Proceedings of the Annual Meeting of the Cognitive Science Society

This paper presents a simulation of the selective deficits and the partial breakdown patterns characteristic of the oral reading performance of deep dyslexics. The most striking symptom of deep dyslexia — usually considered its defining characteristic — is the occurrence in oral reading tasks of semantic paralexias: the vocalization of a word semantically related to an isolated, printed target word. The pattern of simulated paralexic errors by the neural model is strongly controlled by the similarity structure of the training set stimuli and, to a lesser extent, the frequency of presentation of stimuli during learning by the model. This result fits well with effects of stimulus type on patterns of paralexic error among deep dyslexics. Further, the model very naturally reproduces the patterns of partial breakdown observed in deep dyslexics, including a slow response time (RT) and within subject variation of response to a particular target word in successive test sessions.