- Moran Cerf is a professor of neuroscience and business at Kellogg School of Management.
- He regularly answers questions about psychology, business, and behavior via email from people who attend his talks.
- This week, he explains why handshaking and ‘chemosignaling’ are important for human interactions.
- See more stories on Insider’s business page.
Q: Handshakes used to be a common gesture in the business world. Will they become obsolete post-pandemic, and if so, what do you think will replace them?
A: There is a debate among scientists about what handshakes are for. Historic arguments suggest it was a medieval way people showed they’re not carrying a weapon, by offering their dominant hand (most people in the world are right-handed and they would use their sword with that hand). Other cultural arguments speak to the need for touch as a gesture of goodwill – you offer a person access to your personal space upon meeting them.
One of the recent arguments for handshakes that neuroscientists use, however, is that handshakes allow you to measure the synchrony between two individuals as a chemosignaling.
In plain words, we rub our hands on one another so that our odors will blend, and we can smell whether we are compatible – sexually, or simply on histocompatibility and immune system. Our bodies check whether the other person is somehow genetically relevant for us, if we can trust them, or if they are the type of person who would respond to experiences in a similar way.
How handshakes allow for chemosignaling
In a study done by a colleague of mine, they had participants come to the lab for an experiment. Before the experiment officially started, the person administering the test greeted them, shook their hand, and asked them to stay in the waiting room for a few minutes and relax before the study began.
In reality, the study already began. The study was the handshake and the waiting. What the scientists saw was that within the few minutes of waiting, most people bring their right hand – the one used for the handshake – close to their noses, and essentially ‘sniff’ the mixture of the odors generated by the experimenter and the subject. They sniff their hands to see whether the mixture is activating the right processes in the brain, which trigger an unconscious understanding that the other person is potentially a relevant partner.
The experimenters ran the study with numerous controls. For some people the experimenter shaking the participant’s hand was a man, for others it was a woman.
They repeated the experiment with numerous other conditions: they tested participants who were straight/gay (seeing if people sniff only others who match their sexual preferences), while wearing/not wearing gloves (no chemosignaling when a glove is used, and no hand smelling that followed), by shaking the left hand rather than right (people would then bring that hand closer to their nose), etc.
Why chemosignaling is important for human interaction
The point is that handshakes aren’t just a business act that conveys seriousness and legitimacy, for example ‘sealing a deal’ with a handshake. It’s also a way for humans to communicate – brain to brain – unconsciously. It’s a way for us to signal trust, vulnerability, emotions, or interest, in ways that go directly into our brain and activate processes that impact the interaction between people without words.
Because of this, I predict handshakes will be back.