SCIENCE AND KISSING

Why do we kiss?

Kissing is wonderful – so wonderful that most of us can recall 90 per cent of the details of our first kiss. Human beings have been preoccupied with kissing for years. It features as the climax of all great Hollywood love stories, and is celebrated by singers and poets alike. In reality, kissing is nothing more than two people putting their faces together and exchanging spit. How on earth did something so gross become so appealing? The act of kissing has developed to become advantageous to humans: if it didn’t serve an evolutionary purpose, we simply would not do it.

So what’s in a kiss? More than you might think.

Nature versus nurture

A kiss might seem like a natural thing to do for most of us, but the scientific jury is still out on whether it is a learned or instinctual behavior. Approximately 90 per cent of cultures kiss, making a strong case for the act being a basic human instinct. I know what you’re thinking…what about the other ten per cent? If kissing was a natural behavior, surely all cultures would do it? While this small minority doesn’t ‘kiss’ like the rest of us (due to superstitions and cultural beliefs), they may still engage in kissing-like behaviors, such as rubbing noses together.

If kissing is a natural instinct, why don’t animals kiss?

Many animals actually do engage in kissing-like behaviors to show affection. These behaviors are so diverse, from dogs sniffing and licking potential mates, to elephants putting their trunks in each other’s mouths. However, one animal kisses just like we do: the bonobo ape. This isn’t too surprising, considering we share 98.7 per cent of our DNA with this hairy cousin. Bonobos kiss for comfort and to socialize. Sometimes after a fight they even kiss and make up. We humans kiss for the exact same reasons, indicating that kissing might be ingrained deep in our DNA.

How did the kiss evolve?

Many scientists believe that kissing came from the practice of kiss-feeding, where mothers would feed their young mouth-to-mouth. Imagine birds feeding worms to their little chicks. Cute, right? Now imagine someone feeding you your chewed-up breakfast via their mouth. This sounds disgusting to most people, but we humans used to do it all the time! From this passing of food, pressing lips became synonymous with love. Understandable, since the way to most people’s hearts are through their stomachs. Over time, this symbol of affection may have evolved to give us romantic kissing.

To be continued…