Much has been speculated about the handshake, a gesture documented in Egyptian hieroglyphics more than 5,000 years ago: that if it is a reliable clue to find out if your interlocutor is timid or has a firm character, that if it formerly served to make it clear that you weren’t carrying weapons… Now, a study published in the eLife magazine, carried out by scientists from the Weizmann Institute (Israel), suggests that when we shake hands, we are actually collecting molecular samples of the scent that the other person emits .
The experiment, recorded on video, was truly curious. The specialists gathered 280 people and urged them to greet each other, some with a shake and others not. First, the analysis of the recordings revealed that, although we are not aware of it, we constantly sniff our hands : the volunteers held them to their noses 22% of the time.
But, in addition, those who had practiced the squeeze with someone of the same sex touched their face more times with their right hand. Because the study subjects wore a nasal catheter, the scientists later found that the airflow doubled when that hand was brought to the face . In other words, they were actually sniffing each other.
“Our experiment highlights that shaking hands is a way to look for socially significant chemical signals from our peers, ” explained Noam Sobel, a professor at the Weizmann Institute. So do other mammals, albeit in a more direct way. In fact, Israeli scientists also analyzed the gloves that some of the volunteers were wearing and found that there were traces of palmitic acid and squalene, substances that play an important role in the exchange of social signals between dogs and rats.
