Where does nudge collide?

Any aspect of the choice architecture that alters people's behavior in a predictable way without forbidding any options or significantly changing their economic incentives, in Thaler and Sunstein's formulation. The two coined the term within libertarian paternalism, the position that a planner may steer choices toward the chooser's own welfare while leaving every option open and cheap to reach. Placing fruit at eye level counts as a nudge; banning junk food does not, and neither does a tax on it. The construct is fixed by two exclusions, of mandates and of significant incentives, and those exclusions are what the other meanings on this map tend to drop.[1][2]

Unit

A feature of a choice environment

Recovery means

Not applicable

Measured by

Whether options stay open and incentives unchanged; behavioural response to the arrangement

A low-cost intervention that a government tests by trial before scaling, in the behavioural-insights tradition that Halpern's Behavioural Insights Team established and that Benartzi and colleagues assessed for cost-effectiveness. Here a nudge is defined operationally by how it is deployed and evaluated: a cheap change to letters, defaults, or reminders, run as a randomized trial, and compared with conventional instruments on cost per outcome. Benartzi and colleagues found nudges often returned more behaviour change per dollar than tax incentives or mandates, which reframes the term from a description of an arrangement into a class of policy tool. The exclusions of incentives and mandates survive in principle but are treated as a comparison set rather than a boundary.[3][4]

Unit

A government policy instrument, per unit cost

Recovery means

Not applicable

Measured by

Cost per behavioural outcome in a randomized trial; effect relative to incentives and mandates

The use of user-interface design elements to guide behaviour in digital choice environments, which Weinmann, Schneider, and vom Brocke named digital nudging in 2016. The referent moves from the physical choice architecture to the screen: defaults, option ordering, salience, and framing in a form or a menu. Weinmann, Schneider, and vom Brocke carried Thaler and Sunstein's logic into interface design intact, including the claim that the steering leaves choices open. What the move adds is a designer with an interface under full control and a metric of conversion, which is the condition under which the next meaning appears.[5]

Unit

A user-interface design element

Recovery means

Not applicable

Measured by

Interface features that shift choices; observed behaviour on the screen

An interface arrangement that steers users toward choices they would not otherwise make, against their own interest and to the designer's benefit, which Gray and colleagues catalogued as dark patterns in 2018. This is the digital nudge with the welfare condition reversed: the same defaults, salience, and framing, deployed to extract rather than to help. Gray and colleagues sorted the practices into types such as nagging, obstruction, and forced action, and placed them on a continuum with ordinary persuasive design, so the line between a nudge and a dark pattern is a claim about whose interest the arrangement serves, not about the mechanism. Calling both a nudge collapses that line.[6]

Unit

A manipulative interface arrangement

Recovery means

Not applicable

Measured by

Interface features that steer against the user's interest; classified pattern types