The Effect of Implicit Context on Memory Integration

While recent work has shown implicit context effects on memory (i.e. memory effects of learning in a shared context without testing the item-context association) in recall and recognition, none have used shifts in natural environments, limiting the translation of these findings to real learning environments. Further, the role of implicit memory in memory integration, the process of bridging across related experiences through the extraction of overlapping features, has not been described. This study examines the degree to which implicit context influences the ability to bridge across related experiences to form integrated memories, using associative inference as a behavioral measure of memory integration. In Experiment 1, an across subject’s associative inference task described by Preston et al, was used to examine implicit context effects on memory integration. In this task initial pairs (AB) were learned in one context followed by the learning of overlapping (BC) and non-overlapping (XY) pairs in the same or different context. Following learning of the overlapping AB and BC pairs, participants were asked to infer the indirect AC relationship. We found both a significant facilitation of the BC learning as compared to XY learning and reduction in response time when the AB and BC pairs had been learned in the same context. To test the individual variance in the encoding of implicit context, in Experiment 2 we used a within subject design. We found that while there was no significant effect of context shift on the inference task, there was a facilitation of the overlapping pair (BC) learning as compared to nonoverlapping pairs (XY) when they were learned in the same environment as the overlapping AB pairs. The inability to replicate the effect on inference, may be attributed to the added contextual shift before the AC inference test. Thus, we hypothesize that the context of the inference test may also be vital in facilitating implicit context effects on memory. Importantly we found that implicit context exhibits memory effects in an associative inference design, affecting the speed with which inferences are made, suggesting that shared implicit context is important in facilitating memory integration.