I investigate how the visual system transforms spatiotemporally fragmented retinal images into discrete representations of objects and how this transformation becomes compromised during serious mental illness. This question is approached with standard behavioral paradigms--such as multiple object tracking and shape discrimination--and also with more recent techniques such as ideal observer, classification imaging, and adaptive threshold estimation. Over the years, I have also written on theoretical questions in cognitive science that are related to object perception, such as the extent to which early vision is cognitively encapsulated or the best way to characterize the content of sensory representations.
My interest in foundational issues in object perception was originally kindled as a doctoral student at the highly rated Department of Philosophy at Rutgers--New Brunswick. As part of the cognitive science certificate program, I worked with Zenon Pylyshyn to examine whether the visual system can predictively track briefly disappearing objects. It was found that such objects are not tracked predictively but instead are tracked best when they reappear at their last seen locations. Having enjoyed my foray into experimental cognitive science and wanting to extend my inquiries beyond the confines of the armchair, I pursued a second Ph.D, but this time in Phil Kellman’s lab in the Department of Psychology at UCLA. I investigated how, why, and under what circumstances the visual system fills-in illusory contours. A trio of major findings emerged from the dissertation: the visual system effortlessly recovers and fills-in illusory contours during spatiotemporal fragmentation; the filling-in is sensitive to previously undocumented interactions between contour and surface representations; and such filling-in does not strongly depend on whether subjects actually believe the contours are present or absent.
After leaving the Kellman lab, I returned to Rutgers where I apply some of the same behavioral methods to investigate visual disturbances in schizophrenia. These studies are revealing that the illness in some cases dramatically disrupts perceptual organization. Some of the impairments are closely linked to the ability to think clearly and function normally in everyday life. Others arise as early as the first psychotic episode or even during the prodromal phase, suggesting that they may serve as an illness biomarker. More generally, we are finding that relatively simple visual experiments offer surprising insights into how the illness emerges and how it changes the brain over time.