Jocko Willink on Willpower Fatigue

I recently listened to a discussion about willpower fatigue on the Jocko Podcast (check it out! it’s a goldmine of masculine wisdom). You can watch the debate between Jocko and Echo here:

Jocko argues that exerting your will’s power doesn’t fatigue it, while Echo advocates the muscle metaphor of willpower. Let’s take a closer look at their arguments.

Jocko’s Perspective

1) Willpower Momentum

According to Jocko, using willpower propels you in an upward spiral:

You get up before sunrise: you win.
You work out hard: you win.
You stick to your diet: you win.
You focus at work: you win.
You do more awesome shit: you win.

By winning incessantly, your willpower gains more and more momentum. This makes sense because willpower is a function of pride. With every little victory, you experience a little pride, giving you a little willpower boost.

So how can it be, as Kelly McGonigal claims, “that self-control is highest in the morning and steadily deteriorates over the course of the day” (The Willpower Instinct, p. 56)? Since this makes intuitive sense, you can find dozens of blog posts giving advice like, “According to science, you should do everything that requires willpower at the beginning of your day because that’s when you have the most of it.”

Let’s look at the resources. Baumeister & Heatherton (1996) suggest that people’s diminished willpower in the evening is reflected by statistical facts:

Diets are most often broken late in the evening; sexual acts that one will later regret are likewise most common then; people smoke and drink most heavily late in the day; most violent and impulsive crimes are committed between 1:00 and 2:00 a.m.

As an argument for willpower fatigue, that’s hardly convincing. Diets might be broken late in the evening because that’s when people have time to relax, watch TV, and enjoy snacks. Then, how much time do people have in the morning to get hammered and have regretful sex with strangers? And how confident would people feel to commit crimes in broad daylight with masses of people around?

Another popular example is decision fatigue. In his book Willpower, Roy Baumeister describes the case of prisoners asking to be released on parole. After analyzing more than 1,100 decisions of judges, researchers found a peculiar pattern:

70% of prisoners who appeared early in the morning received parole.
10% of prisoners who appeared late in the day received parole.

The time of the day seemed to influence the judges’ decisions stronger than the prisoners’ ethnic backgrounds, crimes, or sentences. Baumeister’s explanation for this oddity is that making choices costs willpower: If you make choices all day long, your willpower will be depleted later in the day. — Do you find this explanation conclusive? I don’t. Working, making decisions, and dealing with prisoners all day long could’ve simply made the judges grumpier and less empathetic.

If you, as a man, feel that you’re more active and productive in the morning, consider that this may only be a result of elevated testosterone levels based on your body’s biological clock. (Still, a circadian rhythm in heart rate variability has been observed by Philippe et al. 2012, indicating that this index of willpower is higher in the morning than in the evening.)

In general, the idea that the human will is strong in the morning, yet weak in the evening is an extension of the ego depletion theory. This theory claims that willpower is a limited resource that can be temporarily depleted. Therefore, if you exert your willpower throughout the day, it’ll gradually decrease until you have little to nothing left by the end of the day, right?

Not necessarily, because eating, napping, meditating, and slow breathing can reverse willpower fatigue (Reichl 2015). More importantly, “temporarily” doesn’t imply “until you wake up from a good night’s sleep.” Scientific experiments on ego depletion are based on a dual-task paradigm: Participants have to use their willpower on a first task, after which a second task tests how much willpower they still have. Such experiments last a few minutes or hours at most, not a whole day through.

Hence, scientific evidence for the claim that willpower deteriorates over the course of the day remains weak. Jocko seems to be right. Now what about ego depletion?

2) Against Ego Depletion

If you study the science of willpower, you come across hundreds of studies that reinforce the idea that willpower is limited and can be depleted. Jocko, however, argues that “discipline enforces discipline: more discipline makes more discipline.”

Even if we assume that something like the ego depletion effect exists, we know today that motivation can override it. Now consider all those psychological experiments investigating willpower, with scientists telling college students to carry out boring-ass tasks in a lab. How motivated do you think they are to actualize their full willpower potential?

Even if participants get a reward, the motivation is only extrinsic. That’s why experimental studies on self-control don’t investigate self-discipline. Self-discipline is self-motivated—intrinsic motivation. Self-discipline means embedding your willpower challenges into your own life and lifestyle, while self-control in a lab is just some random task.

As I’ve explained in my article about the central mechanism underlying fatigue, motivation is a crucial factor in how you experience of fatigue. If you’re extremely motivated to get up early, lift weights, eat healthy, and work hard, then doing those things, no matter how willpower-demanding, will only have a minor fatiguing effect on your willpower (if such an effect even exists in the first place, which I doubt).

