Can Men Fake Their Genital Responses In Sex Studies? Yes, But Their Eyes Reveal The Truth


Sex researchers have long been concerned about the reliability of self-report surveys assessing people’s sexual interests and level of sexual arousal. The fear has always been that people will not answer honestly, either because they are not willing to admit their true sexuality to themselves or to a group of scientists. As a result, sexologists have increasingly been moving away from self-reports and instead toward genital arousal measures, with the thought being that genital responses are hard to fake when we’re in the presence of sexually arousing stimuli. Indeed, many scientists have come to view genital responses as a “truer” gauge of our sexual inclinations. But is this necessarily the case? A new study just published in the Journal of Sex Research reveals that genital responses can indeed be faked in lab studies, which suggests that these measures may not always be as reliable as you think. However, these scientists also discovered a novel way of potentially catching fakers: recording their eye movements while they view sexual stimuli.

In this study, a sample of 24 healthy, adult men (average age of 37) were recruited for a study of sexual arousal. All of these men were predominately heterosexual or homosexual (i.e., their Kinsey Scale scores were either 0, 1, 5, or 6) and all reported that they had never engaged in any “deviant” sexual behaviors (I’m not sure exactly what that means, though, because the authors didn’t explain this).

Participants were shown a series of computer-generated, 3D, male and female human beings who were naked. Each of these images, as well as a neutral stimulus, was shown for 90 seconds at a time. While viewing these images, the men were hooked up to a penile strain gauge, a device that records men’s level of sexual arousal by registering changes in penile circumference. In addition, they were hookup up to a head-mounted device that recorded their eye movement patterns as they viewed each image.

There were two parts to the study. In the first phase (which I will refer to as the “free response condition”), subjects were instructed to “explore the stimuli freely and allow their physiological responses to occur naturally.” Afterward, they were shown the full series of images (nude and neutral) mentioned above.

In the second phase (which I will refer to as the “inhibition condition"), subjects were first shown an aversive stimulus (specifically, a picture of a filthy bathroom) for 30 seconds. After that, they were shown a different image (either a nude male or a nude female, whichever was more likely to be arousing for each subject depending upon their sexual orientation); however, before seeing the arousing image, subjects were instructed to “suppress their erectile responses” by reminding themselves of the disgusting picture they just saw.

So what did the scientists find? First, they found support for the idea that men’s genital responses can be faked successfully. Specifically, in the free response condition, genital arousal levels for men’s preferred sexual stimulus (i.e., an adult female for heterosexual guys and an adult male for gay gays) were significantly higher than they were in the inhibition condition. But not only that, the researchers also found that in the free response condition, genital arousal levels for men’s non-preferred sexual stimulus (i.e., an adult male for heterosexual guys and an adult female for gay guys) were not significantly different compared to the inhibition condition. This second result tells us that these guys were hiding their erections really well.

Second, the researchers found that men’s eye movement patterns were substantially different in the free response and inhibition conditions. In the free response condition, when men were looking at their preferred stimulus, they demonstrated “frequent and lengthy fixations”; when looking at their non-preferred stimulus, they demonstrated “frequent abbreviated fixations.” In contrast, when men were trying to inhibit their erectile responses, they demonstrated “infrequent and lengthy fixations.” In other words, when guys were suppressing their erections, they made far less eye contact with the image.

In addition to differences in overall eye movement patterns, subjects in the inhibition condition also spent less time looking at the erogenous zones of the nude images relative to both their preferred and non-preferred stimuli in the free response condition. So, when subjects tried to suppress their erections, they seemed to make it a point to look away from the most arousing parts of the stimulus.

Obviously, there are many limitations of this study, not the least of which are that it is based on a very small sample, it tested only one arousal inhibition strategy, it relied on computer-generated sexual imagery, and it only sampled men. Although much more research is definitely needed (especially research with female subjects), these findings do suggest that genital arousal measures do not necessarily eliminate the possibility of faking and they may not be quite as reliable some have argued. However, by also capturing eye movement patterns, we may be able to successfully identify the real from the fake in future sexual arousal studies.

Want to learn more about Sex and Psychology ? Click here for previous articles or follow the blog on Facebook (, Twitter (@JustinLehmiller), or Reddit ( to receive updates.

To learn more about this research, see: Trottier, D., Rouleau, J. L., Renaud, P., & Goyette, M. (in press). Using eye tracking to identify faking attempts during penile plethysmography assessment. Journal of Sex Research.

Image Credit:

You Might Also Like: