This shows a woman crying.
Revenge-seeking aggressive behavior during the game dropped more than 40% after the men sniffed women’s emotional tears. Credit: Neuroscience News

Women’s Tears Chemical Diminish Male Aggression

Summary: A new study reveals that women’s tears contain chemicals that significantly reduce aggression in men. The study, which builds on known effects in rodents, employed a two-person game designed to elicit aggressive behavior in men, who unknowingly sniffed either women’s tears or saline.

The results showed a dramatic 40% drop in aggressive behavior and a corresponding decrease in brain activity in aggression-related regions after exposure to the tears. This research not only confirms the presence of social chemosignaling in humans but also challenges the notion that emotional tears are a uniquely human trait.

Key Facts:

  1. Men exposed to women’s tears showed a 40% reduction in aggressive behavior.
  2. Brain imaging revealed decreased activity in aggression-related regions when men sniffed women’s tears.
  3. The study provides evidence of social chemosignaling affecting human aggression, similar to findings in animals.

Source: PLOS

New research, publishing December 21st in the open access journal in PLOS Biology, shows that tears from women contain chemicals that block aggression in men. The study led by Shani Agron at the Weizmann Institute of Science, Israel, finds that sniffing tears leads to reduced brain activity related to aggression, which results is less aggressive behavior.

Male aggression in rodents is known to be blocked when they smell female tears. This is an example of social chemosignaling, a process that is common in animals but less common—or less understood—in humans. To determine whether tears have the same affect in people, the researchers exposed a group of men to either women’s emotional tears or saline while they played a two-person game.

The game was designed to elicit aggressive behavior against the other player, whom the men were led to believe was cheating. When given the opportunity, the men could get revenge on the other player by causing them lose money. The men did not know what they were sniffing and could not distinguish between the tears or the saline, which were both odorless.

Revenge-seeking aggressive behavior during the game dropped more than 40% after the men sniffed women’s emotional tears.

When repeated in an MRI scanner, functional imaging showed two aggression-related brain regions—the prefrontal cortex and anterior insula—that became more active when the men were provoked during the game, but did not become as active in the same situations when the men were sniffing the tears. Individually, the greater the difference in this brain activity, the less often the player took revenge during the game.

Finding this link between tears, brain activity, and aggressive behavior implies that social chemosignaling is a factor in human aggression, not simply an animal curiosity.

The authors add, “We found that just like in mice, human tears contain a chemical signal that blocks conspecific male aggression. This goes against the notion that emotional tears are uniquely human.”

About this aggression research news

Author: Claire Turner
Source: PLOS
Contact: Claire Turner – PLOS
Image: The image is credited to Neuroscience News

Original Research: Open access.
A chemical signal in human female tears lowers aggression in males” by Shani Agron et al. PLOS Biology


A chemical signal in human female tears lowers aggression in males

Rodent tears contain social chemosignals with diverse effects, including blocking male aggression. Human tears also contain a chemosignal that lowers male testosterone, but its behavioral significance was unclear. Because reduced testosterone is associated with reduced aggression, we tested the hypothesis that human tears act like rodent tears to block male aggression.

Using a standard behavioral paradigm, we found that sniffing emotional tears with no odor percept reduced human male aggression by 43.7%. To probe the peripheral brain substrates of this effect, we applied tears to 62 human olfactory receptors in vitro. We identified 4 receptors that responded in a dose-dependent manner to this stimulus.

Finally, to probe the central brain substrates of this effect, we repeated the experiment concurrent with functional brain imaging. We found that sniffing tears increased functional connectivity between the neural substrates of olfaction and aggression, reducing overall levels of neural activity in the latter.

Taken together, our results imply that like in rodents, a human tear–bound chemosignal lowers male aggression, a mechanism that likely relies on the structural and functional overlap in the brain substrates of olfaction and aggression.

We suggest that tears are a mammalian-wide mechanism that provides a chemical blanket protecting against aggression.

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  1. The article and study didn’t specify wether the aggressive suubjects were in fact acting aggressively towards their spouse. There are many situations where a man can act aggressively but still not be an abuser.

