Bobby Knight once defined discipline as "Doing what you have to do, doing it as well as you possibly can, and doing it all the time." The problem, of course, is all of the distractions and temptations drawing us away from always doing the necessary well. And when we are tired and frustrated, concepts of self-control and discipline seem almost mythical, and largely a trait possessed or extolled only by others (Knight, Vince Lombardi, Lao Tzu, etc.) Accordingly, failures of will are typically chalked up to moral shortcomings.
However, self-control and discipline are not necessarily the product of some sort of "folk concept" or "free will." As described in Willpower: Discovering the Greatest Human Strength, and in two NYT articles about it (Do You Suffer from Decision Fatigue?, and The Sugary Secret of Self-Control) the exercise of self-control is largely governed by the machinery of the brain.
The brain has a finite amount of the mental energy necessary for self-control, and like a muscle can be depleted or exhausted over the course of a day by the decisions we make. Roy F. Baumeister and John Tierney call this process "decision fatigue." Decision fatigue explains why trade-offs are difficult to make as the day wears on, and why some parole boards are less likely to grant parole in the late afternoon. Long term thinking gives way to the immediate, and the self-control to eat and act appropriately slips. And we suffer the effects of decision fatigue without even knowing it. Unlike physical fatigue, which manifests itself in ways visible to us, mental fatigue takes place without our awareness. So we think we are behaving rationally and intelligently even as our ability to do so grinds to a halt.
Decision fatigue manifests itself in two main ways: 1) reckless and impulsive behavior (this needs no explanation); and 2) doing nothing. "Doing nothing" may mean that you punt the decision to another day, or you make a decision involving less import (deferring action to the future, making interim determinations).
The authors reveal a very simple way to fight decision fatigue: glucose. The brain's power supply is sugar, and when it is low on power, the decision making process suffers. Replenishing with glucose reverses the effects of decision fatigue:
"The restored willpower improved people’s self-control as well as the quality of their decisions: they resisted irrational bias when making choices, and when asked to make financial decisions, they were more likely to choose the better long-term strategy instead of going for a quick payoff."
So how to make better decisions and exert self-control? According to Baumeister, conserve your willpower, know your limitations, and don't make important decisions while hungry:
“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.” His studies show that people with the best self-control are the ones who structure their lives so as to conserve willpower. They don’t schedule endless back-to-back meetings. They avoid temptations like all-you-can-eat buffets, and they establish habits that eliminate the mental effort of making choices. Instead of deciding every morning whether or not to force themselves to exercise, they set up regular appointments to work out with a friend. Instead of counting on willpower to remain robust all day, they conserve it so that it’s available for emergencies and important decisions.
“Even the wisest people won’t make good choices when they’re not rested and their glucose is low,” Baumeister points out. That’s why the truly wise don’t restructure the company at 4 p.m. They don’t make major commitments during the cocktail hour. And if a decision must be made late in the day, they know not to do it on an empty stomach. “The best decision makers,” Baumeister says, “are the ones who know when not to trust themselves.”