Whether their hype has been inflated by romantic movies,
or they really are a good way to know if someone is The One,
we put a lot of value on a first kiss. But why is kissing so special?
One idea is that as babies we have an innate liking for lip-touching.
From breastfeeding onwards we associate our lips with
positive reinforcements. There is a suggestion,
and bear with me on this, it s not very pleasant,
that we re specifically fine-tuned to like lip-on-lip kissing because,
back in our evolutionary past, after weaning our mothers would
chew our food for us and then transfer it into our mouths.
This is called premastication food transfer and is a known behaviour
in our great ape relatives. Thankfully we now have baby food.
Secondly, our lips are very sensitive - in fact they are one of the
few very sensitive parts of us that we don't cover with clothes.
The more clothes you wear,
the greater the frequency of kissing. The less clothes you wear, the lower
the frequency of kissing.
And the interesting exception, if you recall I said, with
hunters and gatherers, we find no kissing,
with one exception. The Inuits in the Arctic Circle.
They are the only hunter and gathering group that we found that
kiss - that's the famous oceanic kiss, rubbing your noses which they're
not they're just rubbing their mouth over each other's mouth. Why?
In all other places where there's hunters and
gatherers, they wear no clothes.
That means they can have a sensual encounter with any part of the body,
but when you wear clothes, the only sensuality that's available,
the only tactile feel that's available, is the human face.
Lastly, there might be an evolutionary purpose to kissing.
By getting up close to one another, we can pick up on cues in each other's scent.
This last point might explain why romantic lip-to-lip kissing isn't
even a particularly common human behaviour. According to one analysis,
less than half of all cultures kiss with their lips.
Across 168 cultures from around the world, Professor William Jankowiak
found that only 46% use lip-to-lip kissing in the romantic sense.
So that is excluding things like parent-child kissing or greetings.
I think the key on the human universal of kissing, or the absence of it, is
that people's sensuality can be met many ways other than just kissing.
But interesting enough, there was a strong pattern, the
greater the social complexity, the more frequently you find kissing.
The oldest written evidence of a kissing-type behaviour comes
from 3,500-year-old Hindu Vedic Sanskrit texts.
So there are of course many cultures that have kissed mouth to mouth,
that we would recognise as what we do today. But there's the Malay Kiss
that Darwin described, where women would squat down on the ground and
men would kind of hang over them and take a quick sniff of each other,
a quick sample of their partner scent. There's the Trobriand Islands, which
is one of the strangest practices I came across in my research.
Their lovers would sit face to face and when they were intimate nibble
at each other's eyelashes, which I think to many of us today doesn't
sound like the height of romance but for them that did the trick.
All of this implies a sense of trust to get that close to another
individual, it's about trust and it's about connection and they all serve
a common purpose to bring us closer to the people that we care about.
Kissing by pressing our lips together is an almost
uniquely human behaviour. So, if kissing has an evolutionary
purpose, why don't we see more animals kissing?
While some bird species knock bills in courtship, and many mammal species
rely heavily on close sniffing to determine friend from foe,
very few animal species actually plant their lips on one another.
It might be because humans' scent abilities are quite poor compared
to many of our mammal relatives, so other animals can pick up on those
important scent cues without needing to press their faces together.
Humans might have needed to get much closer to one
-another to have a good sniff. In doing so, we started to kiss.
But why do some cultures not kiss? And will we always kiss?
We've seen kissing arrive and dissappear around the world for a variety of different reasons.
From disease, even before we knew about germ theory, it was clear
that there were certain things that we could do to avoid getting sick.
There were emperor's that would ban kissing among their people,
because they thought that wasn't a privilege people should have.
But the one thing you can count on that we've seen over and over again,
is despite proclamations where it's been banned,
despite disease and plague, it always comes back.