(I'm looking for a reference to an experiment I read of: birds being fed or not at random when they pressed a lever. The chance of being fed was determined only by chance, but the birds constructed all manner of increasingly elaborate rituals before pressing the lever, timing, etc. in an attempt to make the food come more reliably. Does anyone know the one I mean?)
I read about it in a book by Derren Brown - I've just found the page and he says it was done by B. F. Skinner in 1948.