The Market: Catalyst for Rationality and Filter of Irrationality

Assumptions of individual rationality and preference stability provide the foundation for a convenient and tractable modeling approach. While both of these assumptions have come under scrutiny in distinct literatures, the two lines of research remain disjointed. This study begins by explicitly linking the two literatures while providing insights into perhaps the central issue facing behavioral economics today: to what extent does market experience mitigate various forms of individual irrationality? We find considerable evidence that the market is a catalyst for rationality. The study then focuses on aggregate market outcomes by examining empirically whether individual rationality is a prerequisite for market efficiency. Using field data gathered from more than 380 subjects of age 6-18 in multi-lateral bargaining markets at a shopping mall, we find that the market is a filter of irrationality—even when markets are populated solely by irrational buyers, aggregate market outcomes quickly converge to neoclassical predictions. JEL: C93 (Field Experiments), D4 (Market Structure and Pricing)