Kritik av behavioral economics

På senare tid har behavioral economics blivit en populär inriktning inom nationalekonomin. Tanken är att använda insikter från psykologiskt baserad forskning för att försöka förstå hur mänskligt beslutsfattande går till i verkligheten. Detta i kontrast till den traditionella inriktningen på nationalekonomin, som har tenderat att utgå från beslutsfattare som egoistiska, perfekt informerade och perfekt rationella.

Nu presenterar Steven Levitt och John List en kritik av denna nya inriktning i Science:

Perhaps the greatest challenge facing behavioral economics is demonstrating its applicability in the real world. In nearly every instance, the strongest empirical evidence in favor of behavioral anomalies emerges from the lab. Yet, there are many reasons to suspect that these laboratory findings might fail to generalize to real markets. We have recently discussed several factors, ranging from the properties of the situation — such as the nature and extent of scrutiny — to individual expectations and the type of actor involved. For example, the competitive nature of markets encourages individualistic behavior and selects for participants with those tendencies. Compared to lab behavior, therefore, the combination of market forces and experience might lessen the importance of these qualities in everyday markets.

Jag delar i mycket denna kritik, som emellertid inte är ny. Ekonomipristagaren Vernon Smith har t.ex. fört liknande resonemang.* Hans huvuidé är att även om individuella beslutsfattare präglas av olika typer av imperfektioner, kan institutioner och marknadsinteraktion minska eller eliminera dessa ”rationalitetsproblem”. Citat (s 11, s 23):

What is imperfectly understood is the precise manner in which institutions serve as social tools that reinforce, even induce, individual rationality. … Why is it that human subjects in the laboratory frequently violate the canons of rational choice when tested as isolated individuals but, in the social context of exchange, institutions serve up decisions that are consistent (as if by magic) with predictive models based on individual rationality? Experimental economists have no good answers to this question, although adaptive learning models such as those of Lucas (1987) are suggestive. … It seems evident that an important part of the answer resides in the properties of exchange institutions and how privately informed, but globally poorly informed, decision making is mediated by institutions. … I want to suggest that perhaps the structures we observe have survived because of their merit in coaxing Pareto-efficient behavior out of agents who do not know what that means.

Se också spelteoretikern Ariel Rubinsteins kritik. Hans slutsats:

For Behavioral Economics to be a revolutionary program of research rather than a passing episode, it must become more open-minded and much more critical of itself.

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* Vernon Smith (2000). “Rational Choice: The Contrast Between Economics and Psychology,” i Bargaining and Market Behavior: Essays in Experimental Economics, kap 1, s 7-24, Cambridge: Cambridge University Press.