Laughter predates language in human evolution. Infants laugh before they speak. Chimpanzees produce a vocalization during play that is functionally identical to human laughter. This deep evolutionary origin suggests that whatever laughter does for us, it matters a great deal.
The leading theory: benign violation
The most widely accepted theory in humour research is the Benign Violation Theory, developed by Peter McGraw at the University of Colorado. According to this framework, something is funny when it is simultaneously a violation of how things should be (a norm, an expectation, a belief) AND somehow benign — safe, acceptable, or already resolved. Too much violation and it becomes disturbing. Too much benign and it is boring. The sweet spot between these produces laughter.
Why we laugh with other people
Research by Robert Provine at the University of Maryland found that people are 30 times more likely to laugh in social situations than when alone. Laughter is primarily a social behaviour, not a response to jokes. Most laughter in daily life accompanies ordinary statements, not punchlines. It is a bonding mechanism — a signal of safety, acceptance and shared understanding.
Laughter and health
The evidence for laughter as medicine is mixed but promising. Short-term effects are well established: laughter reduces cortisol and adrenaline, temporarily lowers blood pressure and activates the immune system. The long-term claim that "laughter is the best medicine" is an overstatement, but regular positive social interaction — of which laughter is a key component — is strongly associated with wellbeing and longevity.
