Sunk Cost Fallacy
Behavioral economics · The Psychology of Sunk Cost (Arkes & Blumer, 1985) (1985)
The sunk cost fallacy is the tendency to continue investing in a losing proposition because of the resources already committed, rather than making a rational decision based on future expected value.
Core Concepts
The Problem
People let past irrecoverable investments dictate future actions, leading to wasted resources, extended bad relationships, and stubborn portfolio positions.
The Claim
Past costs should be ignored when making forward-looking decisions; only marginal costs and benefits matter.
Key Evidence
- •Arkes & Blumer (1985) experiments showing participants more likely to continue a project when they had already invested time or money.
- •Replicated across domains from business to personal relationships.
- •Neuroimaging studies show activation of loss-aversion regions when facing sunk costs.
Practical Implication
Awareness of the fallacy doesn't automatically cure it; structured decision-making processes (e.g., pre-commitment rules, separate review of past and future costs) are needed to counteract it.
Nuance & Limits
Sunk costs can sometimes signal commitment to a larger goal, but when they conflict with new information, they become an irrational anchor.
Source Material
Citation Density
Highly cited across behavioral economics, psychology, and finance literature
Citation Trend
Who's Talking About This
7 episodes reference this idea.
The sunk cost fallacy causes people to continue investing in losing endeavors because of the resources they've already committed.
People often keep going down a wrong path because they've already invested time and energy, even when continuing is no longer beneficial.
People continue down unfulfilling paths because they’ve already invested time, money, or identity—even when the future payoff is nonexistent.
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