Why is Laughter Contagious?

All people laugh almost every day. someone looks funny videos, someone laughing at a joke. We always wondered when our friends laugh why we laugh with them? And I decided to find out the cause and read one article about laughter. I think you also interested in the answer ... I want you to know about it too ...

Why does one person pick up another's emotions so easily? It seems that human emotions are highly contagious. For example, one person's laughter is soon shared by another's.contagious laughter is usually a social catharsis from a stressful situation, so given any such setting we should be able to create our own epidemic of laughing.

http://www.psyarticles.com/emotion/contagious-laughter.htm