Five descriptive personality scales evaluating the individual's internal-external orientation were administered to 120 educable mentally handicapped children, 30 each at chronological age levels 9, 11, 13, and 15. Reading and arithmetic achievement tests were also given. Results indicated a significant relationship between three of the personality scales and achievement. In addition, the results demonstrated a significant relationship between the various scales at all age levels under consideration. A developmental trend across the age range was represented with responses tending to move toward an increasingly greater internal frame of reference with increasing age. Almost three-fourths of the document consists of statistical tables and charts as well as copies of the instruments used. (Author/JD)