Perceiving a New Category: The Neurobiological Basis of Perceptual Categorization

Current models and theories of categorization have tended to assume that categorization and perception are separable processes, with perception preceding categorization. In contrast, this paper argues that categorization is a solution to a conflict faced by all information processing systems and gives evidence demonstrating that the visual system faces this conflict and solves it by categorizing. Neurobiological data suggest that perceptual categorization begins to take place in the earliest stages of visual processing and is highly developed in visual areas such as the inferotemporal cortex. Attention and experience can be shown to affect the neurophysiology of visual cortex in a manner analogous to their effects on categorization behavior. Together, these sources of evidence support an inherent relationship between visual perception and perceptual categorization. Based on this relationship, observed differences in visual processing between the cerebral hemispheres can be used to predict hemispheric differences for perceptual categorization, and here evidence is described that supports those predictions. It is concluded that categorization is rooted in perception and thus constrained by the structure and function of the human brain. Federmeier: Perceiving a New Category 2