Human-machine interaction is the study of how people control, interpret, and trust machine behavior. It covers the design of controls, screens, alerts, and feedback that let an operator understand what a system is doing and choose the right action. In cyber-physical systems, this includes industrial machines, vehicles, medical devices, and other tools where software and hardware affect the real world.
It matters in cyber security because the interface is part of the trust chain. A confusing display, ambiguous button, or misleading alert can cause unsafe actions even when the underlying system is working correctly. Attackers may try to abuse this layer with fake prompts, altered readings, or deceptive status messages, while defenders use clear feedback, permission checks, and fail-safe design to reduce error and make dangerous commands obvious. Good human-machine interaction helps operators respond quickly without losing situational awareness.