Why people support their past ideas, even when presented with evidence that they're wrong?


Commitment Bias

, explained.

What is the Commitment Bias?

The commitment bias describes how people and groups are willing to support their past ideas and decisions – even when new evidence or events makes doing so irrational.


This bias is also known as escalation of commitment or the sunk cost fallacy. It was initially described by Barry M. Staw in his 1976 paper, “Knee deep in the big muddy: A study of escalating commitment to a chosen course of action”.

The commitment bias explains that we tend towards being consistent with our prior commitments, actions, thoughts and dispositions, even when it is against our own interests. As a byproduct of confirmation bias, we rarely seek out disconfirming evidence of what we believe. Instead, we tend to interpret evidence in a way that makes our past ideas seem better than they truly were. When we only seek out favorable evidence, it becomes easier to maintain our positive self-image.

An additional contributor to the commitment bias is an inherent desire to feel like we are right. We hold certain ideals about ourselves and the world, and we want to demonstrate to our peers these convictions. This shouldn’t come as a surprise. Society values consistency and conviction even when the ideas or beliefs behind the conviction may be questionable or problematic.  Consistency is associated with intellectualism, rationality, honesty and stability. Confirmation bias can also lead to escalation of commitment as individuals are then less likely to recognize the negative results of their decisions. On the other hand, if the results are recognized, they can be blamed on unforeseeable events occurring during the course of the project (Kelly, 2013).

Commitment Bias and Beliefs

We tend to invest heavily in our beliefs about the world and about ourselves. The more time and energy we invest in our beliefs —think money, effort, or pain – the more sunk costs we accumulate. The greater the sunk costs, the harder it becomes to change our mind. Whether or not we are actually right, we have strong convictions to believe that we are. Think about the last time you assembled a shelf. Even if the shelf has deficiencies, or doesn’t fit well into a room, you will likely find it much harder to give it away.

Three things you should know about the commitment bias:

  1. “Don’t make any promises that you can’t keep.”  – The commitment bias can be helpful in relationships as it binds people to uphold their promises.
  2. Commitment biases can be advantageous – Pre-commitment devices can be used to stave off procrastination and temptation in order to achieve goals.
  3. Marketing – Companies often use the commitment bias to their advantageous by trying to get customers to make small commitments early on such as signing up for a trail membership). Once a commitment has been made, it is less likely people will alter their behavior.

How to Confront the Commitment Bias

The first true defense to the commitment bias is developing an awareness about how it weighs in on our decision-making, and about the harm a certain rigidity in our decisions can cause us.

Psychology professor and author Robert Cialdini suggests two approaches to recognizing when these biases are influencing our decision making.

  1. Listen to your gut feeling – we often have a physical reaction to unfavorable requests such as when a salesperson is pushing us to far. Even if we have complied with similarly unfavorable requests in the past, we should not use that precedent as a reference point.
  2. Recall past actions and ask yourself: “Knowing what I know, if I could go back in time, would I make the same commitment?”



Pre-commitment devices can be used to stave off procrastination and temptation in order to achieve goals. For example, if someone publicly commit to their intentions (like going to the gym three times a week) so they become more likely to follow through on their plans. The website Stickk allows people to publicly commit  to a positive behavior change (e.g. give up junk food). The goal-setting platform created by behavioral economists at Yale University and draws on the principle of loss aversion. For example, if a user wants to lose weight, the decision to not go to the gym may be coupled with the fear of loss (see loss aversion) —a cash penalty in the case of non-compliance.

Education – Commitment to Beliefs

In his book Outliers, Malcolm Gladwell talks about how teachers who tend to identify students as smart not only affected how the teachers saw the student’s work but, more importantly, affected the opportunities teachers gave the students. Smarter students received better opportunities which shaped them to be better students. The teacher’s  early commitment to an individual student’s intelligence can perpetuate a self-fulfilling prophecy.


This concept is notable in the field of finance. Investors will often hold a position such as keeping a stock longer than would be advantageous, simply because they already committed to the investment.

TDL Insights

Pre-commitment and Procrastination: Behavioral Tools for Students

Pre-commitment strategies involve blocking out some of our future choices, in the knowledge that we will not have the willpower to resist them later. Many tools are available which can help students make small commitments to reduce procrastination and increase their chances at attaining their academic goals.

Financial Decision-Making

In the area personal finance, ample research has found that people sometimes purposefully choose not to access potentially helpful information, even when it is free and readily available, or ignore such information, even when it has been directly provided to them. This corresponds to what Golman et al. (2017) call hedonic reasons for information avoidance — namely “a desire to avoid bad news because it will make one feel bad”.


Gladwell, Malcolm. 2008. Outliers: The Story of Success. 1. ed. New York, NY: Back Bay Books.

Golman, Russell, David Hagmann, and George Loewenstein. “Information Avoidance.” Journal of Economic Literature 55(1) (2017): 96–135. https://doi.org/https://doi.org/10.1257/jel.20151245.

Hugill, Johhny. “Precommitment and Procrastination: Behavioral Tools for Students”. The Decision Lab. 2017. https://thedecisionlab.com/precommitment-and-procrastination-behavioral-tools-for-students/

Kelly, Theresa F; Milkman, Katherine L (2013). Escalation of Commitment”. In Kessler, Eric H (ed.). Encyclopedia of Management Theory. Thousand Oaks, CA: Sage Publications,pp. 256–259. doi:10.4135/9781452276090.n78.

Petrova, Petia K., and Robert B. Cialdini. 2011. “New Approaches toward Resistance to Persuasion.” In The SAGE Handbook of Social Marketing, 107–22. 1 Oliver’s Yard,  55 City Road, London EC1Y 1SP  United Kingdom: SAGE Publications Ltd. https://doi.org/10.4135/9781446201008.n8.

Shakhina, Natalia. “Are You Making Bad Financial Decisions Because of Information Avoidance. The Decision Lab. 2018. https://thedecisionlab.com/are-you-making-bad-financial-decisions-because-information-avoidance/

Smith, Adam. 2011. The Theory of Moral Sentiments. Kapaau (T.H.): Gutenberg publishers.

Staw, Barry M. 1981. “The Escalation of Commitment to a Course of Action.” The Academy of Management Review 6 (4): 577. https://doi.org/10.2307/257636.

Staw, Barry M. 1976. “Knee-Deep in the Big Muddy: A Study of Escalating Commitment to a Chosen Course of Action.” Organizational Behavior and Human Performance 16 (1): 27–44. https://doi.org/10.1016/0030-5073(76)90005-2.