Humans are the only living things that cry when they are overcome with emotion. Why do we do this?
A study by Noam Sobel and colleagues at the Weizmann Institute provide part of the answer, at least as it relates to women. The scientists showed that when men get a whiff of women’s tears, they experience a temporary, generalized loss of libido and a dip in testosterone. Really.
(And you thought that red, runny nose was the turn-off, didn’t you?)
Scientists have known for decades that the chemical composition of “emotional tears” differs from tears shed due to simple irritation. But now, it appears that some of the chemicals contained in the former are actually pheromones; biological substances that create behavioral changes in others who are exposed to them. Such chemicals were known to exist in urine in anogenital gland secretions (dont ask), but not in tears.
Sobel’s team began its study by posting ads on Israeli college campus bulletin boards in which they sought volunteers who cried easily. Seventy-one people responded. All but one were women. From that group, the scientists identified 6 who were, like, seriously profuse criers and who could return to their labs every other day.
The scientists then asked each one to select a movie that was guaranteed to make them break down, to watch it in private, and to collect their tears in a vial. For the controls, Sobel’s group trickled a saline solution down the same women’s cheeks and collected that.
Sobel’s group subsequently asked male volunteers to sniff the contents of the 2 vials and ran a battery of psychological and physiological tests to measure their responses.
The men could not distinguish the odorless, colorless liquids, but boy oh boy did their responses differ! In one study, men rated women in photos as less sexually attractive after sniffing “emotional tears” than after they sniffed the saline solution. In another study, men watched scenes from a sad movie after sniffing either the real stuff or saline. They were equally sad regardless of which mixture they sniffed, but the tear-sniffers had lower sexual arousal and lower testosterone levels.
To compare these behavioral results with physiological findings, the scientists had men watch a sexually provocative film (“9 ½ Weeks”, the European cut, if you must know) while undergoing a functional MRI scan. Sure enough, men who had sniffed the tears showed less activity in regions of the brain that normally light-up during sexual arousal.
In addition, salivary testosterone levels dropped 13% after men sniffed tears but they remained unchanged after the men sniffed saline. Skin temperature, heart rate and respiratory rate also diminished after men sniffed emotional tears.
“Chemical signaling is a form of language,” said Sobel. “Basically what we’ve found is the chemo-signaling word for ‘no’ — or at least ‘not now.’ ” “We have . . . identified an emotionally relevant function for tears.”
By the way, the death scene in the 1979 film “The Champ” was the most successful tear-inducing film. Other reliable tear-jerkers were “Terms of Endearment,” “Life Is Beautiful,” “My Sister’s Keeper,” “When a Man Loves a Woman” and the Israeli flick, “Broken Wings.”
In an interview with the Washington Post, Sobel said he doubted that chemical signals exist solely in the tears of women. He and his team simply were unable to find enough male criers to test that part of the story.
Maybe they should recruit John Boehner. In any case, Sobel’s write-up appears in Science.