Cognitive rigidity in the aged and the mentally retarded.

Three groups, one of elderly, one of young mentally retarded, and one of non-retarded young persons were compared on a visual recognition task which involved changing from one category of identification to another. The mentally retarded participants had greater difficulty in changing categories than did the non-retarded participants. Results for the elderly were similar but may have been partly due to the choice of stimulus material. In a second task, the same elderly and non-retarded young participants named as many objects as possible in one minute. The elderly group produced fewer responses on average than the young group and fewer categories of such responses. Results suggested that older persons find it more difficult to change between different categories of identification.