Sunk Cost Fallacy

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.

High-stakes domains (medicine, law, finance) have developed entire systems to counteract Sunk Cost Fallacy. If professionals need safeguards, so do you.

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.

• 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."

Ignore the past cost. It is gone. Ask: "If I started today with what I have now, would I make this choice?"

1. Seek disconfirming evidence: Actively look for data that challenges your current belief.
2. Use decision journals: Write down predictions before outcomes are known, then review accuracy.
3. Consult diverse perspectives: People with different backgrounds spot different biases.
4. Implement decision rules: Pre-commit to criteria before emotionally charged situations arise.
5. Time-box decisions: Revisit important conclusions after a cooling-off period.