Quote of the day from a page entitled "Perceptual Fallacies":

There is a tribe called the Ba Mbuti that provide evidence that size constancy is learned. This tribe lives in a thick jungle where they never are able to see more than a few yards away. When taken into a field and shown Buffalo in the distance, they asked what kind of insects they were. When told that the animals were buffalo, the tribespeople thought it was witchcraft.