Behavioral Economics

Behavioral economics integrates insights from psychology into economic models, challenging the traditional assumption that humans are perfectly rational decision-makers. By documenting systematic deviations from rationality, this field has transformed our understanding of how people actually make choices about money, health, time, and risk.

Developed by Daniel Kahneman and Amos Tversky, prospect theory describes how people evaluate outcomes relative to a reference point rather than in absolute terms.

Loss aversion is the finding that losses loom roughly twice as large as equivalent gains, losing $100 feels about twice as painful as gaining $100 feels pleasurable.

The value function is concave for gains (diminishing sensitivity) and convex for losses, and steeper for losses than gains.

People also overweight small probabilities and underweight moderate-to-large probabilities, explaining behaviors like buying lottery tickets while also purchasing insurance.

Kahneman and Tversky identified mental shortcuts (heuristics) that simplify decision-making but can lead to systematic errors:

Anchoring: Initial information disproportionately influences subsequent judgments. A high initial price makes later discounts seem more attractive.

Availability heuristic: Events that come easily to mind are judged as more probable. Media coverage of plane crashes inflates perceived risk of flying.

Representativeness heuristic: Judging probability by similarity to a prototype, leading to base-rate neglect and the conjunction fallacy.

Richard Thaler and Cass Sunstein's nudge theory proposes that the way choices are presented (choice architecture) significantly influences decisions without restricting freedom.

Default effects: People tend to stick with pre-selected options. Changing organ donation from opt-in to opt-out dramatically increases donation rates.

Framing effects: Describing meat as '95% lean' vs. '5% fat' changes preferences despite identical information.

Nudges are used in retirement savings (auto-enrollment), health (cafeteria food placement), and environmental policy (social norm messaging on energy bills).

Mental accounting (Thaler) describes how people categorize, evaluate, and track financial activities in separate mental 'accounts' rather than treating money as fungible.

People treat a tax refund differently from regular income, spending it more freely despite identical economic value.

The sunk cost fallacy is the tendency to continue investing in a losing proposition because of what has already been spent, rather than evaluating future costs and benefits.

Endowment effect: People value items they own more than identical items they don't own, demanding more to sell an object than they would pay to acquire it.

People systematically discount future rewards, preferring smaller immediate rewards over larger delayed ones, a pattern called hyperbolic discounting.

This explains procrastination, under-saving for retirement, and difficulty maintaining health behaviors.

Present bias leads to preference reversals: people may prefer $110 in 31 days over $100 in 30 days, but reverse this preference when both options are moved to today versus tomorrow.

Commitment devices (e.g., automatic savings plans, public pledges) help people overcome self-control problems by binding their future selves.

Behavioral economics has been applied across numerous policy domains through 'nudge units' (behavioral insights teams) in governments worldwide.

Financial behavior: Auto-enrollment in retirement plans, simplified disclosure requirements, cooling-off periods for major purchases.

Health: Calorie labeling, default healthy options in school cafeterias, simplified medication regimens.

Environmental policy: Social comparison on energy bills, green default options, carbon footprint labeling.