What will stunt your willpower momentum, though, is shame. As Jocko points out, if you have just one first bite of a donut, “that donut gets crushed.” As soon as you put yourself in a situation where you think, Ah fuck it!, the shame that follows your failure initiates a momentum away from discipline, trapping you in a downward spiral. Instead of being proud, you feel ashamed, leading to stress, which makes you likely to attack this bad feeling by giving you a “treat” (= more shitty food or shitty entertainment)—this amplifies your shame, and down you go even lower.

As Kelly McGonigal put it,

the what-the-hell effect describes a cycle of indulgence, regret, and greater indulgence. […] You say to yourself, “I’ve already broken my [diet, budget, sobriety, resolution], so what the hell. I might as well really enjoy myself.” Crucially, it’s not the first giving-in that guarantees the bigger relapse. It’s the feelings of shame, guilt, loss of control, and loss of hope that follow the first relapse. (pp. 144f.)

Update: New research suggests that willpower depletion/elevation depends on one’s mindset, particularly cultural beliefs about self-control. If you believe that discipline enforces discipline, then it will; if you don’t, then it won’t. It’s a self-fulfilling prophecy.

Echo’s Perspective

3) Muscle Metaphor of Willpower

What Echo talks about in the video is well-documented in the scientific literature. A host of longitudinal studies have shown that exercising willpower on a regular basis increases domain-unspecific willpower over time (Baumeister et al. 2006):

When people engaged in a regular self-regulatory exercise like tracking food eaten or improving posture for two weeks, their persistence at holding a handgrip improved relative to people who didn’t exercise their willpower muscle.
When people adhered to an exercise program for two months, their willpower to resist distraction increased.
When people kept track of their spending for one to four months, their visual tracking performance improved in similar fashion.
When people adhered to a study program, they consumed less nicotine, alcohol, and caffeine, exercised more, did more household chores, ate a more healthy diet, and showed improved self-regulatory capacities as compared to those who were on a waiting list for the program.
When subjects used their non-dominant hand for everyday activities for two weeks, their anagram performance got less impaired by an ego depletion task.
The same was found in subjects who monitored their language (i.e., avoid curse words, substitute “yeah” by “yes,” etc.) for two weeks.

In a more recent study, Bray and colleagues (2015) found that when people squeezed a handgrip twice a day for as long as possible, their performance after two weeks in a maximal incremental exercise test on a bicycle ergometer was significantly better than the performance of subjects who didn’t exercise their willpower muscle with a handgrip.

According to a neurobiologically informed strength model of self-control (Berkman et al. 2012), such willpower training may be effective due to functional and structural changes in the right inferior frontal gyrus, a brain area in the frontal lobe.

Furthermore, heart rate variability, the variation in the time interval between consecutive heartbeats (Acharya 2006), has been found to be a physiological substrate of willpower, at least in the sense that it can predict willpower performance (Reichl 2015, Segerstrom & Solberg Nes 2007, Reynard et al. 2011). Therefore, you can strengthen your will by increasing your baseline heart rate variability (more accurately, by strengthening your vagal tone). In fact, since regular physical exercise elevates this baseline (Sandercock et al. 2005), you literally exercise your willpower muscle when you exercise your skeletal muscles.

Overall, there seems to be plenty of evidence for that fact that willpower can be trained like a muscle. Echo is right. When you fatigue your willpower today, it will be stronger tomorrow. So fatigue your willpower today!

Update: A new study suggests that self-control training might be ineffective after all.

4) Not just a metaphor

Echo also suggests that muscle fatigue is comparable to willpower fatigue. In my article about the nature of fatigue I advocate the idea that they are largely the same phenomenon because:

Structurally, both share the central governor framework.
Neurally, both are associated with similar brain structures, for example, prefrontal cortex (Tanaka & Watanabe 2012, Suchy 2009), anterior cingulate cortex (Tanaka & Watanabe 2012, Inzlicht & Gutsell 2007), and anterior insula (Tops et al. 2013, Evans et al. 2015).
Chemically, both have the same physiological inputs influencing the experience; for example, stimulants and carbohydrates increase, while cytokines (proteins built by the immune system to trigger “sickness behavior”) decrease both muscle and willpower performance (Evans et al. 2015).
Behaviorally, both are associated with an impaired ability to perform optimally at a challenging task.
Experientially, both are associated with low desire to perform optimally at a challenging task.
Psychologically, both can be affected by motivation, beliefs, and other cognitive processes.

However, one difference seems to be that while willpower fatigue is based solely on fatigue of the central nervous system, muscle fatigue might additionally (yet not primarily) depend on local metabolic limitations such as a buildup of metabolites within the muscle fiber (Allen et al. 2008, Enoka et al. 1992).

