Disposition Effect Investing: The $1,785 Mistake Hiding in a Routine Withdrawal
An investor needs $9,800 out of a taxable brokerage account for a roof repair. Two positions could fund it: one up $7,500, one down $5,200….
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Anchoring Bias When Buying a House: The 3-Line Formula That Beats the List Price
Forty-seven licensed real estate agents toured the same house in Tucson, Arizona. They got the same 10-page packet: the MLS sheet, six months of neighborhood…
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Decoy Effect Pricing: The Bias That Barely Replicates (And Still Costs You Money)
Across 91 separate attempts covering 23 product categories, marketing researchers Sybil Yang and Michael Lynn could only reproduce the decoy effect 11 times. That is…
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Endowment Effect Examples: 5 Places Ownership Quietly Doubles What You Think Things Are Worth
In a Cornell classroom in 1990, half the students were handed a $6 coffee mug and the other half were handed nothing. When both groups…
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Ostrich Effect Investing: What Eleven Months of Not Looking Actually Costs
Researchers with access to 1.2 million Vanguard accounts found something uncomfortable: the day after the Dow falls, the number of investors who log in to…
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Recency Bias Investing: Why “What’s Working Now” Is the Worst Signal You Can Follow
Between January 2016 and December 2025, U.S. mutual funds and ETFs returned 9.9% a year. The average dollar actually invested in those same funds earned…
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Sunk Cost Fallacy Personal Finance Decisions: A $6,300 Case Study in Letting Go
In 1985, two psychologists asked people to imagine they were an airline president who had already sunk $9 million into a plane a competitor had…
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Present Bias and Retirement Contributions: Why “Just Save More” Almost Never Works
In a study of one mid-sized manufacturing company, workers who were asked to commit to saving more later raised their average savings rate from 3.5%…
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The Diderot Effect: Why “Buy It Once, Buy It Right” Quietly Costs More
In 1769, Denis Diderot was given a scarlet dressing gown. Within a year he had replaced his desk, his chair, his prints, his bookshelves, and…
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The Planning Fallacy in Personal Finance: Why a $30,000 Kitchen Closes at $41,000
Thirty-seven psychology students were asked how long their senior thesis would take. Their average estimate was 33.9 days. The average actual completion time was 55.5…
