Love goes through the ears
Scientists have discovered the first physiological differences between people with heterosexual and homosexual tendencies. According to their measurements, echoic sounds produced by the inner ears are weaker in homo- or bisexual women than in heterosexually oriented women. "The results suggest that the inner ears and some as-yet-unknown brain structures responsible for sexual orientation become masculinized in gay and bisexual women because men also produce weaker echoic sounds in their inner ears," says Dennis McFadden of the University of Texas in Austin. "The study also suggests that the inner ear may be an important window into events that take place during brain development and sexual differentiation." The research is available in the March 3 issue of the Proceedings of the National Academy of Sciences.
"The report is an elegant study of subtle auditory phenomena in gay and straight people," says Sandra Witelson of McMaster University in Ontario. "The results supported the theory that central nervous system differences exist between homosexual and heterosexual people…"
In the past, research on the neurobiological differences between homosexuals and heterosexuals has focused more on males than females. To this day, the findings are linked to differences in brain structures, left- or right-handedness, and fingerprint patterns.
In the new study, researchers examined a sound produced by the inner ear known as click-evoked otoacoustic emission. This echo-like sound is made by the inner ear in response to a faint clicking sound, such as tapping a pencil on a desk. "Emissions are generally higher in women than men throughout life," says McFadden. "However, we found that emissions from 61 homosexual and bisexual women were lower than those from 57 heterosexual women." The strength tended toward the level that is common in men. The researchers found no differences in intensity between gay and bisexual women or gay and straight men.
People with strong click-evoked otoacoustic emissions can generally hear weaker sounds more clearly. The researchers plan to determine whether lesbian women have lower hearing sensitivity compared to straight women. They also want to check whether there are other hearing differences between homosexuals and heterosexuals.
Note that the study has statistical value only. A statement about the sexual orientation of an individual is not possible based on the noise in the ears.
The Heidelberger Verlag Spektrum der Wissenschaft is the operator of this portal. Its online and print magazines, including "Spektrum der Wissenschaft", "Gehirn&Geist" and "Spektrum – Die Woche", report on current research findings.