Does science buy male bisexuality?

Bonobo apes frequently engage in bisexual play.
Bonobo apes frequently engage in bisexual play.
Martin Harvey/Getty Images

To witness male bisexual behavior in action, a trip to a bonobo habitat would suffice. The apes engage in sexual play with neighboring females and males alike as a form of conflict resolution [source: Doig]. That doesn't just entail occasional forays into the switching-hitting habit, either. Bonobo bisexuality helps explain how the apes instigate sexual activity every 90 minutes, an estimated 75 percent of which is for nonreproductive purposes [source: Owen].

For bonobos' human relatives, however, that type of behavior isn't as readily accepted. To start, the very term "bisexuality" is troublesome for some since it implies a sexual binary, a sharp divide between heterosexual and homosexual, rather than the spectrum espoused by Alfred Kinsey's Scale of Sexual Attraction [source: Angelides]. The bisexual orientation also has been fraught with legitimacy problems, often scrutinized as a faddish label people adopt for brief stints. Psychoanalyst Sigmund Freud, for instance, espoused the theory of innate bisexuality in which people are thought to be born with bisexual tendencies, which they inevitably grow out of in favor of hetero- or homosexuality [source: Haggerty]. In 1974, Newsweek snarkily headlined a report on it entitled "Bisexual Chic: Anyone Goes," hinting at freewheeling promiscuity rather than a bona fide sexual identity [source: Newsweek].

Advertisement

Advertisement

A couple decades later, Newsweek changed its tone dramatically, declaring in a 1995 cover story that a bisexual movement was afoot, though it couldn't project the size of the sexual community [source: Newsweek]. Conversely, a year earlier, leading gay publication The Advocate stole some wind from the bisexual sails when it published a survey reporting that 40 percent of gay men initially self-identified as bisexual, lending credence to notion of bisexuality as temporary [source: Carey]. Today, population survey analyses from the Williams Institute on Sexual Orientation Law and Public Policy derived a ballpark estimate of 1.7 percent, or roughly 4 million, American adults who openly identify as gay or lesbian [source: Leff]. Slightly more -- 1.8 percent -- label themselves bisexual [source: Leff].

As sexology has transitioned from surveys and self-reporting to more rigorously controlled laboratory settings, thanks to technological advances in measuring arousal, female bisexuality has been met with more empirical acceptance because bisexual female arousal patterns have been documented and replicated. Male bisexuality, on the other hand, has been caught in the scientific crosshairs because come to find out, whereas men possess statistically stronger sex drives, the directions they're steered tend to be more rigid and direct than what women experience.

Bedroom Science: Measuring Bisexuality

How do you measure sexual attraction?
How do you measure sexual attraction?
Javier Pierini/Getty Images

Although science can't explain the interpersonal aspects of attraction that serendipitously draw people toward each other from amid a sea of strangers, it's certainly figured out how to track and quantify the less romantic stuff. To evaluate sexual orientation, researchers can collect psychophysiological data on what stimulates people's inner urges. In other words, science can verify in the most basic terms what turns us on.

Functional MRI data is allowing researchers to glimpse into how and where the brain manages arousal. Not surprisingly, titillating thoughts and material literally wash over the brain, lighting up visual processors and attention processors, as well as motivation and reward systems. Sexual orientation may also influence which parts are triggered, although scientists have yet to substantively confirm distinct differences [source: Bailey].

Advertisement

Advertisement

Currently, the main instrument for measuring sexual arousal is the plethysmograph, which is a gauge designed to capture volume expansion, such as how much people's lungs can fill with air [source: Bergner]. Penile and vaginal plethysmographs can therefore identify the amount of blood flow to the genitals in response to sexual and non-sexual stimuli (generally pornographic film clips and nature footage, respectively). Researchers typically will assess study participants' sexual orientation through self-reporting and the Kinsey scale and then compare those results to plethysmograph data and evaluate how the information matches up.

Joint studies conducted in the early 2000s at Northwestern University found two stark characteristics of male arousal. Compared to women, gay and straight men exhibit significantly more "category-specific" arousal [source: Chivers et al]. Or, what evokes male sexual excitement correlates much stronger to their stated real-world sexual preferences, whereas straight and gay women displayed more sexual fluidity, meaning they were physiologically stimulated by a range of material [source: Chivers et al]. When the Northwestern researchers replicated the experiment on a group of bisexual men, the categorical specificity remained, rather than the expect fluidity. Bisexual men, the 2005 data seemed to indicate, expressed heterosexual or homosexual arousal patterns like the rest of their male cohorts [source: Rieger, Chivers and Bailey].

In a major blow to male bisexuality, science had chipped away at any social progress that had been made toward accepting it as a valid, long-term sexual orientation. But not for long.

Male Bisexuality Exists

Can science completely unravel sexuality?
Can science completely unravel sexuality?
Tim Kitchen/Getty Images

This concluding sentence in the 2005 Northwestern study on bisexual men initially rang out like death knell: "Indeed, with respect to sexual arousal and attraction, it remains to be shown that male bisexuality exists."

