Pupil dilation reveals sexual orientation in new Cornell study
August 7, 2012
You are hot, reader! (Credit: iStockphoto)
There is a popular belief that sexual orientation can be revealed by one’s pupil dilation when viewing attractive people, but there has been no scientific evidence.
Now Cornell University researchers have confirmed it in an experiment, using a specialized infrared lens to measure pupillary changes in participants watching erotic videos.
Pupils widened most to videos of people who participants found attractive, thereby revealing where they were on the sexual spectrum from heterosexual to homosexual.
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 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.”
Panel A shows men’s responses and Panel B shows women’s’ responses. Y Axes reflect z-scores within participants: positive numbers indicate dilation to the same sex, and negative numbers indicate dilation to the other sex. X Axes reflect self-reported sexual orientation: 0 represents an exclusive heterosexual orientation, 3 an even bisexual orientation, and 6 an exclusive homosexual orientation. Triple lines represent regression coefficients with 95% confidence intervals. Dots represent participants’ average scores.
The new Cornell study adds considerably more to the field of sexuality research than merely a novel measure. As expected, heterosexual men showed strong pupillary responses to sexual videos of women, and little to men; heterosexual women, 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 sexual identity on their physiological sexual arousal but on romantic and identity issues. Contrary to this claim, bisexual men 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 pupils,” 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.
Comments (25)
by christine j sojka
i’m not a gay person but there are MANY good looking males THAT I DONT RESPOND TO AT ALL.some of these males are proffessional models.justin bieber is GREAT looking.I DONT RESPOND TO HIM.I DONT RESPOND TO FEMALES AT ALL EITHER.I’M NOT GAY.IT’S EXTREMELY RARE THAT I RESPOND TO ANYONE AT ALL THAT WAY.WHAT WOULD YOU CALL ME?
by NakedApe
Yes, our sexuality is a very emotional topic. We should accept that it is NOT solely about reproduction otherwise we would all make love only 2 or 3 times in a lifetime or else have thousands of children. If sexual behaviour has other functions besides reproduction (which I am arguing is true) then it can find expression with a partner you like as a person, whether of the opposite sex or the same. I think it is high time that people recognized and acknowledged that our sexuality is only partially reproductive and serves many other, complex social functions. (Read up on our cousins, the Bonobo chimpanzees).
On an even more serious note, I think that it should be a part of the Charter of Human Rights for people to stop worrying about who is sleeping with whom (the only proviso being that they are consenting adults). This would immediately make it illegal to hate people on the basis of their sexual orientation, cut off little girls’ genitalia, murder teenage girls in ‘honour’ killings, harrass women because you want to have sex with them, force women to stay in abusive relationships, prevent women from accessing birth-control or safe abortions. Imagine a world like that — where no self-righteous busy-bodies force their ‘morality’ on any other human being. This would make the world a far better place.
by Bri
You bring up some important points that I’d like to add to. Before I do that, I can’t resist, with a name like Naked ape, you definitely are speaking from the Bonobo within. Our society used to be more matrilineal. I’ll never forget watching the movie What’s up doc with Barbara Striesand, when I was a child. I had no reaction to Babs for the entire movie, but then the scene came on where she slinks across the piano in a seductive way. I blushed!!! I was very young and didn’t know what was happening. I went beet red. A friend of Maralyn Monroe talked about walking down the street together. She was asking Norma about the character of Maralyn. Norman said ” do you want to see her, and then quickly donned the persona. She said it was amazing. Nobody noticed them when Norma was Norma. As sone as she started to move in the Maralyn manner, all the people noticed her. Some of this is readily noticeable to small girls as they enter puberty. They start to develope what I like to call ” headlights” or mammalian protuberances. You don’t need to follow the bouncing ball, to sing along with Mitch Miller. A well placed jiggle is all it takes to get someone to sing for thier supper. Lethal weapons they can be. Weapons of mass destruction. Yea they are going to have a lot of fun using this technique to plumb human behavior. There are going to be a lot of glassy eyed volunteers!
by Editor
The experimental design seems weak because it doesn’t control for other transient pupil-enlargement causes such as fear and anger by using additional physiological monitoring.
by Guillermo Valle
But isnt this why averages and fit lines are calculated?
by Dan Robinson
Couldn’t this principle be applied (and isn’t it) to many of other facets of life, and don’t each of these facets pollute findings about the others?
by eldras
There is a condition where the pupils dont dilate.
by Chrispium
Asexuality?
by Durabys
Or they dilate at all times..
by Richard Sittel
Ha, I would love to see some of the gay bashers in Congress and the Tea Party take this test and see the results. I’d be willing to bet………
by Bruce Wright
This is very interesting, but as I noted in my reply to GatorALLin, the range of responses is very high across the sexual orientation scale, to the extent that there is significant overlap between the responses of completely straight or completely gay individuals of both sexes. On its face, this makes the test practically useless for identifying the sexual orientation of specific individuals unless they test at one of the extremes of the scale (very high same-sex or opposite-sex pupil dilation). Obviously it’s much more useful as a measure of large populations, since the correlation is still pretty good over a large enough sample size.
The interesting question is, “what does this mean?” Is the pupil dilation test actually getting at the basic underlying neurological reality of an individual’s sexual orientation, or is it only measuring one of several competing neurological factors? If the former, that would tend to indicate that a significant number of individuals on both ends of the spectrum have their sexuality conditioned by non-biological factors (perhaps mostly events in childhood, perhaps also some adult experiences). It’s a common observation that many who claim to be “straight” are often bi or gay but try to repress that in order to fit into society better; this may be direct evidence of that. What’s somewhat surprising is that this would imply that the converse is also true: That some who self-identify as “gay” may in fact have biological responses more like straight individuals, but presumably because of life experiences have come to identify themselves as gay. (This is surprising because even today the stigma associated with the gay lifestyle would make it a more difficult choice for one’s life, and it’s somewhat surprising that some people might choose it even against their biological tendencies).
