Why do we make worse decisions at the end of the day?

Decision Fatigue

, explained.

What is Decision Fatigue?

Decision fatigue describes how our decision-making gets worse as we make additional choices and our cognitive abilities get worn out. Decision fatigue is the reason we feel overwhelmed when we have too many choices to make.1

Decision fatigue

Where this bias occurs

Decision fatigue is a cognitive shortcut that causes irrational trade-offs in decision-making.2 One prominent example is Barack Obama’s presidential outfits. He claims to have worn the same colored suits every day so as to limit the number of decisions he has to make.3 Obama understood decision fatigue and how it can compromise the quality of important choices. 

The phenomena of decision fatigue can affect even the most rational and intelligent individuals, as everyone can become mentally exhausted. The more decisions made throughout the day, the harder each decision becomes for us. Eventually, the brain looks for shortcuts to circumvent decision fatigue, leading to poor decision-making.

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Individual effects

Decision fatigue causes the quality of our decisions to decline as we become mentally exhausted. Decision fatigue causes us to make poor decisions, because, as we reach mental exhaustion, our brains take illogical shortcuts to aid us in our decision-making. These shortcuts result in less deliberate decisions. Another shortcut involves procrastinating the decision-making task.1

Systemic effects

On a large scale, decision fatigue could impact decision-making at a high-level, and affect the choices taken by company executives, academic leaders, and politicians. Globally, we regularly make choices and decisions that can impact the world. 

Systemically it is hard to address decision fatigue, as mental fatigue occurs for all us. Creative responses to tackle issues like decision fatigue and preventing burnout have included proposals for shorter workdays, or 4-day workweeks, as is being done in New Zealand.4

Why it happens

Decision fatigue occurs due to the mental exhaustion we face from having to make too many decisions. The following factors can contribute to the development of decision fatigue. 

People who more frequently have to make decisions based on trade-offs experience decision fatigue more intensely. As an example, those who live in poverty typically have to struggle with trade-offs continually. The average American usually won’t have to struggle over deciding if they can afford soap, but that decision may be more common in, for example, rural India.4

Dean Spears is an economist and researcher at Princeton University. Spears experimented to understand better and document the impact of trade-offs in more impoverished communities and its effect on an individual’s willpower. In 20 different villages in Rajasthan, Spears offered individuals the option to buy bars of soap for the equivalent of fewer than 20 cents, a steep discount in comparison to the typical price.4

Regardless of the cut, the dollar amount was still a straining factor for individuals, especially in the ten most impoverished villages. Additionally, the decision-making effort involved for the more impoverished participants took an amount of mental energy for them to verify if the trade-off was worth the cost. Whether or not the individuals chose the deal and bought the soap, the consideration needed in making the decision left each person with less willpower which was measured later by researchers.4

In comparison, participants from the more affluent villages were not as affected by the decision, and when tested, their willpower wasn’t as tarnished by the previous decision-making task. Researchers believe this was due to their socio-economic background, as they had more money and did not require to assess the trade-offs of buying soap as intensely as those with less money.1

Spears argued that this type of decision fatigue trapped people in poverty, as their financial situations forced them to make more trade-offs when making decisions. The additional decision fatigue experienced by these individuals led to them having less willpower to devote to school work, careers, and other activities then help them achieve middle-class status.4

The recommendation to never go grocery shopping while hungry has actual merit. The impact glucose levels have on decision fatigue was first accidentally discovered by a failed experiment at the Baumeister lab. The brain is better at avoiding decision fatigue when adequately supplied, deriving its energy from glucose, the sugar obtained from a wide variety of food. Researchers at Baumeister’s lab tested the impact of glucose on participants and found that supplying glucose helped individuals mitigate ego depletion and sometimes completely reversed it. The restored willpower people would then develop, would better their ability to self-control, and make decisions.5

Why it is important

We need to be mindful of decision fatigue, as it is both prevalent in our lives and can lead to bad decision making and burnout for many people.6

Decision fatigue can also lead people to avoid making decisions all together, a phenomenon referred to as decision avoidance.8 Due to the growing body of research on this topic, specific techniques have been developed to aid managers across industries deal with decision fatigue and decision avoidance.9 Without an awareness of decision fatigue, individuals would not be able to help themselves, or those in managerial positions combat decision fatigue.

