Plans and Situated Actions: The Problem of Human-Machine Communication

Lucy Suchman was an anthropologist embedded at Xerox PARC who filmed people trying to use a photocopier and discovered something that shattered a core assumption of both AI and interface design: people do not follow plans. They improvise constantly, adapting to circumstances as they unfold. This ethnographic finding demolished the symbolic AI paradigm that assumed human action was essentially plan execution, and it redirected a generation of interface designers toward contextual, situated design. The implications extend well beyond HCI — product managers who believe users follow the happy path in their journey maps are making the same mistake Suchman identified forty years ago. The book is also an early, rigorous argument for why building products requires observing what people actually do, not what they say they do.