The hardest part of a diet is sticking to it. So how can you keep from backsliding and hitting the junk food again? Psychologist Roy Baumeister, author of the new book Willpower: Rediscovering the Greatest Human Strength, argues that practicing self-control in one specific task -- like standing up straight -- improves self-discipline in other parts of your life as well. In a recent Bloggingheads.tv diavlog with Joshua Knobe of Yale, Baumeister discussed the evidence for this effect:
Baumeister's work calls into question the distinction between the mental energy required for self-control and the energy used in physical exertion, suggesting that both draw from the same reservoir. And that, as Baumeister argues in the following excerpt, explains why an illness can visibly affect your behavior before it produces such symptoms as a cough or a runny nose.