Heritability is defined as the proportion of a manifested trait's varience that is due to genetic variation. Sixty-five pairs of twins were employed to investigate the heritability of: (1) short term memory (Jensen's Level 1), operationalized using of modified "digit span" test; (2) the general intellective factor (Jensen's Level II), operationalized as the score on Raven's Progressive Matrices; and (3) Divergent Thinking, operationalized as scores on the Torrance Tests of Creative Thinking. Utilizing both identical twins, who have exactly the same genes, and fraternal twins, who share only about half of their genes, the authors concluded that (1) short term memory has a moderate index of heritability; (2) the general intellective factor has a somewhat high heritability index; and (3) there is no evidence of heredity variation in Divergent Thinking measures. Possible implications for compensatory education programs, as well as for training classroom teachers, are mentioned. (TL)