How old is the laugh? Well, it’s a funny story...

Laughter, it turns out, originated at least 10 million years ago. Among apes. See which other species enjoy a chuckle and why the guffaw survived.

We’ve been trying to unlock the laugh for over half a century, and we’re finally forming some idea of where it comes from.

The earliest scientific research in this field was conducted in the 1960s, as part of gelotology, or the study of the psychological and physiological effects of humour. In one experiment, Stanford University professor William F Fry drew his own blood at intervals, while watching Laurel and Hardy films. Later analysis showed that laughter increased the activity of