『The Design of Everyday Things』要約

Don Norman’s The Design of Everyday Things is a foundational text of user-centered design, first published in 1988 as The Psychology of Everyday Things and revised in 2013. Norman argues that when people struggle with doors, switches, or stoves, the fault lies not with the user but with the design itself. His central framework distinguishes affordances (what an object allows you to do), signifiers (clues that indicate where action should happen), mapping (the relationship between controls and their effects), and feedback (information about what an action accomplished). He illustrates these with examples such as the Norman door—a door whose handle suggests pulling when it must be pushed—and complex control panels like those of a nuclear power plant or an airplane cockpit. The book introduces the seven stages of action, a cycle from forming a goal to evaluating the result, and identifies gulfs of execution and evaluation where design breaks down. Norman also explores human error through slips and mistakes, arguing that most errors are predictable consequences of poor design rather than carelessness. He discusses the paradox of technology, where added features increase complexity, and calls for designs that make the correct action discoverable and the wrong action difficult. Later chapters examine how design must account for human cognition, memory, and emotion, and how good design balances aesthetics with usability. The revised edition adds considerations of business constraints and the design of everyday digital interfaces. Widely assigned in design, engineering, and psychology courses, the book remains a standard reference for human-centered design principles.