Love is All the Same :: Neurologically, Gay and Straight Don’t Matter

by Kilian Melloy
Tuesday Jan 11, 2011

There is some evidence that gays and straights are neurologically different from one another, with brain structure accounting for why a small, but consistent, fraction of human beings find themselves primarily or exclusively attracted to members of their own gender. But in matters of the heart, new research suggests, the brain activity is the same whether a person is in love with a woman or a man--suggesting that the emotions are exactly the same as well.

The paper, titled The Brain Reaction to Viewing Faces of Opposite- and Same-Sex Romantic Partners, was published Dec. 31, 2010, at PLos One. Two University College London researchers, Dr. Semir Zeki and Dr. John Romaya, designed and carried out medical scanning of a dozen individuals of each gender. Half of each group was straight, and half were gay. Ethnically, the participants were a mix; in age, they ranged from 19 to 47.

"Differences between homosexual and heterosexual brains have been described," both in terms of brain structure and neurological response patterns when subjects become sexually aroused, the paper noted. "But such differential activations as have been described have been in response to sexually arousing stimuli," the paper added, "not in response to the sentiment of love.

"Given the profound similarity in the sentiment of love expressed in the opposite- or same-sex contexts, we hypothesized that we would see no differences when females or males, or heterosexual or homosexual subjects, viewed the face of their loved partners," the researchers wrote.

The experiment's results confirmed their hypothesis, noted an article on the experiment that appeared Jan. 11 at MediLexicon. When the test subjects scrutinized photos of their sexual partners, the medical imaging showed virtually indistinguishable response patterns in their brains. This included activation of pleasure centers, and de-activation of areas of the neo-cortex. All of the research participants said that they were passionately in love with their significant others; the relationships varied in length from several months to more than two decades.

The sexual orientation of the research participants had no bearing on the results. "The pattern of activation and de-activation was very similar in the brains of males and females, and heterosexuals and homosexuals," wrote the paper's authors. "We could therefore detect no difference in activation patterns between these groups."

When the same research participants looked at photos of friends they were not in love with, no such changes occurred in brain activity. The people in the photos were of the same gender as each participant's significant other.

The fact that viewing photos led the participants' pleasure centers to become active, while the portions of the brain responsible for higher-level mental processes such as judgment became less active, invited commentary on the nature of love. "Passionate romantic love, commonly triggered by a visual input, is an all-consuming and disorienting state that pervades almost every aspect of a lover's life," the paper stated. "Yet human brain imaging studies show that the neural correlates of viewing the face of a loved person are limited to only a few, though richly connected, brain regions."

Even as science has showed differences in brain structure between gays and straights--thus supporting gays' claims that they do not "choose" their sexual orientation and that being gay is natural to them--research has also suggested that homophobia may be partly a matter of how people are hardwired--or how prejudices can become integrated into the brain's circuitry.

According to a Feb. 6, 2010, Psychology Today article, a study reveals that when heterosexuals--male or female--read accounts of anal sex between men, they respond with disgust. Moreover, their disapproval is more marked toward the man on the bottom--the receptive partner--than toward the man on the top, or the active partner.

But when given accounts of anal sex between mixed-gender partners, the response is different--for men, at least; whereas the same percentage of women remain disgusted regardless of the genders of the participants, disgust among men falls drastically.

"Together, these studies suggest that disgust is increased by gay male anal sex, and especially for the male in the penetrated role," wrote researcher Nathan Heflick. "A wide range of research shows that disgust triggers an avoidance response."

Heflick went on to posit that the (assumed) "primary sex act" between gay men might trigger a wish among heterosexuals to reject gays due to "feelings of ickiness," or disgust.

But it's an open question as to how much of that disgust may be inborn to human beings, and now much may be ingrained by societal lessons. In a sense, homophobia may turn out to be largely a kind of "bad habit" that is instilled into some people's neural circuitry in the same way other habits are: through simple, repeated instances of reward and punishment.

Next: A Complex Dance of Nature and Nurture


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