Imagine your golden retriever is taking you for a walk on a beautiful spring day. He sees another dog approaching on the sidewalk and runs up to greet him. Unlike you and the other dog’s human, who shake hands, the dogs immediately begin to sniff each other’s backsides. You may blush at this vulgar greeting. Even though it’s considered fairly normal dog behavior, humans would never engage in such a barbaric salutation. However, scientists have found that shaking hands may be rooted in the very same method of recognition: smell.
Researchers at the Weizmann Institute conducted research on the neurological and biological origin of handshaking, and found that it was related to individuals recognizing people via scent. Whether or not we are aware, we are constantly smelling ourselves and familiarizing ourselves with our own scent. After shaking someone else’s hand, Frumin (2015) found that people smelled their hand more than twice as often as when no handshake occurred. Frumin (2015) confirmed that the participants were in fact smelling their hand (not just lifting it to their face) by measuring nasal air intake before and after the hand was near the participants face.
Frumin (2015) then attempted to determine whether the scent was an innate recognition/memory function by manipulating the scents from natural human odors to artificial perfumes. He found that when he added artificial smells to the interaction, participants spent a significantly greater amount of time smelling their hand. In contrast, when scents derived from human sex hormones were introduced the amount of hand sniffing increased. This confirmed that it was an innate olfactory process designed to discern specific human odors (Frumin 2015).
While neurologists have known that smell and chemical signaling play a role in human interaction, Frumin’s research provides valuable information about how traditional human greetings originate from our more basic biological tendencies. Even though the practice is innate and unconscious, its nice to know that at your next job interview or important meeting, you can accurately leave the interaction with a casual “smell ya later!”
Frumin, I., Perl, O., Endevelt-Shapira, Y., Eisen, A., Heller, I., Shemesh, M., … Sela, L. (2015). A social chemosignaling function for human handshaking. ELife, 4. Retrieved March 4, 2015.