Changes in the level of unitization moderate the impact of unitization on associative memory

Abstract

Recent studies revealed that unitization could promote familiarity to support associative memory. However, its effects on the associative memory and recollection remain controversial. The current study aims to explain these mixed results by considering a potential moderator: Changes in the level of unitization between the studied and rearranged pairs. In this study, participants were required to learn both related and unrelated picture pairs during the encoding phase. Subsequently, they needed to distinguished intact pairs form rearranged-change and rearranged-no-change pairs at retrieval. The results revealed that unitization can enhance familiarity to support associative memory, while its impact on associative memory and recollection varied depending on the level of unitization changes. Specifically, under the no-change conditions, unitization enhanced the role of absolute familiarity and recollection in supporting associative memory, but it did not lead to a significant improvement in the overall performance. Conversely, under the change conditions, unitization not only strengthened the contributions of both types of familiarity (i.e., absolute and relative) but also enhanced the role of recollection, leading to an improved associative memory. These findings not only clarify some of the inconsistencies in the literature concerning the impact of unitization on associative memory, but also suggest that unitization affects the contributions of absolute familiarity and relative familiarity differently, with its effectiveness varying according to the level of unitization changes.