Why do humans kiss?

You might think it is a universal trait, something that we all do. But when European explorers travelled the world, they met tribes that didn’t kiss. So is it a learnt response after all?

It can be used as a greeting, a sign of reverence or supplication, but we will be talking about the romantic kiss: Face to face, lips to lips.

We examine the biochemistry, psychology, anthropology and history of kissing. Where does it come from?

Image: Two women kissing at a festival (Credit: AFP/Getty Images)