Performance of retarded adolescents and nonretarded children on one- and two-bit logical problems

Abstract

Groups of adolescents of retarded and borderline intelligence, ranging in IQ from 44 to 80 and in mean MA (mental age) from 8 to 12 yr, and groups of nonretarded children ranging in mean MA from 6 to 12 yr, were given logical problem solving tasks. In the nonretarded groups, on a one-bit problem only the kindergarten children (mean MA = 6 yr) failed to perform above chance, and were not tested further. On a two-bit problem, only the first graders (mean MA = 7 yr) failed to perform above chance. Conversely, in the low IQ groups, only the borderline group (mean MA = 12 yr) performed reliably above chance on the one-bit problem, and none performed above chance on the two-bit problem. There is a profound deficiency in low IQ individuals on certain tasks requiring logic and foresight, and MA markedly over-estimates their performance relative to the performance of nonretarded individuals.