Sniffing women's tears found to reduce aggressive behaviour in men

NEW DELHI: A study has found that sniffing women's tears leads to reduced aggression in men.

The research led by Weizmann Institute of Science, Israel, showed that tears from women contained chemicals that lowered men's brain activity linked to aggression and thus, weakened aggressive behaviour in them.

While this process of social chemosignalling is known to be common in animals - male aggression in rodents is blocked when they smell female tears - the process is less understood in humans, the researchers said in their study published in the journal PLOS Biology.

To investigate this, the researchers exposed a group of men to either women's emotional tears or saline while they played a two-person game, designed to elicit aggressive behaviour against the other player, whom the men were led to believe was cheating.

When given the opportunity, the men could get revenge on the other player by causing them to lose money. Also, the men weren't aware of what they were sniffing - women's tears or saline solution, both of them odourless.

The researchers found that vengeful aggressive behaviour in men dropped by more than 40 per cent after they sniffed women's emotional tears.

They also studied these men's brain activity and found using functional MRI that two aggression-related brain regions - the prefrontal cortex and anterior insula - became more active when the men were provoked during the game.

However, these aggression-linked brain regions did not become as active when the men were sniffing the female tears, the team found.

Individually, the greater the difference in this brain activity, the less often the player was seen to take revenge during the game.

The findings regarding this link between tears, brain activity and aggressive behaviour imply that the process of social chemosignalling is a factor in human aggression, not just in animals, the researchers said.