Laughter is regularly promoted as a source of health and well being, but it has been hard to pin down exactly why laughing until it hurts feels so good.RSS Feed Get Science News From The New York Times »The answer, reports Robin Dunbar, an evolutionary psychologist at Oxford, is not the intellectual pleasure of cerebral humor, but the physical act of laughing. The simple muscular exertions involved in producing the familiar ha, ha, ha, he said, trigger an increase in endorphins, the brain chemicals known for their feel-good effect.

via Laughter Produces Endorphins, Study Finds – NYTimes.com.