Pupil dilation reveals sexual orientation: study

August 6, 2012, Cornell University

There is a popular belief that sexual orientation can be revealed by pupil dilation to attractive people, yet until now there was no scientific evidence. 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.

The findings were published August 3 in the scientific journal PLoS ONE.

Previous research explored these mechanisms either by simply asking people about their sexuality, or by using physiological measures such as assessing their genital arousal. These methods, however, come with substantial problems.

"We wanted to find an alternative measure that would be an automatic indication of sexual orientation, but without being as invasive as previous measures. Pupillary responses are exactly that," says Gerulf Rieger, lead author and research fellow at Cornell. "With this new technology we are able to explore 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 new Cornell study adds considerably more to the field of sexuality research than merely a novel measure. As expected, showed strong pupillary responses to sexual videos of women, and little to men; , however, showed pupillary responses to both sexes. This result confirms previous research suggesting that women have a very different type of sexuality than men.

Moreover, the new study feeds into a long-lasting debate on male bisexuality. Previous notions were that most bisexual men do not base their on their physiological sexual arousal but on romantic and identity issues. Contrary to this claim, in the new study showed substantial pupil dilations to sexual videos of both men and women.

"We can now finally argue that a flexible sexual desire is not simply restricted to women – some men have it, too, and it is reflected in their ," says Ritch C. Savin-Williams, co-author and professor in Human Development at Cornell. "In fact, not even a division into 'straight,' 'bi,' and 'gay' tells the full story. Men who identity as 'mostly straight' really exist both in their identity and their pupil response; they are more aroused to males than straight men, but much less so than both bisexual and gay men," Savin-Williams notes.

The researchers are confident that their new measure will aid in understanding these groups better and point to a range of sexualities that has been ignored in previous research.

Explore further: Sexual orientation has 'in between' groups, study shows

More information: http://dx.plos.org/10.1371/journal.pone.0040256

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not rated yet Aug 06, 2012
Ethanol ingestion appears to cause pupil dilation via its effects on gonadotropin releasing hormone (GnRH). That epigenetic effect on the hormone, which controls all of mammalian reproductive sexual physiology and behavior, links the odor of alcohol to receptor mediated events in GnRH neurons and down-stream affects on sex steroid hormones and behavior. How does visual input alter receptor-mediated events in GnRH neurons of brain tissue (e.g., in the hypothalamus), which is the only way known to neuroscience that visual input could have evolved different meanings in men and women?
5 / 5 (1) Aug 06, 2012
As a totally open homosexual living and growing up in the Bible belt south. I have no problems saying I am gay, nor letting anyone else know what they can do with their opinions if they do not like it. That being said, about midway through reading this article, I had a chill consume my entire body and a knot in the pit of my stomach. Do ANY of these people involved with this not see the danger in it? A danger that rivals the splitting of Uranium 235. If you are saying to yourself... "huh?"...just imagine a medical test for homosexuality in say...Iran.

For hearing the phrase "what you do in your private life is your business", you heterosexuals have almost an obsessive preoccupation with "whos gay and who isn't".

Bad idea. Bad bad bad idea.
not rated yet Aug 07, 2012
Great way to catch pedophiles too. And perhaps screening for closet psychopaths who get excited at gratuitous violence visual tests!
not rated yet Aug 07, 2012
...And perhaps screening for closet psychopaths who get excited at gratuitous violence visual tests!

Careful what you wish for, you may actually find yourself in the minority.

Just think about all those who like to watch violent movies and play violent games.

And then, just think; where would that leave people like you? Awk-ward.
not rated yet Aug 07, 2012
"As a totally open homosexual living and growing up in the Bible belt south."

On behalf of rational people everywhere, I am so sorry...

I'm not homosexual, but I fight for your cause every time I come up against ignorance regarding it, including against my own fundamentalist family members living in Alabama...

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