This subdiscipline of economics studies how the economic decisions made by individuals and institutions are influenced by psychological, cognitive, emotional, cultural, and social factors. Specifically, it busies itself with looking at rational decision making - and its boundaries - in contrast to how decision making is seen in classical economics.

Bertrand competition is a model of competition in which two or more firms produce a homogenous good and compete in prices. Theoretically, this competition in prices, providing the goods are perfect substitutes, ends with the firms selling their goods at marginal costs and thus making zero profits. The result is also called the Bertrand paradox named after the economist Joseph Bertrand (1822–1900).