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van Zantwijk, L.

Publications and source records attributed to van Zantwijk, L..

2 recordsLinked to original sources

The Spatial Specificity and Recovery from Visual Adaptation in Causality Perception

When one object approaches another object which, upon touching, moves in the same direction, humans report a vivid impression of one launching the other. Visual adaptation can alter this perception of causality: observers less often report seeing a launch after viewing a stream of launch events. In three experiments, we further characterised how visual adaptation influences the perception of causality by determining the spatial specificity of adaptation and timecourse of recovery from adaptation. In Experiment 1, observers saw ambiguous test events (i.e., the overlap between the two objects varied over trials) at three different horizontal eccentricities. Adaptation was strongest when adaptor and test event were presented at the same eccentricity, and absent when the two were separated by just three degrees of visual angle. Moreover, the perception of causality gradually recovered from adaptation, but remained incomplete. In Experiment 2, both long and short adaptation sequences were highly effective in driving adaptation, and showed no difference in the recovery timecourse, which was complete following more experimental blocks. In Experiment 3, a break without any task-relevant visual input also led to a recovery over the same timespan, but this time, the recovery was instantaneous and incomplete. Altogether, our results provide evidence for highly spatially specific computations, instananeously responding to the onset of adaptation and then gradually recovering from the adaptation over a short time window.

neuroscience↗

Attention Samples Items in Visual Working Memory Rhythmically

Attention allows us to selectively enhance the processing of specific locations or features in our external environment while simultaneously filtering out momentarily irrelevant information. It is currently hypothesized that this is achieved through the boosting of relevant sensory signals which biases the competition between competing neural representations. Recent neurophysiological and behavioral studies have revealed that attention is a fundamentally rhythmic process, tightly linked to neural oscillations in fronto-parietal networks. Instead of continuously highlighting a single object or location, attention rhythmically alternates between multiple relevant representations at a frequency of 3 - 6 Hz. However attention can not only be directed towards the external world but also towards internal visual working memory (VWM) representations, e.g. when selecting one of several search templates to find corresponding objects in the external world. Two recent studies have revealed that objects in VWM are attended in a similarly rhythmic fashion as perceived objects. We add to the current literature by showing that retro-cues towards multi-feature gratings in VWM initiate a similar theta-rhythmic competition, modulating reaction times in an anti-phasic manner. Our findings add to the converging body of evidence that external and internal visual representations are accessed by highly similar, rhythmic attentional mechanisms.

neuroscience↗