James R. Rogers writes about Richard Thaler and behavioral economics:

[M]edia treatments of Thaler’s work, and of behavioral economics more generally, suggest that it provides a much-deserved comeuppance to conventional microeconomics. Well . . . Not quite….

… Economists, and rational choice theorists more generally, have a blind spot, [Thaler] argues, for just how often their assumptions about human behavior are inconsistent with real human behavior. That’s an important point.

Yet here’s where spin matters: Does Thaler provide a correction to previous economics, underscoring something everyone always knew but just ignored as a practical matter, or is Thaler’s work revolutionary, inviting a broad and necessary reconceptualization of standard microeconomics?…

… No. He has built a career by correcting a blind spot in modern academic economics. But his insight provides us with a “well, duh” moment rather than a “we need totally to rewrite modern economics” moment that some of his journalistic (and academic) supporters suggest it provides….

Thaler’s work underscores that the economist’s rationality postulates cannot account for all human behavior. That’s an important point. But I don’t know that many, or even any, economists very much believed the opposite in any serious way. [“Did Richard Thaler Really Shift the Paradigm in Economics?“, Library of Law and Liberty, October 11, 2017]

I have made the same point:

Even in those benighted days when I learned the principles of “micro” — just a few years ahead of Thaler — it was understood that the assumption of rationality was an approximation of the tendency of individuals to try to make themselves better off by making choices that would do so, given their tastes and preferences and the information that they possess at the time or could obtain at a cost commensurate with the value of the decision at hand.

Highly recommended reading: my previous post about Thaler and the many related posts listed at the end of it.