This article discusses the limitations of expected utility theory in explaining risk aversion. While the theory is widely used to explain economic behavior, it fails to account for many observed risk attitudes, particularly in cases involving modest stakes. The authors argue that the theory's assumption that risk aversion arises from the concavity of a person's utility function leads to implausible conclusions when applied to large stakes. For example, if an individual is risk-averse in small bets, expected utility theory would imply an extreme risk aversion in large bets, which is not observed in reality. The authors use a quiz to illustrate this point, showing that if someone is risk-averse in a small bet, they would also be risk-averse in a large bet, even if the large bet has a much higher potential gain. This suggests that expected utility theory is not a plausible explanation for many instances of risk aversion. The article also discusses the implications of this finding for economic theory and practice. It argues that expected utility theory is not a good explanation for most risk attitudes and that other theories, such as prospect theory and mental accounting, may be more appropriate. These theories incorporate concepts like loss aversion and the tendency to evaluate risks in isolation, which better explain observed behavior. The authors also challenge the idea that expected utility theory is a valid explanation for risk aversion, arguing that it is an ex-hypothesis and that better descriptive models of choice under uncertainty are needed. They conclude that economists should focus on developing better models of risk attitudes rather than relying on expected utility theory.This article discusses the limitations of expected utility theory in explaining risk aversion. While the theory is widely used to explain economic behavior, it fails to account for many observed risk attitudes, particularly in cases involving modest stakes. The authors argue that the theory's assumption that risk aversion arises from the concavity of a person's utility function leads to implausible conclusions when applied to large stakes. For example, if an individual is risk-averse in small bets, expected utility theory would imply an extreme risk aversion in large bets, which is not observed in reality. The authors use a quiz to illustrate this point, showing that if someone is risk-averse in a small bet, they would also be risk-averse in a large bet, even if the large bet has a much higher potential gain. This suggests that expected utility theory is not a plausible explanation for many instances of risk aversion. The article also discusses the implications of this finding for economic theory and practice. It argues that expected utility theory is not a good explanation for most risk attitudes and that other theories, such as prospect theory and mental accounting, may be more appropriate. These theories incorporate concepts like loss aversion and the tendency to evaluate risks in isolation, which better explain observed behavior. The authors also challenge the idea that expected utility theory is a valid explanation for risk aversion, arguing that it is an ex-hypothesis and that better descriptive models of choice under uncertainty are needed. They conclude that economists should focus on developing better models of risk attitudes rather than relying on expected utility theory.