There is a popular belief thata person’s sexual orientation can be detected by the dilation of their pupilswhen they see an attractive guy. For the first time, researchers at Cornell University have tried to find out if this idea has any scientific basis. Using infrared lenses to measure pupillary changes that occur in heterosexual, homosexual and bisexual people while watching erotic videos, they have shown that sexual orientation can be “guessed” by the behavior of the pupil. Their conclusions are published in the magazinePLoS ONE.
According to the study authors, the advantage of this technology is thatsexual orientation can be explored in a non-invasive way. In the experiments, heterosexual men showed a strong pupillary response to the sexual videos of women, and hardly any when the protagonists were men. However, heterosexual women showed pupillary responses to both sexes, thus confirming that female sexuality is different from male. In the case of bisexual men, it was observed that the pupils increased in size in the presence of scenes starring both men and women. And the pupils of the men declared homosexual were dilated much more than those of their heterosexual partners in the face of erotic images of other people of the same sex.
According to the scientists, the results show thatthere is no such sharp separation as is often thought between “hetero”, “homo” and “bi”. When it comes to human sexuality, one should speak of “mostly heterosexual to mostly gay,” says Ritch C. Savin-Williams, a co-author of the paper. According to their interpretation, “the different sexualities would rather fall within a range,” the authors conclude.
