The Sex Files
Women are more flexible in their desires than men, study suggests
By Jennifer Abbasi Posted 08.08.2012 at 8:56 am 34 Comments

Pupil Sarah Cartwright

Cornell University researchers used porn and measures of pupil dilation to study arousal in straight-, gay- and bisexual-identifying men and women, reports a study published April 3 in PLoS ONE. The results, which point to surprising differences in arousal based on a person's sex and sexual orientation, corroborate previous research using measures of genital response, opening up a less-invasive method of studying arousal and orientation.

Human development experts Gerulf Rieger and Ritch Savin-Williams measured pupil dilation in 325 people as they watched two 30-second videos -- one of a woman masturbating and one of a man -- as well as a 1-minute clip of a neutral landscape that served as a palate-cleanser and a control between the porn clips. Participants in a pilot study chose the clips based on the attractiveness of the models, and the order they were shown in (man first versus woman first) was selected randomly during the dilation study.

Unsurprisingly, "heterosexual men dilated most to the other sex, homosexual men dilated most to the same sex, and bisexual men dilated more equally than other men to both sexes," the authors wrote. The same wasn't true for straight women, though. On average, heterosexual women dilated more to images of a man than to a landscape, but they also responded more strongly to images of a woman masturbating compared to heterosexual men watching a man. Lesbians and bisexual women in the study more closely followed the male patterns.

The finding that straight women more so than straight men are likely to get turned on by both sexes could be explained by evolutionary theory, Rieger says. In 2000, Roy Baumeister, a psychologist then at Case Western Reserve University, proposed that the female sex drive evolved to be more malleable than the male sex drive. Then, in 2007, Canadian researchers studying the genital response to watching videos of human and animal sex suggested that whereas the biological function of arousal in men is to become erect and penetrate women, in women it has historically been to self-protect (with lubrication) during forced sex, which ostensibly required them to be more automatic and flexible in their arousal to any stimuli. "Forced copulation in several species and in most human societies indicate that it may have occurred throughout human evolution," Rieger and Ritch Savin-Williams write.

Here's how the Canadian authors explained it in 2007: "Reflexive vaginal responding may have had fitness benefits for our female ancestors because vaginal vasocongestion produces lubrication, which reduces the likelihood of injury and subsequent infection during vaginal penetration. Ancestral women who did not reflexively lubricate would have been more likely to experience injuries or infections that could have rendered them reproductively sterile or resulted in their deaths."

Rieger says a less plausible theory that has been suggested is that "because women are less exposed to pornography than men, they might respond strongly to anything erotic they see. It could be a novelty effect. I do not buy it, but it is possible."

The results of the study are in line with previous research that measured arousal based on penis circumference in men and vaginal pulse amplitude, which reflects changes in vaginal engorgement, in women. Genital response studies have found that, "the relationship of genital arousal to either male or female sexual stimuli with self-reported sexual orientation is considerably stronger in men than in women," the authors write. "Most men are exclusively aroused to the sex consistent with their reported sexual orientation; for example, most heterosexual men are almost exclusively aroused to women and most homosexual men are almost exclusively aroused to men. In contrast, women's sexual orientation is poorly reflected in their genital response because they respond with substantial arousal to both sexes."

Pupil dilation has been used before in sex research-in Canada in the 1950s through '70s to weed out gays, "who were at the time considered a national risk"-but those studies were riddled with problems, like failing to factor in bisexuality and measuring dilation by hand rather than with a camera and a computer program (an infrared gaze tracker automatically recorded pupil size and dilation in the new study). The agreement between genital response and pupil dilation results bolsters the reliability of the less-used method.

Switching to measuring pupil dilation in arousal studies has several benefits, Rieger says, starting with using the same method for both sexes. Some people can suppress genital arousal, but because pupil dilation is controlled by the automatic nervous system, study participants can't affect the measurements. Plus, the less-invasive method will be palatable to more study participants, allowing researchers to learn about arousal and orientation in traditional cultures and even children -- using less sexy images, of course.

