If left to their own devices, would babies instinctively choose a well- balanced diet? What is the secret to falling asleep on a plane? Which really tastes better in a blind tasting - Coke or Pepsi? Have you ever wondered if a severed head retains consciousness long enough to see what happened to it? Or whether your dog would run to fetch help if you fell down a disused mineshaft? And what would happen if you were to give an elephant the largest ever single dose of LSD? The chances are that someone, somewhere, has conducted a scientific experiment to find out . . .