In fact, the smile has a fascinating, if much-neglected past. It seems only one step further to claim that the smile has no history. The smile has always been with us then, and it would appear it’s always been the same. From The Expression of the Emotions in Man and Animals (1872) by Charles Darwin.

He also showed that the great apes’ smile has something of the gesture’s polyvalence among humans: it can denote pleasure (notably under tickling) but also aggressive self-defence. It was Charles Darwin, in his classic The Expression of the Emotions in Man and Animals (1872), who gave the first scientific demonstration of a great ape smiling. Many great apes are known to produce them, suggesting that the smile first appeared on the face of a common ancestor well before the existence of Homo sapiens. The smile may even predate the human species. The facial muscles required to smile are in fact present in the womb, ready for early deployment to anxious parents. It may denote sensory pleasure and delight, gaiety and amusement, satisfaction, contentment, affection, seduction, relief, stress, nervousness, annoyance, anger, shame, aggression, fear and contempt. As well as being easy to make and to recognise, the smile is also highly versatile. The smile needs only a single muscle to produce: the zygomaticus major at the corner of the mouth (though a simultaneous twitching of the eyelid’s orbicularis oculi muscle is required for a sincere and joyful smile). Other facial expressions denoting emotion – such as fear, anger or distress – require up to four muscles.

It is also an easier expression to make than most others. The smile is the most easily recognised facial expression at a distance in human interactions.

Smile drawing