Money
Behavioral Economics
Behavioral economics is the study of how people actually make decisions about money, not how they should. Classical economics assumed people weigh costs and benefits rationally. Decades of experiments say otherwise: decisions run on mental shortcuts, and the shortcuts miss in predictable directions. Predictable enough to measure. Predictable enough for stores, apps, and casinos to build around.
What is behavioral economics?
Behavioral economics measures the gap between the choices economic theory predicts and the choices real people make. The field's central experiments came from two psychologists, Daniel Kahneman and Amos Tversky, who spent the 1970s testing how people choose between gambles. Their 1979 paper on prospect theory became one of the most cited works in social science and contributed to Kahneman winning the Nobel Prize in economics in 2002. The core discovery: people don't weigh gains and losses equally, and the imbalance shapes almost every money decision you make.
Why do smart people make bad money decisions?
Because the mistakes aren't about intelligence. In Kahneman and Tversky's experiments, losing $50 registered roughly twice as strongly as winning $50 felt good. That asymmetry sits underneath sunk costs, overpriced insurance, and holding a losing investment years too long. If you've ever kept paying for a gym you stopped visiting because canceling felt like admitting the loss, you've felt the mechanism yourself. Knowing the math doesn't switch the feeling off. Knowing the pattern, though, lets you catch it before it decides for you.
The findings
Loss Aversion: Why Losing $50 Hurts More Than Winning It
Loss aversion, Kahneman and Tversky's finding that losses loom larger than gains, explains sales tactics, sunk costs, and why saving feels like losing.
The Diderot Effect: Why One Purchase Triggers the Next
In 1769, a philosopher got a beautiful dressing gown as a gift and ended up in debt. The Diderot effect explains why one upgrade triggers the next.