The study in question, however, wasn't flawless and underscored the importance of rigorous methodology. In it, the male participants were shown pornographic film clips featuring either two men or two women, which were selected under the assumption that bisexual men would become more aroused by both sets of stimuli compared to their straight and gay counterparts [source: Rieger, Chivers and Bailey]. Instead, the bisexual men became aroused by one or the other.

Advertisement

Advertisement

When a separate pair of studies published in 2011 put more emphasis on controlling for long-term bisexual participants and bisexual-oriented sexual stimuli for study participants to view, the results changed. Once researchers culled a group of men who reported not only bisexual urges, but also bisexual long-term relationships, their orientation better predicted their plethysmograph readings [source: Rosenthal et al]. Specifically, the bisexual participants were more turned on by both heterosexual- and homosexual-oriented pornography, versus the gay and straight participants who showed marked preferences for one or the other. Next, another group of researchers similarly identified the existence of male bisexual arousal patterns by tweaking experimental methodology to include bisexual erotic material in its stimuli, unlike the previously mentioned sexuality studies which involved only heterosexual and homosexual pornography [source: Cerny and Janssen]. That way, the study didn't parse out whether bisexual men show equally gay and straight tendencies but rather their own behavioral hallmark of heightened sexual interest in bisexual scenarios.

With the existence of male bisexuality empirically proven, albeit rare, some wonder whether it's accurate to conflate sexual orientation with sexual arousal. After all, gay and straight women involved in the same studies exhibited sexual fluidity, as they were physiologically piqued by a wider range of material than their male counterparts [source: Bergner]. And for men and women alike, real-world sexual behavior can't be perfectly replicated in a laboratory setting, causing some to argue that ignoring the emotions and social pressures that compel long-term bonding inherently mars the research process [source: Bailey]. The 1.8 percent of the population that self-identifies as bisexual might heartily agree with that strand of scientific theorizing.

Related Articles

Sources

  • Angelides, Steven. "A History of Bisexuality." University of Chicago Press. Sept. 15, 2001. (Jan. 17, 2012) http://books.google.com/books?id=UN2ZqXzmQJ0C&dq=bisexuality+history&source=gbs_navlinks_s
  • Bailey, J.M. "What is sexual orientation and do women have one?" Contemporary Perspectives on Lesbian, Gay, and Bisexual Identities. 2009. (Jan. 17, 2012) http://www.ncbi.nlm.nih.gov/pubmed/19230524
  • Bergner, Daniel. "What Do Women Want?" The New York Times Magazine. Jan. 22, 2009. (Jan. 17, 2012) http://www.nytimes.com/2009/01/25/magazine/25desire-t.html?pagewanted=all
  • Carey, Benedict. "Straight, Gay or Lying? Bisexuality Revisited." The New York Times. July 05, 2005. (Jan. 17, 2012) http://www.nytimes.com/2005/07/05/health/05sex.html?pagewanted=all
  • Cerny, Jerome A. and Janssen, Erick. "Patterns of Sexual Arousal in Homosexual, Bisexual, and Heterosexual Men." Archives of Sexual Behavior. Jan. 01, 2011. (Jan. 17, 2012) http://www.kinseyinstitute.org/publications/PDF/Cerny%20and%20Janssen%202011.pdf
  • Chivers, Meredith L. "A Sex Difference in the Specificity of Sexual Arousal." Psychological Science. 2004. (Jan. 17, 2012) http://www.canyons.edu/faculty/labriem/Psych230/SexDifferencesInSpecificitySexualArousal.pdf
  • Doig, Will. "Love Thine Enemy." Nerve. July 20, 2005. (Jan. 17, 2012) http://www.nerve.com/regulars/lifeswork/bonobo
  • Haggerty, George E. "Gay Histories and Cultures: An Encyclopedia." Taylor & Francis. 2000. (Jan. 17, 2012) http://books.google.com/books?id=406CCTn4AAQC&dq=freud+innate+bisexuality&source=gbs_navlinks_s
  • Leff, Lisa. "Gay Population in U.S. Estimated at 4 Million, Gary Gates Says." Huffington Post. April 07, 2011. (Jan. 17, 2012) http://www.huffingtonpost.com/2011/04/07/gay-population-us-estimate_n_846348.html
  • Newsweek. "Bisexuality." July 16, 1995. (Jan. 17, 2012) http://www.thedailybeast.com/newsweek/1995/07/16/bisexuality.html
  • Owen, James. "Homosexual Activity Among Animals Stirs Debate." National Geographic. July 23, 2004. (Jan. 17, 2012) http://news.nationalgeographic.com/news/2004/07/0722_040722_gayanimal.html
  • Rieger, Gerulf; Chivers, Meredith L.; and Bailey, J. Michael. "Sexual Arousal Patterns of Bisexual Men." Psychological Science. Vol. 16. No. 8. 2005. (Jan. 17, 2012) http://www.susiebright.blogs.com/BiMen.pdf
  • Rosenthal, A.M. et al. "Sexual arousal patterns of bisexual men revisited." Biological Psychology. 2011. (Jan. 17, 2012) http://www.thestranger.com/images/blogimages/2011/08/16/1313530258-rosenthal_et_al.pdf

Advertisement