The Hidden Costs of Reward and WAIS Subscale Performance

mediate task performance, 76 female undergraduate students were matched on age and initial IQ and were then assigned to one of four treatment groups. Subjects were administered six subscales of the Wechsler Adult Intelligence Scale identified as algorithmic tasks (Information, Digit Symbol, Picture Completion), which require rather straightforward, well-rehearsed skills; or as heuristic tasks (Block Design, Picture Arrangement, Object Assembly), which require more insight and discovery. Subjects were tested under either standard, nonreward conditions or one of three reward conditions (noncontingent, contingent, and social competition). Results revealed no differences between the three reward groups on either algorithmic or heuristic tasks. Nonreward and reward subjects performed in similar fashion on the algorithmic tasks, but nonreward subjects performed significantly better than the three reward groups did on the heuristic tasks (p< .05). This result was due to a differential error rate rather than to the amount of time spent on the items. Nonreward subjects made significantly fewer errors than reward subjects did on the heuristic tasks (p < .01). Results were related to the McGraw model, which predicts when rewards should be expected to facilitate or impair performance, and were seen as consistent with a developmental regression interpretation.