Expanded vs. equal interval spaced retrieval practice: Exploring different schedules of spacing and retention interval in younger and older adults

The present study was designed to help answer several questions regarding the impact of spacing and expanded retrieval on memory performance in younger and older adults. Three expanded/equal interval schedule pairings, matched in average spacing (1-2-3/2-2-2; 1-3-5/3-3-3; and 1-3-8/4-4-4), were compared, and the effect of retention interval on spaced retrieval benefits was examined by comparing performance on a same day test to a test delayed by 24 h. Both age groups showed a learning phase retrieval success advantage for expanded items compared to equal interval items. Only older adults in the same day test condition showed a significant expansion effect in final recall. After a 24-h delay, the final recall advantage for items in the expanded condition was lost in both groups, and in fact these items were at a significant recall disadvantage for younger adults. Results indicate that younger and older adults benefit from a rehearsal technique that incorporated any type of spaced retrieval whether it is distributed as an expanding schedule or not. Although we did not find robust advantages for expanded retrieval compared to equal interval practice, there could be certain advantages (such as reinforcement due to high success rates) to using expanded retrieval depending on the ultimate goals of an individual memory training program.