The Six Fundamental Principles of Interaction
Good design rests on two characteristics:
- Discoverability — can you figure out what actions are possible, and where/how to do them?
- Understanding — what does it all mean? how is it meant to be used?
Discoverability results from the appropriate application of five psychological concepts plus a sixth, "perhaps most important of all":
- Affordances — what actions are possible (a relationship between object properties and an agent's capabilities).
- Signifiers — perceptible signals of where the action should take place. In design, signifiers matter more than affordances.
- Four Kinds of Constraints — physical, cultural, semantic, logical limits that guide and ease interpretation (developed in ch.3–4).
- Mapping and Natural Mapping — the relationship between controls and their effects; exploit natural (spatial/cultural) mappings.
- Feedback and Feedforward — full, immediate, prioritized information about results and current state.
- Conceptual Models and Mental Models — a simplified explanation of how the thing works; provides true understanding. Communicated via the The System Image.
The seven design principles (ch.2 restatement)
The same spine restated from the The Seven Stages of Action, adding discoverability and feedback as principles in their own right: discoverability · feedback · conceptual model · affordances · signifiers · mappings · constraints.
Why this is the spine
Every later chapter (knowledge, constraints, error, process) is an application of these. The principles are claimed to be timeless because they derive from human psychology, not technology.
Confidence
1.0 — these are the book's explicitly enumerated organizing principles.
Sources: ["DOET ch.1 'Fundamental Principles of Interaction' p.10; ch.2 p.71-72"]