human–robot interaction (HRI)
Human–robot interaction is the study of how people and robots communicate, work together, and shape each other's behavior. It asks the very human-side questions that the mechanics and the code leave out: How should a robot signal what it is about to do so a person nearby feels safe? When a robot speaks, gestures, or simply turns its 'head,' how do people read that? And how does sharing space and tasks with a machine change what the people themselves do? It treats the human and the robot as one team, not as a tool and its user.
It is deliberately interdisciplinary, stitching together engineering with psychology, design, and the study of language and gesture. A robot that hands you a cup is not just solving a motion problem; it has to reach out at a pace you can predict, look where it is about to move so you can anticipate it, and let go at the right moment. Getting any of that wrong feels jarring or even unsafe, even when the underlying machinery works flawlessly. So HRI cares as much about how an action is perceived as about whether it technically succeeds.
Why it matters grows as robots leave fenced-off factory cells and move into homes, hospitals, shops, and roads, where the other party is an untrained person, not an engineer. Trust becomes central: people who trust a robot too little ignore its help, while people who trust it too much rely on it past its real abilities. HRI studies how to calibrate that trust — through clear, honest signals — so the partnership is both effective and safe.
A delivery robot rolling down a sidewalk slows and tilts slightly toward the curb before turning, so pedestrians can read its intention the way they would another person's body language.
Good HRI makes a robot's next move legible — readable by an ordinary person without any training.
HRI overlaps with, but is broader than, human–computer interaction: a robot shares physical space and can move and touch, so its body language and timing matter in ways a screen's never do.