Visual object categorization and representation in primates: Psychophysics and Physiology

MPI Series in Biological Cybernetics, Bd. 3

Anastasia Sigala

ISBN 978-3-89722-961-7
40 Seiten, Erscheinungsjahr: 2002
Preis: 40.50 €

A basic cognitive capacity of primates is the ability to make sense of the perceptual world by discriminating features and catecorizing objects. Recognition and categorization are very simlar processes, and both are concerned with the question "what is this object?" To recognize an objest as a 'car', a 'face', or an 'apple' is equivalent to assigning it in the 'car', 'face', or 'apple' category. In both cases, the problem is to match input information with information in memory. The question of how we construct internal representations of the external world has attracted attention since the time of the ancient Greek philosophers.

Simple observation of the categorizations we make reveals that each object may belong to a number of categories, depending on the context, the experience we have with it, or the purpose of the categorization. The object 'knife' may be a tool, a bargain or a weapon.

The aim of this study is to compare categorization strategies between human and non-human primates and test how categorization training affects the reprentations of the visual stimuli. The changes on the representations are studied both psychophysically and physiologically, by virtue of single-unit extracellular recordings in a brain area known to be important for object recognition and perceptual learning, namely the inferior temporal cortex of the monkey.

As a separate question relating to the issue of representation, it is tested whether monkeys perceive pictures as symbolic representations of familiar objects. It has been reported that members of remote cultures, who are not familiar with pictorial materials, do not recognize pictures of familiar objects effortlessly. Although research of primate recognition often employs monkeys performing tasks with pictures shown on computer screens, it is not clear if the monkeys perceive the pictures as representations of familiar objects.