Det neoklassiska rationalitetsbegreppet har utmanats av beteendekonomin, vars betoning av icke-rationalitet i en hel del mänskligt beslutsfattande har fått stor uppmärksamhet och stort genomslag. Ett sätt att beskriva denna utmaning är att mer realistiska, på psykologisk analys grundade antaganden om vad som kännetecknar en ekonomisk beslutsfattare har kommit att föredras. Men det är inte självklart hur psykologi och nationalekonomi ska kombineras.

I den just publicerade artikeln ”Two Types of Ecological Rationality: Or How to Best Combine Psychology and Economics” utvecklar Erwin Dekker och Blaž Remic vad som skiljer och förenar två sådana ansatser, som båda betonar förekomsten av ekologisk rationalitet (ER). Den ena, ER1, representeras av Gerd Gigerenzer och den andra, ER2, av Ekonomipristagaren Vernon Smith. Dessa står i viss kontrast mot det dominerande beteendeekonomiska synsättet, som i artikeln kallas för ”heuristics-and-biases”-programmet (H&B):

H&B has become widely accepted as the standard way of integrating psychology and economics (Angner 2018). The H&B program presents itself as a serious challenge to the neoclassical picture of the rational economic man, and argues that a serious reconsideration of rationality is necessary, since individuals are only boundedly rational (Tversky and Kahneman 1974; Kahneman 2003; Camerer, Loewenstein, and Rabin 2004; Mullainathan and Thaler 2000). The proponents of ecological rationality do not seek to challenge this claim of bounded rationality. They fully accept it – in fact, they sometimes go even further in emphasizing the cognitive limitations of individuals. However, they argue that in the interaction with their (social) environment individuals are nonetheless able to make reasonably good, or as good as rational, decisions, because they are able to use the environment to their advantage through cues or institutional features of that environment.

Men det finns skillnader mellan ER1 och ER2:

ER1, part of Gigerenzer’s fast-and-frugal heuristics approach, is based on the picking up of cues in the environment, which are inputs for heuristics used to arrive at quick decisions. The individual is ‘ecologically rational’ to the extent that the strategies, the heuristics, used are well adapted to her environment. ER2, part of the market-experimental approach developed by Smith, Plott and others, is based on institutional constraints and social and cultural norms, which help the individual to navigate his social environment. The system is ‘ecologically rational’ to the extent that it facilitates this navigation by the individual by means of embedded norms, learning or feedback mechanisms, and leads to outcomes that are efficient in the aggregate. Both the institutional rules and in particular the social norms emerge in the process of social interaction, and represent the cognitive content that is off-loaded to the environment.

I denna figur kontrasteras de tre ansatserna för att kombinera psykologi med nationalekonomi:

Slutsatsen, vad gäller implikationerna för det beteendeekonomiska forskningsprogrammet, är intressant:

It is tempting to accept the standard narrative that modern behavioral economics is the reintroduction of psychology into economics. However, that narrative relies heavily on the idea that there is one economics and one psychology. In this paper, we demonstrate that this narrative is severely complicated when we look at the two conceptions of ecological rationality, which are offered as alternatives to modern behavioral economics and accounts of ‘bounded rationality’. As we have demonstrated, these present two alternative combinations of economics and psychology. The methodological question for economists, therefore, shifts from a concern over whether economics needs psychology to what type of integration of the two fields is desirable and fruitful.  … To move forward the fruitful discussion between these different programs, it is important to realize that such deep methodological differences exist. Psychology is and will remain relevant to economics, as is by now broadly accepted. But importing parts of another discipline, or even merging the two, should not and cannot occur without a good understanding of which goods we are importing.

Själv är jag (likt David Levine) mindre övertygad om värdet av integration av psykologi och nationalekonomi, men givet att man är positivt inställd till en sådan utveckling kan denna artikel erbjuda grund för en del nyttiga reflexioner. Inte minst finner jag det fascinerande att, likt Gigerenzer, peka på att det finns kognitiva genvägar och att, likt Smith, peka på att det finns informella och formella institutioner som har förmåga att få människor att nästan förefalla rationella.

Läs mer:

• Vernon Smith Ekonomiprisföreläsning ”Constructivist and Ecological Rationality in Economics”.
• Vernon Smiths bok Rationality in Economics: Constructivist and Ecological Forms.
• Gerd Gigerenzers artikel ”Why Heuristics Work”.
• Gerd Gigerenzers bok Simply Rational: Decision Making in the Real World (särskilt kapitel 11, som finns i en preliminär version här).
• Inlägget ”Kritik av behavioral economics” .