Nudge
A nudge is a change in how choices are presented that steers behaviour without forbidding options or changing incentives.
You can change what people do without changing what they are allowed to do, just by changing how the choice is arranged. That is a nudge.
A nudge is a change in the way choices are presented that predictably alters people's behaviour without forbidding any options or significantly changing their economic incentives. Popularised by Richard Thaler and Cass Sunstein, it uses insights from behavioural economics to steer decisions gently.
Steering without coercion
The defining feature of a nudge is that it preserves freedom of choice. It does not ban, mandate, or heavily tax; it rearranges the choice so that the easier or default path tends toward a better outcome. Automatically enrolling employees in a pension scheme while letting them opt out is the classic example: no one is forced to save, but far more do, because inertia now works for saving rather than against it.
Why defaults are so powerful
Much of the power of nudging comes from defaults and the human tendency to stick with them. People often take the path of least resistance, so whatever is set as the default, the pre-ticked box, the standard option, the automatic choice, exerts enormous influence. Since some default must always be chosen, the designer of the choice unavoidably nudges; the only question is whether they do so thoughtfully and in the chooser's interest.
The ethics
Nudging is not free of controversy. Critics argue that steering people, even for their own good, is a form of paternalism that can shade into manipulation, especially when the nudger's interests differ from the nudged. The same techniques that help people save or eat better can push them to spend, gamble, or consent against their interest. The defence, libertarian paternalism, is that choice is preserved and that some arrangement of the options is inevitable, so it may as well help.
A nudge is a quiet but real lever on behaviour, and its rise has changed how governments and firms design choices. Its power and its danger are the same fact: small features of how a decision is framed shape what people do, whether or not anyone intended them to.