Sexual Diversity

Pupil dilation and sexual orientation

Can be known sexual orientation of the people by analyzing the pupil dilation?

Minority heterosexuality?

Some time ago, began circulating through the networks the news about people’s sexual orientation could be known by measuring the pupil dilation. The news seemed interesting, but each of the links provided the same information and it did not report too much. As you know, in Moscas de Colores, we are very interested in any scientific information on sexual diversity in any of its aspects, so this news needed more detail to know if it was true or not and, in the second case, find out what was behind so much headline. That’s why we visited the website of the Cornell University (US) to look for that study and to see what we found.

The first thing that struck us is that the result of the study, made by Gerulf Rieger and Ritch C. Savin-Williams, both of Cornell University, was published in August of 2012 and by that time already had the corresponding diffusion in the social networks, blogs and newspapers. Why now again? No idea. What really interested us was if they could know that I was a pussy, studying the dilation (you can make the joke) of my pupils, or if the dilation of the pupils can find out if one is straight or not. And this, in this international context, in which many parliaments work to exterminate all non-heterosexual people, is a matter of tremendous importance. Maybe that’s why the news is back now.

The precedents of the study.

It is not the first time that the sexual response to the vision of an erotic stimulus is investigated by measuring how much the pupil dilates, since pupil dilation is considered as an uncontrollable autonomic response to the sexual stimulus. It’s hard to believe but, between 1950 and 1970, the Canadian government did the same research with the aim of detecting homosexual people because they considered them a “national risk.” At that time the research failed because the measurement tools were not appropriate and the results of the measurement were not reliable, but also because it was not easy to find people who were volunteer in the experiment. With those intentions it is not surprising.

To date, investigations of the sexual response, of excitation, have been performed by monitoring the genitals, specifically by measuring the circumference of the penis in men, and by measuring the amplitude of the vaginal pulse, for the case of women. This genital method had serious drawbacks, as it was too invasive with the studied subjects, and the subjects themselves were biased because they were, somehow, more predisposed to this type of study, and for the same reason was not a method that allowed the study of sexuality in more conservative societies and in younger individuals.

The study of Cornell University.

This study has been able to monitor the pupil dilation in an accurate way by an infrared tracer, a noninvasive technique that can be used to know in greater detail the human sexuality, which is different depending on the analyzed society. The work has consisted in trying to corroborate ideas obtained through genital analysis and other issues pointed out by other types of studies and researchers.

For this, they made a selection of 325 people between 23 and 27 years old, 165 men and 160 women. The majority came in response to the request of participants in several university web pages with the exception of 22 men picked up in contact pages, who sought sex with men and with women, that is, men who, in fact, had sexual activity with both sexes. To the subjects were shown 24 videos of 30 seconds of masturbating men and women, and 2 videos of 1 minute with landscape images, considered neutral, for control. After seeing each image they were asked if they were attractive people, desirable and if they would like to have an appointment with them. Finally, participants completed a questionnaire on demographic information and sexual orientation. In total 45 minutes. Participants were distributed according to their declared sex and orientation as shown in the following table:

Classification table of people based on their declared sexual orientation, used in the study on pupil dilation.

The interest of this table is to show that in scientific fields sexual orientation goes beyond 2 or 3 categories. According to a Kinseyscale type, 0 would be a person only heterosexual and 6 totally homosexual.

Pupil dilation. The conclusions.

To discuss the study’s findings should be borne in mind that what we are dealing with this article is to approach the study in understandable language, so it will not be very accurate in statistical terms. If anyone has an interest in analyzing the study in detail, at the end you will find the links. Among other conclusions, these appear to us of interest::

1) Coincidence between the sexual orientation revealed by the people and the sexual reaction shown in the experiment. People were telling the truth. If a woman said she was a lesbian, her pupil response corresponded to that orientation.

2) The method provides quantifiable data on sex, orientation and response differences between men and women.

3) In the case of men, pupil dilation was greater facing the sexual stimulus that was more exciting to them, irrespective of their orientation. That is, the pupil dilation was the same in heterosexuals facing an erotic image of a woman, as in gays versus that of a man.

4) Bisexual men dilated the pupil equally facing an image of a man than of a woman, but they dilated it less than heterosexuals and gays. Before, there was a tendency to accept that bisexual men had a predilection for either sex, and the study showed that this was not true, as well as important novelties about bisexuality and the sexual flexibility of men.

5) The women showed, for each degree of declared sexual orientation, a similar dilation to male erotic stimulus than to female ones, with the exception of lesbians, who showed greater dilation to female sexual stimulus. In this sense the pattern of dilation of lesbians would be like the pattern of dilation of men. To date, researchers have tended to think that women have a flexible sexuality and this experiment corroborates it.

6) The applied statistical technique demonstrated the reliability of the data obtained with the experiment.

7) The researchers exposed the need for further testing.

8) These comments by Savin-Williams, one of its authors, seem particularly interesting to us:

“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”

“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”

What is true in the news?

After that we return to the question raised. Is it true that one can find out the sexual orientation of a person with the analysis of pupil dilation? The answer is no. The technique employed may be useful for understanding human sexuality, but it can not be an effective tool in all situations and, therefore, is not valid to find out the sexual orientation of a person in a certain way. The reasons are as follows:

a)It is very different to do the experiment with a person who has revealed the sexual orientation and who has answered several questions about each image, than with a person you do not know anything and you want to get information.

b) I also think that however much a person presents a certain degree of excitement to an image, does not mean that person actually has a sex life as suggested by his pattern of dilation.

c) Sight is not the only sense involved in sexual desire, they are all.

d) The non-inclusion in the experiment of individuals who do not fit into the proposed categories, such as transgender, intersexuals, pansexuals.

e) The experiment talk to us about how is a person at that time and not another’s. Data analysis shows that bisexuality increases with age.

f) People with more specialized and refined sexual preferences, or very habituated to pornography, probably do not show significant or comparable pupil dilation.

g) The experiment performed under duress probably has distinct pupil responses. Stress causes dilation of the pupils.

In the film Minority Report the pupils were the key element of identification.

The future.

The interesting thing will be when the technique of pupil dilation is used extensively to know the response of thousands of people, millions of people, at various times in their lives to get an idea of what happens inside us, beyond prejudices and moralities. How is sexuality of the human being? What is its usefulness? What is its evolutionary foundation? They are big questions that must answer the science stripped of any macho and heterocentric bias. This new method developed by Cornell University can help answer these questions.

For people who consider this a dangerous technique and feel some kind of fear, I will tell you that if homophobic people want to use this technique in order to exterminate any non-heterosexual person, in a strict sense and according to the test offered by this study, they would probably have to annihilate the majority of the population, including homophobes. Some experiments point out that homophobic men aroused with gay porn. In this sense it would be interesting to test the dilation of the pupils of Putin, Donald Trump, the religious fundamentalists emigrated to Uganda, the president of Iran, Sarah Palin, Benedict 16, etc … Surely we will be surprise and they too.

Cornell University publication:
 Eye pupils reveal sexual orientation, study shows.