The human brain contains many characteristics that have to do with the behavior patterns of different types of people. In some ways, the way in which the neurons in our brain activate and communicate with each other reflects the propensities and tendencies that are reflected in our way of acting. And yes, this is also true for different sexual orientations .

Thus, the brains of heterosexual and homosexual people show some differences in the way they function in certain contexts, for example.

However, the brains of bisexual people (who are attracted to both men and women, although not necessarily with the same frequency or intensity) do not show a mixture of the activation patterns of the other two, as one might think. According to recent research published in the journal Nature , bisexuality is associated with neurobiological characteristics that are qualitatively different from those of homosexuals and heterosexuals.

The brain in bisexuality

The study in question, conducted by psychologists and psychiatrists from Northwestern University and the University of Magdeburg, has shown that the brains of bisexual people have certain characteristics in their functioning that, under certain conditions, allow them to be distinguished from the rest of the population .

This difference, however, does not have to be evident in every situation, such as sleeping or solving a mathematical problem. The context in which it has been proven to exist is in the perception of sexually charged images. This is important, since a difference in the brain’s activation patterns shows that the brain is physically different from others.In neuroscience, there is no distinction between software and hardware: the way in which different parts of the brain are “turned on” shows us how the networks of neurons of which they are made are woven together.

How was the research conducted?

Almost 80 people participated in this research: 28 bisexuals, 26 heterosexuals and 28 homosexuals. All of these individuals were between the ages of 25 and 50 and from different ethnic groups and backgrounds, so that the sample included different cultural variables. In addition, in the case of bisexual persons, it was a requirement for participation to have had at least one lover of each sex.

On the other hand, the sexual orientation of each person was recorded from a questionnaire based on the Kinsey scale, which established a scale ranging from exclusively homosexual to exclusively heterosexual through some intermediate grades.

From that point on, each of the participants watched a series of videos with adult content that included both heterosexual and homosexual sexual scenes. During this phase, the researchers tracked the participants’ brain activation patterns using magnetic resonance imaging.

The most activated parts of the brain in bisexual people

The results of the research showed a curious pattern of neuronal activation that depended on each participant’s sexual orientation. Specifically, the patterns of activation of a part of the brain linked to the basal ganglia called the striated nucleus, specifically its lower or ventral part . This area of the striated nucleus is related to the mental processes of motivation and the search for pleasure, so it also has an important role in the experience of sexuality.

As anticipated, this area responded by showing a preference for images depicting the opposite sex, in the case of heterosexuals, and the same sex in the case of homosexuals. In the case of bisexuals, however, this zone of the brain (and secondarily, some others) behaved as if the differentiation between the category “man” and “woman” were not important ; somehow, the border between these two concepts was blurred, in the same way that little importance can be given to the color of the eyes of others.

However, reactions of pure bisexuality, understood as one in which there is no clear preference for men or women, were rare. Judging by the images obtained through brain scans, the activation of the encephalic regions of bisexuals generally showed a tendency to find one of the two sexes more attractive .