Pheromones play a role in communication in other species, so why not in humans too? This study looked for pheromones in women’s tears and asked what their possible function could be. The summary of the study states that tears shed emotionally have a different chemical composition from tears in reaction to an irritant (like cutting on an onion). They didn’t teach that to us in medical school so it caught my attention immediately. Why would that be? It implies that emotional tears have a mysterious function and started me wondering why people cry when they are upset anyway. Notably infants cry a lot but don’t shed tears with their crying until they are several weeks or even months old. But I digress.
The study in question measured the effect of smelling a woman’s tears on sexual arousal in men. I can’t imagine why they thought of asking this question, but they did. The control substance for the study was some saline that had been trickled down the cheeks of the women to pick up the scent of any perfume or skin cream etc. They measured sexual arousal by physiological factors such as heart rate, testosterone level and skin temperature. They also inferred it from how the men rated the attractiveness of pictures of women’s faces which seems like a rather indirect measure of arousal. The best measure that they used was looking at how intensely brain regions lit up in a specialized brain scan when the men were shown erotic images. There was a distinct decrease if the men had been exposed to the tears first.
What possible role could there be for this unidentified substance in a woman’s tears that decreases the tendency for men to be sexually aroused? I am stumped. Ideas, anyone?
