A recent study found that contaminated objects were better recalled than non-contaminated objects in the context of COVID-19. This study was published in Evolutionary Psychology.
Memory is an important component of the Behavioral Immune System (BIS), a defense system that protects against pathogens. The BIS involves various psychological mechanisms that serve to avoid pathogens that may pose a threat, or otherwise expel them if ingested.
Disgust is an important part of the BIS and is believed to have evolved as a way of preventing humans from ingesting things that could risk contamination. Disgusting stimuli capture more attention than neutral stimuli and are also better remembered. Stimuli encoded in memory in a survival context are better remembered than those encoded in a non-survival context. Relatedly, contaminated (vs. non-contaminated) stimuli are also better remembered.
In the present work, Gaëtan Thiebaut and colleagues examine contamination effects in memory with regard to COVID-19. Given the number of asymptomatic carriers throughout the pandemic, most people would not see visual signs of disease (e.g., blood, pale skin, bodily fluids) when coming into contact with infected individuals. Thus, infected persons cannot be identified as health threats.
Given visual cues of infection are largely absent in most individuals infected with Covid-19, there are fewer signs that can trigger disgust. Memory, which is sensitive to disgust, may not be suited for the context of COVID-19, potentially rendering the BIS unsuitable for dealing with modern disease.
The authors write, “one key issue investigated in the current study was whether contamination effects in memory can be obtained when there are no visible disgust-inducing signs.”
A total of 80 participants (68 females) were included in this research, with 77 recruited from the University of Bourgogne Franche-Comté. At the time of participation, they were not taking medication that could affect memory. Participants were randomly assigned to the “healthy” or “COVID-19” condition, and proceeded to provide demographic information (e.g., age, gender).
In the healthy condition, the instructions outlined that the 30 images of the objects participants would see were held in the hands of a healthy person who had a recent medical check-up that revealed excellent health. In the COVID-19 condition, this person was described as “sick” and infected by the contagious virus. For each image, participants rated the extent to which they found the presented object as useful in everyday life on a 5-point scale (encoding phase).
Following a three-minute filler task, participants were prompted to write out all the objects they remembered (recall period). Afterwards, they completed two questionnaires assessing perceived vulnerability to disease (including perceived infectability and germ aversion) and disgust (including moral, sexual, and pathogen disgust) on a 7-point scale.
Thiebaut and colleagues found that participants had better memory for objects presented in the hands of an individual infected with COVID-19, compared to the same objects presented by a healthy person. Despite the absence of visual signs of disease to elicit disgust, the context of COVID-19 still enhanced memory for these items. Participants assigned to the COVID-19 condition did not have higher levels of germ aversion, perceived infectability or pathogen disgust, suggesting that disgust is unlikely to be involved in the observed effect.
A limitation to this work is the overwhelmingly female sample. Prior studies have reported sex differences in disgust sensitivity and germ aversion, with women (vs. men) exhibiting more disgust and germ aversion. Thus, one important avenue for future research could be examining whether the current findings are moderated by sex.
The study, “COVID-19 and Memory: A Novel Contamination Effect in Memory”, was authored by Gaëtan Thiebaut, Alain Méot, Arnaud Witt, Pavol Prokop, and Patrick Bonin.