Tighten Your Belt, Strengthen Your Mind

Thursday, April 3rd, 2008

Tighten Your Belt, Strengthen Your Mind:

The brain’s store of willpower is depleted when people control their thoughts, feelings or impulses, or when they modify their behavior in pursuit of goals. Psychologist Roy Baumeister and others have found that people who successfully accomplish one task requiring self-control are less persistent on a second, seemingly unrelated task.

In one pioneering study, some people were asked to eat radishes while others received freshly baked chocolate chip cookies before trying to solve an impossible puzzle. The radish-eaters abandoned the puzzle in eight minutes on average, working less than half as long as people who got cookies or those who were excused from eating radishes. Similarly, people who were asked to circle every “e” on a page of text then showed less persistence in watching a video of an unchanging table and wall.

Other activities that deplete willpower include resisting food or drink, suppressing emotional responses, restraining aggressive or sexual impulses, taking exams and trying to impress someone. Task persistence is also reduced when people are stressed or tired from exertion or lack of sleep.

What limits willpower? Some have suggested that it is blood sugar, which brain cells use as their main energy source and cannot do without for even a few minutes. Most cognitive functions are unaffected by minor blood sugar fluctuations over the course of a day, but planning and self-control are sensitive to such small changes. Exerting self-control lowers blood sugar, which reduces the capacity for further self-control. People who drink a glass of lemonade between completing one task requiring self-control and beginning a second one perform equally well on both tasks, while people who drink sugarless diet lemonade make more errors on the second task than on the first. Foods that persistently elevate blood sugar, like those containing protein or complex carbohydrates, might enhance willpower for longer periods.

The key takeaway is that willpower grows stronger with use:

The idea of exercising willpower is seen in military boot camp, where recruits are trained to overcome one challenge after another.

In psychological studies, even something as simple as using your nondominant hand to brush your teeth for two weeks can increase willpower capacity. People who stick to an exercise program for two months report reducing their impulsive spending, junk food intake, alcohol use and smoking. They also study more, watch less television and do more housework. Other forms of willpower training, like money-management classes, work as well.

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