The privileged role of thematic conceptual relations in episodic memory

Prior knowledge has long been known to influence retention of newly learned information. In particular, known semantic associations across items facilitate subsequent retrieval for these items. However, whether distinct forms of semantic relations vary in the influence they exert on memory remains unclear. We took inspiration from the field of concepts and categories and compared two major types of semantic relations between concepts: taxonomic (e.g., dog-bird) and thematic (e.g., dog-leash) relations. In Experiment 1, we show that cued recall for word pairs with thematic relations was faster and more accurate, followed by pairs with taxonomic relations and finally unrelated pairs. We hypothesized that thematically related words are more quickly and more accurately retrieved because they are more accessible in one’s semantic memory. To test this, we designed a second experiment where participants encoded word pairs of the same relations as in Experiment 1 and completed a forced-choice associative memory test with options sharing different semantic relations to the cue. In addition to corroborating the findings of Experiment 1, Experiment 2 demonstrated that participants were more prone to incorrectly guessing a thematic alternative. We conclude that thematic relations outperform taxonomic relations in driving memory performance and speculate that this may result from their dominance in organizing episodic memory.