Sniffing out a partner

Beneath the perfume, soap and deodorant, it seems that the old smelly rules of attraction still apply.

Flinders University psychologist Dr Yolanda Martins is the co-author of a recently released study into body odour, which reveals that one person's preference for another's body odour depends in part on the gender and the sexual orientation of both individuals.

Dr Martins co-directed the research with American psychologist Dr Charles Wysocki of the Monell Chemical Senses Center in Philadelphia. The results of the study will be published in the September issue of Psychological Science.

For the study, samples of underarm sweat were collected from 24 volunteers of varied gender and sexual orientation. 82 heterosexual and homosexual men and women were then asked to indicate their preference between two samples in a series of choices.

In animals, smells - particularly natural pheromones - are integral to attraction and the identification of potential mates.

A succession of trials has shown that there is an olfactory element in human attraction and recognition - one study, for instance, demonstrated that women could identify their partners by body odour left on T-shirts.

"Since the system does work to some extent in humans, we were curious to know if it is the case that it differs as a function of sexual orientation," Dr Martins said.

The study found that sexual preferences as well as gender preferences were reflected in preferences towards body odour.

Homosexual men and lesbian women had patterns of body odour preferences that were distinct from those of heterosexual men and women.

In particular, gay men were noticeably different from heterosexual men and women and from lesbian women, both in terms of which odours they themselves preferred and how the odours from homosexual men were regarded by the other groups.

Gay men preferred odours from gay men and heterosexual women, whereas the body odour of gay men was least preferred by heterosexual men and women and lesbians.

Intensity of the odour was not a governing factor; perceptions of pleasantness or unpleasantness were considered more important. Because the perceptual differences were related to odour quality, this suggests that at least some of the chemical attributes that contribute to human body odours are related to an individual's gender and sexual orientation.

"In the real world, this is not usually the way the system functions because we are suppressing our scent," Dr Martins said.

"Our smell is one more thing that is linked to attraction, but in humans so many other things come into play."

Dr Martins said that while smell may represent a very small component of attraction in practical terms, the study showed that the capacity for attraction through body odour is still operating.

"In addition, now that we know odour preference is a function of both gender and sexual orientation, it provides further support for the possibility that there is a biological rather than an environmental or cultural mechanism underlying homosexuality," she said.

Perceptions of smell and also texture are integral to Dr Martins' current research projects, which focus on the mechanisms and factors that underlie positive or negative responses towards different types of food in adults and children.