Somehow I suspect, however, that this is in fact measuring just one (or perhaps a small number of closely related) out of many underlying neurological processes that cooperate with an individual’s environment (particularly during childhood) to produce an adult person’s sexual orientation. Nothing else in human development and psychology appears to be particularly simple; why should sexual orientation be any different?
by Khannea Suntzu
Omnivorous!
by Bri
Yes, view the formation at any age. I could write enough to fill this web page, in relation to this. Human sexuality is central to our behavior.
by AZryan
Your ideas are a mess. The first sentence doesn’t make any sense at all. The second seems like a goofy figure of speech at best, since ‘filling a web page’ is nonsensical. And the third sentence is, at best, obvious and only part of the big picture of what drives us. Getting food is just as obvious and ‘key’.
by Bri
AZryan did you wake up grumpy? Gatorallin posted first about pedophiles . I intended my response to be cryptic. There are so many angles to take, on every aspect of this article. I didn’t want to commit to any one particular issue. Not to mention, I didn’t have the time. To fill out my initial statement, “at any age” I was referring to this technique being used on all age groups. By this we could have a better understanding of how pedophilia evolves. Food is important, but in my eyes, sexuality is responsible for far more human behavior. My mother was a psychologist. Her focus was PTSD. Approximately 70 percent of the cases are from sexual molestation. This typically happened at a very early age. Two to three years old. When I say, “I could fill up this web page” I mean that I have read mountains of literature in reference to human sexuality, and I would bore you to tears with all the examples. It’s a very charged emotional topic, that can make people fly into rage. I’ll give just a few examples and musings. To do justice to the subject, I would have to do such an introduction. A very famous case of PTSD, was of a senators daughter. She would go catatonic at night. Her heart rate would drop dangerously. Her breathing would almost stop. Doctors could find nothing wrong with her. After much effort they discovered her father had been sleeping with her since early childhood, and she did the physical response to block out the emotional pain. Can’t forget the Bobobos. Everybody likes to refer to the sexual similarities to our closest related species. They do everybody. Like the omnivorus comment. Doesn’t matter what age, or what coupling, there are no taboos. They don’t have religion, for them it’s natural. One of my personal favorites are dung beetles. Let’s just get out of the mammalian category for a sec. For many millions of years they have had the same homosexual issues, just in a slightly different form. The males compete for females. Over the corse of millions of years of evolution, they have diversified to all poop niches. Each subspecies has it’s own armaments for battle. Horns, antlers, you name it, they’ve got it. The female builds a borrow, and the males fight to protect thier mate. Some males in every species, don’t grow those armaments. They look like females. They burrow along side a real female’s den, and break in to inseminate the female. Bringing it back to us and culture, poligamy was widely practiced in the aboriginal world( not Australia). For the most part, a man could have as many wives as he could provide for. In rare instances polyandry is practiced. The show I saw on this was hilarious. The researcher was asking the man what he does if he comes home, and his wife was with another man. He said he would go to a friends house till she was finished. Another one was with a single family. I mean to say a women married all the men in the family. They shared intimacy based on age. Eldest first, all the way down to the age of puberty. Studies on sexuality, please , don’t get me started!!!!!
by GatorALLin
Wondering if they can use this same research to aid them in catching pedophiles who claim not to be.
by Khannea Suntzu
And then what? Send them to a concentration camp?
The one thing I like even less than a practicing pedosexual is a bully who thinks he or she knows what’s best for the world.
by rob falgiano
Possibly. But that’s a slipperly slope there. If someone shows me a picture of a 14, 15, or 16-year-old girl with the body of a grown woman, I don’t doubt my pupils will dilate. But it’s my judgment and moral compass that kicks in to tell me she is jailbait and off-limits. And it wouldn’t make me a pedo.
by Nikolaj
I hope you mean when they are suspected of doing harm to others.
by Mortran
Pedophile inclination itself is not illegal, only acting on it. So you can’t “catch” anybody this way.
by GreenSamurai
Isn’t that a thought crime?
by Bruce Wright
Dubious that you could use this very reliably to identify pedophiles – the distribution is very “loose” across the sexual orientation scale, which complicates things considerably. There’s an obvious question about what that means, but without more research it doesn’t look possible to use this to identify someone’s sexuality reliably without other clues, unless they’re at one of the extreme ends of the response scale. As it stands, it’s more useful in studying populations, not individuals.
by AZryan
Pedophilia is the ‘act’ being the crime. You’re suggesting trying to convict people on thought crime like in 1984. Probably not a good idea.
We should probably stick to having actual evidence to imprison people.
Probably will happen though that everyone will start to know everything about everyone else and privacy will die. We’ll all be secretly recording everyone else. Video/Audio, testing everyone’s eyeballs, saliva, how they walk, what books they read, tracking their daily routines with GPS locations 24/7. Most everyone will be Big Brother. The government won’t even have to bother being corrupt spies. We’ll do it to ourselves.
by Bruce Wright
There’s certainly a pedophile orientation – being sexually attracted to children – but that in and of itself isn’t a crime (though acting upon it is). If you could identify such people before they commit a crime, it may be possible to provide them with psychological help that might be able to prevent them from committing a crime. I would hope that that would be what that kind of technology would be used for, not simply locking people away before they actually commit any crimes. This doesn’t look like it would be able to identify such people very reliably, however.
by Robofan
AZryan
You’re right, except it’s already happening, and we’re giving people the data to mine and correlate about us through social networking, comments and so on.