic eye movements for further scrutiny. Thus, there is usually peripheral information available before and foveal information after a saccade. In this study we investigated the integration of inf...
Article
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Adaptation of saccades can be induced by different error signals, such as retinal position errors, prediction errors, or reinforcement learning. Recently, we showed that a shift in the spatial goal of a perceptual task can induce saccadic adaptation, in the absence of a bottom-up position error. Here, we investigated whether this top-down effect is...
Article
Traffic reports consistently identify speeding as a substantial source of accidents. Adequate driving speeds require reliable speed estimation; however, there is still a lack of understanding how speed perception is biased during driving. Therefore, we ran three experiments measuring speed estimation under controlled driving and lighting conditions...
Article
Superposition of two dot clouds moving in different directions results in the perception of two transparent layers with ambiguous depth order. Intriguingly, the layer moving downwards or rightwards is preferentially seen in front (Mamassian & Wallace, 2010). Here we investigated which motion properties are causing these directional biases. In four...
Article
When an error is injected to saccade endpoints by displacing the target midflight during saccades, observers typically adjust their saccade amplitudes on later trials to reduce landing error. Since target displacements are much harder to see during a saccade than during fixation (termed "saccadic suppression of displacement"), it is often assumed t...
Article
Full-text available
Eye movements, attention and adaptation adjust visual sensitivity continuously. In particular, during the execution of saccades, visual sensitivity is reduced by an active process suppressing low-frequency luminance stimuli, but not isoluminant color stimuli (Burr, Morrone & Ross, 1994). During smooth pursuit, there is a small decrease in sensitivi...
Conference Paper
Visual acuity is best in the fovea and declines in the peripheral retina. Eye movements are used to project interesting objects onto the fovea, to acquire high-acuity information. Consistently, it has been shown that eye movement latencies are reduced if participants have to perform a perceptual task at the saccade target (Montagnini & Chelazzi, 20...
Conference Paper
In everyday behavior there are multiple competing demands for gaze; for instance, walking along a sidewalk requires paying attention to the path while avoiding other pedestrians. Therefore, humans make numerous fixations to satisfy their behavioral goals. One attempt to explore suitable strategies of gaze allocation for natural situations was made...
Article
Both the perceptual system and the motor system can be faced with ambiguous information and then have to choose between different alternatives. Often these alternatives involve decisions about directions, and anisotropies have been reported for different tasks. Here we measured interindividual differences and temporal stability of directional prefe...
Article
Full-text available
The human motor system and muscles are subject to fluctuations in the short and long term. Motor adaptation is classically thought of as a low-level process that compensates for the error between predicted and executed movements in order to maintain movement accuracy. Contrary to a low-level account, accurate movements might be only a means to supp...
Article
Reading is a complex visuomotor behavior characterized by an alternation of fixations and saccadic eye movements. Despite the widespread use of drifting texts in various settings, very little is known about eye movements under these conditions. Here we investigated oculomotor behavior during reading of texts which were drifting horizontally or vert...
Article
Full-text available
Abnormal smooth pursuit eye movements in patients with schizophrenia are often considered a consequence of impaired motion perception. Here we used a novel motion prediction task to assess the effects of abnormal pursuit on perception in human patients. Schizophrenia patients (n = 15) and healthy controls (n = 16) judged whether a briefly presented...