To determine whether the distraction effect associated with material rewards in discrimination learning can account for the superior performance of reward groups in probability learning, the performance of 144 school children (preschool, second, and fifth grades) on a two-choice successive discrimination task was compared under three reinforcement conditions (material reward, marker, and knowledge of results). The two events in the task had different frequencies of occurrence, as in probability learning, yet they appeared in a constant order to make 100% payoff possible. The subjects in the reward and marker groups learned the task more slowly, and the nonlearners among them used stereotyped alternation patterns to a greater degree than subjects in the knowledge-of-results condition. These findings suggest that a distracting effect of material reward is present in probability learning and may explain the superior performance of reward groups typically found in probability learning studies. © 1974.
McGraw, K. O., & McCullers, J. C. (1974). The distracting effect of material reward: An alternative explanation for the superior performance of reward groups in probability learning. Journal of Experimental Child Psychology, 18(1), 149–158. https://doi.org/10.1016/0022-0965(74)90096-4