A Context-Aware Approach to Personal Security in Smartwatches: An Interaction Design Framework for High-Stress Safety Systems

Commercial smartwatch emergency features are almost uniformly reactive: they require the wearer to locate, press, and hold a physical button, or to navigate a touch target on a display of 34–45 mm diagonal, in precisely the circumstances where the underlying motor and attentional resources are least available. Laboratory evidence on acute stress shows that threat-type stressors degrade fine force control by a substantial margin while leaving gross force production intact, that usable visual field area contracts under cognitive load, and that threat raises blink frequency such that the wearer is intermittently not looking at anything at all. A reactive interface therefore fails at the moment of need, while the automatic-detection alternative fails in the opposite direction: published evaluations of commercial wrist-worn fall detection report sensitivity of 77% with a 1.7% per-event false-positive rate in induced-fall protocols, and as low as 4.7% sensitivity in populations outside the tuning distribution — and deep models trained on laboratory falls collapse to 0.37 precision on real-world data.