The following list is by Robert Provine, author of Laughter: A Scientific Investigation
- Laughter is an instinctive behavior, produced and recognized by people of all cultures.
- Most laughter is not about humor; it’s about relationships between people. We are 30 more times likely to laugh in a social situation than when we are alone (without the presence of TV, books, radio).
- Laughter usually follows comments in conversation rather than intentional jokes.
- The speaker tends to laugh more than the audience.
- In groups, women laugh more than men. Women also laugh more at men more than men laugh at women.
- Laughter tends to occur in short bursts of vowel-like sounds such as “ha-ha,”, “ho-ho” or “he-he” which are repeated every fifth of a second.
- Most people can’t laugh on command. Laughter is not something we produce consciously.
- Laughter is contagious. The sounds of laughter often trigger laughter.
- Laughter is believed to have its origins in rough and tumble play, evolving from the panting behavior of our primate ancestors (when tickled, chimpanzees and gorillas pant).
- Laughter usually doesn’t interrupt a sentence structure of speech. We really only laugh during the pauses we make for coughing or breathing.