Researchers find that similar to in mice, human tears include a chemical signal that obstructs conspecific male hostility. Credit: SciTechDaily.comExposure to tears caused less revenge-seeking behavior and lower aggression-related brain activity.New research, published on December 21st in the open-access journal PLOS Biology, shows that tears from ladies include chemicals that obstruct hostility in males. The research study led by Shani Agron at the Weizmann Institute of Science, Israel, discovers that smelling tears leads to lowered brain activity related to aggression, which results in less aggressive behavior.Human Response to Emotional TearsMale aggression in rodents is known to be blocked when they smell female tears. This is an example of social chemosignaling, a procedure that is common in animals however less typical– or less comprehended– in humans.To determine whether tears have the very same effect on individuals, the scientists exposed a group of males to either womens emotional tears or saline while they played a two-person video game. The video game was designed to generate aggressive behavior against the other gamer, whom the guys were led to believe was cheating. When given the chance, the men might get revenge on the other gamer by causing them to lose money. The guys did not know what they were sniffing and might not identify in between the tears or the saline, which were both odorless.Impact of Tears on Aggression and Brain ActivityRevenge-seeking aggressive behavior during the game dropped more than 40% after the men sniffed womens psychological tears. When duplicated in an MRI scanner, functional imaging showed 2 aggression-related brain areas– the prefrontal cortex and anterior insula– that became more active when the men were provoked throughout the game, however did not ended up being as active in the very same situations when the males were sniffing the tears.Individually, the greater the distinction in this brain activity, the less typically the gamer took revenge throughout the game. Discovering this link in between tears, brain activity, and aggressive habits suggests that social chemosignaling is an aspect in human aggression, not just an animal curiosity.The authors add, “We found that just like in mice, human tears consist of a chemical signal that obstructs conspecific male aggression. This breaks the notion that emotional tears are distinctively human.” Reference: “A chemical signal in human female tears lowers aggression in males” by Shani Agron, Claire A. de March, Reut Weissgross, Eva Mishor, Lior Gorodisky, Tali Weiss, Edna Furman-Haran, Hiroaki Matsunami and Noam Sobel, 21 December 2023, PLOS Biology.DOI: 10.1371/ journal.pbio.3002442.