Robert Provine looked at the role of laughter in our society. Highlights include:

• Women are attracted to men who will make them laugh, and men are attracted to women who laugh around them. This might explain why female comedians are rare, and why they generally aren’t considered sexually appealing.
• Women laugh 127% as much as men in a given audience.
• Some of these gender differences appear as early as age six.
• The average speaker laughs 46% more than the audience – the opposite of what happens in standup comedy routines.
• Perhaps this is why laughter begets laughter. In India one man has built an entire movement around people spontaneously laughing in groups.
• Most conversational laughter is not a response to a joke. It’s normally the charisma of the speaker that drives laughter.
• Laughter has a dark side. It is generally present during horrible events such as murder, rape and pillage.

The full article is much longer and it goes into much more detail about many aspects of laughter, including laughter epidemics. You can find it here.

Source: The Guardian