– by Jessica Hlay & Carolyn Hodges-Simeon
March of 2020 remains a memorable time in most people’s lives. Few will forget the breakout of COVID-19 and resulting pandemic: cities were shut down, people were quarantined, homes were locked, and fear of infection was at an all-time high. However, news programs started showing a different picture in some areas: large groups of university students did not cancel spring break trips. Instead, people drove en masse to beaches, partying as usual, undoubtedly sharing drinks and breathing each other’s air. A disease transmission nightmare. This scenario reveals the inherent trade-offs between two fundamental evolutionary goals: health management and reproduction. Under what circumstances to people choose reproduction over health? Or vice versa? Is it possible that the chance of sex and socialization is great enough to override an adaptive disease avoidance response, especially in young, healthy adults?
One of the ways that we measure differences in people’s health-protective behavior is through disgust sensitivity. It is defined as an individual’s sensitivity to infection-related stimuli. It affects what we touch, consume, and with whom we interact — for example, those with higher disgust sensitivity are more likely to avoid things they find disgusting and feel more anxious about interacting with strangers. Reproduction is risky from an infection standpoint — sexual activity, by nature, involves close contact.
Our research team decided to explore whether an individual’s disgust sensitivity is related to their sociosexuality (also known as, attitude, desire, and behavior towards casual sex). Previous research led us to believe that we would find results supporting our hypothesis, such that increased disgust would be associated with decreased interest in casual encounters. However, we noticed a few gaps in previous studies exploring this question: 1) Disgust sensitivity has many domains (pathogen, sexual, and moral), however previous studies only gauged the relationship between sexual disgust sensitivity and sociosexuality. Since we’re interested in how pathogen risk relates to casual sex, we included all domains of disgust in our study. 2) Sociosexuality also has three domains (attitude, desire, and behavior), however previous studies only explored composite sociosexuality scores, limiting our understanding of the relationship between each of the three domains and disgust (e.g., does disgust affect sociosexual attitude more than behavior?). And finally, 3) most studies only collected responses from the United States, or their sample demographics are not reported. Since disgust sensitivity and sociosexuality are thought to be at least partially influenced by culture, economic development, and environment, we sought to include a wide range of countries in our samples. Additionally, with the help of online data collection, we were able to collect samples before and during the COVID-19 pandemic.
Using an online survey platform, we conducted a study including data from four different timepoints and in 22 countries. In our survey, participants provided demographic information and responded to the Three Domains of Disgust Sensitivity Scale and the Sociosexuality Orientation Inventory-Revised Scale. We then conducted tests to assess our main question: How does each domain of disgust sensitivity (i.e., pathogen, sexual, and moral) predict each domain of sociosexuality (i.e., attitude, desire, and behavior)? We included all domains of disgust in our model to account for their shared variance, as well as age, sex, and country.
Several of our findings were just as predicted: sexual disgust negatively predicted sociosexuality overall. That is, the more sexually disgusted someone was, the less open to casual sex they were. Specifically, sociosexual attitude seemed to be the driving domain of this relationship. In addition, women and older adults showed higher disgust sensitivity than men and younger adults. These findings were consistent across diverse countries.
However, we found some surprising results when we examined the association between pathogen disgust sensitivity and sociosexuality. Interestingly, pathogen disgust positively predicted composite sociosexuality and sociosexual attitude, opposite of our prediction. Also opposite of our predictions, sexual disgust positively predicted sociosexual behavior. We found this in both pre- and post-COVID samples. These results suggest that those with greater pathogen disgust (holding other domains of disgust constant) are more open to casual sex and the more they engage in it. In other words, if you are low in sexual disgust, a pandemic may make you *more likely* to seek out casual encounters (and all the more if you are young and/or male). This accords with our observations of those young adults who seemingly put themselves at great risk to party on a beach in Florida.
Evolutionary theorists may be quick to challenge such a counterintuitive finding — that is, what is the benefit of increasing sexual content when infection risk is higher? While still unclear, one useful theoretical model may be the “bet-hedging” hypothesis. Like the Red Queen Hypothesis, this idea builds on the knowledge that offspring genetic diversity is a powerful intergeneration weapon against pathogens. That is, individuals can diversify their offspring by engaging in multiple mating. While much more research is needed to understand the costs and benefits of less restricted sexual behavior under pathogen threat, these findings suggest it could be a fruitful avenue of study.
Read the original paper: Hlay, J., Albert, G., Batres, C., Waldron, K., Richardson, G., Placek, C., Arnocky, S., Senveli, Z., Lieberman, D., & Hodges-Simeon, C. (2022). Disgust sensitivity predicts sociosexuality across cultures. Evolution and Human Behavior, 43(5), 335-346.