Effect of mentally retarded persons' level of stereotypy on their learning.

The effect of level of stereotypy on learning a discrimination for 30 mentally retarded persons was examined. A factorial design with high and low levels of stereotypy and three levels of IQ was employed. The number of days to acquire the discrimination differed among the IQ groups, but there was no main effect of stereotypy. An interaction was found indicating that a high level of stereotypy slowed learning only in the lowest IQ group. We concluded that the effects of stereotypy upon learning were different across the IQ levels and that high levels of stereotypy did not uniformly interfere with the acquisition of the discrimination.