Humans sniff their hands after a handshake to learn about others

Some skepticism is probably warranted here, but new research suggests that humans subconsciously sniff their hands following a handshake in order to interpret chemical information about those around them. Compared with a baseline level of hand sniffing, researchers found that participants were twice as likely to sniff their handshake hand after shaking with a member of the same sex. For members of the opposite sex, people tended to sniff their nonshaking hand with roughly the same increased frequency. New Scientist reports that the behavior may be a subconscious effort to interpret chemical signals transmitted by touch, but what information is being received is still unknown.