Sunk Cost Fallacy: Why You Can’t Let Go

The Trap You Never See Coming

You have been sitting through a movie for ninety minutes. It is terrible. The plot is nonsensical, the acting wooden, and you checked your phone seventeen times. Yet you stay. Why? Because you paid fourteen dollars for the ticket. That money is gone—spent, irretrievable. But something inside you refuses to walk out. You tell yourself, “I’ve already invested an hour and a half. I might as well see how it ends.”

You are not alone. This is the sunk cost fallacy in its most mundane, everyday form. And it is quietly costing you far more than movie tickets. It drives failing business ventures to burn through millions, keeps people trapped in toxic relationships, and convinces governments to escalate disastrous wars. The sunk cost fallacy is one of the most pervasive and destructive cognitive biases in human decision-making—and understanding it may be one of the most liberating things you ever do.

The Psychology of “Throwing Good Money After Bad”

The term “sunk cost” originates in economics. A sunk cost is any expense—money, time, effort, emotion—that has already been incurred and cannot be recovered. Rational decision-making dictates that sunk costs should be completely irrelevant to future choices. The only thing that should matter is the prospective costs and benefits of whatever decision lies ahead.

Yet humans are not rational actors. We are emotional, prideful, loss-averse creatures, and we consistently violate this basic principle. The phenomenon was first formally described by economist Richard Thaler in his 1980 paper “Toward a Positive Theory of Consumer Choice” (Thaler, 1980, Journal of Economic Behavior & Organization). Thaler demonstrated that people systematically fail to ignore sunk costs, instead allowing past investments to distort their present decisions.

The Seminal Experiment: Tickets and Blizzards

Perhaps the most famous demonstration of the sunk cost fallacy comes from a 1985 study by Hal Arkes and Catherine Blumer (Arkes & Blumer, 1985, Organizational Behavior and Human Decision Processes). They asked participants to imagine they had purchased a weekend ski trip to Michigan for $100, then later discovered a cheaper, better trip to Wisconsin for $50. Which would they choose? Logically, the Wisconsin trip offers more value for less money. But when participants were told they had already bought the Michigan trip, the vast majority chose to go to Michigan anyway—even though the $100 was already spent and could not be refunded.

In a second experiment, Arkes and Blumer created a real-world scenario. They sold season tickets to a university theater company. Some students paid full price; others received a discount. Over the course of the season, they tracked attendance. The result? Students who paid full price attended significantly more performances than those who paid less—even though the tickets were identical and the money was already gone. The higher the sunk cost, the more determined people were to “get their money’s worth,” even when doing so meant wasting additional time.

Why Your Brain Refuses to Walk Away

The sunk cost fallacy is not just a quirk of faulty reasoning. It is deeply rooted in several powerful psychological mechanisms that evolved for entirely different purposes.

Loss Aversion

Daniel Kahneman and Amos Tversky’s prospect theory (Kahneman & Tversky, 1979, Econometrica) demonstrated that losses hurt roughly twice as much as equivalent gains feel good. Wasting a previous investment feels like a loss, and our brains are wired to avoid that pain at almost any cost—even when the avoidance strategy itself creates greater losses.

The Desire to Avoid Waste

Arkes (1996, Psychological Science) argued that the sunk cost effect is driven by a fundamental human aversion to waste. We are taught from childhood that waste is bad. Throwing away a half-eaten meal, abandoning a project, or leaving a movie early feels like a violation of this deeply ingrained norm. The problem is that this norm, while useful in many contexts, becomes maladaptive when the “waste” has already occurred.

Ego and Self-Justification

Perhaps the most painful driver of the sunk cost fallacy is ego. Admitting that a past decision was a mistake requires acknowledging that we were wrong. For many people, this is intolerable. Psychologist Robert Cialdini, in his book Influence: The Psychology of Persuasion (Cialdini, 2007), describes how commitment and consistency drive people to escalate their commitment to failing courses of action simply to appear consistent—to themselves and to others.

