Twenty-four trainable mentally retarded school age children were matched on the basis of CA and ITPA language age. The experimental group of 12 subjects received 33 instructional sessions of 45 minutes each for language improvement over an 11 week period. The language age gain scores of the two groups did not differ significantly although the experimental group showed a mean gain 2 months higher than that of the control group. The experimental subjects below CA 13-4 made far greater gains than did those above that age.
C. Milton Blue (Thu,) studied this question.