Overview

Traditional economics assumes we are “Homo economicus”—perfectly rational calculators. Behavioral economics says we are Homer Simpson—impulsive, emotional, and prone to mistakes.

Core Idea

Bounded Rationality: Our rationality is limited by our cognitive capacity, the information we have, and the time available. We don’t optimize; we satisfice (aim for “good enough”).

Formal Definition (if applicable)

Prospect Theory: People value gains and losses differently. The pain of losing $100 is greater than the joy of finding $100 (Loss Aversion).

Intuition

Why do you buy a gym membership but never go? Why do you save more if the plan is “opt-out” rather than “opt-in”? Because we are lazy, optimistic, and bad at predicting our future selves.

Examples

  • Nudge: Putting fruit at eye level in the cafeteria to encourage healthy eating.
  • Sunk Cost Fallacy: Finishing a bad movie just because you paid for the ticket.
  • Anchoring: Buying a $50 shirt because it was marked down from $100 (even if it’s only worth $50).

Common Misconceptions

  • “It proves we are stupid.” (No, it proves we are human. Our biases often serve as useful shortcuts or heuristics.)
  • “It replaces standard economics.” (It complements it by adding psychological realism.)
  • Heuristics: Mental shortcuts used to make quick decisions.
  • Hyperbolic Discounting: Preferring $10 today over $15 next week (impatience).
  • Choice Architecture: Designing the environment to influence decisions.

Applications

  • Policy: Designing 401(k) plans to increase savings rates.
  • Marketing: Pricing strategies (e.g., “Buy one, get one free”).
  • Finance: Understanding market bubbles and crashes.

Criticism / Limitations

Some findings have failed to replicate (Replication Crisis in psychology). Also, “nudging” can be seen as manipulative or paternalistic.

Further Reading

  • Kahneman, Thinking, Fast and Slow
  • Thaler & Sunstein, Nudge