Pity your prefrontal cortex--the CEO and chief justice of the bedlam that is your brain. It's the prefrontal that has to reconcile the artiste of your right hemisphere with the logician of your left, the tough guy of your hypothalamus with the drama queen of your anterior cingulate cortex. All that seems like more than enough. But then comes the job of wrangling the dorm rats and party animals of your midbrain, the place where your most decadent appetites--for drinking, gambling, eating, smoking, shopping, sloth, sex--come to get fed.
The battle between your noble lobes and your ignoble ones isn't even close. Eating, having sex and sleeping are vital for the survival of the species, so evolution arranged for them to be irresistibly pleasurable. Acquisitiveness is important too, so shopping and gambling carry kicks of their own. As for smoking, drinking and taking drugs, they have no survival value, but they don't need to, since they sidestep evolution and pick the chemical locks of the brain's pleasure centers directly.
The higher brain isn't completely unarmed in this fight. Indeed, it has one very powerful resource on its side: willpower. You need to lose 20 lb. (9 kg), so you pass up dessert and double down on exercise, and when your resolve starts to slip, you square your shoulders and push on through. The same resolve is at work when you say no to the new gadget you really, truly want but really, truly can't afford and even (or especially) when that sexy co-worker flirts with you at a party and you shake off the heady feeling and go home to your spouse and kids. We work that willpower muscle every day--and like any muscle, it often goes weak. Also like a muscle, however, willpower can be strengthened, and a growing number of researchers--using brain scans, virtual reality and more--are learning what kind of psychic calisthenics it takes to get us in shape. Much of that research hasn't made it into popular consciousness yet, but the more the scientists publish, the more we all learn.
"Our brains operate at three levels: I will, I won't and I want," says psychologist Kelly McGonigal, author of The Willpower Instinct and a professor at Stanford University. "For many of us, the I-want part wins."
It's easy to call a lot of this addiction, particularly when drugs, alcohol or behaviors like gambling are involved. But that can be glib. Addiction is not always easy to define, but it might best be described as knowing that a substance or behavior is wrecking your life and yet being unable to stop. Failure of will is more about behaviors that are compromising your life--making it less healthy or prosperous than it could be--yet can't quite be controlled even though you try.
It's no wonder we get fatigued from the effort. Just deciding what to eat in the course of a day requires us to make 227 discrete choices, according to McGonigal. And food is only part of it. Every evening brings a happy hour that invites you to join; every block brings a store that's designed to make you buy. "We're living in a world that is constantly tantalizing the reward centers in our brains--retail, phones, computers," says McGonigal. "Short bursts of dopamine that come from things like e-mail make it hard to focus on long-term goals."