The opposite effects of semantic retrieval on prior and future learning

Recently, interest in the effects of testing on memory has increased. In this set of experiments, I examined the effects of interleaved semantic retrieval on previous and future learning within a multi-list learning paradigm. Interleaved retrieval led to enhanced memory for lists learned following retrieval. In contrast, memory was impaired for lists learned prior to retrieval (Experiment 1). These results are consistent with recent work in multi-list learning and in the list-before-the-last paradigm, both of which reveal a crucial role for retrieval in enhancing list segregation. This pattern of results also follows clearly from a theoretical perspective in which retrieval drives internal contextual change, and contextual overlap between study and test promotes better memory. Consistent with that perspective, a 15-minute delay before the final test eliminated both effects (Experiment 2). Experiment 3 replicated the results of Experiment 1 with materials more appropriate for educational settings: interleaved semantic retrieval led learners to be more able to answer questions correctly about later texts but less likely to do so about earlier texts.