Semantic overlap protects from interference by restoring encoding mechanisms

Abstract

Overlap between experiences can have both facilitative and detrimental effects for memory. Our aim was to establish whether overlap along one dimension (e.g. contextual, semantic, temporal) can counteract overlap-driven interference along another dimension. We hypothesized that semantic overlap facilitates episodic memory formation by modulating encoding mechanisms. We recorded scalp electroencephalography (EEG) while human participants performed a free recall task. Half of the items from late in each study list semantically overlapped with an item presented earlier in the list. We find that semantic overlap selectively improves memory and influences the neural signals engaged during the study of late list items. Relative to other recalled items, late list items that are later recalled consecutively with semantically overlapping items elicited increased high frequency activity and decreased low frequency activity, a hallmark of successful encoding. Our findings demonstrate that semantic overlap can protect from interference due to temporal overlap by modulating encoding mechanisms.

Response-locked theta dissociations reveal potential feedback signal following successful retrieval

“…Forty (30 female; age range = 18-42, mean age = 21.9 years) native English speakers from the University of Virginia community participated. Our sample size of N = 40 was selected based on prior scalp EEG studies conducted in our lab (Smith, Moore, & Long, 2022; Moore & Long, 2022). All participants had normal or corrected-to-normal vision.…”