men show less aggression when they smell women’s tears

New research shows that women’s tears contain substances that appear to block aggressive behavior in men.

It may sound a bit crazy. But this phenomenon had already been observed in rodents. For example, it is known that when these animals smell the tears of females, this counteracts aggression in males. Now researchers have decided to study this peculiar phenomenon in humans as well. Does sniffing tears have the same effect on men?

Rodents
Rodent tears contain chemical signals that have various effects, including counteracting male aggression. For example, in female mice, the tears contain substances that reduce fighting tendencies in males. Subordinate male blind mole rats also smear themselves with their tears to dampen the aggressive behavior of dominant males. At the same time, we know that human tears also contain a chemical signal that lowers testosterone levels in men. However, its precise meaning was still unclear. “Since a decrease in testosterone may be associated with reduced aggression, we tested the hypothesis that human tears, similar to what has been observed in rodents, are able to reduce male aggression,” the researchers wrote in their study.

Game
For this study, the team gathered a group of men and invited them to participate in a two-person game. The game was designed to provoke aggressive reactions towards the other player, who the men thought was cheating. If given the opportunity, the men could take revenge on the other player by making them lose money. While playing the game, the men smell either women’s tears or saline solution. The men were unaware of what they were sniffing and could not distinguish between the two.

More about human tears
Human tears can be classified into three categories based on how they form. First, there are psychological or emotional tears, which occur with intense emotions, both positive and negative. In addition, there are basal tears that are continuously produced in small amounts to keep the eye moist. Finally, you have reflexive tears, which are released by irritation such as dust or tear gas, and also when cutting onions. These tears differ not only in their origin, but also in their composition. For example, emotional tears contain proteinaceous hormones, one of which is a neurotransmitter that naturally has an analgesic effect on people experiencing stress.

The findings from the study are remarkable. For example, it appears that vengeful, aggressive behavior during the game decreased by more than 40 percent after the men smelled the tears of women.

Brain scans
The researchers then repeated the experiment in an MRI scanner. And it shows that two brain areas related to aggression – the prefrontal cortex and the anterior insula – showed more activity when the men were provoked during play. However, these areas were less active when the men smelled tears. The greater the difference in brain activity, the less often the player took revenge during the game.

Substances
It means that smelling female tears also leads to reduced aggression in men in humans. It appears that women’s tears contain substances that dampen aggression in men. This indicates that there is a link between tears, brain activity and aggressive behavior in humans. “We showed that tears activate olfactory receptors and change brain circuits associated with aggression, leading to a significant reduction in aggressive behavior,” said researcher Noam Sobel. “The results show that tears provide a kind of chemical protection against aggression. This effect therefore occurs in both rodents and humans – and possibly also in other mammals.”

Dogs
For example, recent research has shown that even dogs shed emotional tears. But to know for sure whether these tears contain chemical signals that can be picked up by other dogs or people, more research is needed.

Baby’s
Why tears reduce aggression? The researchers speculate that this is mainly relevant for babies. “Babies can’t talk to protect themselves from aggression,” says researcher Shani Agron. “That’s why they may rely more on chemical signals.”

Women
In future research, the researchers plan to study whether the results also apply to women. “When we looked for volunteers to donate tears, we mainly found women, because it is much more socially acceptable for them to cry,” says Agron. “We knew that smelling tears lowers testosterone levels. Because this affects aggression more in men than in women, we started studying the effect of tears on men. However, now we also want to investigate whether this has the same effect in women, so that we understand the complete picture.”

All in all, the researchers point out the striking similarities between mouse tears and ours. “We found that human tears, similar to mice, contain a chemical signal that suppresses male aggression in others of the same species,” the researchers concluded. “This refutes the idea that emotional tears are something uniquely human.”