Jakob's Law

Users bring expectations learned from other products and usually benefit when familiar conventions continue to behave in familiar ways.

External conventions reduce learning cost. A magnifying-glass icon, browser back behavior, common form patterns, platform navigation, and established ecommerce flows arrive with expectations before the user sees the product's documentation. Novel interaction can be worthwhile when it creates clear value, but novelty should pay for its learning cost.

Users arrive with prior experience. They already understand common browser behavior, platform controls, ecommerce conventions, search patterns, form semantics, navigation models, and keyboard expectations. Reusing those conventions lets users spend their learning effort on what is unique about the product.

Novel interaction is justified when it produces enough task value to repay the learning cost. The standard should be high for routine tasks such as closing, searching, going back, submitting forms, selecting items, or editing text. Product differentiation usually belongs in the domain workflow rather than in reinventing basic controls.

Layr should consider both external conventions and internal consistency. A product can violate expectations even when a pattern is not globally standardized if it behaves differently from its own established behavior.

Compare controls against platform norms, domain conventions, and the product's existing patterns. Check semantics, keyboard behavior, focus, browser history, gestures, and labels. Novelty should be evaluated in relation to measurable benefit and learnability.

A custom component that looks familiar while dropping accessibility behavior is a high-confidence problem because it borrows the expectation without delivering the behavior.

• Standard icons trigger unexpected actions.
• Browser back behavior is intercepted in surprising ways.
• Custom form controls lose native keyboard and focus behavior.
• A familiar gesture performs a different destructive action without warning.
• The product uses multiple internal patterns for the same common task.

• What expectation would an experienced user bring to this control?
• Does the product preserve that expectation or intentionally teach a better model?
• What measurable value does the novelty provide?
• Is there a familiar fallback or recovery path?

High — The magnifying-glass icon opens workspace settings. This icon carries a mature search expectation across desktop and mobile products. Use the established settings icon or label for workspace settings and reserve the magnifying glass for search behavior.

Prefer established platform and domain conventions for ordinary tasks. Introduce novel patterns deliberately, with clear affordance and a measurable advantage.

• Navigation, authentication, search, forms, tables, settings, checkout, mobile gestures, keyboard shortcuts, and common component behavior.

• A common symbol performs an unexpected action.
• The product changes standard platform behavior without visible explanation.
• Basic controls are replaced with custom components that lose keyboard, focus, or semantic behavior.
• A new interaction requires onboarding for a task users already know how to perform elsewhere.
• The same convention is implemented differently inside the product.

• Use platform-native or well-established patterns where they satisfy the task.
• Keep common labels and control semantics recognizable.
• When novelty is valuable, preserve familiar fallback paths and teach by interaction rather than long documentation.
• Test custom components against accessibility and input expectations.

Familiarity is not a ban on invention. A new pattern can be justified when it materially improves the task and remains learnable, reversible, and accessible.

• Default severity: Medium to high when convention mismatch causes wrong actions; low for learnable novelty with little consequence.
• Typical confidence: High for mature conventions; medium when domain conventions vary.
• Primary evidence: Platform conventions, common product patterns, component behavior, labels, user domain.
• Related rules: Mental Model, Law of Similarity, Paradox of the Active User, Aesthetic-Usability Effect