This experiment studied the effect on intelligence test scores of a probable reinforcer given for correct responses. Eleven pairs of 5-to 7-yr-old children were matched on the basis of a strong liking of candy, no physical problems associated with eating it, parent permission to receive and eat the candy, age, sex, and a revised Stanford-Binet Scale Form L IQ score. The control group was given the revised Stanford-Binet Scale Form M, as prescribed in the test manual. The experimental group was also given Form M according to the manual, except M&M candy was given for each plus or correct response. There was an appreciable, statistically significant difference between the resulting IQ test scores of the two groups.Several studies have sought to determine the effect various rewards have on children's intelligence test scores. Hurlock (1924Hurlock ( , 1925 studied the effects of praise and blame in three early experiments. In the first two, she used the National Group Intelligence Tests. In the first experiment, she divided third-, fifth-, and eighthgrade children into groups by age, sex, race, and intelligence, and on a test-retest design, over a one-week span, studied the effects of praise and blame. After the first testing, one group was praised for its test scores, and a second group was reproved for its test scores. The second experiment was a followup of the first and in both she found no difference between the effects of praise and blame, yet both were more effective than practice alone.Benton (1936) Klugman (1944) also studied the effects of the promise of two presumed reinforcers on IQ scores. He made use of alternate forms of the Stanford Binet, 1937 revision. His subjects were 72 children from grades 2 to 7. Praise and money were the reinforcers given if the children did better on the second testing. Although he found no significant difference overall between the two reinforcers, scores of the Negro children were substantially raised when tested with money as compared to praise, and scores of the white children were raised more by praise than were the scores of the Negroes.The effects of reinforcement on the IQ scores of 480 second and third graders divided into three groups (middle-class white, lower-class white, and lower-class Negro) were studied by Tiber and Kennedy ( 1963 (FALL 1972)