Retroactive Facilitation and Change Awareness Across Lags and Retention Intervals

Memory for an earlier event can be impaired by later studying a related event (retroactive interference). However, when later events cue retrievals of earlier events that also enable integrative encoding, memory for the earlier event can be enhanced (retroactive facilitation). Two experiments using continuous A-B, A-C paired-associate tasks examined retroactive memory effects across lags and retention intervals. We indexed study-phase retrieval and integrative encoding by examining associations between awareness of changes and memory for first responses. Participants studied A-B, A-C, and retention-interval-matched A-B pairs and indicated when they detected response changes. The lag between A-B and A-C and the retention interval between A-C and test trials varied factorially across 4, 16, and 48 intervening items. Cued-recall test formats differed: Experiment 1 prompted direct retrieval of first responses, with participants reporting recollected changes. Experiment 2 used modified-modified free recall in which participants reported responses as they came to mind and indicated whether they were the first, second, or only responses; the first two decisions indicated recollection of changes. Both experiments showed the greatest retroactive facilitation at the longest retention interval and intermediate lag. Retroactive facilitation co-occurred with and was statistically associated with detection and recollection of changes, suggesting these processes contributed to the observed effect. Negatively curvilinear, non-monotonic lag functions occurred for A-B, A-C recall at the longest retention interval and were associated with detected changes, especially those not recollected. These findings may be accounted for by a memory-for-change framework with a role for contextual variability that determines study-phase retrieval success.