Every Saturday The CSPH highlights news or recent research in the field of human sexuality. This week we’re discussing a new study that claims to show that pupil dilation in response to sexual stimuli can be used as an indicator of sexual orientation.
The body experiences a number of physiological responses as it moves through the cycle of excitement, arousal, and orgasm, including pupil dilation, elevated heart rate, genital swelling, and blood flooding into the capillaries at the surface of the face, neck, and torso. Seeking to extrapolate on this knowledge, researchers Gerulf Reiger and Ritch C. Savin-Williams from the Department of Human Development at Cornell University proposed a study to determine whether pupil dilation could be used as a less invasive and more accurate means of determining sexual orientation than the typical measures of self reports of sexual identity or measures of genital response. To this end, they gathered a sample of 325 individuals, about equally male and female, and measured their pupil response to a series of sexual stimula (videos of naked males and females masturbating).
Through the study, the researchers confirmed several of their hypotheses. They found that pupil dilation does appear to serve as a proxy for sexual orientation, showing physical responsiveness that was similar to findings for genital arousal tests. Additionally, the results indicated a difference in the magnitude of pupil dilation and responses to differently-gendered stimula between males and females, as well as between people of different orientations. Indeed, all findings appear to uphold results from prior studies into sexual stimula and sexual orientation, showing that heterosexual men were more likely to be stimulated by other-sex images, homosexual men by same-sex, and bisexual men by a more equally split variety of images. Heterosexual females, meanwhile, were more likely to dilate for stimula featuring both males and females, with homosexual females responding more frequently towards females and less to males.
In many ways, the execution of this study was well done, with an attempt to minimize bias where it might arise. Distance from the stimula was standardized with a headrest and spatial measurements, while the luminance of stimuli was regulated as much as possible to prevent differences in dilation due to brightness. A neutral stimulus (landscapes) was included to minimize leftover dilation, and the stimuli themselves represented only the most “sexually attractive” stimuli as determined by a pilot study of heterosexual and homosexual men and women (although the paper itself was vague about the source of this pilot study, whether or not it was conducted by the researchers or by an outside and unverified source).
Despite the valid means of collecting data, the entire premise of the study is flawed, as are many of the conclusions or research bases that appear in the paper. The authors justify this study by claiming that pupil dilation measurement can be more valid and accurate than previous tests because they do not rely on either self reports or genital responses. However, such a justification stems from a drastic misunderstanding of sexual orientation, which consists not only of sexual attraction to a gendered object, but also behavior and self-identity. It ranks pupil response, which they claim to be a better measure because it is “autonomic and unconscious” and thus cannot be intentionally altered or misinterpreted, as more important than one’s own name for one’s orientation. In doing so, they are redefining and reprioritizing sexual orientation, making one’s own sense of self less valid than an involuntary bodily response that individuals may not even be conscious of experiencing.
The entire study, as well, relies on a simplistic understanding of the complicated matters of sexuality and bodies, which reduces its validity. There is an utter ignorance of gender variation in this study, or that there can indeed be any difference between gender and physical sex for individuals. When looking at sexual orientation, this is hugely important: are genitals and body shape the more salient characteristics for sexual attraction, or are gendered expressions, such as masculinity or femininity? Or can sexual attraction be affected more by qualities that are not even physical, such as intelligence or confidence? By merely presenting nudes masturbating, and never asking individuals about their responses to the genders as well as the physical sexes, the researchers are relying on their own assumptions about the defining characteristic of sexuality, the physical body, and ignoring the complexity of expression that is more key for many people. At the same time, the study utterly ignores the existences of trans* individuals, both in their population pool and in the images they used as stimuli. This, unfortunately, is something that happens time and time again in sexuality research, but it should no longer be tolerated or permitted to continue. In leaving trans* individuals out of studies such as this one, it merely reinforces the idea that these people do not exist, that they are not important, and that they are not erotic, attractive, or indeed relevant to sexuality at all.
Studies such as this one do not appear to serve a purpose outside of finding more efficient means of determining what is really going on in individuals’ heads, of who is really gay and who is not. It is such a letdown to be continually presented with researchers that perpetuate stereotypes or clichés, that use their extensive talents, time, and financial resources for studies that serve no purpose other than to identify difference and “other” people. Who really cares how somebody’s pupils behave in response to sexual images? Why does it matter to whom individuals experience sexual attraction, if indeed that is what is happening in an unconscious optical reaction?
Often, the people who are invested in the answers of studies such as this one are the ones who hold bigoted beliefs about sexual orientation and sexual variation, the ones who hold some sort of moral quandary about queerness and are invested in finding the root cause of such non-heterosexual inclinations in order to squash or isolate them. Too, though, these studies keep being produced because we as a society have been told to be paranoid of sexual “deviance,” to be so scared of being anything other than heterosexual that we try to get to the root of that thing that makes such people who they are. Yet science should be held to a higher ethical standard and should not be employed to justify such harmful beliefs or cultural patterns. It is frustrating that such research continues to exist to refine news ways of identifying, fallaciously and simplistically, the marginalized groups in our communities.