People with similar body odours are more likely to ‘click’ and become instant friends, according to several experiments.
When people meet others for the first time, they sometimes experience an “immediate strong click that makes us feel as if we have already been good friends for years,” says Inbal Ravreby at the Weizmann Institute of Science in Israel.
She wondered if this may have something to do with body odour, because previous research has found that human beings subconsciously sniff each other on meeting – for example, by lifting our hand to our nose after shaking someone’s hand.
Ravreby and her colleagues recruited 20 pairs of same-sex, non-romantic friends – half female and half male – who said they clicked straight away on first meeting.
An electronic nose – a device that senses the chemical components of odours – was used to sniff T-shirts that had been worn by each of the participants. The nose found that body odour was more similar between the friend pairs than between random pairs that were formed by shuffling the participants.
A group of 25 independent adults who sniffed the participants’ T-shirts also reported that the friend pairs smelled more alike than random pairs did.
Next, Ravreby and her colleagues recruited 17 people who had never met previously and used the electronic nose to analyse their body odours. Each individual then took turns playing a non-verbal game with other participants of the same sex.
The results were consistent with the earlier experiments: the pairs that smelled more like each other were more likely to report feeling as if they clicked during this game. The findings make sense because research shows that human beings tend to become friends with people who share attributes, for example, in terms of age, ethnicity, education, religion, physical appearance, personality and values, says Ravreby.
Other mammals also use smell to help decide who is friend or foe, such as dogs that sniff each other’s rear ends when they meet in a park, she says.
In contrast, heterosexual people appear to be attracted to members of the opposite sex who smell different from them. One study, for example, has found that women were more attracted to odours of men who had different immune genes to them, possibly because their pairing would produce offspring with stronger immune systems.