What's the point of laughter?
We teamed up with the folks behind BBC World Service's CrowdScience to answer your questions on one topic. You can tune in to CrowdScience every Friday evening on BBC World Service, or catch up online at bbcworldservice.com/crowdscience
Why do we laugh?
Laughter is packed with information. We use laughter to show others that we’re being playful and non-threatening, and this serves to make and maintain social bonds. Much of the time laughter is involuntary and contagious, particularly between friends. The sound of laughter broadcasts loudly and widely, so that other people outside of the laughing group can get information about the relationship of the laughers. In fact, Dr Greg Bryant at University of California, Los Angeles, has found that we’re so adept at interpreting laughter that, in over 20 cultures, people can usually tell from just one second of laughter whether the laughers are friends or strangers.
Which came first, language or laughter?
Most anthropologists think that language originated within the last few hundred thousand years, but it looks like we’ve been laughing for much longer. In 2009, psychologist Dr Marina Davila-Ross at the University of Portsmouth recorded the vocalisations of baby ape species while they were being tickled. By analysing their sounds, she found that great ape laughs share the same structure as human laughs, and that these are most similar in the chimpanzees and bonobos, our closest animal relatives. Her work suggests that laughter arose from a common primate ancestor millions of years ago – long before language evolved.
Why does tickling make us laugh?
Laughter is most often associated with pleasure, but, for many people, tickling brings with it a certain amount of pain. So laughing when being tickled is a rather odd response, especially when you consider that tickling has historically been used as a form of torture. Prof Sophie Scott, a neuroscientist and laughter expert at University College London, believes that the laughing response evolved in mammals as a form of social bonding. It’s a way for parents to bond with their children, and for children to play and compete without being hurt. As well as great apes, we also find social laughter in rats – they make high-pitched squeaking noises when being tickled, particularly the younger rats.