In the movie Legally Blonde, a civil procedure professor tells her first-year students on their first day of class at Harvard Law School that Aristotle stated, “The law is reason free from passion.” Since Aristotle, there has been much written about whether passion and reason are complements or substitutes. In Two Conceptions of Emotion in Risk Regulation, Professor Dan M. Kahan analyzes two important and related questions: First, what roles do emotions play in risk perceptions? Second, what is the regulatory significance of these roles?

Professor Kahan describes three models of how individuals can perceive risk—namely, as rational weighers, irrational weighers, or cultural evaluators. For rational weighers, emotions play no role in risk cognition but can show up as consequential by-products of information processing. This is a normative as opposed to descriptive model, based upon the consequentialist expected utility theory of neoclassical economics. For irrational weighers, emotions play a heuristic role in risk cognition due to bounds on computational abilities, information, and time. Emotions are distortions that underlie cognitive biases. This is a descriptive model, based upon empirical and experimental data from cognitive and social psychology and behavioral economics. Lastly, for cultural evaluators, emotions play an expressive role in risk cognition. Emotions enable people to identify social meanings of risk that cohere with their values. This model is also descriptive, with roots in Aristotelian philosophy, and based upon recent experimental and empirical research in affective, cognitive, and social neuroscience and psychology.