Why does collaborative retrieval improve memory? Enhanced relational and item-specific processing

Engaging in collaborative retrieval practice increases performance on subsequent memory tests taken individually (Blumen & Stern, 2011). However, the basis of these post-collaborative benefits is largely unexplained. Thus, the primary goal of the current research was to investigate the cognitive mechanisms underlying post-collaborative benefits vis-à-vis the theoretical framework of distinctiveness theory, which postulates that two processes influence memory. Relational processing refers to the encoding of similarity among a set of items, whereas item-specific processing refers to the encoding of information that differentiates items from one another. The central claim of distinctiveness theory is that memory is enhanced when differences among individual items are processed in the context of the similarity among those items (referred to as distinctive processing). The basic design of all three experiments was similar (i.e., close replications with intent to provide multiple estimates of effect sizes on which to base conclusions): Learners were asked to study lists of exemplars from taxonomic categories, followed by recall practice that occurred either collaboratively or individually. All learners completed individual final tests, immediately after practice and/or after a delay. Of greatest theoretical interest for diagnosing the extent to which post-collaborative benefits reflect distinctive processing, we examined indicators of relational processing (clustering and category access) and item-specific processing (items recalled per category and recognition performance). Results across the three experiments established that distinctive processing (i.e., enhancements in both relational and item-specific processing) contributes to post-collaborative benefits across both short and long retention intervals.