Interference Effects, Age, and the Spacing Benefit

Improving memory is a high priority for many. One strategy that reliably improves long-term memory is spacing of learning. Using a within-subject cued recall task, we compared recall of 50 weakly associated word pairs in older (55–89 years) and younger (18–22 years) adults across 3 different spaced trials with constant temporal gaps but of varying types of interference (related, unrelated, none). Two control conditions were also included (massed- and single-presentation word pairs). We measured recall performance after a brief delay. During training, recall was lowest for the words in the related interference condition with the remaining groups statistically equal, and younger adults showed better overall performance compared with older adults. At test, both groups showed comparable spacing benefits (with no performance differences between interference conditions), and older adults' performance equaled that of younger adults. It appears that delay, and not type of interference during the delay, was critical to the spacing benefit.