What Is HRI Design?

In 2016, a small yellow robot named Pepper rolled into a SoftBank retail store in Tokyo and attempted to greet a customer. The customer stepped aside. Pepper followed. The customer stepped aside again. Pepper followed again, politely, persistently, and without a single ounce of malice. Within seconds, a friendly retail greeting spiraled into a low-grade physical confrontation. The machine had no concept of when to stop.

The engineers had built a flawless navigation system. The product team had written a delightful script. But nobody had designed the space between them.

That invisible social contract humans follow automatically when approaching a stranger? That gap between what a machine can do and how a human experiences it? That is exactly where Human-Robot Interaction (HRI) design lives. It is not UX design. It is not robotics engineering. It is the discipline of intentionally shaping how people and robots share physical space.