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Handshakes tell us a lot about the person we’re meeting. In North America, a firm, quick handshake helps make a good first impression. Pumping is seen as optional, and one must not appear too sweaty during the act. With all of these things to worry about, science has given us another dubious gift — the secret reason why we shake hands in the first place.
A new paper in eLife Sciences may make you want to never shake hands again. Israeli researchers led a study of 271 covertly filmed handshakes. Their surprising finding — many people absentmindedly sniffed at least one hand after a handshake. According to the study’s co-author, Professor Noam Sobel, 22% of participants put their hands to their noses after the social ritual. This surprising finding reveals that people are much like other animals who overtly sniff each other. We’re simply a little better at hiding our sniffs than, say, dogs.
Sobel and his team believe that the act of human hand sniffing is mostly unconscious and a method of body-language reading by scent. Humans make use of soaps and deodorant, but traces of neurochemicals remain. Most times, our noses won’t consciously detect these lingering scents. Our brains make use of the information.
The study used a number of methods to gather results:
(1) One group of volunteers greeted others with a handshake; another group greeted without handshakes. The behaviors of both groups were monitored. Those who shook hands were more likely to get down to sniffing business.
(2) The researchers measured chemicals left on latex gloves after the handshakes. The gloves revealed the presence of transferred neurochemicals.
(3) Volunteers wore nasal catheters to make sure subjects were actually breathing in while placing their hands to their noses. The catheters were disguised with electrodes from an EEG device.
(4) All of the volunteers who sniffed their hands were shocked to witness the act during video playback. Sobel revealed, “Everyone was blown away when we showed them their own videos. It was universal. Nobody was aware of this behavior.”
(5) The purpose of the hand sniffing isn’t clear and requires further experimentation. Neurochemicals are known to reveal stress and other emotions. People may unconsciously process these scents to draw preliminary judgments about others.
The grand conclusion? Now we have another reason to worry about handshakes. No matter how firm, quick, or self-assured one plans their greeting, those pesky neurochemicals may reveal our nervous states.
Source: eLife Sciences