Take one man, the smell of a female armpit and a written description of a woman and place them in a room together. Do not tell the man that he is being exposed to female armpit odour. Result?
When asked to describe the woman he is reading about, the man will judge her as more sexually and physically attractive - and more "likable" - than men not exposed to the armpit odour.
Take one woman, the smell of a male armpit and a written description of a man and place them in a room together. Again, do not tell the woman that she is being exposed to male armpit odour. Result?
Like the man she will be roused to describe the man in the literature as sexually and physically attractive. She will not, however, describe him as more likable than normal.
These are the results of research by Andrew Scholey, director of the human cognitive neuroscience unit at the University of Northumbria at Newcastle. "I don't know if it's something to do with men," Dr Scholey said. "If they find a woman physically and sexually attractive, then they seem to find her more likable too, where women seem able to separate straightforward biological attractiveness from how likable they find a man."
For his research Dr Scholey recruited volunteers to take part in mood questionnaires. He gave them no indication that some were being exposed to sweat from the opposite sex while filling in the forms. Instead the volunteers were given drinks and thought they were involved in studies to see the effects of glucose on mood.
Dr Scholey, who will present his research to a conference, "The brain: a user's guide", run as part of European Brain Week, found women exposed to male sweat were far more likely than women not so exposed to rate a male character as sexually and physically attractive. Women exposed to sweat also reported feeling more energetic and clear headed than the other women.
Dr Scholey says this was one of the first experiments to use the whole armpit secretion, rather than selective secretions such as androstrenols, to test attractiveness. "We wanted to use the whole cocktail as in real life - including skin cells that may also have pheromonal properties. Secretions are obviously playing some part in the way people form impressions of each other," he said.
He is now increasing the research to see the effect of such secretions on homosexuals. He is keen to learn whether the effects are innate or can be learned.