The twenty-dollar bill.

Imagine you put on an old coat and find a $20 bill in the pocket. Notice the small lift: a little luck, a little surprise.

Now imagine a different day. You reach into your pocket for a $20 bill you know was there, and it’s gone. Dropped somewhere, lost for good.

The amount is exactly the same. But for many people, the second moment lingers much longer. You retrace your steps. You replay where it might have fallen. It may still bother you that evening.

Now picture someone offering you a coin toss: heads, you win $100; tails, you lose $100.

Most people would turn down that coin toss. Research suggests losses feel roughly twice as strong as gains of the same size. This is called loss aversion.

Fear of loss can protect us. It can also keep us stuck: holding on to something that isn’t working because letting go would make the loss feel real, or avoiding every risk even when waiting has a cost too.

Past experiences shape this fear. Someone who has lived through a job loss, debt, or hard times may feel it far more strongly, and for good reason.

How loss shows up

A brief history of loss aversion

• 1738 — Mathematician Daniel Bernoulli suggests that the value of money depends on how much a person already has.
• 1979 — Daniel Kahneman and Amos Tversky publish prospect theory, showing that losses loom larger than equal gains.
• 1980s–1990s — Economist Richard Thaler and others show how loss aversion shapes everyday choices, from holding on to things we own to how we save.
• 2002 — Kahneman is awarded the Nobel Memorial Prize in Economic Sciences, partly for this work.

A loss and a gain can be the same size and still not weigh the same.