Disgust and Short-Term Relationships
Inducing disgust can make us less interested in uncommitted sex
Disgust is a powerful psychological and physical response. It protects us from consuming spoiled food and makes us recoil at the sight of parasitic or infectious creepy crawlies. But disgust also has an impact on our social behavior: think of the moral disgust you feel toward a politician exposed as corrupt, or a sportsperson whose victories are discovered to be tainted by doping.
Think too of how disgust regulates our sexual behavior. Some sexual behaviors or potential partners are highly desirable, some less so, and some may be downright nauseating. For example, most people find the idea of sex with a sibling to be so repellent it is difficult even to imagine.
In all these cases, natural selection has favored the evolution of pathogen, moral, and sexual disgust because these feelings have helped our ancestors to avoid disease and to seek partnerships with only the best allies and mates.
However, even at the best of times, sex is a mucky business. All intimate contact comes with a risk, and sexual disgust helps us to regulate which sexual encounters are worth pursuing and which are better passed up.
In recent years, psychologists have drawn a link between sexual disgust and desire for short-term mating. Some people are more easily disgusted than others; some people are more interested in short-term mating than others. Research shows that these differences are connected: people who are more inclined toward uncommitted sex tend to be less sensitive to disgust, and people who prefer long-term relationships are more prone to disgust.
Laith Al-Shawaf of the University of Colorado recently led a new study of disgust and mating preferences. Although it is interesting that people who are disposed to pursue uncommitted sex are less likely to feel disgust, he wondered whether it might be possible to change a person’s relationship preferences by inducing disgust.
In other words: is the link between sex and disgust a static aspect of who we are, or can a changing environment affect what kind of relationship we desire?
Sick-bags on standby
Al-Shawaf invited 350 men and women to his lab. Each volunteer answered questions about their current desire for sex with someone they had just met, and were then shown a series of images. Some of the volunteers, selected at random, saw sexually disgusting images: for these student-aged volunteers, the images included photographs of naked elderly people or of genitalia with visible cues to infectious disease. Another subgroup of volunteers saw images selected to induce non-sexual pathogen disgust (e.g. rotting food, rodents). The remaining volunteers saw either images of threatening men or nothing at all.
Afterward, all volunteers once more answered questions about their desire for uncommitted sex. Would the type of image the volunteers had seen change their desires?
Al-Shawaf found that desire for a short-term fling was seriously curtailed by sexually disgusting images. Provoking pathogen disgust also reduced short-term desire, but the reduction was only about half the size. Images of threatening men likewise reduced short-term desire, but the effect was halved again. It was important to check for this effect of threat, because it demonstrates that any effect of disgusting images is mostly due to how disgusting they are and not to a more general feeling of threat (if threat was the most important variable, we wouldn’t expect disgusting images to have a bigger impact on desire).
In a follow up study, Al-Shawaf tested whether other methods of inducing disgust would have a similar impact on short-term desire. Volunteers again rated their desire for a fling, before an research assistant burst into the lab with a canister of “Liquid ASS®” (a commercially available novelty product that mimics the odor of feces), sprayed it on a rag, and asked the volunteers to take a deep whiff. Twice.
Other, more fortunate, volunteers were randomly assigned to undergo some other treatment, such as reading a short story about a person suffering a parasitic infection, or one of the treatments used in the first experiment. Afterward, the volunteers again rated their desire for a fling.
As before, the sexually disgusting photographs had the biggest dampening effect on desire for a short-term relationship. Pathogen disgust — whether induced by photographs, a story, or the smelly spray — also reduced desire but, again, the effect was not as strong as for sexual disgust.
Al-Shawaf’s results suggest that it’s not simply that some people are less prone to disgust and those same people are more motivated to have uncommitted sex. Although this may be part of the picture, it also seems to be true that when any of us is made to feel more sexually disgusted we will become less interested in pursuing a fling.
Al-Shawaf points out that the effect could also travel in the opposite direction. It’s known that our sexual motivation changes according to life events, such as having a child or separating from a partner. Might these changes in circumstances also have an impact on our sexual disgust, thereby making it more or less likely that we will embark on a sexual affair?
Al-Shawaf, L., Lewis, D. M. G., Ghossainy, M. E., & Buss, D. M. (in press). Experimentally inducing disgust reduces desire for short-term mating. Evolutionary Psychological Science. doi:10.1007/s40806–018–0179-z