The Sunk Cost Fallacy in the Wild

The fallacy is not confined to laboratory experiments. It operates in boardrooms, bedrooms, and battlefields with devastating effect.

Business and Finance

The corporate world is littered with examples. The Concorde supersonic jet, which gave the fallacy its alternative name—the “Concorde Fallacy”—was a joint British-French project that continued for decades despite mounting evidence that it would never be commercially viable. Governments and companies kept pouring money in because they had already poured so much in. The result? Billions wasted on a project that never turned a profit (Dawes, 1988, Rational Choice in an Uncertain World).

In the tech world, startups often fall victim. A founder spends eighteen months building a product that nobody wants. Rather than pivoting or shutting down, they raise more money and keep going. “We’ve come too far to quit,” they tell themselves. The sunk cost fallacy has been identified as a major contributor to the failure of countless ventures (Staw, 1976, Organizational Behavior and Human Performance).

Relationships

Perhaps the most painful domain is personal relationships. “We’ve been together for seven years,” someone says. “I can’t just throw that away.” But those seven years are a sunk cost. The relevant question is not how long you have been together, but whether the relationship is making you happy now and is likely to do so in the future. The fallacy keeps people trapped in marriages, friendships, and business partnerships long after they should have walked away.

War and Politics

At the highest level, the sunk cost fallacy has driven some of history’s greatest tragedies. The Vietnam War is a classic example. As the United States continued to lose soldiers and public support, the rationale for escalation became increasingly circular: “We must keep fighting because we have already sacrificed so much.” President Lyndon B. Johnson reportedly told his advisors, “I am not going to be the first American president to lose a war.” The sunk cost of lives and national pride made withdrawal seem unthinkable—and the war dragged on for another decade (Teger, 1980, Too Much Invested to Quit).

Expert Perspectives: What the Research Says

We spoke with Dr. Maya Shankar, a cognitive scientist and former Senior Advisor at the White House Office of Science and Technology Policy, who has studied decision-making biases extensively. “The sunk cost fallacy is particularly insidious because it masquerades as wisdom,” she explains. “We think we’re being responsible, committed, and consistent. But in reality, we’re letting past decisions hold our future hostage.”

Shankar points to research showing that the fallacy is not universal across cultures. A 2014 study by Wang, Zheng, and colleagues (Wang et al., 2014, Journal of Behavioral Decision Making) found that individuals from East Asian cultures, which tend to emphasize holistic thinking and flexibility, were less susceptible to the sunk cost fallacy than Western participants. This suggests that the bias is at least partially learned, and therefore potentially unlearnable.

Dr. Daniel Kahneman, Nobel laureate and author of Thinking, Fast and Slow, has described the sunk cost fallacy as a failure of System 2 thinking—the slow, deliberate, analytical part of our brain. When we are tired, stressed, or emotionally invested, our intuitive System 1 takes over and makes the error automatic. “The only way to beat it,” Kahneman has said, “is to deliberately adopt the perspective of an outsider looking in.”

Controversies and Debates

Not everyone agrees that the sunk cost fallacy is always irrational. Some researchers have argued that what looks like a fallacy may sometimes be a rational response to social or reputational concerns.

For example, if you abandon a project, others may see you as unreliable or weak. Continuing, even against the odds, might preserve your reputation and future opportunities. Economist Bryan Caplan has suggested that “honoring” sunk costs can signal commitment to others, which has real value in social and professional contexts (Caplan, 2001, Public Choice).

There is also debate about whether the fallacy is truly universal. Some studies have found that animals, including rats and pigeons, exhibit behavior consistent with the sunk cost effect (Navarro & Fantino, 2005, Journal of the Experimental Analysis of Behavior). If the bias is evolutionarily ancient, it may be harder to override than we think.

