Item responses of two samples each of 622 normal and 573 educable mentally retarded children, 6 to 15 years of age, on Raven's Colored Progressive Matrices were submitted to a principal components analysis and varimax rotation. The following four factors were obtained: continuity and reconstruction of simple and complex structures, discrete…

Tests were administered to 209 educable mentally handicapped children (mean age 10.8, mean IQ 77) to determine factors related to speech hearing. Results indicated that mental age, intelligence quotient, physiological age, institutionalization, and organic bases for retardation were not significantly related either to speech reception threshold or…

A longitudinal program of workshop-centered rehabilitation services was administered to mentally retarded adolescents. Results with the 36 remaining at the end of the 3rd year indicated that most characteristics central to vocational development were stable by early adolesence; a "competence cluster" of variables covaried systematically; high and…