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title: Nudge Theory
modified: 2026-06-10
tags: []
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= 輕推理論 = 助推理論

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[Nudge theory](https://youtu.be/F9wv9go5I_4) is a behavioral economics concept proposing that small, indirect suggestions and environmental tweaks (“nudges”) can influence human [decision-making](decision-making.md).

Popularized by Richard Thaler and Cass Sunstein in their 2008 book _Nudge_, the theory is based on the premise that [human beings are not always perfectly rational](the-mueller-lyer-illusion.md). Instead, our choices are heavily shaped by cognitive biases, inertia, and how options are presented (the “choice architecture”).

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To be considered a true “nudge,” an intervention must meet several criteria:

* **Preserve Freedom:** People remain completely free to choose otherwise. There are no mandates, bans, or heavy financial penalties.
* **Easy to Avoid:** The desired action should not be difficult, but individuals can opt out without hassle.
* **Benefit the Chooser:** The nudge is designed to steer individuals toward choices that improve their health, wealth, or happiness.

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# Examples

* Supermarkets and Cafeterias: Placing healthy items (like fruit) at eye level, while putting less healthy options out of the way, increases the likelihood that people will choose the healthier option.
* **Setting Defaults:** Opt-out organ donation systems (where you are automatically a donor unless you actively choose not to be) in Singapore significantly increase donor rates compared to opt-in systems.
* **Visual Cues:** Etching the image of a fly into the center of a men’s urinal gives people a subconscious target, drastically reducing spillage and cleaning costs.
* **Digital Design:** Automatically enrolling employees into retirement savings plans (while allowing them to opt out if they wish) increases savings rates.