Laughter is a very natural thing. Babies laugh well before they can talk and even as adults, we laugh every day. Admittedly, kids do laugh a lot more than adults. The research tells us that children laugh on average 400 times per day, whereas adults only get their chuckle on about 15 times daily. Maybe we get distracted as we get older and we don’t see the humour in life quite so easily, or maybe children have needs that are fulfilled by laughter. Either way, laughter is something we do without thinking, so we are going to reverse that trend here and give laughter some thought. This is not going to be one of those “join a laughter club and burn calories” explorations, it is going to be a deep dive into what laughter is and why we do it. So, snorkels off, don your scuba tanks filled with nitrous oxide on and let’s get giggling.
The first laugh
The fact that babies laugh tells us that it is an instinctive behaviour. There is nothing surprising in that, but what might be less expected is that laughter has a wide evolutionary purpose. We know this because humans and apes are not the only animals that laugh.
Many animals produce sounds during play that are unique to that form of interaction. This “play vocalisation” is a version of human laughter and according to a study published in the journal Bioacoustics, there are 65 species that laugh while playing. Most of those species are mammals but a few are birds. The Australian magpie (Gymnorhina tibicen) and the New Zealand kea parrot (Nestor notabilis) are two bird species that vocalise during play. In fact, one study found if a kea’s warbling laughter is recorded and then played back to other keas, those keas will start playing.
It is possible, too, that the 65 species estimate is low-balling the laughers of this world. Rats, for instance, do laugh but it is a high-pitched chirping that is above the register for normal human hearing. We have had to use technology to measure rat laughter, so it is highly possible that many other mammals laugh too, if only we had the ears to hear it.
As far as humans go, the belief is that our “ha, ha, ha” laugh evolved from the panting that occurs during play. The estimates (such as those published in The Quarterly Review of Biology) are that laughter became a customary behaviour in our hominid ancestors somewhere between two and four million years ago. Researchers from the University of Sussex have pushed that date back further and suggest that the evolutionary origins of laughter can be traced back between 10 and 16 million years. These are estimates based on theoretical evolutionary frameworks because we just didn’t have the smartphones on hand to record those first laughs, but we do have a good idea of what happened when those initial laughs occurred.
Remote grooming
Humans have been wondering what is happening when we laugh for a very long time, thousands of years in fact. Plato and Aristotle both worried that laughter might undermine authority structures, and they realised that we can laugh when doing some very bad things as well as when we are doing something pleasurable. What we now know that the ancient philosophers did not know is that the physical nature of a “ha ha” laugh and the muscular movements that it requires stimulates the release of endorphins in the brain. These feel-good chemicals are why a laugh can make us feel better and why Oxford University researcher Professor Robin Dunbar has quipped beautifully that laughter is “grooming at a distance”. We know that grooming, brushing or stroking another individual, is a way of bonding and it functions through the release of these endorphins, but laughter acts in another way