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Schizophrenia is marked by a variety of cognitive and biological abnormalities. In the first part of this paper we describe schizophrenic cognitive deficits in three experimental tasks which tap attention and language processing abilities. We also review biological disturbances that have been reported involving the frontal lobes and the mesocortical dopamine system. In the second part of the paper we present three computer models, each of which simulates normal performance in one of the cognitive tasks described initially. These models were developed within the connectionist (or parallel distributed processing) framework. At the behavioral level, the models suggest that a disturbance in the processing of context can account for schizophrenic patterns of performance in both the attention and language-related tasks. At the same time, the models incorporate features of biological computation that address the biological processes underlying cognitive deficits. All three models incorporate a mechanism for processing context that can be identified with frontal lobe function, and a parameter that corresponds to the effects of dopamine on frontal cortex. A disturbance in this parameter is sufficient to account for schizophrenic patterns of performance in all three of the cognitive tasks simulated. Thus, the models offer an explanatory mechanism linking performance deficits to a disturbance in the processing of context which, in turn, is attributed to a reduction of dopaminergic activity in prefrontal cortex. In the General Discussion, we consider the implications of these models for our understanding of both normal and schizophrenic cognition. We conclude with a discussion of some of the general issues surrounding the modelling endeavor itself.