Loss aversion.
Losing something hurts more than gaining the same thing feels good.
People often pay more to avoid a loss than to gain the same amount. Under the cleanest tests, with equal gains and losses and no suggestive ordering, the ratio falls to about 1.07—barely above even.
2 to 1
Roughly how much more a loss weighs than an equal gain, averaged across 607 published estimates from 150 studies.
The evidence for this is contested.
Also under Preferences.
Kahneman & Tversky 1979 · Brown, Imai, Vieider & Camerer 2024 · Yechiam & Zeif 2025 · Gal & Rucker 2018