Somebody, anybody, please put this theory out of its misery.
Evolutionary biologists have traced the origins of laughter back 4m years to pre-humans slipping and stumbling in their first faltering attempts to walk on two legs.
According to the theory, when they saw a member of their group lose his footing they would laugh as a sign to each other that something was amiss, but nothing too serious.
The theory could explain why, to this day, the ungainly walk remains a staple element of slapstick humour from John Cleese’s “Ministry of Silly Walks†to Rowan Atkinson’s accident-prone Mr Bean. . . .
http://www.timesonline.co.uk/article/0,,2087-2157946_1,00.html