THURSDAY, Jan. 6 (HealthDay News) -- Crying may be nature's way of telling men to give women some space: A new study indicates the smell of women's tears considerably dampens men's sexual desire.
Research by Israeli scientists examining the significance of emotional human tears suggests they are far more than watery drops squeezed from glands around the eyes. Women's tears play a functional role by emitting chemical signals that reduce testosterone levels and sexual arousal in men, the study found.
Men's and children's tears have not yet been analyzed, according to researcher Noam Sobel, of Israel's Weizmann Institute of Science, who hopes to learn if the tears from these groups also send biological signals to others.
Earlier studies had established that emotional tears contain different molecules than tears produced from cutting onions, for example, or those protecting the eyes from debris.
"The fact that emotional tears are different in content was a strong clue for us that they served as a chemo-signal," said Sobel, a professor of neurobiology at the institute. "For sure, it's a means of chemical communication. We communicate in many ways."
In a series of experiments, Sobel and his fellow researchers first determined that men could unconsciously distinguish between the smell of women's tears -- which have no discernable odor -- and odorless saline solution.
The 24 participants then viewed emotionally ambiguous pictures of women's faces, rating the sadness and sexual attractiveness of each. For 17 of the men, the faces appeared less sexually attractive after sniffing tears than after sniffing saline.
Fifty men later watched a sad film after sniffing either tears or saline, which produced a modest drop in self-rated sexual arousal and a pronounced drop in salivary testosterone levels in those who sniffed tears.
Lastly, MRI brain images of 16 me
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