A comparison of normally achieving, mildly retarded, and learning disabled students on a perceptually based oddity task

Abstract

The oddity performance of mildly mentally retarded (MMR), learning disabled (LD) and normally achieving (NA) 6-through 8-year-old grade school students was compared in two-group (NA vs. MMR and NA vs. LD) and three-group (NA vs. MMR vs. LD) contrasts. The oddity arrays displayed on each card consisted of single or multiple letter-groups (1,2, ... 7 letters per group). Regardless of the number of letters per group, the odd array differed from the other two by one letter. Performance differences between the NA and LD groups were minimal, while both groups performed at significantly higher levels than the MMR group. The two-group contrasts indicated that failure level, one of two dependent measures examined, could accurately identify 84% of the MMR sample, and 97% of the NA group. The second measure, level of first error, enabled the isolation of a small subgroup of LD students from their chronological NA peers. Demonstrated cognitive differences in the competencies of the two handicapped groups on this as well as other tasks, raised questions about the advisability of a combined classification and/or educational setting for these two mildly impaired groups.