When you think about it, kissing is strange and a bit icky. You share saliva with someone, sometimes for a prolonged period of time. One kiss could pass on 80 million bacteria, not all of them good.
Yet everyone surely remembers their first kiss, in all its embarrassing or delightful detail, and kissing continues to play a big role in new romances.
At least, it does in some societies. People in western societies may assume that romantic kissing is a universal human behaviour, but a new analysis suggests that less than half of all cultures actually do it. Kissing is also extremely rare in the animal kingdom.
So what's really behind this odd behaviour? If it is useful, why don't all animals do it – and all humans too? It turns out that the very fact that most animals don't kiss helps explain why some do.
According to a new study of kissing preferences, which looked at 168 cultures from around the world, only 46% of cultures kiss in the romantic sense.
Previous estimates had put the figure at 90%. The new study excluded parents kissing their children, and focused solely on romantic lip-on-lip action between couples.
Many hunter-gatherer groups showed no evidence of kissing or desire to do so. Some even considered it revolting. The Mehinaku tribe in Brazil reportedly said it was "gross".
Humans lived in hunter-gatherer groups for most of our existence, until the invention of farming around 10,000 years ago. If modern hunter-gatherer groups do not practice romantic kissing, it is possible that our ancestors did not do so either
However we cannot be certain of this, as modern hunter-gatherer groups do not live in the same ways as the ancestral hunter-gatherers, because their societies have changed and adapted in the meantime.
Regardless, the study overturns the belief that romantic kissing is a near-universal human behaviour, says lead author William Jankowiak of the University of Nevada in Las Vegas. Instead it seems to be a product of western societies, passed on from one generation to the next, he says.
There is some historical evidence to back that up.
Kissing as we do it today seems to be a fairly recent invention, says Rafael Wlodarski of the University of Oxford in the UK. He has trawled through records
The oldest evidence of a kissing-type behaviour comes from Hindu Vedic Sanskrit texts from over 3,500 years ago. Kissing was described as inhaling each other's soul.
In contrast, Egyptian hieroglyphics picture people close to each other rather than pressing their lips together.
So what is going on? Is kissing something we do naturally, but that some cultures have suppressed? Or is it something modern humans have invented?
(Foreign Health magazine reports)
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