After all the more or less fruitless posts on free will as a metaphysical problem, here’s something a little more practical. The following is from a recent article by John Tierney discussing some of Roy F. Baumeister’s research on what they are calling “ego depletion” or “decision fatigue.”
[Baumeister’s] experiments demonstrated that there is a finite store of mental energy for exerting self-control. When people fended off the temptation to scarf down M&M’s or freshly baked chocolate-chip cookies, they were then less able to resist other temptations. When they forced themselves to remain stoic during a tearjerker movie, afterward they gave up more quickly on lab tasks requiring self-discipline, like working on a geometry puzzle or squeezing a hand-grip exerciser. Willpower turned out to be more than a folk concept or a metaphor. It really was a form of mental energy that could be exhausted. The experiments confirmed the 19th-century notion of willpower being like a muscle that was fatigued with use, a force that could be conserved by avoiding temptation.
According to this view, the best way to maintain a high level of willpower is to conserve it by not using it too much! This can be contrasted with the view that sees willpower as a muscle to be built up by constant exercise — what we might call the Hamlet theory of self-control (“Refrain to-night, and that shall lend a kind of easiness to the next abstinence”).
As the muscle metaphor suggests, the two views are not necessarily incompatible. Other things being equal, someone who has just run a mile will be weaker than someone who has not — but someone who runs a mile every day will be stronger. Baumeister’s experiments (at least the ones mentioned in the article) only measure the short-term effects of decision fatigue, so they do not rule out the possibility that willpower works the same way. It would be interesting to see the results of a study on the effects of a long-term regimen of willpower training.
There can be little doubt that, when it comes to any one specific behavior, Hamlet is right that each abstinence makes the next easier — but this probably has more to do with establishing or disrupting habits than with building up willpower. Once something becomes a habit, it no longer requires much in the way of decision-making or willpower. The Spartans didn’t have to force themselves every evening to have nothing but black broth for dinner; this habit was probably so entrenched that nothing else even seemed like a live option. Once your brain has got the idea that this is just what we do, that no decision-making is required, willpower ceases to be an issue. When I was a Mormon missionary, I had an enormous number of rules to follow — get up at 6:00 every morning, never put your hands in your pockets, refrain from using the word “guy,” etc. — but after a few months none of them were very difficult to follow. This was not because my willpower had increased, but because the behaviors in question had shifted out of the realm of conscious decision and into the realm of habit. This is what Hamlet means when he says that use almost can change the stamp of nature.
I’m interested in a different question, though: whether exercising one’s willpower can make it stronger in general, aside from the effect habituation may have on any one specific behavior.
Mormons have a practice of fasting for 24 hours (a complete fast: no food, no water) on the first Sunday of every month. Though there are other purposes for this (for example, the money saved by not eating is supposed to be given as alms), one rationale which I often heard was that by practicing self-control in this arbitrary matter, one built up one’s ability to control oneself in general, resulting in an increased capacity to resist temptation. I suppose similar thinking underlies other forms of asceticism and “mortification of the flesh.” Baumeister would probably say that fasting is bad for willpower in the short term (low glucose levels were found to negatively affect willpower), but could regular fasting really build up willpower in the long run?
One thing that makes this difficult to test (or to practice, for that matter) is that, whatever regimen of willpower training one decides to use, it is itself in danger of becoming a habit and thus ceasing to be a meaningful exercise in self-control. The Mormon program of fasting addresses this issue to some extent; because the fasts only occur once a month, they always represent a break in one’s routine and never become fully habitual. Still, though, one becomes accustomed to fasting and it ceases to be difficult. As a Mormon, I was virtually never seriously tempted to break my fast early, and it’s not clear that I was actually exercising self-control in any meaningful sense. Of course I felt hungry and thirsty, but mere desire does not always constitute a real temptation which must be resisted by force of will. Walking down the street on a hot summer’s day, you may feel uncomfortably warm, but are you ever seriously tempted to take off all your clothes? Does it really take any self-control to keep them on? When you see something in a shop which you want but can’t afford, is it really willpower that keeps you from stealing it? Our habits, and our idea of which actions are thinkable and which are not, determine whether or not willpower even comes into play.
I suppose a regimen of real (non-habitual) willpower training would look something like a kung fu movie, where the master trains his student by making a series of unpredictable and often whimsical demands.