Look down. What do you see? Your hands, your desk, the floor, maybe a cup of coffee, or a laptop computer or a newspaper. What do they have in common? These are things you can touch. What you see when you look down are things within your reach, things you can control right now, things you can move and manipulate with no planning, effort, or thought. Whether it's a result of your work, the kindness of others, or simple good fortune, much of what you see when you look down is yours. They're things in your possession.↵
Now look up. What do you see? The ceiling, perhaps pictures on a wall, or things out the window: trees, houses, buildings, clouds in the sky-whatever is in the distance. What do they have in common? To reach them, you have to plan, think, calculate. Even if it's only a little, it still requires some coordinated effort. Unlike what we see when we look down, the realm of up shows us things that we have to think about and work for in order to get.↵
To the brain this distinction is the gateway between two wildly different ways of thinking-two utterly different ways of dealing with the world. In your brain the down world is managed by a handful of chemicals-neurotransmitters, they're called-that let you experience satisfaction and enjoy whatever you have in the here and now. But when you turn your attention to the world of up, your brain relies on a different chemical-a single molecule-that not only allows you to move beyond the realm of what's at your fingertips, but also motivates you to pursue, to control, and to possess the world beyond your immediate grasp. It drives you to seek out those things far away, both physical things and things you cannot see, such as knowledge, love, and power.↵
To your brain, this single molecule is the ultimate multipurpose device, urging us, through thousands of neurochemical processes, to move beyond the pleasure of just being, into exploring the universe of possibilities that come when we imagine. Mammals, reptiles, birds, and fish all have this chemical inside their brains, but no creature has more of it than a human being. It is a blessing and a curse, a motivation and a reward. Carbon, hydrogen, oxygen, plus a single nitrogen atom-it is simple in form and complex in result. This is dopamine, and it narrates no less than the story of human behavior.