Bruce Tognazzini: First Principles of Interaction Design

Evidence class: single-expert practitioner guidance. Read: 2026-09-13. Source: Revised and expanded First Principles, dated 5 March 2014. Coverage is selected sections on discoverability, consistency, user efficiency, state, aesthetics, and latency.

Verified guidance

Prioritize human productivity, preserve work, make controls discoverable, and keep status accurate. Similar appearance must not conceal different behavior. Learned interaction meaning deserves more stability than surface styling. Visual redesign should be tested rather than assumed harmless.

Website application

Our proposed review asks whether a visitor can find controls without hover hunting and predict what a familiar control will do. Review the result after visual changes, not only before them.

Tension and limits

The strong warning against hiding complexity needs to be read alongside selective disclosure, not as a mandate to display every option. The author's 50-millisecond acknowledgment recommendation is verified as his advice, not a normative web standard or proof that all work must complete in that time. Preserve the distinction between feedback and completion.