Smith J, Kaufman H, Dutch S, Frost R
Am J Ment Defic. 1975 Sep;80(2):191-6.
The effects of number and type of dimension of stimulus variation, type of dimensional combination, and delay of response upon the identification performance of retarded and nonretarded children were examined. A retarded-nonretarded subject difference in identification ability and delay effects found in an earlier study (Smith & Kaufman, 1972) was replicated, and a developmental effect for nonretarded children was found as well. A retarded-nonretarded subject interaction was indicated for the effects of increasing number of dimensions of variation and for the effects of type of dimensional combination (figure-figure combinations as opposed to figure-ground combinations).
