Matching-to-sample assessment of stimulus overselectivity in students with intellectual disabilities.

A delayed matching-to-sample task with multiple sample stimuli was used to evaluate stimulus overselectivity in 70 individuals attending residential special-education schools. A Mental Age Equivalent score (MAE) was obtained for each student using the Peabody Picture Vocabulary Test. Twenty-one participants failed to complete matching-to-sample pretests (mean MAE = 3.70 years). Results on the multiple-sample test for the remaining 49 participants indicated no overselectivity for 14 students (mean MAE = 7.44 years) and were consistent with overselectivity for 35 students (mean MAE = 5.28 years). Performances of students with overselectivity were more variable than those with no overselectivity. The MAE scores were related to both matching-to-sample performance and stimulus overselectivity.