Why do we laugh?  Introspection and common sense tell us that we laugh because someone said or did something funny.  This is usually incorrect, however.  In Laughter (2000), Robert Provine reported the results of his carefully conducted experiments, showing that in social situations, between 80 and 90% of laughing is not a response to jokes or other formal attempts at humor.  Rather, most laughing is in response to innocuous statements such as “I’ll see you guys later.” “I should do that, but I’m too lazy” or “I told you so!”

Provine has found that laughing serves a function similar to small talk:  it facilitates or maintains social bonds.  “Laughing plays a . . . nonlinguistic role in social bonding solidifying friendships and pulling people into the fold.  You can define ‘friends’ and ‘group members’ as those with whom you laugh.”  In The Human Story, Robin Dunbar cites studies finding that laughing is correlated with the release of endorphins and that this release of hormones facilitates bonding.

Unless we’re at a comedy club, then, laughing usually serves a function much different than common sense and introspection suggest.  The research of Provine and Dunbar is but one of many examples where conventional wisdom and introspection fail to explain human behavior. Where one truly wants to understand human cognition, one must turn to the scientific method.

We need to keep this caveat in mind because common sense seduces us with powerful illusions, illusions that look like uncontestable “facts” to those of us who …