Jennifer Abbasi is a science and health writer and editor living in Portland, OR. Follow Jen on Twitter (@jenabbasi) and email her at popsi.thesexfiles@gmail.com.

34 Comments

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democedes
08/08/12 at 11:08 am

"Forced copulation in several species and in most human societies indicate that it may have occurred throughout human evolution"

We should never forget the darker side of human nature. No matter how civilized think we have become, there is the capability to perform unspeakable acts within each of us. While the idea of centuries of forced sex shaping the sexual responses of the fairer sex makes sense intellectually, it still blows my mind. We as a species seem a little less noble than we were a minute ago.

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Kokopure
08/08/12 at 11:29 am

Agreed, democedes. Although, while I can certainly understand the researchers' theory as it pertains to evolutionary fitness, I can't help but wonder.

If it's evolutionarily advantageous for women to self-lubricate (even in the case of rape), why is it that only -heterosexual- women follow an unusual pattern of arousal? One would assume that, historically, lesbians (by virtue of not being attracted to men) would have far more use for such an evolutionary reflex; yet they apparently do not display evidence of it. I'm open to more interpretations, but it really does seem like more study is warranted here. If nothing else, these findings are interesting, if very darkly so.

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baddogbob52
08/08/12 at 12:24 pm

Sounds like Weird Science to me! Guess your having a hard time finding something worth while to study! I doubt the validity of this study.

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kathywhatley
08/08/12 at 12:50 pm

Maybe the reason straight women get turned on by seeing other women, more than straight men seeing other men, has nothing to do with evolution. Maybe it simply has to do with the fact that women are able to FEEL what someone else is feeling better than men, and seeing another woman masturbating makes them feel how THEY would feel if they were doing it. It's not that the other woman is turning them on, it's the FEELING of how they would feel that is turning them on.

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Robot
08/08/12 at 1:03 pm

Maybe.... is not science. Why not just ask people what they like and prefer over a large stastical group. Gosh, they just might just tell you.

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kathywhatley
08/08/12 at 1:10 pm

You are right, maybe is not science, but neither is "could be explained by..."

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kathywhatley
08/08/12 at 1:12 pm

But then, that's what any science starts out with, a maybe or a could be explained by, and then after research it is possibly proven as fact.

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killerT
08/08/12 at 1:20 pm

1. Finally we have proof that women are part lesbian.

2. Why do we need a way to positively determine a person's orientation? Couldn't we just ask them?

Sounds like someone wanted an excuse for all the porn on his harddrive.

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Robot
08/08/12 at 1:24 pm

kathywhatley,
Maybe your having a conversation with yourself on PoPSCi, ending with you agree with yourself, lol. I am glad the voices in your head are nice. No worries, mine are too.;)

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Robot
08/08/12 at 1:30 pm

....long long ago, in a far away land, was a bunch of philosphers who wonder how many teeth were in a mules mouth. So all they long they argued to how many teeth existed in a mules mouth, back and forth, back and forth, until one philospher got the briliant idea of looking inside the mouth of mule and counting the teeth.

Yes killerT ash people what they prefer, you win a cookie!

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kathywhatley
08/08/12 at 1:34 pm

No Robot, I was not having a conversation with myself, I was giving my opinion, just like everyone else on here! I am not saying I agree or disagree because obviously at the moment there is no way to prove it. Just because I think something does not mean I think I am automatically right. I am just giving another option. Isn't that what science is all about - looking at ALL options and finding the correct one - not just the ones that are easily or conveniently explained?

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democedes
08/08/12 at 1:34 pm

@Robot

"I've found that when you want to know the truth about someone, that someone is probably the last person you should ask." -Dr. House

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kathywhatley
08/08/12 at 1:38 pm

Yes, people could be asked, but that would be defeating the whole point of this study. It was to find out how a person's body reacts AUTOMATICALLY to these things - not what they like or prefer.

