Selective verb deficits in SLI: another look at the autistic spectrum problem

Bishop (2000) has recently raised the question of discriminating between grammatical SLI, pragmatic impairment, and social cognition problems linked to a spectrum of autistic behaviour. In this paper we report pilot findings which indicate that grammatical SLI may be associated with a lexical deficit in verbs that involve interpersonal action, and in particular verbs whose meanings involve mental states. These findings offer some support for Bishop's multi-dimensional model permitting grammatical SLI and certain autistic characteristics to be non-exclusive of each other. On a test of verb use elicited by video pictures, with the verb prompted, a group of 10 children aged 5;10-8;0 with grammatical SLI showed a marked deficit in the use of verbs expressing the intention of an agentive subject towards another person (e.g. help), and the mental state of another person (e.g. frighten) as compared to their BPVS peers. They failed the majority of the time to express the person affected by the action as a grammatical argument of the verb. With verbs whose meaning involves the physical action of an agent on an inanimate entity (contact verbs and causative verbs of motion) their performance was equivalent to that of their BPVS peers. The entity affected by the action strongly tended to be syntactically realised as in adult-like use. Overall, despite their apparent vocabulary equivalence, the children with grammatical SLI were significantly less able to encode an event where the verb denoted interpersonal action. Possible reasons for this outcome are discussed.