Stepping back into the psychology world for a moment, this is another way your body responds to signals.
The guy I wrote Mind Hacks with noticed something that happened when it was late at night at he was making coffee to stay awake. He found that just making the coffee – not even drinking it – was enough to keep him going for a bit more. I get the same effect first thing in the morning: I’m sleepy before my first cup of tea, but often just filling the kettle and switching it on will wake me up.
Okay, what’s going on is Pavlovian conditioning. You know the experiments Pavlov did with his dogs: he’d ring a bell every time they were fed, and eventually they’d start salivating just from the sound of the bell.
The same is happening with the coffee. The process of making the coffee is being done just before drinking the coffee, every time. And because coffee’s a drug, and it gives you a hit, you body is being trained into regarding everything running up to that hit as something great in itself, too.
Incidentally, these automatic responses of the body and the mind are another way, like attention, that we can cope with little brains in a big world. There are many more, but I don’t think we have time right now. I can tell you some more experiments if you’re interested, afterwards.