  2. My multi-billion-dollar idea: produce chemically engineered artificial women’s tears in a laboratory and sell it to the military complex. Win wars by showering the enemy’s armies with drizzles and mists of women’s tears, rendering their soldiers more docile and less prone to combat.

  3. Was this tears of only emotional females. Was consideration given to non emotion teats or to male tears and if so, what were those results.

    1. Yes, only the tears of emotional female subjects were used. There was only one independent variable in the study and one control, so no, consideration was not given to non-emotional or male tears. To test for the effects of non-emotional tears or male tears, the researchers could conduct a different study.

  4. Did they test it with male tears?

    And how do they class “emotional tears” as you couldn’t get different types of tears from mice…unless of course being subject to tests makes all their tears ones of sadness.

    1. Read the actual study. They used tears from women. “To obtain tears, the donor women watched sad film clips in isolation and used a mirror to place a vial and capture the tears trickling down their cheeks.”

  5. And it wasn’t body language, changes in behavior, self-awareness after the fact or other factors? Riiiight…

  6. Is this peer reviewed? This sounds arbitrary How are you supposed to quantify aggression? Is the chemical responsible for this decrease in aggression? Why didn’t they try the study with men’s tears? Can the hormonal cycle of women affect the tears? Doesn’t sound like a study this sounds made up.

  7. Except this conclusion is a non-sequitur. Human female tears being a chemical signal that diminishes male aggression don’t imply that “This goes against the notion that emotional tears are uniquely human”, it just imply that our tears can have this chemical effect, and does not refute the notion that emotional tears are uniquely human by itself. Neither it can prove that our tears have the role of diminishing male aggression on itself either, it can be simply a evolutionary side effect.

  8. Makes sense for those men who beat their spouse and the she cried and he feels less aggressive and has the need to apologize. Also men who get annoyed when their wife “makes them” feel “bad” for doing or saying something when she cries. Too bad chemical reaction in the tears only elicits the response after the deeds are done. Very interesting study

  9. The women are all so responsible for getting a man to calm down by crying? Seems to me men are just too emotional to be in control, I say women take over now. Y’all had your chance and you fucked it up.

  10. Not for me. A woman crying angers me even more. But maybe I’m excusing myself because I’ve been raised by a narcissistic mother who used crocodile tears often to manipulate the situation to her advantage.

    1. Soooooo… My questions are these…,
      How were the emotional tears from women collected? What emotions were the women feeling when the tears were collected?
      Were the emotional tears tears of joy? Pain? Loss? Grief? Would the different emotions create different tears, chemically, and if so, would the men react differently to each of the types of emotional tears? Were the emotional tear samples from just one woman or were the samples from multiple women that were mixed together?
      Also, what were the ethnic backgrounds of the women and what had they had to eat or drink within the last few days before the samples were taken? I have many more questions, but I think this is plenty for now. Hopefully someone will answer : )

  11. Well then why is it that when I cry every man that has ever been upset with me gets even more mad and leaves me?? And that is everyone of them that has ever been in love with me will and have left me if I start to cry. Only in one occasion with a friend that I was not romantically involved with did my tears stop a man from being angry with me…

  12. This is bs science. There’s also documented cases of the opposite. Check your facts and publish them or keep being biased.

    1. It’s not BS science. It’s a single statistically significant finding, i.e., a fact. (In this study, emotional tears did, in fact, decrease male aggression.) The nature of research is that one study will find one thing and then another will find an opposite effect. That’s why multiple studies are conducted until there’s a large body of research to support a finding.

  13. I wonder if men who are abusive and sociopathic have a different brain chemistry response to a woman’s tears. They seem to enjoy a woman’s tears and exhibit even more aggression in the presence of tears.

  14. It would be nice if you were a little bit more specific about the findings and mention which were the activated odorant receptors. The findings are indeed remarkable. Congratulations to the authors.

  15. Hmmmmm :-(
    The problem is that abusive men tend to ill-treat their women until the woman cries.
    It is a very, very sad thing that women have to be driven to tears for the abuse to stop (and only temporarily at that) :-(

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