Men have been found to become less aggressive if they smell women’s tears, a study has found.
The reason for tears when someone is upset other than to demonstrate their emotion has long been questioned and debated. But now, research shows that women’s tears contain chemicals that significantly reduce aggression in men.
It was found that men sniffing the tears were 44% less aggressive when playing games that were designed to provoke a response. The study, published in PLOS Biology, stated that there was a corresponding decrease in brain activity in the areas that are related to aggression, when there are tears.
“The reduction in aggression was impressive to us, it seems real,” said Noam Sobel, a professor of neurobiology at the Weizmann Institute of Science in Israel, who led the research along with Dr Shani Agron. “Whatever is in tears actually lowers aggression.” In the game the aggressive response was introduced as the men were led to believe that the woman was cheating and they could get revenge by making the other player lose money.
And the use of an MRI scanner showed that the prefrontal cortex and anterior insula, areas associated with aggression, were calmer. “This chemical (in the tears) appears to be orchestrating the brain response to aggression,” Prof Sobel said.
Scientists discover why our hair turns grey and may be able to 'reverse ageing'It has previously been known that male aggression in rodents is reduced when they smell female tears due to social chemo signalling - a process which is less understood in humans.
Prof Sobel believes that chemicals are unlikely to have much of an impact on the social interaction between adults but the tears may have evolved to protect babies. The authors add: “We found that just like in mice, human tears contain a chemical signal that blocks conspecific male aggression. This goes against the notion that emotional tears are uniquely human.”
And Prof Sobel added: “Babies can’t say: ‘Stop being aggressive towards me’. They are very limited in their ability to communicate, and they are helpless as well. They have a vested interest in lowering aggression and that reflects the sad reality of aggression towards babies."
Meanwhile, Ad Vingerhoets, an emeritus professor of emotions and wellbeing at the University of Tilburg, who was not involved in the study, said: “It makes sense if tears in some way inhibit aggression because it’s common knowledge that infants that cry a lot are at risk for physical abuse. It might help them to survive.”