Preview
Consumer Nudges and Calculations of Government Intervention Effects
IB DP Economics — Unit 2: Microeconomics | HL | 2.7 Role of Government in Microeconomics [HL Extensions]
📋 What You Will Learn
- Define behavioural economics and explain how it challenges the assumption of rational consumer behaviour
- Identify and explain the main types of consumer nudges: defaults, framing, social norms, and salience
- Analyse how nudge theory can be used as a government policy tool to correct market failures
- Calculate the effects of government intervention (specific taxes, subsidies, price ceilings, price floors) on consumer surplus, producer surplus, government revenue, and deadweight welfare loss
- Apply quantitative techniques to evaluate the net welfare effects of different policy interventions
- Evaluate the effectiveness and limitations of nudge policies compared to conventional interventions
🔍 Guiding Question If consumers do not always act rationally, should governments use subtle behavioural interventions to guide choices — and can we calculate whether these interventions actually improve social welfare?
🌍 Why This Matters In 2023, the UK government made pension auto-enrolment the default option for workers — without banning anything or paying anyone. Participation in workplace pensions jumped from under 55% to over 88%. No tax, no subsidy, no regulation: just a change in the default setting. Meanwhile, economists in Denmark calculated that a sugar tax generated €320 million in government revenue but reduced consumption by only 4% — raising serious questions about whether the welfare gains justified the deadweight loss imposed on consumers.
Part 1: Behavioural Economics and Consumer Nudges
Standard microeconomic theory assumes consumers are rational — they process all available information, weigh costs and benefits, and make decisions that maximise their utility. But decades of psychological research show that real consumers systematically deviate from this model in predictable ways. Behavioural economics studies these deviations and asks: what do they imply for policy?
📖 Definition — Behavioural Economics Behavioural economics is a field that incorporates insights from psychology into economic models to explain why individuals often make decisions that deviate from the predictions of rational choice theory.
📖 Definition — Bounded Rationality Bounded rationality refers to the idea that individuals make decisions that are rational within the limits of the information they have, the cognitive limitations of their minds, and the finite amount of time available to make decisions — leading to systematic, predictable biases.
Key Behavioural Biases Relevant to Economics
- Present bias: consumers overweight immediate costs and benefits relative to future ones — they choose a smaller reward now over a larger reward later (e.g. choosing fast food over long-term health)
- Status quo bias: consumers tend to stick with the current default option rather than actively switching, even when switching would benefit them
- Loss aversion: the psychological pain of losing something is approximately twice as powerful as the pleasure of gaining the equivalent — consumers are more motivated to avoid losses than to acquire gains
- Anchoring: consumers rely heavily on the first piece of information they encounter (the "anchor") when making decisions — e.g. a price shown as "was $100, now $70" anchors perception of value
- Herd behaviour / social norms: consumers are influenced by what they believe others are doing — they conform to perceived group behaviour
- Framing effects: the way information is presented affects decisions — "90% fat-free" and "contains 10% fat" are identical facts but produce different consumer responses
- Cognitive overload: when faced with too many choices or too much information, consumers make worse decisions or avoid choosing altogether
📖 Definition — Nudge A nudge is any aspect of the choice architecture that alters people's