The magic of sexual attraction
Romance has long been described as a process of bewitchment, but scientists have found that
there may be more truth to this than meets the eye.
They say female chemical messengers known as pheromones may help dupe men into thinking plain women are
more attractive and beautiful women are less attractive than they actually are.
Pheromones - the colourless, odourless chemical signals given off by the body - are thought to affect behaviour
in both animals and humans at a sub-conscious level.
Research by biologists Astrid Juette and Professor Karl Grammer from the University of Vienna has found that
men's perception of a woman's attractiveness is altered by the chemical signals she sends out.
They exposed 66 men to synthetic vaginal pheromones without their knowledge.
They then showed them a series of photographs of women and played tapes of their voices.
The pheromones, which can be perceived by the nose even though they are odourless, were then replaced by water
and the men's reactions were studied.
In each case, the men were asked to grade the women's attractiveness.
They were more likely to think the women were attractive when they were exposed to
the pheromones and the testosterone in their saliva increased.
There were also fewer differences in perceptions about attractiveness between the men
when they were under the influence of the chemical messengers.
Professor Grammer said: "The most astonishing thing is that the attractive women lose and what they lose the others gain.
"This is part of what we call the chemical warfare between the sexes, in which one tries to exploit the other."
He thinks the pheromone system evolved over millions of years to help plain women
find a mate and stop very attractive women being pestered.
However, other scientists say pheromones are only one ingredient of sexual attraction and only affect physical attraction.
They do not alter a person's perception of an individual's intelligence or self assurance.
Professor Grammer presented the University of Vienna findings to a British Psychological Society (BPS) conference in London on Wednesday.
He also said the oral contraceptive pill could stop a woman producing pheromones
and undermine her ability to pick up the right chemical signals from men.
Scientists believe pheromones may help people choose biologically compatible mates.
Professor Grammer said the pheromone confusion caused by the pill could cause a woman to choose a mate
with whom she could not produce a child.
"She picks out the genetically wrong mates. It's highly possible that she will not be able to produce offspring with her mate," he said.