Social distancing has been difficult to comply with and hugging is very much missed, and it seems that the need for touch is deeply embedded in humans, and indeed many other species, especially those that are highly social. Physical contact greetings are found in many cultures - handshakes, hugs, social and romantic kisses, and nose rubbing - while other cultures prefer more distance by bowing. Some more recently invented greetings are fist bumps and elbow bumps. Understanding the role such greetings play in other species (especially primates) can give an insight into our behaviour.
- Mammals tend to use scents to 'suss each other out', which is why their greetings are so intimate. Sniffing another individual's face, flanks and genitals for volatile chemicals that reveal its hormonal state, reflecting its strength and fertility, allows animals to size up potential opponents and mates.
- The duration and intimacy of the exchange reflects the nature of the relationship. Subordinate rats submit to prolonged sniffing from a more dominant one, but risk a fight if they become over-friendly themselves.
- Cats and dogs exchange smells with a characteristic rub of the head. A study of cats and dogs living in the same household found that 75% regularly engage in nose sniffing, which appears to help them live together. A cat's raised tail and a dog crouching and looking upwards both seem to signal friendly intent.
- Some baboons use lip-smacking, head-bobbing, and touching buttocks or genitals, while white-faced-capuchin rituals include finger-clasping.
- Many behaviours - especially those involving the genitals - include an element of risk and vulnerability. So there must be a significant benefit to outweigh the danger.
- The riskier and more intimate behaviours are more common in highly co-operative species. It is thought that greetings help individuals build their trust in each other and build alliances that could improve their chances of survival in the future.
So what about humans?
- Any greetings that involve bodily contact may offer us a way to pick up chemical cues. Research suggests that a possible explanation for romantic kissing is that we may be able to assess someone's physical fitness and fertility from compounds in their saliva.
- There is evidence that body odour can communicate someone's emotional state and even their sexual arousal. Our greetings can allow us to sample this without openly sniffing someone. (A researcher noted that at a conference, people often ran their hand under their nose after shaking hands with someone.)
- Our tactile greetings also allow us to assess someone's character and establish our trust in them. One study found that the strength and duration of a handshake offered a fairly accurate assessment of personality traits such as extraversion, neuroticism and open-mindedness, while another found that hand shaking before a task promoted honesty.
- Sports teams that use fist bumps, high fives, hugs and huddles signal our willingness to work with the other person in good faith.
The downside of contact
- No matter how much we trust another person, close contact brings the risk of transferring infections. Many cultures recognised this long ago and modified their greeting etiquettes. Where risk is high, distanced greetings symbolically express the desire for co-operation and trust, and romantic kissing is much less likely.
- We find it especially difficult to stop hugging or kissing our family and friends as we assume they are part of our 'in group' and so less likely to transmit diseases than strangers. The problem is made worse because these are the people we crave the most physical contact to reaffirm bonds.
Source: Article Greetings! Evolution holds the key to why social distancing is so difficult by David Robinson, New Scientist, 14 Nov. 2020.
