The smell of women’s tears makes men tamer

It has already been proven for rats, but now it appears that emotional human tears also contain a substance that influences the mood of others. If men had sniffed women’s emotional tears several times beforehand, they played a money game on the computer less aggressively afterwards. In a certain calculation method, aggression during the game even decreased by 50 percent.

This behavioral effect has also been supported by physiological evidence. The (odorless) emotional tears appear to act in cell culture on four of the 63 human odor receptors examined. And an fMRI showed that the activity of a few typical ‘aggression regions’ in the brains of the tear-sniffing money game players had decreased. A team including the well-known Israeli tear researcher Noam Sobel (Weizmann Institute in Rehovot) published the research at the end of last month in Plos Biology.

Six donor women who watched emotional videos produced tears

Direct (and unconscious) influence of fragrances on behavior is controversial in humans, because in the human nose never the ‘vomeronasal’ receptors for such ‘pheromones’ have been found that many animals do have. In recent years, attention has mainly been paid to the effect of (ordinary) odor on human behavior. This research fits in with that trend.

Because the effect of tears can be seen in behavior, in brain activity and in activation of odor receptors, the researchers led by Shani Agron (Weizmann Institute) and Claire A. de March (Duke University, USA) call their conclusions “strong”. But one limitation was a dire lack of emotional tear fluid, which was obtained from six ‘donor women’ who watched emotional videos in a booth an average of fifteen times. The women managed to extract 1.6 milliliters of tear fluid per session. In the current study, this supply was used up in cell tests and sniffing by the twenty male test subjects. There were now not enough tears for research on women.

In the Netherlands, tear researcher Ad Vingerhoets (Tilburg University) reacts with pleasant surprise to the new research. And a little cautiously. “Because in 2011 Noam published Sobel an investigation in which women’s tears are said to have an effect on sexual arousal. That’s us then did not succeed to replicate, even with 250 subjects.” Sobel made that then quite angry, Vingerhoets remembers, “but he then promised his own replication. It never came.”

The functions of crying

Vingerhoets is more interested in the current research on aggression. Because an effect on aggression fits better with existing theories about the functions of crying. Crying and tears form a kind of ultimate signal to get help from someone else. Until now, it has always been controversial whether, in addition to the evident acoustic and visual signal of crying, substances in the tears themselves could also play a role. Clear chemical differences have never been found between the different types of tears (normal eye lubrication, wind tears and ’emotion tears’).

Vingerhoets: “The question now is how exactly it all works. First of all, the effects are not very large. And then, what distance could such an influence bridge? In practice, it does not happen very often that you come so close to someone that your tears are ‘smeared’ under the other person’s nose. And what about the effects of ‘tears of happiness’?”

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