Decision fatigue can also influence how we impulsively purchase in both big and small ways. For example, when we are grocery shopping, we have to make many choices, especially regarding the trade-offs of buying certain items. If we chose to go grocery shopping with low glucose levels, our decision-making ability could especially be affected by decision fatigue. For this reason, it is always advised to eat before buying purchases. Decision-making choices while making purchases could result in over-buying or buying items we don’t need.1

Finally, decision fatigue can significantly impair our ability to self-regulate. Experiments have shown connections between decision fatigue and ego depletion, where the more choices we make, the higher the impact on our ability to self-control against impulses.10

How to avoid it

Researchers have identified different ways to reduce or eliminate decision fatigue in our decision-making process.

Reducing necessary choices or decisions to make is a common technique used to curve the decision fatigue. A typical example of this is from the initial example with Obama, where he told Vanity Fair in 2012: “you’ll see I wear only gray or blue suits. I’m trying to pare down decisions. I don’t want to make decisions about what I’m eating or wearing, because I have too many other decisions to make.”3

Famously, other prominent businessmen, such as Steve Jobs and Mark Zuckerberg, have also used this trick to eliminate unnecessary decision-making and focus on more relevant decisions.13 By creating and sticking to routines, we will have fewer decisions to make in our day-to-day activities. An example of habits we can set would include having strict bedtimes, and morning wake-ups, specific days and times to exercise, and specific days to do chores throughout the week.13

As previously noted, glucose levels can impact our ability to make consistent decisions. Managing and maintaining blood sugar levels can be done by snacking throughout the day, or only making decisions after eating, which can help prevent decision fatigue.13 Also mentioned earlier on is that we make better decisions earlier in the day. To avoid decision fatigue, we can schedule work meetings and critical decision making at the beginning of the day to take advantage of this trait.13

Finally, resting helps us to maintain balance and better make decisions. People who burnout and are continually making decisions and overwhelming their cognitive processes. By taking time-off on weekends or throughout the day, we can help reduce decision fatigue in our decision-making process.13,5 

How it all started

The term decision fatigue was first documented by the social psychologist, Roy F. Baumeister, to describe the mental and emotional strain resulting from the burden of making choices.

The term decision fatigue also looks at the concept of ego depletion, first discussed by Freud. Freud theorized that our egos depend on mental activities, which involved the transfer of energy. Freud’s theory of a mental energy model was primarily ignored until Baumeister studied mental disciplines at Case Western and Florida State University. Freud’s mental energy model inspired Baumeister’s work on decision fatigue and its impact on decision-making.1

The experiments conducted by Baumeister demonstrated that mental energy is finite, especially regarding its impact on our self-control. Baumeister noted that when we avoid temptations, such as eating chocolate chip cookies, we cannot resist other temptations. For example, Baumeister noted that study subjects gave up more quickly when asked to solve problems, such as working on a geometry puzzle when not indulging their primary temptations. Based on Baumeister’s investigations, he concluded that willpower was a form of mental energy that could be exhausted.10 His experiments confirmed the 19th-century assumptions that willpower was like a muscle, which eventually became fatigued by use.

Example 1 - Parole decisions

A famous example of decision fatigue is its influence on decision making at the judicial level. 

Certain prisoners in the justice system are given opportunities for parole throughout their sentence. Parole hearings, which occur between judges and prisoners, are typically assigned randomly throughout the day. Due to decision fatigue, the time of a parole appointment is particularly important, and an indicator of parole hearing results. Prisoners with earlier parole hearings are more likely to be given parole than prisoners with afternoon hearings, due to judges suffering from decision fatigue by afternoon time. The decision fatigue causes judges to choose the default option typical in parole hearings, which is to deny parole.1

The scenario described above has been tested through several experiments, including one study published in The Proceedings of the National Academy of Sciences (PNAS) examining parole procedures in an Israeli prison system. The analysis follows three different men in the Israeli prison system and the decision of a parole board. All three prisoners in question had completed at least two-thirds of their sentences. The order of the parole cases was as followed:

Case 1: Took place at 8:50 a.m. and involved an Arab Israeli who was currently serving a 30-month sentence in jail for fraud. 

