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  • Writer's pictureAlyssa

Willpower is a Muscle: Ego Depletion and Decision Fatigue

Updated: May 31, 2019

I survive on willpower alone for many things; neither caffeine nor energy drinks affect me or keep me awake. Many all-nighters in college were done through sheer willpower alone and I’m proud of my ability to overcome obstacles based on my inner strength. However, as I get older, I notice that lack of sleep catches up on me more easily and late night decisions are harder to make. Many of my late nights are actual a vicious, self-perpetuating cycle because it is easier to stay awake then stop what I am doing, get up and get ready for bed.

For this reason, it was very interesting to discover that willpower is actually a finite resource that diminishes throughout the day – through each decision you make!

Self-Control and Willpower Can Be Depleted

A 1996 study by Roy Baumeister tested participants’ willpower by forcing them to eat radishes over chocolate chip cookies, after tantalizing them with the smell of the freshly baked treats. After the food experiment, participants were then given a second test using a persistence-testing puzzle. Those who were forced to choose the radishes over the cookies made fewer attempts and were far less interested in solving the puzzle versus a control group who did not make the food choice. Those who had to resist the cookies and eat an unappealing vegetable instead were too tired to engage in another difficult task. They were too tired because of the previous conscious control of willpower.

“…self-control is a general strength that’s used across different sorts of tasks  — and it [can] be depleted.”

This proved that self-regulation is not a skill to be mastered or a rote function that can be performed with little consequence. It’s like using a muscle: After exercising it, it loses its strength, gets fatigued, and becomes ineffectual, at least in the short-term. The Chocolate and Radish Experiment that Birthed the Modern Conception of Willpower

Making Decisions Requires Energy

Studies have found that willpower is linked to our glucose levels and with each decision we make, these glucose levels decrease. Blood glucose is believed to be an important part of self-control.

Enforcing self-control causes glucose levels to decrease – each decision made throughout the day depletes glucose supplies and a lack of self-control is linked to low glucose levels, or glucose cannot be reached quickly by the brain (such as when insulin is low or insensitive).

Willpower, or the ability to show self-control, can be depleted by acts of self-control as well as making decisions and choices, executing plans, and exerting initiative.

Alcohol also reduces glucose throughout the body and is known to impair many forms of self-control. (The Physiology of Willpower)

Freud first posed the idea of “ego depletion” (Roy Baumeister’s term) with his hypothesis that the self (or ego) transfers energy to perform mental activities and that these stores of energy are finite.

A study by the University of Wurzburg tested willpower and found three things:

People spend 3-4 hours a day struggling on whether or not to resist a particular desireFrequent episodes of denial made it increasingly likely an individual would give into temptationGlucose levels influence the ease with which an individual approaches each struggle of will

Glucose Levels Affect Willpower and Mental Focus

The discoveries about glucose help explain why dieting is a uniquely difficult test of self-control — and why even people with phenomenally strong willpower in the rest of their lives can have such a hard time losing weight. They start out the day with virtuous intentions, resisting croissants at breakfast and dessert at lunch, but each act of resistance further lowers their willpower. As their willpower weakens late in the day, they need to replenish it. But to resupply that energy, they need to give the body glucose. They’re trapped in a nutritional catch-22: In order not to eat, a dieter needs willpower. In order to have willpower, a dieter needs to eat.
Do You Suffer From Decision Fatigue?

How to Increase Depleted Willpower Glucose Levels

Get More Sleep – Studies show that those who are better rested have more willpower than tired people. Eating – Eating helps restores glucose levels. An interesting point: Hungry people are more likely to give into the need to be cranky and impatient rather than use their willpower to resist such urges. For those who are dieting, rather than resist food, eat small meals throughout the day. Positive Mood Experiences – Being put into a positive mood by pleasant experiences, socializing with friends, watching a movie, etc can all help improve depleted willpower levels. Exercise It – Like a muscle, willpower can become depleted, but it can also be exercised to increase its strength.

Further Blog Articles on the Topic of Ego Depletion

Understanding the Dangers of Ego Depletion – by Tim Ferris Willpower: How to Improve Your Personal Self Discipline

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