Eyes may be the window to your soul, but, according to a new study, they're also the window to your sexuality.
Cornell University researchers have determined that a person's sexual orientation can be revealed by the degree of pupil dilation when looking at images of attractive people.
The study was published on August 3 in the journal PLoS ONE.
"For the first time, researchers at Cornell University used a specialized infrared lens to measure pupillary changes to participants watching erotic videos. Pupils were highly telling: they widened most to videos of people who participants found attractive, thereby revealing where they were on the sexual spectrum from heterosexual to homosexual." e! Science News reports.
The study found that while heterosexual men showed strong pupillary responses to sexual videos of women and little to men, heterosexual women showed strong responses to both sexes, confirming previous research suggesting that women have more fluidity in their sexuality, ABC News reports.
"Women respond to anything that is in some way sexual," says Gerulf Rieger, lead author and research fellow at Cornell. "That doesn't mean they are bisexual. Their body is not connected to their mind, which is very different from guys."
The purpose of the study was to find an "unconscious measure" to assess sexual orientation rather than invasive strategies like measuring genital arousal or asking personal questions.
"What if someone comes in and says one thing and responds a different way?", says Rieger. "We wanted to really find a measure of sexuality that goes beyond what people tell us."
"With this new technology we are able to explore sexual orientation of people who would never participate in a study on genital arousal, such as people from traditional cultures. This will give us a much better understanding how sexuality is expressed across the planet."
The Cornell scientists applied this technology to 325 subjects — 165 men and 160 women, between the ages of 20 to 35 — all open about their sexual orientation.
The study adds to an on-going debate about male-bisexuality. Skeptics have claimed that bisexual men don't base their sexuality on sexual arousal, but on romantic and identity issues. The study countered this by finding that self-identified bisexual males "showed substantial pupil dilation to sexual videos of both men and women."
The next step in the research will include comparing pupil measurements with genital measurements to see how their responses to erotic images correspond, LiveScience reports.
The researchers hope that their research will help point to a range of sexualities and aid in understanding individuals who don't identify as straight. Study researcher Ritch Savin-Williams says this research could also help people who are confused about their sexuality to sort through their desires.
Watch the video below for some common mistakes straight men make in the bedroom.