Sunk Cost Fallacy
AKA: "Throwing Good Money After Bad"
The phenomenon where a person is reluctant to abandon a strategy or course of action because they have invested heavily in it, even when it is clear that abandonment would be more beneficial.
What is Sunk Cost Fallacy?
The phenomenon where a person is reluctant to abandon a strategy or course of action because they have invested heavily in it, even when it is clear that abandonment would be more beneficial.
Sunk Cost Fallacy is a cognitive bias in which the phenomenon where a person is reluctant to abandon a strategy or course of action because they have invested heavily in it, even when it is clear that abandonment would be more beneficial. It occurs when loss aversion. We hate losing more than we like winning. For example, staying in a bad job, relationship, or investment because "I've already put so much into it."
The Trap (Example)
Staying in a bad job, relationship, or investment because "I've already put so much into it."
Why This Matters
High-stakes domains (medicine, law, finance) have developed entire systems to counteract Sunk Cost Fallacy. If professionals need safeguards, so do you.
Mechanism of Action
This error is driven by Loss aversion. We hate losing more than we like winning..
This bias exists because human brains evolved for survival, not accuracy. Loss aversion. We hate losing more than we like winning. served our ancestors well. In modern contexts, it often misfires.
Real-World Examples
In investing: Sunk Cost Fallacy leads to holding losing positions too long or selling winners too early.
In relationships: This bias causes people to interpret ambiguous signals in ways that confirm existing beliefs about partners.
In work: Sunk Cost Fallacy makes it harder to update strategies when market conditions change.
In health: People ignore symptoms that contradict their self-image as "healthy" or "young."
Research Background
Sunk Cost Fallacy has been studied extensively since the cognitive revolution. Research consistently shows that even warned subjects fall for it—awareness alone doesn't provide immunity.
Debug Protocol
Ignore the past cost. It is gone. Ask: "If I started today with what I have now, would I make this choice?"
Debiasing Strategies
Seek disconfirming evidence: Actively look for data that challenges your current belief.
Use decision journals: Write down predictions before outcomes are known, then review accuracy.
Consult diverse perspectives: People with different backgrounds spot different biases.
Implement decision rules: Pre-commit to criteria before emotionally charged situations arise.
Time-box decisions: Revisit important conclusions after a cooling-off period.
Related Reading
Is Your Hardware Faulty?
Some brains are more susceptible to this than others. Test your Discipline to find out.
Quick Facts
- Also Known AsThrowing Good Money After Bad
- CategoryCognitive Bias
- PrevalenceUniversal
Other Cognitive Biases
- Confirmation Bias
- Dunning-Kruger Effect
- Anchoring Bias
- Availability Heuristic
- Negativity Bias
- Planning Fallacy
- Survivorship Bias
- Hindsight Bias
- Halo Effect
- Framing Effect
- Status Quo Bias
- Bandwagon Effect
- Optimism Bias
- Curse of Knowledge
- Authority Bias
- Recency Bias
- Peak-End Rule
- Spotlight Effect
- Illusion of Control
- Self-Serving Bias
- Actor-Observer Bias
- Just-World Hypothesis
- Gambler's Fallacy
- Hot Hand Fallacy
- Blind Spot Bias
- Mere Exposure Effect
- IKEA Effect
- Endowment Effect
- Zero-Risk Bias
- Normalcy Bias
- Hyperbolic Discounting
- Affect Heuristic
- Fundamental Attribution Error
- In-Group Bias
- Choice Overload
- Decoy Effect
- Outcome Bias
- Distinction Bias
- Projection Bias
- Restraint Bias
- Reactance
- Proportionality Bias
- Naive Realism
- Moral Licensing
Sources
- Kahneman, D. (2011). Thinking, Fast and Slow
- Tversky, A. & Kahneman, D. (1974). Judgment under Uncertainty
- Ariely, D. (2008). Predictably Irrational
References & Sources
Kahneman, D. (2011). Thinking, Fast and Slow. Farrar, Straus and Giroux.
Tversky, A., & Kahneman, D. (1974). Judgment under Uncertainty: Heuristics and Biases. Science, 185(4157), 1124-1131. https://doi.org/10.1126/science.185.4157.1124
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Sunk Cost Fallacy: Frequently Asked Questions
What is Sunk Cost Fallacy?+
The phenomenon where a person is reluctant to abandon a strategy or course of action because they have invested heavily in it, even when it is clear that abandonment would be more beneficial.
Why is Sunk Cost Fallacy also called "Throwing Good Money After Bad"?+
The alternate name "Throwing Good Money After Bad" captures the intuitive essence of the bias. Sunk Cost Fallacy is the formal psychological term, while "Throwing Good Money After Bad" describes what it feels like in practice.
How do I stop Sunk Cost Fallacy?+
Ignore the past cost. It is gone. Ask: "If I started today with what I have now, would I make this choice?"
Why does Sunk Cost Fallacy happen?+
The underlying mechanism is loss aversion. we hate losing more than we like winning.. Human brains evolved heuristics for speed and survival, not accuracy in modern contexts.
Can smart people fall for Sunk Cost Fallacy?+
Yes. Intelligence doesn't provide immunity—sometimes it makes the bias worse because smart people are better at rationalizing. Awareness and structured decision processes are more protective than raw IQ.
What's an example of Sunk Cost Fallacy in real life?+
Staying in a bad job, relationship, or investment because "I've already put so much into it."
