Differentiating between Two Groups that Fail in School: Performance of Learning Disabled and Mildly Retarded Students on Oddity Problems

Normally achieving, learning disabled, and mildly retarded 6- through 9-year-old students, matched on chronological age, were trained to select the odd picture in a three-picture array. Subsequently, their ability to apply this relational rule was assessed on eight different oddity variations. Group comparisons yielded large, consistent performance differences between the mildly retarded and both other groups, which were subsequently associated with high levels of classification accuracy. There were small, consistent differences between the normally achieving and the learning disabled students, which were significant for some of the oddity variations. Accurate classification was possible for the learning disabled students when they were compared to the mildly retarded, but was not possible when learning disabled students were compared to their normally achieving peers.