Case 2: Took place at 3:10 p.m. and involved a Jewish Israeli who was currently serving a 16-month sentence in jail for assault. 

Case 3: Took place at 4:25 p.m. and involved an Arab Israeli who was currently serving a 30-month sentence in jail for fraud.

Of these three men, only the first prisoner was granted parole: the prisoner whose parole sentence was in the morning. Even though case 1 and case 3 had similar prisoners serving the same sentence, the third prisoner did not receive parole. In case 2, the prisoner had initially received a shorter sentence and was still not granted parole. The study authors concluded that the results occurred due to the timing of the appointments.1

The above example is consistent with an over-arching pattern found within the prison parole process. After analyzing more than 1,100 parole decisions over a year, the journal found that timing was the primary indicator of parole approval. Prisoners who had earlier scheduled appointments received parole in around 70% of cases, whereas prisoners with later parole hearings were granted parole around 10% fewer cases.1

Researchers Jonathan Levav of Stanford University, and Shai Danziger of Ben-Gurion University, state that this type of behavior is not unusual or malicious. The judges’ decision making becomes erratic due to the mental work required to rule on each case. As the day progresses decision fatigue influences the decision of the judges more.14

Example 2 - Self control

Another example of decision fatigue is exemplified by the experiment conducted by the postdoctoral fellow Jean Twenge at the Baumeister laboratory. Twenge investigated the impact of decision fatigue and self-control on students when making decisions.1

For the first part of the experiment, Twenge retrieved an array of items from a department store that would appeal to college students. The researcher told participants they would be allowed to keep an item for themselves only after answering a series of questions. Students made choices that involved choosing between the department stores items, such as choosing between keeping a pen or a candle, or between two different scented candles. The students had to make several decisions throughout the experiment process.1

The second group of students in this study was called non-deciders. The non-deciders had to assess all department store products without making any choices. This group of students only gave their opinion on each product and reported how often they had previously used it in the past six months.1

The second part of the experiment then tested both groups and their self-control. They tested participants’ self-control by asking them to hold their hand in ice water for as long as possible. Individuals needed the self-discipline to keep their hands in the water, as the natural impulse is to pull their hand out of the uncomfortable water. Researchers thus measured self-discipline by how long participants were able to keep their hands in the water. The first group of participants, which consisted of students who had to make many decisions, kept their hands on average for twenty-eight seconds in the cold water. In comparison, participants who were not asked to make decisions kept their hands in the water on average for sixty-seven seconds, more than twice as long as the other control group.1

Researchers concluded that participants who were not required to make decisions earlier in the experiment could hold their hands longer in the cold water due to their increased willpower. Students who experienced decision fatigue from previously having to make so many decisions lacked willpower when it came to the second part of the experiment.1


What it is

Decision fatigue is a phenomenon that occurs when individuals make worse decisions as time goes on. Decision fatigue is why individuals feel overwhelmed when they have too many choices to make. 

Why it happens

Decision fatigue occurs for various reasons, including but not limited to: mental exhaustion faced by trade-offs, economic background, and glucose levels. 

Example 1 – Parole Decisions

Decision fatigue is notable in judges when granting parole for prisoners in the judicial system. Prisoners approved for parole usually had earlier parole appointments. This behavior occurred in the judge’s decision making because as the day progressed, decision fatigue would further influence the judges’ decision on parole approval. 

Example 2 – Self control

Another example of decision fatigue was demonstrated by Jean Twenge while working at the Baumeister laboratory. His experiment looked to identify if decision fatigue impacted self-control. The test confirmed that the control group who faced decision-making questions was more affected by decision fatigue and had less self-control than the other control.

How to avoid it 

Individuals can avoid decision fatigue by reducing choices in their everyday lives, creating routines, managing glucose levels, resting, and making decisions earlier in the day. 