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Robot
08/08/12 at 1:44 pm

kathywhatley,
I like you, you ask good questions and are persistant in asking more questions. Please continue on! ;)

democedes,
Yes, I do imagine in any verbal survey, you may have folk that do not answer or lie in their answers, which is why I suggest taking a LARGE survey. By the way, do you actual depend upon a fictional TV characters opinions? Now worries, I like when you comment!;)

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kathywhatley
08/08/12 at 1:55 pm

Thanks Robot! When I think of the next comment or question I will! :) :)

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suggestivesimon
08/08/12 at 2:17 pm

@baddogbob52
based on what, exactly?

@Robot
"... maybe" is the first step in science. Hypothesis, predictions, experimentation, analysis, conclusion. Furthermore, your whole argument about "just asking them" seems utterly besides the point given what this study set out to test. So why reply so cockily to everyone?

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democedes
08/08/12 at 2:28 pm

@Robot
The quote was submitted mostly for entertainment purposes. But you have to admit there is a nugget of truth in there, otherwise it would not be humerous.

Sample size would not remove the influence of "liars" on the study. If 5% of people would lie in your study, then your results will be off by 5% regardless of how many people you asked. You would never how many people are lying without an objective test. It could be 0.01% or 30%.

This would be an interesting study in itself: How many people would lie about, or are not consciously aware of their true sexual orientation.

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Robot
08/08/12 at 2:29 pm

suggestivesimon,
Hmmm, you say I respond so cockily to everyone. Well, I read the article and it seem to judge people from afar via their eye dialation and I just could not understand to myself the premise of trying to find an answer to a question from such a distance, verse a direct approach of asking people of their gender preference in my opinion sir.
But, I am learning too, by peoples comments. I look forward to yours in regards to this article.

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Robot
08/08/12 at 2:34 pm

Imagine some social group is making a judgement upon another group and finds a person of a certain way, via their pupil dialation or not and then makes a life changing judgement upon them, not knowing the light was in the persons eyes or this persons eyes were sensitive to light from some unknow unique biological problem.
Had the social group just ask this person their preference too, the outcome of the judgement could of been completely different.

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spark55155
08/08/12 at 2:38 pm

The larger question remains: why would you need to know if someone is gay? Wouldn't it make more sense to know if someone is an arsonist or adulterer or psycopath, and develop stealth tech to discover that? Nowadays, if you just ask someone, they will probably tell you.

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Robot
08/08/12 at 2:41 pm

Suppose this science via eye dialation says YOU are an arsonist, adulterer or a psycopath. How would you feel if you are being judge by a electronic device and software program indicating a fate upon you, verse a personal interview with you and that judgement be made?

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Robot
08/08/12 at 2:49 pm

Mrs Watson, please sit down and put your eyes into this machine. Ah yes, we have a few questions for you. We like for you to relax.

Ok. nice the test is done.

Yes, what was the result.

Well Mrs. Watson, our device indicates you eyes dilate and you get excited to female horses...

Oh, I see, dear me... So what does that mean?

Well, Mrs. Watson, the state has decided to have you commited to a public mental home.

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suggestivesimon
08/08/12 at 3:04 pm

@ Robot
The test subjects aren't being "judged from afar". The researches are from Cornell's Department of Human Development, which "addresses the biological, emotional, cognitive, and social factors that shape human behavioral development". This is their area of work. Their opinion was that previous research carried out to link sexual orientation with sexual response used experimental methodology that was lacking, which resulted in conflicting conclusions. They set out to develop a new technique so as to get better quality results.

So, the reasons to not "just ask them" are:
- Development of a new test methodology and better experimental techniques
- Resolution of the conflicting evidence in literature, by testing the link between self-identified sexual orientation and sexual response using said experimental techniques
- Lastly, my intuition is that self-identification of sexual orientation in the general public isn't a reliable metric. There is still a strong social stigma attached to homosexuality, so someone's self-identification as heterosexual is no guarantee that they actually are. Having said that, this study was done with volunteer subjects, so I would imagine that they weren't able to draw any broad conclusions on this topic.

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suggestivesimon
08/08/12 at 3:09 pm

@Robot

I understand what you're saying, but I doubt the researchers above have the goal you describe in mind. Are you saying that it's wrong of them to try to understand a fundamental aspect of human behavior?

