Mayor, J.
Basque Center on Cognition, Brain and Language, Donostia, Spain
Williams Syndrome (WS) children possess relatively large vocabularies when compared to their other, impaired, cognitive skills. However, their language acquisition is delayed, their vocabulary spurt is less marked than for typically-developping infants, categorisation skills are weak when their vocabulary is already large and they do not respond taxonomically. This pattern of findings led Nazzi and Bertoncini (2003) to suggest that WS children acquire a large "proto-lexicon" by gradually attaching several exemplars of a category to their appropriate sound pattern in an associationist mechanism. This hypothesis is tested by hindering the formation of visual categories in a model of early word learning (Mayor and Plunkett, 2010) so as to mimic WS weak categorisation skills. In the absence of lesions, the model accounts for the emergence of taxonomic responding and displays a vocabulary spurt. Generalisation of word-object associations relies on categorical representations. In contrast, when categorisation is impaired, lexical acquisition is delayed, a vocabulary spurt is absent and word-object associations are not generalised. However, through repetitive labelling events, the system is still able to map several object exemplars to their appropriate sound patterns in a fashion described in Nazzi & Bertoncini (2003), thereby leading to the formation of a surprisingly large vocabulary.