Organizational Dynamics of Memory Across Days

Poster Session E - Monday, April 15, 2024, 2:30 – 4:30 pm EDT, Sheraton Hall ABC

Daniella Rafla¹ (rafla@sas.upenn.edu), Brandon Katerman¹, David Halpern¹, Michael Kahana¹; ¹University of Pennsylvania

How does the organization of memory change over several repeated experiences? Previous studies of multi-trial free recall investigated changes in patterns of retrieval for the same list within a single learning session. In the present study, we examine changes in memory organization when learning occurs over multiple days. Past work typically finds that subjects recall items in increasingly stereotyped orders, with less reliance on the temporal characteristics of the most recent experience. Here we investigate how semantic, temporal and subjective clustering evolve across a multi-session experiment. We analyze data from a free recall experiment previously reported by Katerman et al. (2022). In each of five sessions, subjects studied a list of 576 words, with the words appearing in a new random order in each session. Prior to encoding, subjects performed a 10-minute recall task in which they attempted to recall as many words as they could from the previous session, which occurred at least one and often several days earlier. We found preserved contiguity effects reflecting previous recall order instead of encoding order. This effect increased across subsequent sessions, attesting to the important role that retrieval plays in shaping memory for items. Next, we asked how intrusions may interact with study-test delays. We found that long study-test delays favor the generation of intrusions which are additionally likely to be carried across subsequent sessions. These new findings provide support for subjects’ tendency to strongly encode associations made during free recall.

Topic Area: LONG-TERM MEMORY: Episodic