What's the Latest Development?

Experiments conducted by social psychologist Roy Baumeister demonstrate that there is a finite store of mental energy for exerting self control. In other words, willpower depletes itself throughout the day, especially if your body is low on sugary glucose. When judges are tasked with either giving an inmate parole or sending them back to prison, for example, they were far more likely to grant parole in the morning, when willpower had not yet been depleted, or just after lunch when they were given a boost by the glucose in their midday meal.

What's the Big Idea?

Today we are swamped with more decisions to make than ever before. Choosing what to have for breakfast, where to go on vacation, who to hire, how much money to spend—all these deplete your willpower. "Good decision making is not a trait of the person, in the sense that it's always there," Baumeister says. "It's a state that fluctuates." Rather than constantly exercising willpower, it is better to structure your day around not having to make decisions. So instead of forcing yourself to exercise, set a date and time to go running with a friend.