From The Economist:
The true story of how your wife’s stalker rang her to discuss killing you isn’t supposed to provoke mirth. But when John Morreall, of the College of William and Mary in Virginia, related the events last week to a group of scholars in Tuebingen in Germany, they were in stitches as he divulged the details of how his wife tried to dissuade the confused young man by pleading that her mortgage was too large to pay without her husband’s help.
So why did they laugh? Dr Morreall’s thesis is that laughter, incapacitating as it can be, is a convincing signal that the danger has passed. The reaction of the psychologists, linguists, philosophers and professional clowns attending the Fifth International Summer School on Humour and Laughter illustrates his point. Dr Morreall survived to tell the tale and so had an easy time making it sound funny.