Episodic learning-induced representational change is both influenced by and re-sculpts semantic memory

Abstract

While semantic and episodic memory have been shown to influence each other, uncertainty remains as to how this interplay occurs. We introduce a novel behavioral representational similarity analysis approach to index how semantic space is re-sculpted by episodic learning. Eighty participants learned word pairs that varied in semantic relatedness and whose learning was bolstered via either testing or restudying. Next-day recall was superior for semantically related pairs, but there was a larger benefit of testing for unrelated pairs. Critically, representations of cue words in semantically related pairs were drawn asymmetrically towards their targets, while cue and target representations in unrelated pairs were drawn together symmetrically. Testing additionally repelled semantic representations away from normative semantic space moreso than restudying. Taken together, we show that episodic learning can induce distortions of semantic space to improve later recall by making cues more predictive of targets, reducing interference from potential lures, and establishing elaborative links within pairs.