Immediate and delayed reinforcement on WISC-R performance for mentally retarded students.

Thirty white mentally retarded children were administered the WISC-R under one of three conditions: standardized testing conditions, standardized plus immediate reinforcement, standardized plus delayed reinforcement. One reinforcement group earned tokens immediately after each correct response and the other reinforcement group received their earned tokens halfway through and at the end of the IQ test. Both reinforcement groups exchanged their tokens for a variety of backup reinforcers at the halfway point and at the end of the test. Both the immediate and delayed reinforcement groups showed significantly better performance than the standardized testing group, although the two reinforcement groups did not differ from one another. Half of the children in each of the groups that earned tokens scored above the mentally impaired range while only one child in the standardized testing group scored above the mentally impaired level. Implications for the use of intelligence tests for mentally retarded students are discussed.