There is an experiment that has been running in your head every single day without you noticing. Imagine you bought a ticket to a ski trip for $100. Then you find out about another ski trip — better location, closer distance, and it only costs $50. Which one do you go to? Almost everyone says the $100 trip. But pause for a moment: that $100 is gone either way. It cannot be recovered. The rational choice, purely from an economics standpoint, is to pick the better value trip regardless of what you’ve already spent. Yet your brain screams “but I already paid for it!” and drowns out logic. That scream is the sunk cost fallacy — the irrational tendency to let past, unrecoverable costs influence decisions about the future.
🧠 The Classic Experiments
Psychologists Hal Arkes and Catherine Blumer published the definitive paper on this in 1985, and their experiments are beautifully simple. In the ski trip scenario described above, they showed that people consistently chose the less-optimal option because they couldn’t stomach “wasting” the initial investment. But the real magic came in a field experiment at a university theater. Arkes and Blumer sold season tickets at three different prices — full price, discounted, and free via lottery. Here’s the kicker: every ticket was identical in value. Every seat was the same. Yet the people who paid full price attended significantly more performances than those who got a discount or free tickets. The same ticket. The same show. Different decisions. All because of what they’d already paid.
This wasn’t a one-off finding. Another study by Staw and Fox gave business students a scenario where a company division was underperforming. Half the participants were told they themselves had made the initial investment that went wrong; the other half were told a previous manager had made it. The high-responsibility group was far more likely to throw good money after bad — investing additional funds into a failing project because they couldn’t admit their earlier decision was a mistake.
🤔 The Counterintuitive Twist
The most brilliant and frustrating thing about the sunk cost fallacy is that it hits hardest on people who care the most. If you’re the kind of person who follows through, who commits, who hates to let people down — you’re actually more vulnerable to it. Because the mechanism isn’t really about money. It’s about ego protection. Admitting you made a bad decision means admitting your time, energy, and previous choices were wasted. The brain hates that feeling so much that it would rather double down on a losing hand than face the discomfort of saying “I was wrong.”
This effect is so powerful that it has its own name in business history: the Concorde Fallacy. The British and French governments jointly funded the development of the Concorde supersonic jet. From day one, costs spiraled out of control and the economic projections looked grim. But both governments kept funding it, year after year, because they’d already sunk so much into it. The Concorde never turned a profit. And the term “Concorde Fallacy” is now synonymous with letting past investment trap you in a losing course of action.
🔗 Why It Matters
If you design pricing or subscription products, sunk cost is your best friend. Annual memberships, prepaid bundles, progress bars that reward cumulative usage — all of these work because once a customer has invested time or money, they’re more likely to stick around. The psychology is baked into the business model.
But if you’re the one spending money or making decisions, it’s your hidden enemy. The video game you bought on sale and never played but can’t bring yourself to uninstall. The relationship you’re staying in because “we’ve been together for years.” The SaaS tool you keep paying for because you’ve already spent weeks learning it. Every single one of these has a simple diagnostic question: if you could go back in time and choose again, knowing everything you know now, would you make the same choice? If the answer is no, the sunk cost is not a reason to stay — it’s a trap disguised as loyalty.
For someone building a product like DuXinGe (渡心阁), the insight cuts both ways. On the design side, bundled fortune-telling packages with tiered pricing can use the sunk cost effect to keep users engaged. On the personal side, recognizing the fallacy in your own decisions — whether it’s continuing to study a psychology module that doesn’t resonate, or sticking with a pricing strategy that isn’t working — is the difference between stubbornness and wisdom.
🎲 Bonus
Dutch researchers discovered a simple mental trick to neutralize the sunk cost fallacy: pretend you’re a consultant. Ask yourself, “If my friend came to me with this exact situation — the same money invested, the same evidence, the same odds — would I tell them to continue or to walk away?” When we give advice to others, sunk costs magically vanish. The “waste” doesn’t feel personal. The ego isn’t on the line. And suddenly the right decision becomes obvious. The fact that this works so reliably is also a pretty good argument for why “hindsight is 20/20” and “the outsider perspective” are real psychological phenomena, not just clichés.
Try it right now: is there something in your life — a project, a subscription, a creative work, a course — that you’re continuing mainly because you’ve already started it? Ask your imaginary-friend consultant. The answer might surprise you.