What Is Behavioral Economics?

Behavioral economics, also written behavioural economics, is the branch of economics that builds psychologically realistic assumptions about human judgment into economic models and tests them against observed choices. It replaces the standard depiction of an agent with unlimited computational capacity, consistent preferences, and perfect self-control with descriptions drawn from experimental psychology and the wider behavioral sciences. The resulting models retain the formal apparatus of economics, including utility functions and equilibrium analysis, but parameterize the systematic ways in which real decisions depart from that benchmark.

The field grew out of work in the 1970s by Daniel Kahneman and Amos Tversky on judgment under uncertainty, and it gained institutional footing through the Alfred P. Sloan and Russell Sage Foundations' behavioral economics program in the 1980s and the Russell Sage Behavioral Economics Roundtable established in 1993. Kahneman received the 2002 Sveriges Riksbank Prize in Economic Sciences for integrating psychological research into economic science, and Richard Thaler received the 2017 prize for extending that program to limited rationality, social preferences, and self-control.

Bounded Rationality and Heuristics

The starting premise is that attention and computation are scarce. People rely on heuristics, efficient rules that produce good answers in familiar settings and predictable errors elsewhere. Availability leads to overweighting outcomes that come easily to mind, anchoring leaves numerical estimates tethered to an arbitrary starting value, and representativeness produces base-rate neglect in probability judgments. Framing effects show that logically equivalent descriptions of the same choice can reverse a preference, which violates the invariance assumption underlying revealed preference analysis. Because these deviations are systematic rather than random, they do not average out across a market, and they can persist even where the stakes are large and feedback is available.

Prospect Theory and Reference Dependence

Prospect theory, published in 1979, is the field's central formal contribution. It models value over gains and losses relative to a reference point rather than over final wealth levels, makes the value function steeper for losses than for equivalent gains, and replaces objective probabilities with a weighting function that overweights small probabilities and underweights moderate to large ones. These three features account for the endowment effect, the disposition to hold losing assets too long, and simultaneous demand for insurance and lottery tickets. A survey of three decades of prospect theory in economics reviews how the model has been applied to asset pricing, insurance, and labor supply, and where the evidence has been mixed.

Intertemporal Choice and Social Preferences

A second strand concerns choices across time and across people. Exponential discounting predicts consistent plans, but observed behavior fits hyperbolic or quasi-hyperbolic discounting better, producing preference reversals as a delayed reward draws near and generating an economically meaningful demand for commitment devices. Work on social preferences documents reciprocity, inequity aversion, and conditional cooperation in ultimatum, dictator, and public goods games, showing that fairness considerations shape wage setting and contract enforcement. Both strands rest on laboratory and field experimentation rather than observational data alone, and an editorial on the rise of behavioral economics in Nature Human Behavior describes how far that shift has carried the field into science and policy.

Applications

Behavioral economics has applications in a range of disciplines and policy settings, including:

• Retirement saving policy, including automatic enrollment and escalating contribution defaults
• Consumer finance regulation and disclosure design
• Public health interventions such as vaccination reminders and organ donation registration
• Energy conservation programs using social comparison feedback
• Tax compliance and benefit take-up campaigns
• Marketing, pricing, and choice architecture in digital interfaces
• Behavioral finance, including asset pricing anomalies and investor trading patterns