Scientists confirm tears are a turn-off

John von Radowitz, AAP January 7, 2011

Tears do more than show that we are sad - they transmit subtle airborne chemical messages that have biological effects.

Research has shown that when women cry it makes them less sexually attractive to men.

The effect is not psychological but the result of pheromones, or scent messages, transmitted by the tears.

Scientist believe tears shed by men may send out similar, or different, chemical signals.

Emotional crying is believed to be a uniquely human behaviour, although some animals also produce tears.

Mice shed tears to stop their eyes drying out, but studies have shown that male mouse tears act as an aphrodisiac for females.

When male mice cry, it makes them highly attractive to their mates.

Scientists led by Noam Sobel, from the Weizmann Institute in Rehovot, Israel, wanted to find out if human emotional tears carried similar signals.

They set up an experiment in which male volunteers sniffed either tears from women who watched a sad movie, or drops of salty water trickled down the cheeks of the same women.

In both cases, the men reported that the tears had no odour, but those who sniffed the genuine tears tended to find women in photographs less attractive than those exposed to fake tears.

Tests showed that tear-sniffing men experienced drops in physical arousal and levels of salivary testosterone, the male sex hormone.

Writing in the journal Science, the researchers said the finding raised a number of questions, such as the identity of the active compound in tears.