A recent study from the Weizmann Institute of Science suggests the tears of a woman may have an impact on male aggression. The study, published over the Christmas holidays in PLOS Biology, found that exposure to female tears activates a man’s olfactory receptors, altering aggression-related circuits in the brain, and thereby lowering aggressive behaviour. Weizmann’s Brain Sciences Department PhD student Shani Agron and a group of researchers conducted a series of experiments based on the hypothesis of professor Noam Sobel, where men were exposed to either women’s tears or a placebo made of a saline solution before playing a two-person competitive game. “We’ve shown that tears activate olfactory receptors and that they alter aggression-related brain circuits, significantly reducing aggressive behavior,” Sobel said, per a news release from the American Association for the Advancement of Science. “These findings suggest that tears are a chemical blanket offering protection against aggression and that this effect is common to rodents and humans, and perhaps to other mammals as well.”The researchers arranged for participants to believe their opponent was cheating and in response the men could choose to get revenge by causing the other player to lose money. They found revenge-seeking aggressive behavior dropped 44% when the men had been exposed to female tears. Examining their findings further in the lab, researchers applied tears to 62 olfactory receptors and found four receptors to activate in response. Next, the experiments were repeated while studying the men's brain activity using an MRI machine, revealling decreases in two aggression-related brain regions, the prefrontal cortex and the anterior insula, when exposed to female tears.