(3 of 6)
In one particularly revealing bit of research, cognitive neuropsychologist Reza Habib of Southern Illinois University teamed up with Mark Dixon, an addiction specialist, to peek inside the brains of problem gamblers and compare them with those of casual and nongamblers. When the subjects were inside the fMRI scanner, Habib and Dixon showed them images of slot machines displaying one of three results: a win, a loss and a near miss with, say, two cherries on the center line and a third just below it. "Near misses are inserted into slot-machine cycles to keep you hooked," Habib says. "They cause you to think, Oh, I'm getting close!"
In games of chance, close means nothing, and the rational brain knows that. But the lower brain is another story. When problem and nonproblem gamblers witnessed a payoff, both groups registered reward in the pleasure centers. A loss caused the cautionary regions of the higher brain to light up in both. When it came to a near miss, though, the groups parted ways: the nonproblem players processed it as a loss, while problem players experienced it as something like a win.
As with all such studies, it's difficult to tease out whether a malfunction in the brain led to the compulsive behavior or the compulsive behavior changed the brain. It's even harder to know exactly where on the spectrum problem gambling becomes addictive, though at some point it does. Still, the behaviors have similar roots. "In both cases there is an imbalance between the restraint and indulgence systems," says McGonigal. "Indeed, when you look at true addiction, compared to a moment of giving in, it doesn't even look all that different in the brain."
The Best Intentions
If it's clear that we all occupy different spots on the willpower continuum, it's much less clear why. The first place to turn for an answer is our genes. Few psychologists doubt that the fundamentals of our temperament are set at birth; we're factory loaded for introversion or extroversion, coolheadedness or temper, so why not willpower--or the lack of it? "I wouldn't bet against a genetic piece to willpower," says Baumeister. "Impulsivity data show a pretty good hereditary component, for example."
But environment, as always, plays a role too, and in ways that go beyond the habits you pick up at home. All species are good at reading the larger world into which they're born and determining if it's a safe one, in which moving slowly and taking care will pay dividends, or a dangerous one, in which it pays to grab what you can. Robert Kurzban, an evolutionary psychologist at the University of Pennsylvania, cites studies of neighborhoods torn by gang violence, where people have shorter life expectancies and make their decisions--about smoking, drinking, sex, criminality--accordingly.
"If you're in an environment in which patience is rewarded, you're likelier to put off reward than people who have shorter to live," he says. "They pursue a fast-life strategy." In other words, they never develop a willpower muscle because, really, what's the point?