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suggestivesimon
08/08/12 at 3:18 pm

@spark55155

"The larger question remains: why would you need to know if someone is gay?" Sociologically and anthropologically speaking, the value of knowing someone's sexual response vs their declared sexual orientation is that it provides a potential piece of the puzzle in explaining the why's and how's of sexual orientation. For example, let me quote the study referenced above: "Cross-cultural research compared the same-sex sexual behaviors of heterosexual men in Turkey, Thailand, and Brazil. The incidence of same-sex sexual behavior was greater in the first two groups, but especially among working class Turkish heterosexual men. According to Cardoso, because most Turkish women of this social class are sexually unavailable, men are more likely to engage in same-sex behavior. Hence, the finding that some men show sexual arousal to both sexes, or engage in sexual behavior with both sexes, may be due to cultural and social class influences." So testing like this can help in revealing greater truths about how and why humans behave the way they do, in the context of their societies or cultures.

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Robot
08/09/12 at 6:53 am

suggestivesimon,
From a medical, social or phycology point of view, I hope more tools are given to medical science and this can help people.
But, I also worry people of different types of hate groups in power and authority, may use a tool like this to make harsh negative judgment calls on different types of people.
If you, me or somebody choose to declare their sexual preference to another person, that is their choice. I do not want people secretly using a device, making a data base about me, judgments and upon me of which I may disagree with it or others.
I am all for more tools to help others in medical science. I am against any type of hate crimes and the tools they use.

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democedes
08/09/12 at 8:37 am

@Robot

All scientific progress has the potential for misuse and abuse. At some point you have to trust society to do what is right and moral. And when society violates that trust, remember you have a voice to affect change. The only alternative is to completely halt the advancement of all science. Is that what you are proposing?

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suggestivesimon
08/09/12 at 10:11 am

@ Robot

Your first reaction was to judge this research through the eyes of an intolerant society... but I urge you: don't judge the research, judge society. I am of the opinion that everything is worth knowing. Nuclear physics was invaluable in understand our world... it gave us nuclear power, nuclear medicine, but also the nuclear bomb.

Edward Teller, the controversial physicist who designed the first hydrogen bomb, said "There is no case where ignorance should be preferred to knowledge — especially if the knowledge is terrible." I agree with him. In my view, not pursuing truth because of society's failings is equivalent to book burning, which is nothing more than militant ignorance.

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suggestivesimon
08/09/12 at 10:13 am

... and to be perfectly clear: ignorance is precisely where the true danger lies. Stupidity breeds intolerance, and intolerance kills. The A-bombs might have been mistakes that killed 200000 people in an instant, but religious and ethnic intolerance have killed millions more, one person at a time.

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Robot
08/09/12 at 10:36 am

suggestivesimon,
I didn't speak of an intolerant society, but of grroups.
I live in the real world, do you?

www.niot.org/map?gclid=COCK-OPu2rECFUOQ7QodMmAAPg

www.unitedstatesaction.com/list-us-hate-groups.htm

Hate groups exist and as a society, science and goverment have to mindful of this always.

Let me say once again. I am all for more tools to help others in medical science. I am against any type of hate crimes and the tools they use.

Be aware of the real world we live in.

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suggestivesimon
08/09/12 at 11:15 am

@Robot
You're quibbling about semantics? Whether it's because of specific hate groups, or because of the fact that a quarter of Americans believe that homosexuals shouldn't have the right to be protected against discrimination (and shouldn't have inheritance rights, and shouldn't receive social security), or because of the fact that a quarter of Americans would support the mass detention of Muslims: Society... is... intolerant.

I'm very much aware of the world we live in. The difference between you and me is that you seem content in dealing with the status quo. I'm not. Limiting scientific inquiry because of stupidity and intolerance is a vicious cycle which will get us nowhere.

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Robot
08/09/12 at 1:32 pm

I enjoy an wide area of commentators and opinionators. Take care suggestivesimon. I look forward to be more people commenting on PoPSCI! ;)

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suggestivesimon
08/09/12 at 3:09 pm

Ya me too. Take it easy, Robot.


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