Why do we laugh (an evolutionary perspective)

As much as I enjoy laughter and jokes, I also find these phenomena weird. I mean, if you think about it, laughter is creepy. 

You open your mouth wide open as if to engulf the earth and go ‘HAHAHA’ whilst shaking your body like a vibrator and sometimes even rolling on the floor like a baby.

If you were an alien visiting earth with the objective of studying human behavior, laughter would indeed perplex you. It’s such an intrinsic part of human nature that we often take it for granted and overlook how strange it actually is.


An evolutionary perspective of laughter

All human beings laugh, no matter what part of the globe they inhabit and what language they speak. This suggests that the laughter response is an evolutionary inheritance from our ancestors. Usually, a behavior that is inherited must have an advantage, at least in the context of our ancestral environment.

Our ancestors lived in a world rife with environmental threats. Before they could speak, making shrill sounds and crying must have been the most important means of communication.

Imagine you’re a human ancestor on a hunting trip with a bunch of fellow hunters. Our ancestors preferred to hunt in groups because it was easier that way to hunt down a large animal and avoid the dangers of getting hunted by predators.

If you’re attacked by a predator, you’d cry your lungs out so that other humans nearby hear your alarm call and rush in to rescue you. But what if you hear a rustling in the bush, cry out loud, but immediately realize it’s just a harmless squirrel and not a saber-toothed tiger?

The initial shock of encountering a predator was there but it turned out that the situation was harmless. So your crying had to somehow modify itself to sound less alarming and more relieving. 

Perhaps, in an attempt to impede the crying and breathe out a sigh of relief simultaneously, you broke down your crying into a series of sounds that we today call laughter.


Laughter: A response to harmless shock

When we perceive a situation to be shocking but harmless to us, laughter ensues. The basis of most jokes is that, at the punch line, some disastrous or humiliating event happens to someone. This is why people laugh when they see videos of other people falling, slipping or getting caught in embarrassing or humiliating situations. 

Any sort of physical or psychological threat that is perceived to be harmless has the potential of triggering laughter. If a person jumps from a building with wings on, trying to fly, it may be funny at first but if he dies when he crashes to the ground then it isn’t funny anymore. This is because the ‘harmless’ aspect of the situation got removed.  
I’ve mentioned in a post about smiling that smiling is mostly a fear reaction. The same is true for laughter. The unexpected ending of a punch line ‘frightens’ our subconscious even though we consciously know that the danger isn’t real or isn’t happening to us. So we laugh with sounds very similar to that of chimps warning other chimps of imminent danger.

This is also the reason why puns and other forms of similar wordplay tend to be funny. If you analyze the puns that make you laugh you’ll soon realize that most of them shock you or harmlessly violate your expectations in some way. 

Studies have shown that laughter releases endorphins, boosts immune response and increases pain tolerance. So if there was any chance that the dangerous or painful event turned out to be real, our body would be prepared to deal with it!

Sometimes there indeed is a fine line between crying and laughing. When you laugh your heart out, tears may start to trickle down your eyes. Similarly, when a person faces a serious emotional crisis, such as hearing about death, they may slip into denial mode and start laughing until reality hits them and laughter turns into crying.

Theory of harmless shock applied to babies

The most direct way of seeing the theory of harmless shock in action is by observing what sorts of actions and events make babies laugh. Babies are pure and innocent, still unfamiliar with the ways of the world and without any ulterior motives. So their reactions to situations are more or less purely evolutionary.

Adults usually make babies laugh by playing the game of Peekaboo. They look at the baby, hide, and then quickly look again as the tiny lump of life revels in ecstasy. Tickling the baby works too, so does lifting and throwing it up in the air and catching it safely on its way down. Moving your face very close to the baby’s and uttering gibberish also seems to work.

All these activities make a baby laugh because they frighten it harmlessly in one way or the other. A baby feels safe in the presence of adults and in the game of Peekaboo where this presence is momentarily withdrawn and quickly brought back, laughter is generated as a response to an apparently harmless shock.

Similarly, tickling the baby and moving your face close to theirs are toned down mock threats. Many apes tickle each other for amusement.

we laugh like gorilla
A baby gorilla’s reaction to an adult gorilla’s tickling in an East Germany zoo

Just as you wouldn’t find it amusing if a stranger came up to you and started tickling you, when babies are tickled by strangers and not by their primary caregivers, they may perceive the threat to be real and start crying.
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