Nudge

Any feature of choice architecture that predictably alters people's behavior without forbidding any options or significantly changing their economic incentives. To count as a nudge, the intervention must be easy and cheap to avoid: a default you can change, not a mandate; a reminder, not a fine.

Why it Matters

It names a middle path between doing nothing and coercing. Nudges can move behavior at scale for little cost while preserving freedom of choice, which makes them attractive where bans are illegitimate and incentives are expensive or blunt.

Signals

• An intervention that changes behavior but leaves every original option available.
• The cost of opting out is trivial (a click, a checkbox), not a penalty.
• A change in presentation or default, not in the payoff of the choices.

Benefits

Low-cost, freedom-preserving influence; works with human psychology (inertia, salience) rather than against it; reversible and easy to test.

Risks

Sliding from helping into manipulating; nudges aimed at the architect's interest rather than the chooser's; over-reliance on nudges where a structural fix or an honest incentive is the real answer.

Tensions

A nudge is only as legitimate as the goal behind it and the ease of opting out; the same mechanism that gently helps can quietly exploit. Effectiveness (people don't opt out) is in tension with transparency (people should know they're being nudged).

Examples

Automatic enrollment in a savings plan with an easy opt-out; a default option pre-selected on a form; painting lines on a road to slow drivers; showing a household how its energy use compares to its neighbors'.