ORCID Profile
0000-0001-9671-6983
Current Organisation
Vrije Universiteit Amsterdam
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Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 12-11-2019
DOI: 10.1167/19.13.9
Abstract: In the flash-grab effect, when a disk is flashed on a moving background at the moment it reverses direction, the perceived location of the disk is strongly displaced in the direction of the motion that follows the reversal. Here, we ask whether increased expectation of the reversal reduces its effect on the motion-induced shift, as suggested by predictive coding models with first order predictions. Across four experiments we find that when the reversal is expected, the illusion gets stronger, not weaker. We rule out accumulating motion adaptation as a contributing factor. The pattern of results cannot be accounted for by first-order predictions of location. Instead, it appears that second-order predictions of event timing play a role. Specifically, we conclude that temporal expectation causes a transient increase in temporal attention, boosting the strength of the motion signal and thereby increasing the strength of the illusion.
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 02-03-2021
DOI: 10.1167/JOV.21.3.2
Publisher: Springer Science and Business Media LLC
Date: 12-01-2018
Publisher: Springer Science and Business Media LLC
Date: 31-05-2023
DOI: 10.3758/S13414-023-02735-Z
Abstract: Visual attention may be captured by an irrelevant yet salient distractor, thereby slowing search for a relevant target. This phenomenon has been widely studied using the additional singleton paradigm in which search items are typically all presented at one and the same eccentricity. Yet, differences in eccentricity may well bias the competition between target and distractor. Here we investigate how attentional capture is affected by the relative eccentricities of a target and a distractor. Participants searched for a shape-defined target in a grid of homogeneous nontargets of the same color. On 75% of trials, one of the nontarget items was replaced by a salient color-defined distractor. Crucially, target and distractor eccentricities were independently manipulated across three levels of eccentricity (i.e., near, middle, and far). Replicating previous work, we show that the presence of a distractor slows down search. Interestingly, capture as measured by manual reaction times was not affected by target and distractor eccentricity, whereas capture as measured by the eyes was: items close to fixation were more likely to be selected than items presented further away. Furthermore, the effects of target and distractor eccentricity were largely additive, suggesting that the competition between saliency- and relevance-driven selection was modulated by an independent eccentricity-based spatial component. Implications of the dissociation between manual and oculomotor responses are also discussed.
Publisher: Elsevier BV
Date: 04-2023
Publisher: Society for Neuroscience
Date: 13-08-2018
DOI: 10.1523/JNEUROSCI.0736-18.2018
Abstract: Transmission delays in the nervous system pose challenges for the accurate localization of moving objects as the brain must rely on outdated information to determine their position in space. Acting effectively in the present requires that the brain compensates not only for the time lost in the transmission and processing of sensory information, but also for the expected time that will be spent preparing and executing motor programs. Failure to account for these delays will result in the mislocalization and mistargeting of moving objects. In the visuomotor system, where sensory and motor processes are tightly coupled, this predicts that the perceived position of an object should be related to the latency of saccadic eye movements aimed at it. Here we use the flash-grab effect, a mislocalization of briefly flashed stimuli in the direction of a reversing moving background, to induce shifts of perceived visual position in human observers (male and female). We find a linear relationship between saccade latency and perceived position shift, challenging the classic dissociation between “vision for action” and “vision for perception” for tasks of this kind and showing that oculomotor position representations are either shared with or tightly coupled to perceptual position representations. Altogether, we show that the visual system uses both the spatial and temporal characteristics of an upcoming saccade to localize visual objects for both action and perception. SIGNIFICANCE STATEMENT Accurately localizing moving objects is a computational challenge for the brain due to the inevitable delays that result from neural transmission. To solve this, the brain might implement motion extrapolation, predicting where an object ought to be at the present moment. Here, we use the flash-grab effect to induce perceptual position shifts and show that the latency of imminent saccades predicts the perceived position of the objects they target. This counterintuitive finding is important because it not only shows that motion extrapolation mechanisms indeed work to reduce the behavioral impact of neural transmission delays in the human brain, but also that these mechanisms are closely matched in the perceptual and oculomotor systems.
Publisher: Springer Science and Business Media LLC
Date: 04-04-2022
DOI: 10.3758/S13423-022-02091-3
Abstract: Human vision involves selectively directing the eyes to potential objects of interest. According to most prominent theories, selection is the quantal outcome of an ongoing competition between saliency-driven signals on the one hand, and relevance-driven signals on the other, with both types of signals continuously and concurrently projecting onto a common priority map. Here, we challenge this view. We asked participants to make a speeded eye movement towards a target orientation, which was presented together with a non-target of opposing tilt. In addition to the difference in relevance, the target and non-target also differed in saliency, with the target being either more or less salient than the non-target. We demonstrate that saliency- and relevance-driven eye movements have highly idiosyncratic temporal profiles, with saliency-driven eye movements occurring rapidly after display onset while relevance-driven eye movements occur only later. Remarkably, these types of eye movements can be fully separated in time: We find that around 250 ms after display onset, eye movements are no longer driven by saliency differences between potential targets, but also not yet driven by relevance information, resulting in a period of non-selectivity, which we refer to as the attentional limbo. Binomial modeling further confirmed that visual selection is not necessarily the outcome of a direct battle between saliency- and relevance-driven signals. Instead, selection reflects the dynamic changes in the underlying saliency- and relevance-driven processes themselves, and the time at which an action is initiated then determines which of the two will emerge as the driving force of behavior.
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 10-01-2019
DOI: 10.1167/19.1.3
Abstract: Neural processing of sensory input in the brain takes time, and for that reason our awareness of visual events lags behind their actual occurrence. One way the brain might compensate to minimize the impact of the resulting delays is through extrapolation. Extrapolation mechanisms have been argued to underlie perceptual illusions in which moving and static stimuli are mislocalised relative to one another (such as the flash-lag and related effects). However, where in the visual hierarchy such extrapolation processes take place remains unknown. Here, we address this question by identifying monocular and binocular contributions to the flash-grab illusion. In this illusion, a brief target is flashed on a moving background that reverses direction. As a result, the perceived position of the target is shifted in the direction of the reversal. We show that the illusion is attenuated, but not eliminated, when the motion reversal and the target are presented dichoptically to separate eyes. This reveals extrapolation mechanisms at both monocular and binocular processing stages contribute to the illusion. We interpret the results in a hierarchical predictive coding framework, and argue that prediction errors in this framework manifest directly as perceptual illusions.
No related grants have been discovered for Elle van Heusden.