A simple pair of bets broke the leading theory of rational choice

Offered a choice between a certain win and a slightly-better probable win, most people pick the certainty. But offered the same gamble structured as two probable outcomes instead, most people flip their preference — even though the underlying odds are mathematically identical. Maurice Allais showed in 1953 that real decisions systematically violate expected utility theory, the standard model of rational choice at the time.

— Maurice Allais, Le Comportement de l'Homme Rationnel devant le Risque — Econometrica, 1953