Nudge
Also called: choice architecture, libertarian paternalism
A nudge changes how choices are presented to steer behaviour without removing options — a default, a reminder, a reordering. Auto-enrolment is the canonical financial example and one of the most effective policies ever measured. The critique is legitimate and worth keeping in view: the same techniques that raise savings rates also sell subscriptions people never intended to keep.
Where this is taught
Definitions are the trailer. These free levels turn Nudge into something you play — one bite-size lesson, with worked examples, a quiz and XP.