There are all sorts of things that can turn a guy off, but the smell of female tears could be one of the most unexpected. Research conducted over a decade ago suggested that sniffing the emotional secretions of crying women reduces subjective levels of sexual arousal in men, while also lowering testosterone and dampening activity in brain areas associated with lust and desire.
Previous studies on mice have indicated that the animals’ tears contain pheromones that moderate the sex drive of potential mates. However, the existence of human pheromones is something that has never been proven and is the subject of debate and controversy.
Moreover, humans are much more emotionally complex than mice and cry in response to all kinds of poignant stimuli. It’s therefore unclear if our emotional tears - as opposed to those produced in response to eye irritation - carry social signals designed to convey a sense of sadness or contain chemosignals that influence the biological reactions of others.
In 2011, scientists in Israel collected tears from two women who bawled while watching a stirring movie. To confirm that these lacrimations possessed no discernable smell, the researchers asked 24 men to sniff them.
As predicted, the male participants were unable to tell the difference between genuine tears and drops of saline solution that had been run down the same women’s cheeks. More surprisingly, however, the men reported less sexual arousal when viewing female faces after sniffing the tears than after smelling the saline solution.
In a second experiment, a group of 50 men watched emotional films after smelling either real or fake tears. While neither solution altered participants’ moods, the tears were once again associated with reduced sexual arousal.
Not content with taking volunteers’ word for it, the researchers also tested for physiological signs of horniness. “critically, levels of salivary testosterone were progressively lower after sniffing tears as compared to the baseline period,” they wrote, adding that “reductions in testosterone are a significant indicator of reductions in sexual arousal in men.”
Taking things a step further, the researchers scanned the brains of 16 men after they took a whiff of tears. Results showed that areas linked to sexual arousal - such as the hypothalamus and left fusiform gyrus - became less active, providing a neural basis for the libido-killing effect of blubbing.
“We have thus identified an emotionally relevant function for tears,” conclude the researchers. “These effects materialized despite the fact that participants did not see a woman cry, nor were they aware of the compound source.”
In spite of this curious finding, though, the study authors concede that many questions remain unanswered. For instance, “what if any are the signals in men’s tears or children’s tears, and what are the effects of all these within, rather than across, gender?” they ponder.
It’s also worth noting that these results have not been universally accepted, and were later challenged by a team of Dutch and Croatian scientists who attempted to corroborate these findings without success. “The effects of female tears on male arousal and perception of female sexual attractiveness, if any, are very weak at best,” wrote the researchers following their failed replication attempt.
“Rather, it seems that crying exerts its strong inter-personal effects through the visual and auditory sensory channels.”
In response, the Israeli researchers who conducted the initial study slammed their detractors by accusing them of using “methodology that falls short of standards typically applied in chemosignaling research.” Indeed, rigorous scientific study calls for blood, sweat, and, of course, tears.
The original study is published in the journal Science.