A study discovers a secret hidden in women's tears!

Women's tears contain a substance that reduces aggression, according to a new study. Researchers believe that tears may have evolved over time to become a means of self-defense.

According to the study, inhaling emotional tears from women reduced male aggression by more than 40% in computerized tests, and stimulated similar changes in the brain, although the scientists who conducted this study believe that all human tears would have a similar effect.

"The reduction in aggression was impressive to us, and it seems real. Everything about crying actually reduces aggression," said Noam Sobel, a professor of neuroscience at the Weizmann Institute of Science in Israel.

Naturalist Charles Darwin was puzzled about the cause of crying. In his 1872 book, The Expression of the Emotions in Man and Animals, he declared that crying was “as senseless as the secretion of tears from a blow outside the eye.”

But in the 150 years since then, researchers have proposed different roles for tears, from signaling weakness and disability to removing bacteria from the eyes.

Previous research in Sobel's lab found that inhaling women's tears reduces testosterone in males, but it was not clear whether this affected behavior. As for animals, the picture is clearer: naked mole rats, for example, cover themselves with tears to protect themselves from aggressors.

In the latest study, Dr. Shani Agron and others in Sobel's lab collected the tears that fell down women's faces while they watched sad movies.

The researchers did not specifically announce the tear donors, but almost all of those who applied were women, and six of them were chosen to produce tears.

The experiments involved 31 men who inhaled either a saline solution or women's tears, and the men participated in a computer game used in psychology to provoke aggressive behavior by unfairly deducting players' points.

The scientists wrote in the journal Plos Biology that aggressive behavior, in the form of retaliation, was 43.7% less when the men were inhaling the women's tears compared to the saline solution.

Further tests in a brain scanner revealed that people who smelled tears had more functional connectivity between areas dealing with odors and aggression, while activity in brain networks for aggression was lower.

"This chemical appears to regulate the brain's response to aggression," Sobel said.

One puzzle scientists have faced is that although rodents have a sensory system that can detect such materials, there is no known way for humans to do so. In laboratory tests, researchers on the Duke University team found that four types of receptors on odor-sensitive neurons were activated by human tears, suggesting that they may respond to the substance as an aggressor.

Sobel acknowledges that the chemicals in tears are unlikely to have a significant impact on adults' social interactions, but he speculates that the composition of tears may have evolved to protect vulnerable children.

Sobel's lab hopes to identify the active ingredient in tears. This would open the door to manufacturing the substance and possibly using it to reduce aggressive tendencies.