Two-Point Discrimination

A measure of tactile sensitivity indicating the minimum distance at which two distinct points of contact on the skin can be perceived as separate rather than as a single point. Lower values indicate higher sensitivity. The fingertips have the highest two-point discrimination (~0.3cm), followed by the palm (~0.4cm), making them ideal for detailed haptic exploration. Other body areas have progressively lower sensitivity: head (~0.6cm), foot (~0.6cm), waist (~1.2cm), arm (~1.5cm), wrist (~1.7cm), and shoulder (~1.9cm). This metric is fundamental to haptic assistive technology design, explaining why finger-based interfaces dominate for tasks requiring fine detail perception, while less sensitive body areas may suffice for simpler directional cues.