What Touch Provides That Vision Cannot
Haptic feedback creates a communication channel that bypasses conscious visual processing. When your phone vibrates slightly as you press a virtual key, your brain receives physical confirmation that makes interaction more natural, less cognitive.
Three Levels of Haptic Feedback
Level 1 — Simple vibration (all mobiles):
navigator.vibrate(40); // Short confirmation
navigator.vibrate([50,30,50]); // Error (shaking)
navigator.vibrate([100,50,200]); // Success (long pulse)
Level 2 — Advanced haptics (iOS/Android native): Impact light/medium, success, warning, error — each with specific vibration profiles. Not accessible from the web but essential in native AR/VR apps.
Level 3 — Specialised haptic devices: VR controllers, haptic gloves (HaptX, Bhaptics), vibrating surfaces for spatial, nuanced feedback.
Haptic Design Principles
Congruence: haptic feedback must match the action. Button press → short sharp vibration. Slider drag → continuous light vibration. Task completion → satisfying accomplishment vibration.
Economy: too much haptic feedback = nuisance. Reserve for state transitions, errors, important confirmations.
Context calibration: a vibration designed for a quiet room may be imperceptible at a noisy festival.