My Theory of Human Evolution (Caganers)

A nativity scene in Barcelona:

He is known in Catalan as the caganer. That translates most politely as ‘the defecator’ – and there he is, squatting under a tree with his trousers down.

At the nearby Christmas market amid the sprigs of holly and Santa hats rows of miniature, crouching country boys are lined up for sale.

Innocuous-looking from the front, their buttocks are bare and each one has a small, brown deposit beneath.

“It’s typical of Catalonia. Each house buys one for Christmas,” explains Natxo with a smile and a shrug as he shops. “I don’t know why (we do it), it’s just a tradition.”

Without Christmas, there would be much less demand for these intricate items. I believe the evolutionary reason for festivals and ceremonies is that they create demand for hard-to-make goods. This helps the most skilled artisans (good sources of innovation) make a living and hone their skills.

Via Marginal Revolution. Christmas: an evolutionary explanation.