Modeling Impairments in Lexical Development

We implemented the connectionist model of social-pragmatic word learning (Caza & Knott, 2012) to test the hypothesis that reduced joint attention between infant and mother would increase the difference in acquisition between nouns and verbs as observed in Autistic Spectrum Disorder (ASD). The ratio of objects to actions in the observed event stream was manipulated to create an original noun-verb asymmetry. Ten simulations were run for each of the combinations of three conditions of communicative reliability and two conditions of unfiltered random associative learning, which is regarded by some researchers as the primary mechanism of language learning in ASD. The simulations indicated that the reduction in the reliability of communicative actions does not lead to increased noun-verb asymmetry within the originally planned training epochs. A trend in the predicted direction appeared toward the end of training, suggesting that further simulations may help resolve the issue within the current architecture.