Abstract
Recent memory models highlight the importance of contextual information for remembering episodic events (Polyn et al., 2009). A consequence of binding event memories with their context is that contextually-related memories can interfere with the retrieval of targeted memories, leading to retrieval-induced forgetting (RIF) of the competing memories (Anderson et al., 2000). A model built to explain this effect describes a non-monotonic "U-shaped" relationship between memory activation and changes in memory strength (Norman et al., 2007). Specifically, competing memories that activate to a moderate degree (vs. low or high activation) are more likely to be weakened and subsequently forgotten. However, the factors governing whether and how memories will activate and compete during retrieval are not well understood. Here we test the hypothesis that events experienced closer in time will be more likely to compete and later get weakened in the process during memory retrieval. Various forms of multivariate pattern analyses of fMRI data were used to track memory reactivations of previously learned objects in the ventral visual cortex during a context-based cued-retrieval task. Preliminary results indicate that temporal distance during encoding did not systematically bias the degree of memory reactivation during context-based retrieval. However, we did find a non-monotonic relationship between reactivation strength and recognition performance: competing memories with the highest degree of reactivation (regardless of temporal similarity) were associated with lower subsequent memory performance. These results suggest that incidental reactivation of contextually-related memories during retrieval can trigger forgetting. To replicate and extend these results, we have modified the experimental design to include repeated retrieval attempts (3 per target item) (Kuhl et al., 2007), and a recognition-induced forgetting manipulation (Maxcey & Woodman, 2014) to more reliably induce forgetting of the competing memories. These results provide new understandings of the dynamics of memory competition during retrieval and its impact on forgetting.
Meeting abstract presented at VSS 2018