← Back to list
Term

Sunk Cost Fallacy - Selection Logic

Continuing a behavior because of past costs, rather than future value.

Aliases: Sunk cost fallacy

Definition

Sunk Cost Fallacy: Continuing a behavior because of past costs, rather than future value.

1. Mechanism (why it happens)

Sunk cost effects reflect escalation of commitment: past investments create psychological pressure to continue even when forward value is low. This is strengthened by loss aversion and self-justification.[^2]

2. Classic experiments / evidence

2.1 Sunk cost psychology (Arkes & Blumer, 1985)

  • Design: Field and lab-style scenarios where participants had made prior investments.[^1]
  • Manipulation: Magnitude of sunk cost (higher vs lower) with identical forward prospects.[^1]
  • Key finding: Higher sunk costs increased willingness to continue, even when irrational by forward value.[^1]
  • Notes/limitations: One of the most-cited empirical demonstrations of the sunk cost effect.

2.2 Escalation of commitment (Staw, 1976)

  • Design: Decision-making tasks where prior choices and responsibility were manipulated.[^2]
  • Manipulation: Personal responsibility for prior decision increased commitment to failing course of action.[^2]
  • Key finding: Responsibility can increase escalation even under negative feedback.[^2]
  • Notes/limitations: Explains organizational and consumer persistence in bad decisions.

3. Consumer decision patterns

  • Keeping subscriptions “because I already paid.
  • Staying in a product ecosystem due to accessory investment.
  • Continuing to repair a lemon device instead of switching.

4. How marketing leverages it

Retention strategies increase sunk costs via onboarding effort, loyalty points, and ecosystem lock-in—raising switching friction and perceived loss.[^3]

5. Mitigation (Selection Logic)

  1. Use forward-only evaluation: ignore sunk costs.
  2. Treat reversibility and switching cost explicitly: Decision reversibility.
  3. Set cancellation checkpoints and criteria.
  4. Validate outcomes and reduce future escalation patterns.

References

  1. Arkes, H. R., & Blumer, C. (1985). The psychology of sunk cost. Organizational Behavior and Human Decision Processes, 35(1), 124–40.[source]
  2. 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), 27–4.[source]
  3. Kahneman, D. (2011). Thinking, Fast and Slow. Farrar, Straus and Giroux.[source]

Further Reading