- Define and explain Nudge Theory in your own words
- Use key terms such as nudge accurately
- Apply what you have learned to new examples and questions
- Avoid the common mistakes learners make with this topic
This lesson focuses on Nudge Theory: learn how small design changes steer behaviour.
Learn how small design changes steer behaviour.
Key ideas
From homo economicus to real humans
Neoclassical theory models people as rational utility-maximisers with stable preferences. Behavioural economists show decisions are shaped by framing, emotions and social norms: the same product described as '90% fat-free' versus '10% fat' gets very different responses.
Nudges in action
Because biases are predictable, choice architecture can help: auto-enrolling workers into pensions (with opt-out) hugely raised UK saving; smaller plates reduce food waste; default green-energy tariffs increase uptake. Libertarian paternalism argues such nudges preserve freedom while improving welfare — critics warn of manipulation.
Key term — nudge: A small change in choice architecture that steers behaviour without banning options or significantly changing incentives — Thaler and Sunstein's concept.
Country A uses opt-in organ donation (15% registered); Country B uses opt-out (90% registered). Explain the difference using behavioural economics.
Identify the mechanism: the default option exploits status-quo bias and inertia. Most people stick with the pre-selected option rather than acting to change it. Opt-out still preserves choice — anyone can leave the register — so it is a nudge, not a mandate. The huge gap shows defaults shape behaviour more than preferences alone would predict.
Answer: The default acts as an anchor; inertia keeps most people with it, so opt-out registers far more donors while remaining voluntary — a classic successful nudge.
- Calling every error 'irrational' Behavioural biases are systematic and predictable — that is precisely why they can be modelled and nudged, unlike random errors.
- Assuming lab findings always transfer Behavioural effects are context-dependent; a nudge that works in one culture or setting may fail in another, so field testing matters.
Practice
Any one of: it can be manipulative; it may not address root causes; effects may not transfer across contexts.
Framing — the same information presented positively changes choices.
The idea that people's rationality is limited by information, time and mental capacity, so they satisfice rather than optimise.
Losses hurt roughly twice as much as equivalent gains please, so people avoid risks involving losses.
Quick check
Which of these best defines "nudge"?
What is present bias, and how does it affect saving?
Why did auto-enrolment raise pension saving?
- Nudge Theory: learn how small design changes steer behaviour.
- From homo economicus to real humans: Neoclassical theory models people as rational utility-maximisers with stable preferences.
- loss aversion: The finding from Kahneman and Tversky's prospect theory that losses hurt roughly twice as much as equivalent gains please, making people avoid risks involving losses.
- Watch out for: calling every error 'irrational'