Comparison of verbal typicality judgments of mentally retarded and nonretarded persons.

In Phase I of this study, mentally retarded adults judged whether exemplars were members of their respective categories. In Phase II they judged how representative the exemplars were of their categories. Comparisons were made between this group and the nonretarded groups of Bjorklund, Thompson, and Ornstein (1983) and Uyeda and Mandler (1980). There was little evidence of a developmental relationship between typicality ratings given by retarded and nonretarded persons, but there were significant relationships among the groups for specific categories. Relationships were more category-than mental age-dependent. Other analyses indicated that Rosch's (1975) finding that typical exemplars are incorporated into category structures prior to atypical exemplars was replicated with retarded persons.