Conclusion

Jocko is right that willpower has inertia. When your will moves vigorously on a prideful way of discipline, its power grows and grows. There’s no convincing evidence for the claim that willpower deteriorates over the course of a day. (Fatigue does exist, but it’s not as simple as ego depletion.)
Conversely, if you get weak and take a step toward instant gratification, your momentum can quickly reverse and lead you down a path of shame. Self-discipline fueled by intrinsic motivation can protect you from this.
Echo is right that willpower can be trained like a muscle through regular exercise.
Willpower fatigue is largely the same phenomenon as muscle fatigue.

Be aware that fatigue is only your brain trying to trick you into stopping what you’re doing in order to conserve energy and protect homeostasis. Fatigue is a feeling, a warning system. Just like you can keep pushing yourself when your muscles feel fatigued, you can keep going hard when your will or focus feels fatigued, too. Be warned, then do what you want!

Resources

Acharya, U. R., Joseph, K. P., Kannathal, N., Lim, C. M., Suri, J. S. (2006). Heart rate variability: a review. Medical & Biological Engineering & Computing 44, pp. 1031-1051.

Allen, D. G., Lamb, G. D., Westerblad, H. (2008). Skeletal muscle fatigue: Cellular mechanisms. Physiological Reviews 88(1), pp. 287-332.

Baumeister, R. F., Heatherton, T. F. (1996). Self-Regulation Failure: An Overview. Psychological Inquiry 7(1), pp. 1-15.

Baumeister, R. F., Gailliot, M., DeWall, C. N., Oaten, M. (2006). Self-regulation and personality: how interventions increase regulatory success, and how depletion moderates the effects of traits on behavior. Journal of Personality 74(6), pp. 1773-1801.

Berkman, E. T., Graham, A. M., Fisher, P. A. (2012). Training Self-Control: A Domain-General Translational Neuroscience Approach. Child Development Perspectives 6(4), pp. 374-384.

Bray, S. R., Graham, J. D., Saville, P. D. (2015). Self-control training leads to enhanced cardiovascular exercise performance. Journal of Sports Sciences 33(5), pp. 534-543.

Enoka, R. M., Stuart, D. G. (1992). Neurobiology of muscle fatigue. Journal of Applied Physiology 72(5), pp. 1631-1648.

Evans, D. R., Boggero, L. A., Segerstrom, S. C. (2015). The Nature of Self-Regulatory Fatigue and “Ego Depletion”: Lessons From Physical Fatigue. Personality and Social Psychology Review, pii: 1088868315597841. [Epub ahead of print]

Inzlicht, M., Gutsell, J. N. (2007). Running on empty: neural signals for self-control failure.Psychological Science 18(11), pp. 933-937.

McGonigal, K. (2013). The Willpower Instinct. How Self-Control Works, Why It Matters, and What You Can Do to Get More of It. Penguin Group (USA) LLC.

Philippe B., Wei H. Y., Guy A. D., Diane B. B. (2012). A Circadian Rhythm in Heart Rate Variability Contributes to the Increased Cardiac Sympathovagal Response to Awakening in the Morning. Chronobiology International 29(6), pp. 757-768, doi: 10.3109/07420528.2012.674592.

Reichl, D. (2015). Effects of Paced Respiration on Attentional Impulse Control. Master Thesis. Supervised by ao. Univ.-Prof. Dipl.-Biol. Dr. Karl Grammer. University of Vienna.

Reynard, A., Gevirtz, R., Berlow, R., Brown, M., Boutelle, K. (2011). Heart Rate Variability as a Marker of Self-Regulation. Applied Psychophysiology and Biofeedback 36, pp. 209-215.

Sandercock, G. R., Bromley, P. D., Brodie, D. A. (2005). Effects of exercise on heart rate variability: inferences from meta-analysis. Medicine & Science in Sports & Exercise 37(3), pp. 433-439.

Segerstrom, S. C., Solberg Nes, L. (2007). Heart Rate Variability Reflects Self-Regulatory Strength, Effort, and Fatigue. Psychological Science 18(3), pp. 275-281.

Suchy, Y. (2009). Executive functioning: overview, assessment, and research issues for non-neuropsychologists. Annals of Behavioral Medicine 37(2), pp. 106-116.

Tanaka, M., Watanabe, Y. (2012). Supraspinal regulation of physical fatigue. Neuroscience and Biobehavioral Reviews 36(1), pp. 727-734.

Tops, M., Boksem, M. A. S., Koole, S. L. (2013). Subjective effort derives from a neurological monitor of performance costs and physiological resources [Commentary on Kurzban et al.’s “An opportunity cost model of subjective effort and task performance”]. Behavioral and Brain Sciences 36(6), pp. 703-704.