10 Things Your Body Does That Science Can't Explain

Kissing isn't something that you see throughout the animal kingdom, in fact, it isn't even something you see throughout the human race.

So this must mean that it's a culturally learnt behaviour, and a pretty weird one at that? Well, not quite as it still has physiological effects on us, causing the body to release the bonding hormone oxytocin, so it's actually a bit of both, presenting the possibility that it's more of a culturally unlearnt behaviour.

The reasons thought to be behind why we kiss are many and varied. One of the most common is that our first experiences of comfort, security and love will have come from when our mothers mouth fed us as infants (i.e. chewing food and passing it directly from mouth to mouth) in much the same way as modern day chimps do. This was done by our ancestors and is still sometimes practiced today.

Another theory is that humans are naturally attracted to bright colours such as red to help them spot ripe fruit, and this has somehow transferred over into sexual attraction. This theory also goes on to explain that, because red lips are more prominent in Caucasians, suggesting that it would have developed in northern latitudes and spread culturally from there, explaining why it is not strictly a species-wide phenomenon.

There may also potentially be a link between kissing and assessing the biological compatibility of our potential mates. Some studies have shown that we are more attracted to the smell of sweat from people with immune systems that are most compatible with ours (mmm, sexy), so it could well be that the same thing is happening with kissing and saliva.

Which is a lovely thought.