NNGroup Human-Computer Interaction HCI (Motor Laws Fitts/Steering · Touch Target 1cm · State Switching/Feedback · Tutorials vs Contextual Help · Task Analysis/Data Tables · Smart Home/AI Trust · Virtual Queues · AR Calibration)
16 curated articles from the Nielsen Norman Group Human-Computer Interaction (HCI) knowledge base. Coverage spans three major sections: ① Hard laws of motor control and cognition — Fitts's Law (time to reach a target T depends on distance D and target width W; larger targets are faster · screen edges = infinite targets · padded targets · Woodworth two-phase movement model · distance comparison of linear vs rectangular vs pie menus · place buttons close to the prior action), Accot-Zhai Steering Law (movement time within a bounded path T=a+b·A/W; narrower and longer paths are harder · L-shaped corridors in hierarchical menus · vector triangle buffer zones · Mega Menus · forgiving paths), Touch Targets (minimum 1cm×1cm / 0.4in · average finger width 1.6–2cm · thumb 2.5cm · spacing to prevent accidental taps · View-Tap Asymmetry · use larger 2cm targets for children/older adults/one-handed use), design process (Iterative design +38% per round · Parallel design merge +70%, then iterate for 152% · Competitive testing). ② Interaction patterns and interfaces — State-Switch controls (dual control: state indicator + toggle button vs single control · Mute button counterexample WebEx · positive example Zoom), Tutorials vs Contextual Help (push vs pull · short-term memory load · progressive disclosure), Task Analysis (task vs goal · contextual inquiry · HTA hierarchical task analysis diagram · GOMS · cognitive complexity), four core Data Tables tasks (lookup/compare/edit single row/batch operations · freeze header and first column · zebra striping · in-place editing vs non-modal side panel). ③ Smart homes and new scenarios — 7 best practices for smart devices, 5 guidelines for onboarding and connection, 5 motivations for smart homes (convenience/peace of mind/saving money/useful data/ambience), 3 user types (Managers/Everyday Users/Restricted Users) + Zone×Role dual axis · agentic execution · invisibility of automation · ability to degrade to Dumb Work, 7 principles of smart notifications (timely/relevant/specific/intensity/frequency/channel/adjustable) × 3 types (Reactive/Proactive/Optimization), Smarts over Sentience (warm AI increases error rate by 10–30% · RAG), 13 practices for Virtual Queues, 10 guidelines for AR calibration. Audience = product managers; terms explained in-line, decision-oriented (when to use/how to choose/counterexamples).