Poster C95, Sunday, March 26, 5:00 – 7:00 pm, Pacific Concourse
Disentangling interactions between context switches and the spacing effect
Lynn Lohnas1, Lila Davachi1; 1New York University
Improved memory for spaced over massed repetitions is a well-established finding (Cepeda et al., 2006). Yet one intriguing result concerns the interaction between items repeated in the same vs. different encoding contexts: whereas recall probability is greater for massed items repeated in different contexts, recall probability is greater for spaced items repeated in the same context (e.g., Verkoeijen et al., 2005; Maskarinec & Thompson, 1976). Here we consider the role of context switches, as such switches modulate memory and attentional processes (Ezzyat & Davachi, 2014; DuBrow & Davachi, 2013) yet have not been considered in the aforementioned result. Eighteen participants were presented with lists of words while undergoing functional magnetic resonance imaging (fMRI). Participants performed free recall and source recognition for each list. During encoding, each word had an associated task context, and could be presented once, twice massed (lag=0) or twice spaced (lag=5). At each lag, words could be repeated with the same or different contexts. For a massed item presented with different contexts, the second presentation always immediately follows a context switch. Yet attentional and neural processes were impacted by switches; encoding task response times for once-presented items were significantly slower for those items that immediately followed a switch vs. those that did not (p<.01). We thus introduced a matched control to the massed items whereby a spaced item repeated in different contexts had the second presentation immediately following a context switch. Overall, our results reflect how encoding contexts modulate fMRI activity and behavior to promote successful encoding.
Topic Area: LONG-TERM MEMORY: Episodic