A grain of truth in the grain size effect: Retrieval practice is more effective when interspersed during learning.

Retrieval practice is a powerful method for consolidating long-term learning. When learning takes place over an extended period, how should tests be scheduled to obtain the maximal benefit? In an end-test schedule, all material is studied prior to a large practice test on all studied material, whereas in an interim test schedule, learning is divided into multiple study/test cycles in which each test is smaller and only assesses material from the preceding study block. Past investigations have generally found a difference between these schedules during practice but not during a final assessment, although they may have been underpowered.

Do partial and distributed tests enhance new learning?

Testing facilitates subsequent learning of new information, a phenomenon known as the The effect is often investigated in multilist procedures, where studied lists are followed by a retrieval test, or a control task such as restudying, and learning is compared on the final list. In most studies of the effect, tests include all material from the preceding list. We report four experiments, three of which were preregistered, to determine whether tests that are partial (not including all studied items) and distributed (including retrieval of items from earlier lists) are effective in enhancing new learning.