Psychology of laughter

One psychologist, called P.Ekman wanted to find out if all people smile the same all over the world. He found one tribe in Africa, that have been never heard of white people, radio or television, so they didn’t have an opportunity to see how other people can smile. So Ekman took those tribe people friendly faces and came back to USA. The smiles in USA and Africa were the same. He didn’t stop and made more research and separated 19 types of smile. 18 of them are insincere, they become like masks, when we don‘t want to show out true feelings. There is only one type of a real smile, when mouth lifts up, eyes are squinted and others. Only this smile reflects real joy. This smile was called Duchenne smile. The biggest influence is made by Musculus orbicularis oculi, that makes the smile so special. You can‘t fake this eye muscle, so you can‘t fake Duchenne smile as well.
A person smiles and laughs then, when he is happy. The research show that happiness is related to specific areas of the brain. Psychologists claim that those people who have the right side of the brain more active, are more pessimistic, untrustworthy. For them details can become a disaster, they tend to have depressions. People, who have left side dominated, usually are optimistics, easy going, communicative. Psychologists showed happy and frustrating extracts from movies. The reaction of people were very different, depending which side of the brain was dominating. Those, who had right side more active, were disgusted much more than the others. Although others were much more happier and laughed much more often. The blood of people with the left side domination, has more immune cells.
Talking about laughter, many years ago people believed that it can help to protect against death, old age. People tried to make a pregnant woman laugh that was going to give a birth to a child, to relax.
All these facts improves that we MUST smile and laugh as much as possible.

P.S. You can see the Duchenne smile at the end of this page