Effect of typicality on online category verification of animate category exemplars in aphasia

Abstract

Normal young, elderly, Broca's aphasic, and Wernicke's aphasic individuals participated in an online category verification task where primes were superordinate category labels while targets were either typical or atypical examples of animate categories or nonmembers belonging to inanimate categories. The reaction time to judge whether the target belonged to the preceding category label was measured. Results indicated that all four groups made significantly greater errors on atypical examples compared to typical examples. Young and elderly individuals, and Broca's aphasic patients performed similarly on the verification task; these groups demonstrated faster reaction times on typical examples than atypical examples. Wernicke's aphasic patients made the most errors on the task and were slowest to respond than any other participant group. Also, these participants were not significantly faster at accepting correct typical examples compared to correct atypical examples. The results from the four groups are discussed with relevance to prototype/family resemblance models of typicality.

Fig. 1

Error percentage for typical, atypical examples, and nonmembers across the four participant groups. Errors for each category are collapsed within typicality.

Fig. 2

Mean RTs and error bars for typical, atypical examples, and nonmembers across the four participant groups. RTs for categories are collapsed within typicality.

Fig. 3

Advantage for the typical example over the atypical example (in percentage) for the four participant groups.