Critique of Maximising Behaviour: IB Economics 2.4 (HL)

Why challenge the rational maximiser?

Standard microeconomics assumes consumers maximise utility and firms maximise profit, both with full information and perfect rationality. Behavioural economics, an HL-only topic in 2.4, argues that real people and real firms systematically depart from these assumptions.

This is a critique, not a rejection: the standard model is still a useful benchmark. But recognising its limits helps explain choices the textbook model cannot, and it justifies policy tools like nudges. It connects to the key concepts of choice and intervention.

The four bounds on rational choice

Behavioural economists identify four ways real decisions fall short of the ideal. Bounded rationality: people have limited time and mental capacity, so they cannot process every option and instead settle for a good-enough choice (satisficing) rather than the optimal one. Bounded self-control: even when people know the best choice, they lack the willpower to follow through, for example over-spending or under-saving.

Bounded selfishness: people are not purely self-interested; they act fairly, cooperate, and give to others even at a cost to themselves. Imperfect information: consumers rarely have full, accurate information, so choices are made under uncertainty. Each bound weakens a pillar of the rational-maximiser model.

Biases and rules of thumb

Because thinking is costly, people rely on heuristics (mental shortcuts or rules of thumb) that usually work but can produce predictable biases. Anchoring: judgements are pulled toward an initial reference number, so a high original price makes a discounted price look attractive. Framing: the same choice is evaluated differently depending on how it is presented, for example 90 percent fat-free versus 10 percent fat.

Availability bias: people overweight events that come easily to mind, such as fearing plane travel after seeing news of a crash despite low statistical risk. These biases are systematic and predictable, which is exactly why they matter for policy and marketing.

Choice architecture and nudges

Because presentation shapes decisions, the way choices are arranged (choice architecture) influences outcomes. A nudge is a small change to that architecture that steers people toward a particular choice without banning any option or changing incentives significantly. The classic tool is the default choice: whatever option applies if a person does nothing.

Automatic enrolment in pension schemes, used in the UK and elsewhere, sharply raised saving rates simply by making participation the default while keeping opt-out free. Placing fruit at eye level in a cafeteria, or setting organ donation as opt-out rather than opt-in, are further examples. Nudges are popular because they preserve freedom of choice while improving outcomes.

Business objectives beyond profit maximisation

Firms are assumed to maximise profit, but in practice many pursue other goals. Growth maximisation and market-share maximisation may be chosen to build long-run dominance, sometimes accepting lower short-run profit. Satisficing, an idea from Herbert Simon, means aiming for satisfactory rather than maximum profit, especially where managers and owners are different people (the principal-agent problem).

Corporate social responsibility (CSR) means a firm voluntarily considers social and environmental impacts, linking to the key concept of sustainability. A clothing company paying above-market wages to garment workers in Bangladesh, or a firm cutting emissions beyond legal requirements, sacrifices some profit for ethical or reputational reasons. These alternative objectives further undermine the strict profit-maximising assumption.

Common Paper mistakes

Listing biases without defining them or giving an example. The mark scheme rewards a clear definition plus an applied example for anchoring, framing, or availability.

Confusing a nudge with a regulation or a tax. A nudge preserves free choice and does not significantly change incentives; a ban or tax does. Automatic enrolment with free opt-out is a nudge; a legal requirement is not.

Treating satisficing and profit maximisation as the same thing. Satisficing means aiming for a satisfactory, not maximum, level.

How this is examined

• This is HL-only material examined on Paper 1 (part b evaluation) and Paper 3. SL students do not study 2.4.
• For a nudge or default-choice question, always state that freedom of choice is preserved and no option is removed; that distinction is the key discriminator in the mark scheme.
• When asked about business objectives, contrast at least two alternatives to profit maximisation (for example growth maximisation and satisficing) and explain why a firm would choose them.
• Define each bias precisely (anchoring, framing, availability) and pair it with a concrete real-world example; naming alone earns little credit.

Key terms

bounded rationalitynudge