The smell of women’s tears reduces male aggression: molecules of calm

Research has shown that this calms brain activity

The study found that the smell of women’s tears significantly reduced aggression in men and activity in brain networks associated with it. The effect, which is caused by chemical signals in tears and is also observed in rodents, is thought to have a protective function.

Charles Darwin was puzzled by emotional tears: he believed that they did not serve solely to moisten the eyes. Although shedding emotional tears is considered a uniquely human trait, modern researchers have discovered that mammalian tears contain chemicals that act as social cues, one of which is to reduce aggression.

For example, the tears of female mice contain them, inhibiting activity in brain networks associated with aggression in males. And subordinate blind male shrews cover themselves with tears to reduce the dominant male’s aggression towards them.

Now, researchers at the Weizmann Institute of Science have conducted a series of experiments to find out whether this effect occurs in humans and what functional impact it has on their brains. The material was published in the journal PLOS Biology.

“We knew that sniffing tears lowers testosterone levels, which has a greater effect on aggression in men than in women, so we started by studying the effects of tears in the former because it gave us a better chance of seeing an effect,” explains the study’s lead author. Shani Agron.

Scientists collected “emotional” tears from six human donors aged 22 to 25 who watched sad movie clips in isolation to achieve the result. Twenty-five men were asked to play a two-player money game against an opponent they were told was human but was actually a computer algorithm. The game was designed to provoke an aggressive response from men towards their opponent, whom they were led to believe was being cheated. When given the opportunity, a man could take revenge on his rival by making him lose money without any personal gain to himself.

Before the game began, participants sniffed either the woman’s tears or saline solution—both odorless—and were not told what they were smelling. Researchers observed a 43.7 percent decrease in aggression after exposure to tears. To assess the robustness of their results, they ran a statistical procedure that reuses one set of data to create multiple simulated samples where the probability of finding that result by chance was less than 30 percent.

By examining functional brain connectivity, they found that tears showed significantly reduced increased connectivity to the right amygdala and piriform cortex, regions that are part of a functional network involved in olfaction and aggression.

“We showed that tears activate olfactory receptors and that they alter brain circuits associated with aggression, significantly reducing aggressive behavior,” says scientist Noam Sobel. “These results suggest that tears provide a chemical blanket that provides protection against aggression, and that this effect is characteristic of rodents and humans, and possibly other mammals.”

Having confirmed the influence of the smell of tears on the behavior of men, the researchers are looking to expand their research.

“When we looked for volunteers to donate tears, we found mostly women, because for them it is much more socially acceptable to cry,” the authors of the experiment share details, “but now we need to expand this study to get a more complete picture of this.” impact.”