Why do the effects of delaying reinforcement in animals and delaying feedback in humans differ? A working-memory analysis.

Animal research has shown that reinforcement is substantially less effective when it is delayed, but in studies of human motor learning delays in providing feedback typically have much less effect. One possible explanation is that in human research participants know the response to be learned and can thus focus on it during the delay; that is not the case in experiments on animals. We tested this hypothesis using a task in which participants had minimal information on what movement was correct and found that, as in animal experiments, participants learned only when feedback was immediate. A second experiment confirmed that the effects of the delay depended on how many responses had to be held in working memory: the greater the memory load, the poorer the learning. The results point to the importance of activity during a delay on learning; implications for the teaching of motor skills are discussed.