Imagine that you’re eating your favourite food, perhaps a bloody steak or an obscenely large bar of chocolate. You’re probably quite keen for an actual mouthful now. You may even have started to salivate. But wait – before you dash for the kitchen, imagine eating another one. And another one. In fact, picture yourself guzzling down thirty more. Do you still want a bite?

If you had done this with actual food, the answer would probably be no. The more we expose ourselves to a something, the more we get used to it. This process, known as ‘habituation’, applies to all sorts of things – bright lights, level of wealth and, yes, the taste of food. The first bite of