Role of Reinforcement in Discrimination Learning Set in Monkeys

Following a review of empirical research on the role of reinforcement in learning-set formation, the major theoretical explanations of learning-set formation in monkeys are analyzed. Studies showing that a reward can function to decrease as well as increase the probability of choosing an object cast doubt upon theories based on an automatic strengthening function of reward. Hypothesis or strategy selection theories avoid this problem by assuming hypotheses, rather than responses, are subject to reinforcement principles, but hypothesis theories are at best incomplete in their treatment of retention. A theory which assumes that learning-set formation results from between-problem stimulus generalization of feedback from expected rewards is consistent both with retention studies and with experiments on the function of reward in learning set, suggesting that learning-set formation need not be considered a complex abstractive process.