It goes back a long way.

It’s the response to a joke,a humorous story,or an amusing situation. That’s what happens.What we do.

Yes,except that does not explain laughter. What are we actually doing when we laugh? Why do we make this noise (whether it’s a snigger or a belly-laugh)? What are your body and brain doing? Someone tells you a story,and an unexpected ending causes you to make a loud,inarticulate noise. Or a situation abruptly shows an unexpected ,non-threatening conclusion,and you make this strange sound. Look at those two words again- “unexpected” and “non-threatening”.

It goes back a long way.

You are Cro-magnon Man (or perhaps the later Neanderthal). You are out looking for food. A dangerous world,of which you are not fully capable of controlling. There are many things to kill you,although you hope to kill them first ,for food. The need constantly arises to be more alert and ready for strenuous action. An unexpected ,unidentifiable noise,a glimpse of something too close for comfort,not distinguishable as to what it is. Time for calm investigation is impossible- animals attack in seconds. The initial response to any uncertainty when you have limited powers and much vulnerability,is to run or fight. Running might be best,but it might be the only choice. Fight might be the only choice. Either way,you need extra energy. For Cro-Magnon,there’s only one way- get some instant extra air into the lungs. You have found this gives a sufficient,temporary increase in your ability for action.

You take in some stronger inhalations,and “hold it in” as much as possible. You are ready for whatever it is that might be an imminent threat.

Then the grass parts- and a fellow appears who you recognise is from a group which has sometimes joined your group to drive away wild dogs.

You cannot speak to him- Cro-Magnon Man has not yet managed much articulate communication,and you have lungs full of air,ready for aggression. He is not a target for your potential aggression,so you can relax,breathe out. Be careful! You cannot just blow out in one go,as this might be interpreted by him as a threatening roar of a dangerous animal. Remember that he might not yet have seen you,or recognised you as a previous “co-worker”.He might attack first,before he sees “what” you are. You must therefore let your “attack” ability come out non-threateningly. You pant,push out air in short,noticeable,non-harsh gasps. You are telling him “I see you are not a threat,and by expelling my extra strength (air) in a way recognisable to you,you also will realise that I am not a threat to you”.

Let us summarise this. I am presented with an unclear situation. Prepare for arduous action (breathe in),because there might be danger. The situation clarifies,but proves to be non-threatening (not what was expected). It is now safe to discard the “protection” body mode,and signal to others that neither of us is a threat. Breathe out,using low-level exhalation — “ha ha ha”.

We have laughter.

We are presented with a story or situation,and we ready ourselves to accommodate what might occur. What happens is opposite to our expectation (the punchline of a joke is always an unexpected outcome of the situation presented). We express our recognition of this unexpected ,but safe,conclusion to the situation given by breathing out in short bursts. “I show by breathing out in this manner that I see you /the situation you describe to be non-threatening to me. You are also safe from me.” Now,of course,we hear a joke and know we are not threatened. We accept that a joke/amusing story is a vicarious presentation of an uncertain situation,and we use the exhalation technique because it has proven over millennia to be a handy expression of showing understanding of the theoretical situation presented in the story.

Laughter is an ancient procedure invented for early (and modern) social co-existence. All human actions are anthropological psychology.

Let the ludicrousness of life lead you to laughter.