Nudge Patterns

Code of ethics: nudge, sludge and dark patterns

Where a nudge ends and sludge begins: our terms, five test questions, examples from the guides and our self-commitment.

Terms

A nudge is a design of the choice situation that steers behavior predictably without forbidding options or changing incentives much (Thaler & Sunstein, 2008). Sludge denotes unnecessary friction that makes good decisions harder. Thaler (2018) coined the term in his essay “Nudge, not sludge”, and Sunstein (2020) called for “sludge audits”, that is, regular checks for such friction. Dark patterns are designs that move users through deception or pressure to act against their own interest.

Our five test questions

  1. Truth: Are all statements genuine (prices, scarcity, progress, ratings)?
  2. Transparency: Could we explain the design openly to users without embarrassment?
  3. Autonomy: Does every option remain reachable, and is leaving as easy as entering?
  4. Interest: Does the design also serve users, or only the provider?
  5. Vulnerability: Does it work differently on stressed, older or inexperienced users?

Classification with examples from our guides

Pattern Nudge Borderline Sludge
Strikethrough price Genuine, verifiable comparison price Price charged only briefly Invented starting price
Decoy All options genuinely purchasable and clearly described Tier built only for price comparison Differences obscured
Progress bar Shows the actual status Artificial head start without reason Fake progress, bar sticks at 90%
Checkout funnel Guest checkout, total price visible early Payment details only after much effort Costs only in the last step
Subscription Clear cancellation Cancellation only via a form Hidden cancellation path

Our self-commitment

We do not recommend tactics based on fake scarcity, invented prices or obscured cost structures. We mark borderline cases in the ethics check of each guide. We illustrate dark patterns to make them recognizable, not as instructions.

In Germany, price indication law and competition law apply depending on the case. Examples are section 11 PAngV on price reductions towards consumers and section 312k of the German Civil Code on the cancellation button. Our notes are not legal advice. Have your specific implementation reviewed by a lawyer.

Sources of this page