“Rationality” isn’t always Rational

by Mario Rizzo

Over the past two years I have been reading more than I ever dreamed about rationality in economics, especially in the standard neoclassical theory of choice. I have done this because I want to get at the root of the controversies concerning whether people’s behavior is, in particular contexts, rational or not.  Claims about the rationality of individual behavior are very closely linked to important policy questions about state paternalism. The highly abstract is working its way down the line to practical policy issues.

In all of this I am well-aware of the argument that “rationality” is the result of market processes and of decisionmaking institutions. I have nothing per se against this line of reasoning. Nevertheless, I want to approach the issue on the terms espoused by many choice theorists and behavioral economists themselves. This is the idea that the axioms of rational choice have a normative importance in and of themselves. By and large, behavioral economists accept the normativity of standard rational choice even as they reject the descriptive reality of rational choice.

The funny thing about all of this is that, initially, the axioms of rational choice were supposed to shed light on how people actually made choices. Then a sleight of hand occurred. It was claimed that they shed light on how rational individuals would choose – without addressing the issue of whether people were in fact rational in the sense of the axioms. Finally, it was alleged – in the face of empirical evidence that people often did not choose rationally – that the axioms defined the norms of choice. They told us how rational individuals should choose. More than that. Since being rational is taken as “good,” they show us how people should behave – full stop. Continue reading