In the past, the traditional method of studying sexual orientation via arousal has allowed for a lot of loopholes and prevented a clear conclusion from being drawn. Asking subjects point-blank about their arousal level obviously allowed for lying, and showing people sexual images and monitoring the blood flow to their genitals was flawed as well—not only can certain people suppress their genital arousal, but the lab environment may have affected their sexual inhibitions and the invasiveness has stopped certain individuals from participating at all.
Ritch Savin-Williams, developmental psychologist at Cornell University, has just conducted the first major experiment that links pupil dilation to sexuality, and says that the results show that eyes indicate a foolproof, subconscious sexual response. Savin-Willaism and his colleague selected 165 men and 160 women—gay, straight or bisexual—and showed them images of men masturbating, women masturbating, and neutral landscape scenes while monitoring their pupil dilation. They also showed videos of members of the opposite sex simultaneously and took note where the subject’s focus primarily was.