The people in the room confronted a plate of warm, chocolate chip cookies and a plate of radishes. One group was told to avoid the cookies. Everyone was later given math problems. It turns out, the folks who used willpower to not eat cookies stopped doing math much sooner than the folks who had not yet tapped their reserve of willpower.
Willpower is used to control thoughts, emotions, impulses, and performance. What you use for one you don't have for another.
Let's say that you need to learn a new programming language or scientific theory. Applying yourself to learn that drains willpower. It takes sustained effort and you can drill new vocabulary or run thought simulations about a world in which space is curved for only so long before you feel an irresistible urge to break away to watch cat videos or eat chocolate. You've temporarily exhausted your supply of willpower, using it in this instance to control your thoughts, derailing them from their normal route.
Or perhaps your girlfriend's little brother is staying with you "for just a few weeks - until he gets his feet back under him." You were never a big fan of this potential brother-in-law even when his visits were limited to an evening or weekend. Now he's been in your space for two months and counting. In order not to blow up at him and possibly alienate your girlfriend, you have been controlling your emotions. Sort of. As it turns out, emotions aren't something you directly control; if you are sad, you can't just tell yourself not to be. Willpower in this instance gets used up to direct your thoughts into more pleasant scenarios. Or you focus on not telling him off. In either case, it can leave you feeling exhausted.
Impulse control is what we often think about when we describe someone's lack of willpower, the ability to "resist temptations like alcohol, tobacco, Cinnabons, and cocktail waitresses."
Finally, you deplete your willpower to focus on performance. Are you creating a presentation for a new client? Do you have to analyze data from two different tests? The focus on such tasks leaves you with less willpower to control your thoughts, impulses, or emotions. You're more likely to snap in irritation or reach for that second piece of chocolate when you're pushing yourself to complete such demanding tasks.
There are ways to leverage the willpower you do have (having a habit like rolling out of bed to run 2 miles every morning depletes willpower less than starting such a habit), but for the most part, you define yourself by how you use your limited sum of willpower.
|Life of an undergrad|
If your workplace has rigidly defined process steps that require focus on adhering to certain steps, you'll have less willpower left over to control your thoughts, to immerse yourself in the creative process. A rock band does not have the best reputation for impulse control and the creative crowd is likely to be more tolerant of what "the suits" might think of as a lack of impulse control, indulging in alcohol, drugs, or sex. At some level, though, the difference between the suits and the creatives simply reflects a different allocation of a fixed sum of willpower.
In the end, it might be that how you choose to use willpower does more to define you than how you use time. Willpower is how we push back against all the defaults that would gladly define us, whether those defaults for behavior and thought come from our boss, our family, the media, our church, or our own biology or past.
Willpower is like a blanket too small to cover the whole of you. You decide if it's your feet or your arms that stick out but you can't cover both. At least not at the same time. The sooner you embrace loss (you need to let go of the idea of starting your training for the triathlon) the sooner you can embrace gain (you can't start pushing yourself for triathlon training because you have decided it's more important to start that novel). It's not enough to choose to apply above average willpower on one thing; you have to decide in which other area you are going to apply less willpower.
The research supporting the notion that (at least within a fixed period of time) willpower is a largely fixed sum is explained in Roy F. Baumeister and John Tierney's book Willpower. It's a fabulous and important read.