Anomalies: Risk Aversion

Economists ubiquitously employ a simple and elegant explanation for risk aversion: It derives from the concavity of the utility-of-wealth function within the expected-utility framework. We show that this explanation is not plausible in most applications, since anything more than economically negligible risk aversion over moderate stakes requires a utility-of-wealth function that is so concave that it predicts absurdly severe risk aversion over very large stakes. We present examples of how the expected-utility framework has misled economists, and why we believe a better explanation for risk aversion must incorporate loss aversion and mental accounting.