Smelling the tears of a woman can quell a man's sexual desire, according to a study that determined female crying can have a direct chemical impact on male libido.
Scientists have found evidence to suggest that tears from a weeping woman contain a chemical signal that can have a subconscious effect on a man's sexual desire, even if he is not a witness to the crying.
The findings suggest a functional role for crying in humans, who are unique in the animal kingdom by expressing emotion with weeping eyes.
Crying among women may be a way of controlling male desire and sexual aggression, the researchers suggested.
One of the studies involved asking men to rate a series of photographs of women's faces according to their sadness or sexual attractiveness. Sometimes the men were exposed to the tears of weeping women, and sometimes they were given tissues soaked in saline solution.
None of the men said they were able to detect any difference in smell between the two types of tissue, and none knew that what they were given to sniff contained a woman's tears.
Professor Noam Sobel from the Weissmann Institute of Science in Israel, who led the research team, said that a significant decline in the men's estimation of the women's sexual attractiveness only occurred after they had been exposed to the tears.
Further studies showed that tears also resulted in a decline of testosterone in the men's saliva, as well as their judgement about their own state of sexual arousal.