why do we laught when someone falls?

Every time I see a behaviour I like to trace its origins to some biological advantage. For instance, being stronger than others is a biological advantage and can be the difference between surviving or not. I believe every human behaviour should be traceable to a more primary behaviour or necessity, but so far, I fail to grasp the importance of this.



Could it be bonding with the ones who didn't fall? Could it be that laughter is in reality an hysterical response? What do you think?

via JREF Forum http://forums.randi.org/showthread.php?t=267872&goto=newpost