The Role of Serial Dependence in Visual Perception

University Of California Berkeley, Berkeley CA

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Abstract

? DESCRIPTION (provided by applicant): The goal of this project is to determine how objects in the word are perceived as continuous despite moment-to-moment fluctuations in their image properties due to factors like occlusion, visual noise, and eye movements. The mechanism by which the visual system accomplishes this object continuity remains elusive. Recent results demonstrate that the perception of face identity, orientation and numerosity is systematically biased (i.e. pulled) towards visual input from the recent past. The spatial region over which current face identities are pulled by previously seen identities is known as the object-selective continuity field, which is temporally tuned towards visual input from the past 5-10 seconds. This perceptual serial dependence seems to contribute to the visual stability of low-level features and objects over short time periods. If the continuity field is in fact about object-level information, then it should maintain the continuity of perceived facial expressions over time. If the continuity field facilitates the perception of stable object identities despite occlusions, it should result i serial dependence when objects are obscured to promote perceptual stability. This proposal will employ behavioral psychophysics to determine whether the perceived expression of a face is pulled towards recently seen expressions, as has been already reported for facial identity (Aim 1). Since facial expression has a higher probability of change over time compared to facial identity, the perceptual pull towards previously seen identities should be stronger than the pull towards previously seen emotional expressions. The strength and temporal tuning of the object-selective continuity field should therefore depend on the physical stability of the feature or objet in the world. Furthermore, if the continuity field maintains object identity in the face of decreasd visibility, then there should be a perceptual pull in the appearance of an object before and after it is occluded (Aim 2). Previous research investigating visual occlusion has shown that objects are perceived as persisting even when they can no longer be seen, but these studies don't address how the appearance of the object emerging from occlusion may be dependent on or pulled by the object that initially went behind the occluder. We therefore aim to investigate how an object is actually perceived after it reappears following occlusion. The continuity field predics that appearance should be pulled toward the pre-occluded object in a trajectory-specific manner.