Unfamiliar Contexts Compared to Familiar Contexts Impair Learning in Humans

Context plays a key role in learning and memory processes. Re-exposure to the context that information was learned in facilitates memory retrieval of this information. However, it is currently unclear whether context changes also influence the ability to learn new information, which the present work investigated in two experiments with healthy participants (n = 40 per experiment; 20 female). In experiment 1, participants learned a list of word-pairs (A-B) in the morning and a second non-overlapping list (C-D) in the evening, either in the same context or in a different context than the first list (between-subjects). We confirmed that new learning is enhanced if it takes place in the same context, putatively driven by context-dependent retrieval of meta-learning processes. In addition, new learning in the other context was significantly decreased compared to baseline. In experiment 2, participants were exposed to both contexts in the morning, but only learned word-pairs in one of them. Familiarity with the other context abolished differences between the same and other context group. These data point to the novelty of the context interfering with new learning rather than the familiarity of the context enhancing it. Importantly, the reduction of new learning in the other context in the first experiment, where the context was unfamiliar in both learning sessions, suggests mechanisms beyond attention processes that are bound by the novelty of the other context. Rather, the old context impairs the processing of the new context, possibly by biasing pattern completion and pattern separation trade-offs within the hippocampus.