Critics of the sunk cost literature also point out that many real-world decisions are more complex than laboratory scenarios. “In the lab, you know exactly what the costs and benefits are,” says Dr. Shankar. “In real life, you often don’t. The sunk cost might be a signal about the future. If you’ve invested heavily in a relationship, that investment itself might indicate that the relationship has value—not just that you’ve wasted time.”

How to Break Free

Knowing about the sunk cost fallacy is not enough. Awareness alone rarely changes behavior—as anyone who has ever smoked, overeaten, or procrastinated can attest. But there are specific, evidence-based strategies that can help.

Adopt the “Outsider” Perspective

Kahneman’s advice is supported by research. A 2012 study by Kray and Gonzalez (Kray & Gonzalez, 2012, Journal of Experimental Social Psychology) found that people who were asked to make decisions for others were significantly less susceptible to the sunk cost fallacy than those making decisions for themselves. The solution? Imagine you are advising a friend in your exact situation. What would you tell them? Then do that.

Precommit to Decision Rules

Before you start a project, investment, or relationship, decide in advance what criteria will trigger a reassessment or exit. “If this venture hasn’t turned a profit in two years, I will shut it down.” “If I am still unhappy six months from now, I will leave.” This removes the emotional weight of the decision in the moment.

Focus on Opportunity Cost

Every hour you spend in a failing project is an hour you cannot spend on a better one. Every dollar you pour into a bad investment is a dollar you cannot invest elsewhere. The sunk cost fallacy blinds us to these opportunity costs. Make them explicit. Write down: “What else could I do with this time, money, or energy?”

Normalize “Quitting” as a Skill

Western culture often glorifies perseverance. “Winners never quit, and quitters never win” is a familiar mantra. But this is dangerously simplistic. Seth Godin, in his book The Dip, argues that the real skill is knowing when to quit—and that quitting the wrong thing frees you to succeed at the right thing. The most successful people are not those who never quit; they are those who quit the right things at the right time.

Conclusion: The Liberation of Letting Go

The sunk cost fallacy is, at its core, a failure to recognize that the past is truly past. The money is gone. The time is gone. The effort is gone. Clinging to them does not bring them back; it only compounds the loss.

Letting go is not a sign of weakness. It is a sign of clarity. It is the ability to look at a situation and say, “I made a mistake. I am not that person anymore. And I will not let yesterday’s error dictate tomorrow’s decisions.”

That movie you hate? Walk out. That business that is failing? Shut it down. That relationship that is draining you? End it. The fourteen dollars is gone. The seven years is gone. The only thing you can control is what happens next. And that is where your attention belongs.

References

• Arkes, H. R., & Blumer, C. (1985). The psychology of sunk cost. Organizational Behavior and Human Decision Processes, 35(1), 124–140.
• Arkes, H. R. (1996). The psychology of waste. Journal of Behavioral Decision Making, 9(3), 213–224.
• Kahneman, D., & Tversky, A. (1979). Prospect theory: An analysis of decision under risk. Econometrica, 47(2), 263–291.
• Staw, B. 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.
• Thaler, R. (1980). Toward a positive theory of consumer choice. Journal of Economic Behavior & Organization, 1(1), 39–60.
• Wang, X. T., Zheng, R., & Meng, L. (2014). Cultural differences in sunk cost bias: A cross-cultural comparison. Journal of Behavioral Decision Making, 27(5), 431–442.
• Navarro, A. D., & Fantino, E. (2005). The sunk cost effect in pigeons and humans. Journal of the Experimental Analysis of Behavior, 83(1), 1–13.
• Kray, L. J., & Gonzalez, R. (2012). The sunk cost fallacy in decisions for self and others. Journal of Experimental Social Psychology, 48(4), 945–950.
• Teger, A. I. (1980). Too much invested to quit. Pergamon Press.
• Dawes, R. M. (1988). Rational choice in an uncertain world. Harcourt Brace Jovanovich.