Conceptual development in learning-disabled and normal boys.

In two related studies, a pictorial sorting task served as the means of measuring conceptual development in LD and normal boys. The studies found no differences in the bases on which groups were formed (perceptible attributes, function, or nominal class membership) or in the manner in which groups were structured (thematically, in complexive groups or superordinate groups). Furthermore, parallel developmental trends were found in both LD and normal subjects groups. These findings are not consistent with early studies of concept formation in brain-damaged subjects, most of whom were retarded. Subjects in the present studies were selected on the basis of clinical diagnosis of LD and average IQ. The findings of the present studies suggest that generalizations about conceptual abilities of LD children of normal intelligence should not be based on early studies of the effects of brain damage.