Real people are not cold calculators. This is how one rebel proved it and changed economics forever.
Thaler's early "List" grew into a research program because framing, ownership, and presentation did not merely create random mistakes; they created predictable ones.
Prospect theory's core lesson is that gains and losses are felt relative to where you start, and losing about $100 hurts roughly twice as much as gaining $100 pleases.
In the Cornell mug experiments, randomly assigned sellers demanded about twice what buyers offered and far fewer trades occurred than standard theory predicted.
Thaler calls this transaction utility: the same beer seems worth more from a resort than from a shabby store because expectations set the reference price.
Mental accounting makes an unused ticket or membership feel like an open loss, so people keep consuming, attending, or investing just to avoid 'wasting' it.
At Thaler's poker table, players risked winnings as 'house money,' yet when behind they chased the break-even point—two opposite responses produced by the same mental account.
The rest of this summary — and the one thing to do this week — is in the PDF.
Download the free PDFMisbehaving is both Thaler's memoir and a chronological history of behavioral economics. As a graduate student and young professor in the 1970s, he kept a List of everyday anomalies that rational-choice models could not explain: students cared whether an exam was scored out of 100 or 137, people valued the same object differently depending on who owned it, and 'supposedly irrelevant factors' kept steering choices. His encounter with Daniel Kahneman and Amos Tversky—and with prospect theory—gave those observations a scientific engine.
The human model that emerges is built around reference points and losses. We experience changes rather than final states, feel losses more strongly than equivalent gains, and become attached to possessions almost immediately. In the famous mug experiments, ownership alone roughly doubled asking prices and suppressed trade, challenging the idea that initial allocations do not matter. Thaler treats these not as amusing quirks but as repeatable evidence that economic theory needs Humans in place of perfectly optimizing Econs.
