Sunk cost fallacy
The sunk cost fallacy is the tendency to continue an endeavour because of resources already invested, time, money or effort, even when continuing is no longer the best option. Rationally, past costs cannot be recovered and should not influence future choices, but people honour them anyway. Arkes and Blumer documented the effect in a classic 1985 paper.
| Field | Behavioural economics / psychology |
|---|---|
| Key researchers | Hal Arkes, Catherine Blumer, Richard Thaler |
| Related concepts | Loss aversion, commitment escalation, status quo bias |
How it feeds procrastination
Sunk costs create zombie projects: things you cannot bring yourself to work on or to cancel. A half-finished course, a stalled side project or a degree you no longer want sits on the list generating guilt, and guilt fuels avoidance. Sirois and Pychyl's work on procrastination as mood repair suggests we then dodge these tasks precisely because they carry the heaviest emotional load. Explicitly deciding to quit, or to restart on new terms, often unblocks more than any productivity technique.
A useful test
Ask: if I were starting from zero today, knowing what I now know, would I choose this project? If the answer is no, the only thing keeping it alive is the sunk cost, and quitting is a decision, not a failure.
Related
Procrastinating on side projectsSirois and Pychyl on mood repair
Frequently asked questions
Is quitting because of sunk costs the same as giving up?
No. The fallacy is continuing only because of what you already spent. Quitting a project that no longer fits your goals frees time and attention for one that does, which is the opposite of giving up.