The effect of physical similarity on pantomime recognition in aphasia

Abstract

Abstract The ability of both anterior and posterior aphasic subjects to recognize pantomimes relative to normal controls was examined via a task requiring a ‘yes/no’ judgement as to whether a presented pantomime and pictured object ‘went together’ or not. Pantomime-object combinations were classified as physically similar or dissimilar on the basis of their construction from sets of pantomime pairs rated for similarity. Results indicated a highly significant effect for physical similarity with similar pantomimes being more difficult to recognize than dissimilar, and a significant effect for decision type such that ‘non-matching’ pantomime-object combinations were harder to recognize than ‘matching’ cases. Overall, anterior aphasic subjects performed at an equivalent level to their normal controls. In contrast, posterior aphasic subjects performed more poorly than controls across all conditions of the experiment, representing a quantitative rather than qualitatively different performance pattern. Further analyses examining the high error rate amongst normal subjects revealed a significant correlation between age and error rate. Results are discussed in light of processing demands of the task dictated by the temporal nature of pantomimic stimuli and the degree of ambiguity inherent in the pantomime. A role for semantic processing in pantomime recognition and effects of ageing on pantomime recognition are suggested.