Professor Alan C.N. Wong
Ph.D, Vanderbilt University
Assistant Professor, Department of Psychology
The Chinese University of Hong Kong

Abstract

Cognitive neuroscientists have been fascinated by a long-standing mystery about face perception: Why do faces elicit a unique set of behavioral phenomena and neural activity patterns not shared by other objects? Some say that our visual system has devoted an innate, independent, and self-contained compartment (“module”) for faces, while others suggest that experience plays an important role in the development of face-like expertise. Later studies have found that other non-face object categories also recruited selectively different parts of visual cortex. In this talk we will start with attempts to resolve the face debate and then put this debate into a larger context: How does visual cortex organize itself for the perception of various object categories? Several proposals exist, and I will focus on the role of experience. I will describe our recent study where two groups of participants took part in two different learning regimens requiring either subordinate-level individuation or basic-level categorization of a set of novel, artificial objects (Ziggerins). Individuation training involved learning to categorize Ziggerins at a subordinate level quickly, similar to how people discriminate faces during person identification. Categorization training involved learning to rapidly recognize at the basic level Ziggerins that were presented in spatially organized arrays with coherent styles, similar to how people process letters when reading a text. The two regimens resulted in different patterns of changes in fMRI (functional magnetic resonance imaging) responses. After individuation training Ziggerins were processed holistically and provoked higher activity in the fusiform gyrus, i.e., they are processed like faces. In contrast, categorization training resulted in more fluent processing of multiple objects, as well as increased recruitment of the medial portion of the ventral occipito-temporal cortex relative to more lateral areas. To summarize, qualitatively different learning experience cause qualitatively different activity changes in visual cortex for the very same objects. The demands of prior learning experience could thus be one important factor governing the organization of activity patterns in visual cortex.