Do women’s tears reduce men’s aggression? The researchers conducted the test | Science and the planet

Studies have shown that rodents take full advantage of social chemical cues: they secrete substances that trigger a chemical reaction in the brains of others, leading to different behavior. For example, blind mice roll through their tears to lighten the mood of dominant males.

But there are good reasons not to assume that this also works in other mammals, such as us. “Rodents have a highly developed vomeronasal organ,” explains behavioral biologist Tom Roth of the Universities of Leiden and Utrecht. This is a small organ in the nose that detects odors and pheromones. “For us, this is not the case. Smell for rodents, as for us, is sight.

What people already know: Men produce less testosterone when they smell women’s tears. With what is known about testosterone, it is not too far-fetched to suspect a link to the level of aggression. So it was investigated whether smelling women’s tears actually reduces aggression in men.

To achieve this, a number of men had to play a game, as the researchers explained in their article published in the scientific journal Plos Biology. They played against a pre-programmed computer, but were told it was another man. They were given a stress ball in each hand and had to squeeze it at specific times. In ten seconds, they can earn about 60 cents on a euro.

However, at certain times the “opponent” can choose to steal a portion of the proceeds and add them to his or her own balance, and the computer did just that. The guinea pigs were able to get revenge in the next round. They had the option of hitting only one of the two balls, which could cause the opponent to lose money. It was of no use to them, as they did not receive this money themselves. Pure aggression, in which the motive of self-interest has been excluded.

Then it was a matter of inhaling while they played the game. Participants can have real women’s tears under their noses or saline solution. The solution was dripped onto the cheeks of the tear donors just to be sure, to check whether contact with the cheek would have any chemical effect. The materials were tested as odorless by all test subjects. The difference in behavior between the two was very strong: after inhaling tears, the test participants showed no less than 43.7% aggressive behavior towards their opponent.

To find out what happened in the brain, the experiment was repeated again, but this time using an MRI scanner that monitors the brain activity of the test subjects. After smelling tears, there was a decrease in brain activity mainly in a few areas, including two areas that have previously been linked to aggressive behavior. In addition, they tested in a test tube what happened when they added tears to a number of known olfactory receptors in the human nose. In four of them, they found a clear effect: the tear moved something, but with the saline solution this did not happen.

The researchers concluded that together, these indicators are strong indicators that tearing a woman through a man’s nose triggers a chemical process. A process that manifests itself in less aggressive behavior. They talk about a “chemical protective blanket.”

But this is certainly not the last word on the impact of tears on others. The researchers themselves realize this. Certain brain activity was clearly reduced when tears were smelled, but the decreased aggression observed previously was not replicated during the MRI test. This is of course a problem. New experiments are therefore necessary to see if the first result can be verified. The researchers are also looking to conduct the trial on women. This will cost donors many tears.

Moreover, Roth says, this research opens the door to many of the following questions: Only emotional tears have been tested in women now, but how does that work with men’s tears or with tears caused by wind, for example? Does such an effect also occur with other secretions such as sweat?