Nudge Theory

In behavioural public policy, a nudge is a small change in how choices are presented that predictably influences behaviour while preserving freedom of choice. It modifies the choice architecture without prohibiting options or substantially changing economic incentives, and it should remain easy to avoid. Nudges seek to help people make welfare-enhancing decisions despite common cognitive biases.

How nudges influence behaviour

Nudges respond to predictable behavioural tendencies such as inertia, limited attention, present bias and sensitivity to social norms. They redesign the setting in which decisions are made rather than removing the decision itself.

• A default option uses inertia by preselecting an outcome while allowing a person to opt out.
• Salience and framing make relevant information easier to notice and understand.
• Reminders and simplification reduce forgetfulness and the effort required to act.
• Information about social norms can encourage people to follow beneficial behaviour adopted by peers.

Use in health policy

Health nudges can help convert knowledge or intention into action, especially where immediate convenience competes with long-term health.

• Clear nutrition labels can make the health implications of food choices more visible at the point of purchase.
• Vaccination or medical-appointment reminders can reduce inaction caused by forgetfulness.
• Placing healthier food prominently can alter choices without banning less healthy alternatives.
• Nudges can support preventive behaviour, but they cannot substitute for accessible healthcare, regulation or necessary fiscal measures.

Conditions and limitations

A legitimate public nudge should be transparent, evidence-based and directed towards the welfare of those affected. This approach is often called libertarian paternalism because it combines welfare-oriented guidance with freedom of choice.

• A nudge should preserve meaningful choice and remain reasonably easy to avoid.
• Its effects should be tested because responses may vary across social and cultural groups.
• Manipulative design or sludge, which creates unnecessary friction, can undermine autonomy and public trust.
• Governments should disclose objectives and monitor unintended or unequal effects.