Ladies, be honest: Do certain aspects of sexual activity sometimes gross you out? If you answered yes, you’re not alone, and there’s a psychological and physiological explanation for why you might feel that way. Both sex and disgust are core aspects of human experience. Scientists believe that disgust evolved as a defensive mechanism to keep us from being contaminated by external sources.1 Accordingly, the mouth and the vagina, two body parts that lie at the border of the body (and are therefore at a higher risk for contamination), demonstrate greater disgust sensitivity; for example, we are likely to be especially grossed out by having a spider crawling on/around the mouth or vagina compared to, say, the left arm.2 Add to this the finding that some of the strongest triggers for disgust are body odor, saliva, semen, and sweat, all heavily involved when getting “down and dirty,” and you can see how the relation between sex and disgust seems contradictory or even obstructive. In fact, you might be left wondering how humans manage to have pleasurable sex at all!
Researchers Charmaine Borg and Peter de Jong were intrigued by the sex/disgust puzzle and designed an experiment to find an answer. They reasoned that another very important player in the sexual activity game—namely, sexual arousal—might (a) make stimuli that activate disgust outside of a sexual context seem less disgusting in-the-moment and (b) reduce the hesitation to approach “disgusting” stimuli. In other words, sexual arousal might take the nasty out of “doing the nasty.”3
To test their hypotheses, Borg and de Jong recruited 90 healthy female students at the University of Groningen in the Netherlands. When participants arrived at the lab, they were randomly assigned to one of three experimental conditions. The 30 women in the sexual arousal group were shown a film clip from Christine le Duc’s de Gast, a female-friendly erotica. The 30 women in the positive arousal group were shown a film clip consisting of high-adrenaline sports/activities (e.g., mountain climbing, rafting, sky diving). The remaining 30 women in the neutral group were shown a film clip involving different sceneries encountered on a train ride. The researchers used these particular groups because they wanted to explore the unique influence of sexual arousal (compared to other arousal or no arousal) on disgust. Following the experimental manipulation, participants rated sexual and non-sexual stimuli in terms of how disgusting they thought each stimulus was. They were also asked to physically enact a number of disgust-related behaviors, both sexual (e.g., lubricating a vibrator with the hands, placing a stranger’s used panties/knickers into a bag) and non-sexual (e.g., taking a sip of juice from a cup containing a large insect, rubbing the cheek of the face with a stranger’s used toothbrush). (Before you gag too much, you should know that none of the disgusting elements of these behavior tasks were real; for instance, in reality the vibrator was clean, the insect was made of plastic, etc. The key was that participants perceived the disgusting elements to be real during the study.)
The researchers found that, compared to the positive arousal and neutral groups, women in the sexual arousal group rated sex-related stimuli in particular as less disgusting and completed a higher percentage of disgusting behavior tasks (both sexual and non-sexual). Thus, there appears to be something specific about sexual arousal, over and above general arousal, that reduces disgust and the propensity to avoid disgusting stimuli. Sexual arousal, then, helps to explain why humans have sex for pleasure despite the arguably inherently “disgusting” nature of certain aspects of sexual activity. So perhaps the next time your partner wants to try something in the bedroom that you think is gross, you should get yourself a little hot and bothered and then revisit the idea!
1Curtis, V., Aunger, R., & Rabie, T. (2004). Evidence that disgust evolved to protect from risk of disease. Proceedings of the Royal Society of London B: Biology Letters, 271, S131-S133. DOI: 10.1098/rsbl.2003.0144
2Rozin, P., Nemeroff, C., Horowitz, M., Gordon, B., & Voet, W. (1995). The borders of the self: Contamination sensitivity and potency of the body apertures and other body parts. Journal of Research in Personality, 29, 318-340. DOI: 10.1006/jrpe.1995.1019
3Borg, C., & de Jong, P. J. (2012). Feelings of disgust and disgust-induced avoidance weaken following induced sexual arousal in women. PLoS ONE, 7, e44111. DOI: 10.1371/journal.pone.0044111
Sarah Stanton, Ph.D. – Science of Relationships articles | Website/CV
Sarah is interested in how different types of people think, feel, and behave in relationships, the positive and negative relationship outcomes associated with low self-regulatory ability, and how relationship experiences influence goal pursuit, bodily stress responses, and mental and physical health outcomes. 
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