Retrieval Practice in Free Recall: Effects of Delay, Additional Tests, and Practice Success

Testing (retrieval practice) has been widely reported to lead to better retention than restudying, especially at longer retention intervals. However, this effect has not been extensively explored in free recall. We set out to replicate the retrieval practice effect in free recall and examine the effects of both retention interval and number of tests. In Session 1, subjects studied one word list followed by either restudy or retrieval practice. At the end of Session 1, half of the subjects were tested; 24-48 hours later, all subjects returned for a final test. We found no retrieval practice effect, even after 24-48 hours. However, retrieval practice did protect against forgetting, and final test performance was higher for subjects who completed an additional test in Session 1. These findings suggest that retrieval improves memory for a subset of successfully practiced items. Retrieval practice’s benefits in free recall may depend on initial encoding success.