Barking up the wrong tree? Lexical ambiguity resolution in children with language impairments and autistic spectrum disorders

Lexical ambiguity resolution was investigated in 9- to 17-year-olds with language impairment (LI, n = 20), autistic spectrum disorder (ASD) plus language impairment (ALI, n = 28), ASD and verbal abilities within the normal range (ASO, n = 20), and typically developing children (TD, n = 28). Experiment 1 investigated knowledge of dominant and subordinate meanings of ambiguous words. The LI and ALI groups knew fewer subordinate meanings than did the ASO and TD groups. Experiment 2 used a modified version of the Gernsbacher, Varner, and Faust (1990) paradigm to investigate contextual facilitation and suppression of irrelevant meanings. All groups demonstrated contextual facilitation, responding quickly and more accurately to words following a biased context. However, children with ALI and LI did not use context as efficiently as did their peers without language deficit. Furthermore, for the LI and ALI groups, errors in the suppression condition reflected poor contextual processing. These findings challenge the assumptions of weak central coherence theory and demonstrate the need for stringent language controls in the study of autistic cognition.