The Science of Getting Things Done

Productivity philosophies always sound great on the outside

Photo by J. E. Theriot

Productivity philosophies always sound great on the outside, promising more free time, more autonomy, and a happier lifestyle. But not all of these philosophies deliver, and not everyone will like the same philosophies.

So how do you pick one productivity philosophy over another?

The typical answer is that this is a completely personal decision and you should do whatever works best for you.

We can do better than that. The typical answer doesn’t explain why systems like David Allen’s Getting Things Done (GTD) have such widespread popularity. While good marketing does play a role, I’ve thought of a more satisfying answer based on some recent findings in psychology. I’m talking about two concepts, ego depletion and decision fatigue, which are two of the most fascinating phenomena I’ve read about in the past year.

Ego Depletion

While most people have some intuitive sense that we don’t have infinite willpower and self-control, it’s another thing entirely to reliably demonstrate this effect. Psychologist Roy Baumeister has done just that in several studies, developing the notion of ego depletion.

Resistance is futile

Photo by scubadive67

In those studies, participants are given a task in which they have to exhibit self-control. This task could be to eat radishes at a table while avoiding some nearby chocolate-chip cookies or to suppress one’s emotional reactions to a film. After this depleting task, these people gave up sooner on puzzles and strength tests than those who had been free to do whatever they wanted in the previous task.

From studies like these, Baumeister concluded that willpower is a limited resource—seemingly any exertion of will or self-control will drain it.2

Decision Fatigue

I like to think of decision fatigue as an extension of ego depletion. Psychologist Kathleen Vohs has done some compelling work on decision fatigue, showing that when people are forced to make successive decisions, such as deciding on the size, color, style etc. of a prize, those people will not be able to hold their arms in freezing water for as long as people who didn’t have to make those decisions. As in the ego depletion studies, making decisions depletes your willpower, causing you to “give up” earlier on difficult tasks.3

Deciding between many options can be exhausting

Deciding between many options can be exhausting (Photo by Leon Brocard)

GTD and decision fatigue

Let’s look at where decision fatigue arises in your normal workflow:

  1. At the start of the day, you decide which of your current projects require work that day.
  2. As you finish tasks, you need to decide what tasks to tackle next.
  3. Throughout the day, you receive new tasks and need to decide when they will be done and how they fit in with your existing workload.

GTD helps in all of these cases. In GTD, there are weekly reviews where you make sure all of your projects have “next actions,” which are well-defined actions that can be done as soon as you have time for them—you don’t have to wait for other actions to complete first or other people to get back to you before starting next actions.

By deciding on next actions in advance, you greatly reduce or even eliminate the amount of time you must spend making such decisions when you’re actually working. The structure of GTD also means that you have a better sense of how to fit new tasks into your existing system, which reduces decisions on that front as well.

By reducing the decisions you make when you’re “in the trenches,” GTD allows you to work productively for a longer period of time—you avoid the usual decision fatigue that comes from deciding what to do next.

Last thoughts

Decision fatigue is a pervasive drain on our everyday energy, and it’s great if you have a system in place to reduce its effect. While GTD can help you avoid decision fatigue in some obvious ways, there are many other systems out there to choose from that likely have similar benefits. For my part, though, I’ve already made that decision—I’m moving onto my next action.


1 Tierney, John. “Do You Suffer From Decision Fatigue?”
2 Baumeister, Roy et al. “Ego Depletion: Is the Active Self a Limited Resource?” Journal of Personality and Social Psychology, 1998, Vol. 74, No. 5, 1252-1265.
3 Vohs, Kathleen et al. “Making Choices Impairs Subsequent Self-Control: A Limited-Resource Account of Decision Making, Self-Regulation, and Active Initiative” Journal of Personality and Social Psychology, 2008, Vol. 94, No. 5, 883–898.

2 thoughts on “The Science of Getting Things Done

  1. This is a truly thought provoking post. I never would have associated ego-depletion with decision fatigue in this way. However, I’m concerned that even planning one’s tasks out in advance will not truly eliminate decision fatigue. For instance, how do I decide what to wear, what to eat for lunch? I think this video offers a positive potential solution:

    • Nice video 🙂 Unfortunately, I think most of us will still want to make decisions in our daily lives as a way of expressing our autonomy. You still recover from decision fatigue over time and by eating glucose (according to the NYT article), so it’s not the end of the world, but it’s nice to also minimize it as best you can during the day.

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