Connectionist approaches to language disorders

Abstract

This paper reviews the impact of connectionism upon our understanding of brain-damaged language performance, and attempts to explain why it is of importance for the neuropsychology of language. Connectionism is an approach to modelling cognitive processes using networks of interconnected, simple, neuron-like units. Behaviour emerges as the result of the interaction of these units. It has provided a new way of thinking about cognitive processing, emphasizing its low-level mechanisms. One supposed advantage of connectionism is its biological plausibility. It is possible to «lesion» these systems by destroying some of the units or the connections between them. It is claimed that lesions to connectionist models of particular cognitive systems result in the appropriate acquired disorders. For example, lesioning a connectionist model of reading and word pronunciation results in surface dyslexia. Connectionist models of surface and deep dyslexia, and of word substitutions in aphasia, are described in detail. Some advantages and disadvantages of connectionism are discussed.