Disgust as a Mnemonic Defense: Temporal and Associative Modulation of Memory

Disgust is an adaptive emotion that evolved to protect organisms from pathogens by motivating avoidance of contamination cues. Accumulating evidence suggests that disgust may also operate as a mnemonic defense system, selectively biasing memory toward contamination-relevant information. The present research examined how disgust learning reorganizes episodic memory across temporal boundaries—retrospectively, concurrently, and prospectively—using a category-conditioning paradigm. Across two experiments, neutral object categories were paired with either disgusting or neutral images, allowing emotional value to generalize broadly across category members. Study 1 showed that disgust learning retroactively and concurrently updated memory representations: objects from disgust-conditioned categories were recognized more accurately and liberally biased than neutral-category objects, regardless of whether they were encountered before or during conditioning. Moreover, objects presented during conditioning were remembered better than those presented beforehand. This mnemonic advantage did not increase across longer retention intervals, indicating that disgust-related memory effects primarily reflect encoding or early post-encoding mechanisms rather than delayed consolidation. Study 2 examined prospective generalization and transfer to new associative contexts. Objects from disgust-conditioned categories were again remembered more accurately, even when encountered after conditioning. In contrast, food items paired with disgust-conditioned objects were evaluated as less appetizing but remembered less accurately than foods paired with neutral objects, suggesting that disgust may prioritize avoidance over detailed encoding, potentially via attentional disengagement or adaptive biases favoring memory for appetitive cues. Together, these findings demonstrate that disgust learning broadly reshapes memory across conceptual and temporal dimensions, highlighting its unique role in adaptively guiding what is remembered.