Sunk Cost Fallacy
We continue an endeavor because of previously invested resources even when it no longer makes sense.
The sunk cost fallacy is the phenomenon whereby 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 is demonstrated by the 'on Concorde' expression, referring to the British and French governments' continued investment in the Concorde supersonic jet despite overwhelming evidence that the project was economically unviable.
What it looks like in the wild.
- Everyday life Terrible Movie Staying to the end of a terrible movie because you paid for the ticket — the money is spent regardless of whether you stay or leave.
- Everyday life Bad Relationship Continuing a relationship that is clearly not working because 'we've been together 5 years and I've invested so much'.
Someone has already built a business on this.
Biases are not only private errors. They are design targets — patterns deliberately engineered into interfaces because they reliably work.
- Games Time Investment Trapping Games are designed to require hundreds of hours of 'investment' before the payoff, creating massive sunk cost that makes quitting feel expensive even when the game stops being fun.
Recognising a definition is not the same skill as spotting it.
Two scenarios from the app, with distractors drawn from the same family of biases — which is what makes them hard.
A person finishes a degree program they no longer need because they are close to graduating, even though the time remaining could be better spent gaining practical experience in their actual field of interest through internships or entry-level positions.
A person continues a diet that is making them miserable because they already lost some weight on it, even though switching to a sustainable eating plan would be healthier long-term and less likely to result in weight regain afterward.
Biases rarely arrive alone.
Understand more. Assume less.
188 biases, 18,869 scenarios, and a record of how you actually decide.
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