Retrieval practice decreases processing load of recall: Evidence revealed by pupillometry.

Retrieval practice is an effective long-term learning strategy. Items practiced through repeated retrieval are resistant to interference, stress, and secondary load, which attributes also characterize automatization in skill learning. In two experiments, we investigated whether retrieval practice is associated with decrease in processing load, which is a further attribute of automatization. Participants first learned paired associates, and then they practiced the items either by repeatedly studying or engaging in retrieval practice. Then their memory was assessed after either five minutes (Experiment 1) or one week (Experiment 2). Processing load was measured by assessing task-evoked pupil dilation during both retrieval practice and later recall. The pattern of results was similar in both experiments. During retrieval practice, processing load decreased during consecutive practice cycles. Moreover, during the final recall test, the retrieval of previously retrieval practiced items required less processing resources, as compared to the retrieval of previously restudied items. Our results suggest that repeated retrieval reduces processing load as well as attentional control involvement during practice and later recall.