  1. Danziger, S., Levav, J., & Avnaim-Pesso, L. (2011). Extraneous factors in judicial decisions.Proceedings of the National Academy of Sciences,108(17), 6889-6892.
  2. Lewis, M. (2012, September 11). Obama’s Way. Retrieved August 18th, 2020, from https://www.vanityfair.com/news/2012/10/michael-lewis-profile-barack-obama
  3. Baumeister, Roy F (2003), “The Psychology of Irrationality”, in Brocas, Isabelle; Carrillo, Juan D (eds.), The Psychology of Economic Decisions: Rationality and well-being, pp. 1–15, ISBN 978-0-19-925108-7.
  4. Burrows, M. (2020, June 02). Four-day work week: A silver bullet for New Zealand’s economy post-COVID-19 or an idealist fantasy? Retrieved August 03, 2020, from https://www.newshub.co.nz/home/money/2020/06/four-day-work-week-a-silver-bullet-for-new-zealand-s-economy-post-covid-19-or-an-idealist-fantasy.html
  5. Spears, D., Ghosh, A., & Cumming, O. (2013). Open Defecation and Childhood Stunting in India: An Ecological Analysis of New Data from 112 Districts. PLoS ONE, 8(9). doi:10.1371/journal.pone.0073784
  6. Lamothe, C. (2019, October 03). Decision Fatigue: What It Is and How to Avoid It. Retrieved from https://www.healthline.com/health/decision-fatigue
  7. Fraga, J. (2015, April 24). How to Identify and Prevent Burnout. Retrieved from https://www.healthline.com/health/tips-for-identifying-and-preventing-burnout
  8. Spears, Dan (9 December 2010), “Economic decision-making in poverty depletes behavioral control” (PDF), Griswold Center for Economic Policy Studies, Princeton University, retrieved 24 October 2018.
  9. Anderson, Christopher (2003). “The Psychology of Doing Nothing: Forms of Decision Avoidance Result from Reason and Emotion”. Psychological Bulletin. 129 (1): 139–167. doi:10.1037/0033-2909.129.1.139. PMID 12555797. SSRN 895727.
  10. Mawby, William D (2004), Decision process quality management, p. 72, ISBN 978-0-87389-633-7.
  11. Baumeister, Roy F.; Vohs, Kathleen D. (2003). “Willpower, Choice, and Self-Control”. In Loewenstein, George; Read, Daniel; Baumeister, Roy F. (eds.). Time and Decision: Economic and Psychological Perspectives of Intertemporal Choice. Russell Sage. pp. 201–214. ISBN 978-1610443661.
  12. Lewis, M. (2012, October). Michael Lewis: Obama’s Way. Retrieved August 03, 2020, from https://www.vanityfair.com/news/2012/10/michael-lewis-profile-barack-obama
  13. Baer, Drake (28 April 2015). “The scientific reason why Barack Obama and Mark Zuckerberg wear the same outfit every day”. Business Insider. Retrieved 24 October 2018.
  14. W. (2019, May 17). How to Identify When You’re Experiencing Decision Fatigue. Retrieved from https://www.forbes.com/sites/womensmedia/2019/05/13/how-to-identify-when-youre-experiencing-decision-fatigue/
  15. Danziger, S., Levav, J., & Avnaim-Pesso, L. (2011). Extraneous factors in judicial decisions. Proceedings of the National Academy of Sciences, 108(17), 6889-6892. doi:10.1073/pnas.1018033108

About the Authors

Dan Pilat's portrait

Dan Pilat

Dan is a Co-Founder and Managing Director at The Decision Lab. He is a bestselling author of Intention - a book he wrote with Wiley on the mindful application of behavioral science in organizations. Dan has a background in organizational decision making, with a BComm in Decision & Information Systems from McGill University. He has worked on enterprise-level behavioral architecture at TD Securities and BMO Capital Markets, where he advised management on the implementation of systems processing billions of dollars per week. Driven by an appetite for the latest in technology, Dan created a course on business intelligence and lectured at McGill University, and has applied behavioral science to topics such as augmented and virtual reality.

Sekoul Krastev's portrait

Dr. Sekoul Krastev

Sekoul is a Co-Founder and Managing Director at The Decision Lab. He is a bestselling author of Intention - a book he wrote with Wiley on the mindful application of behavioral science in organizations. A decision scientist with a PhD in Decision Neuroscience from McGill University, Sekoul's work has been featured in peer-reviewed journals and has been presented at conferences around the world. Sekoul previously advised management on innovation and engagement strategy at The Boston Consulting Group as well as on online media strategy at Google. He has a deep interest in the applications of behavioral science to new technology and has published on these topics in places such as the Huffington Post and Strategy & Business.

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