The contamination effect on recognition memory: adding evidence of an adaptive mnemonic tuning

Previous research has revealed enhanced free recall for neutral items previously associated with disease-causing agents, compared to when they are associated with neutral information; this has been termed the contamination effect. However, it remains unknown whether this effect extends to recognition memory and, if so, on what processes it would rely (i.e., recollection or familiarity). This is a relevant question to establish the generality and enrich our knowledge about the effect on the various processes in which memory operates. We employed a Yes/No recognition task with Remember/Know judgments to assess the recognition experience. Online American (Experiment 1) and in-person Portuguese (Experiment 2) samples were used. Furthermore, in Experiment 2, participants responded to a Health Status questionnaire and the Fear of COVID-19 scale, allowing us to explore the relation of the effect with these individual variables. In both experiments, the results revealed that objects were significantly better recognised after having been previously associated with sick faces than with healthy faces. Moreover, participants assigned a higher proportion of Remember-judgments to contaminated (vs. non-contaminated) objects, suggesting these were retained with more contextual information. Exploratory analyses revealed that participants' illness recency correlated positively with the proportion of Remember-judgments. The robustness of this effect is supported by its replication among participants from two different countries, employing both online and on-site procedures. Notably, the to-be-recognised objects were the same across conditions, preventing possible item-selection concerns. Overall, this study expands our understanding of the impact of contamination on memory, emphasising its role in disease avoidance.