Source: Prospect Theory: An Analysis of Decision under Risk (1979), by Daniel Kahneman and Amos Tversky

Prospect theory describes the way people choose between probabilistic alternatives that involve risk, where the probabilities of outcomes are known. The theory states that people make decisions using a set of predictable rules, and these rules often run contrary to the rule of maximizing one’s net worth (also known as maximizing utility). It’s not a stretch to say that the paper "Prospect Theory: An Analysis of Decision under Risk" is the most sited and influential academic paper of the last 50 years.