Laugh, and the whole world laughs with you, as the saying goes. In my opinion, laughter is essentially a social activity, a way of sharing you thoughts and emotions with others- a substitute for, or complement to, language.
Think of the difference between the experiences of a theatre actor and a stand-up comedian. Both perform before a live audience, made up of a host of different people- a wide range of ages, backgrounds, levels of intelligence and so on. Both give their all to prepare and deliver the best performance possible to wow the audience and their talent to the audience and to themselves.
The difference comes in the feedback they get from the audience. For the actor, the majority of the audience will have little insight into his craft and how technically accomplished (or otherwise) his performance is. Aside from the professional observer- the newspaper critic, the rival director perhaps- for each member of the audience, his or her opinion of the show is usually not as specific as “that actor’s performance was great” or “I really disliked the way he delivered Act 2, Scene 3” but much more general, about the show as a whole. In the comedian’s case the situation is much simpler- either he is funny and people laugh or he is not and people do not laugh. Some variation in response is inevitable, taking into account different tastes, cultural backgrounds etc., but in most cases the show is funny or not funny with little grey area between the two.
This is not the only difference though. Maybe even more importantly, this feedback is immediate and shared with others in audience, not to mention the performer himself. Everybody knows if people are enjoying the show or not and they do so collectively. The play is a more isolated experience with each member of the audience left to form their own opinion on what they have seen.
Why do we have this unique form of social interaction? Seemingly, other animals get by successfully without it, why do we humans need it? I’m not so negative as to share Nietzsche‘s opinion that ” Perhaps I know why it is man alone who laughs: he alone suffers so deeply that he had to invent laughter.” There is some value in it, insofar as laughter and humour do hold a place in our lives as a kind of shield, a protection against more troubling emotions- often grief or pain but also others such as embarrassment and even repulsion or disgust.
I believe that its roots are in our uniquely social existence- other animals simply do not interact and communicate to the same extent we do. We alone need to know who to trust, who shares our opinions, we alone have the need to feel comfortable with the other members of our various social circles. Earlier, I compared laughter with language, and I believe it to be a valid comparison. Humans developed language to share information with each other and this is the role of laughter also. It tells us who is ‘on our side’, and who is not, sometimes even used as a weapon to degrade and isolate, just as language can be