Ehhh.
For the longest while, mainstream macroeconomics was grounded on a few insights about irrational behavior. Pre-Keynesian "naive rationality" theory thought recessions would cure themselves as falling demand made prices fall: therefore, recessions caused by "general glut" or "overproduction" would never happen; there would never be "involuntary unemployment".
Keynes and others argued that under systemic falling demand/rising unemployment people would go chicken little and reduce their consumption. That kind of thinking was very very useful and was the basis of how nearly every nation dealt with the Great Depression. To a great degree, it's still reflected in current fiscal and monetary policies.
Textbook macro 101 is actually all behavioral theory: people either consume a fraction of their income (Keynes), of their lifetime income (Modigliani) or of their "permanent income" (the one they're used to in the average and expect for the future.
But this basic Keynesian recipe of assuming consumers behave according to heuristics ran into some rough sand from the 70s on; and a few powerful ideas on the limitations of generalizing psychological insights arose of this period. I think the most powerful of these is the Lucas critique.
To simplify, the Lucas critique says that any attempt to exploit the heuristic nonrationality that economic models in general assume will cause people to change their heuristics. So either economics is fundamentally and hopelessly bogus, or any predictable behavior has to come out of a fixed-point iteration process that may lead to the wrong platonic ideal of "rationality" but leads to Brower's fixed point theorem and game theory.
Thaler comes at the other end of this arc. Has the pendulum again swung too far? World Bank economists have allegedly been misusing DSGE models, for example; but this is more of an institutional flaw that gives entire staffs these crystal balls they aren't. The Lucas critique itself says these models can never predict the future.
So let's recapitulate the pendulum: Ricardo and Malthus used to argue in the 19th century about the possibility of a persistent glut, what the Marxists call an "overproduction crisis". Mixed examples had been seen, but nothing like a developed capitalist economy existed. Then came the Great Depression and the Malthusians rose to the task and fixed the damn thing with the spit and half-baked behavioral psychology you can read in the "General Theory" by Keynes. This works until it doesn't (note that during this period people have also had increasing access to information, etc. rather than behaving as blind mole rats as they might in Ricardo's time) and psychological ad-hockeries fall out of fashion.
Now, in this great arc: Thaler, new Nobel laureate, claims that you can slightly nudge people from Lucasian fixed points. Sure, maybe. My boss is a big fan. The pendulum swings.