This conclusion probably is not likely to surprise bisexuals, who have long asserted that attraction often is not limited to one sex. But for many years the question of bisexuality has tormented scientists.
A widely publicized study published in 2005, also by researchers at Northwestern, reported that “with respect to sexual arousal and attraction, it remains to be shown that male bisexuality exists.”
Bisexual men and women were outraged by this verdict. They said it appeared to support a stereotype of bisexual men as closeted homosexuals. In the new study, published online in the journal Biological Psychology, the researchers relied on more strict criteria for selecting participants.
In order to improve their chances of finding men aroused by women as well as men, the researchers recruited subjects from websites specifically catering to bisexuals, not to gays.
Men in the 2005 study, for example, were recruited through advertisements in gay-oriented and alternative publications and were identified as heterosexual, bisexual or homosexual based on responses to a standard questionnaire.
Northwestern researchers required that these men had sex with both men and women and had been in a relationship for at least three months with someone of each gender. In both studies, men were to watch videos of male and female same-sex intimacy while genital sensors monitored their erectile responses.
The first study reported that the bisexuals generally resembled homosexuals in their responses, while the new one finds that bisexual men responded to both the male and female videos, while gay and straight men in the study did not.
It was also found by both studies that bisexuals reported subjective arousal to both sexes, notwithstanding their genital responses.
The new Northwestern study was partly financed by the American Institute of Bisexuality. This is a group that promotes research and education regarding bisexuality. But the advocates express mixed feelings about the research.
Jim Larsen, 53, a chairman of the Bisexual Organizing Project, a Minnesota-based advocacy group, said the findings could help bisexuals still struggling to accept themselves.“It’s great that they’ve come out with affirmation that bisexuality exists,” he said.
“Having said that, they’re proving what we in the community already know. It’s insulting. I think it’s unfortunate that anyone doubts an individual who says, ‘This is what I am and who I am.’
Ellyn Ruthstrom, president of the Bisexual Resource Center in Boston, echoed Mr. Larsen’s discomfort. “This unfortunately reduces sexuality and relationships to just sexual stimulation,” Ms. Ruthstrom said.
“Researchers want to fit bi attraction into a little box — you have to be exactly the same, attracted to men and women, and you’re bisexual. That’s nonsense. What I love is that people express their bisexuality in so many different ways.”
Allen Rosenthal, the lead author of the new Northwestern study and a doctoral student in psychology at the university, said: “Someone who is bisexual might say, ‘Well, duh! But this will be validating to a lot of bisexual men who had heard about the earlier work and felt that scientists weren’t getting them.”
The Northwestern study not the first published this year which reports a distinctive pattern of sexual arousal among bisexual men. In March, a study in Archives of Sexual Behavior reported the results of a different approach to the question.
As in the Northwestern study, the researchers showed participants erotic videos of two men and two women and monitored their genital as well as subjective arousal. But they also included scenes of a man having sex with both a woman and another man, on the theory that these might appeal to bisexual men.
The researchers in Archives of Sexual Behavior found that bisexual men were more likely than heterosexuals or gay men to experience both genital and subjective arousal while watching these videos.
Dr. Lisa Diamond, a psychology professor at the University of Utah and an expert on sexual orientation, said that these two new studies represent a significant step toward demonstrating that bisexual men do have specific arousal patterns.
“I’ve interviewed a lot of individuals about how invalidating it is when their own family members think they’re confused or going through a stage or in denial,” she said. “These converging lines of evidence, using different methods and stimuli, give us the scientific confidence to say this is something real.”
Lead author Allen Rosenthal says this study, “Will be validating to a lot of bisexual men who had heard about the earlier work and felt that scientists weren’t getting them.” [via The New York Times]