Models and Theories in Human-Computer Interaction/Stages of Action as Design Aids
In his book The Psychology of Everyday Things Donald Norman proposes a 7-stage process of action to describe our, often subconscious, process of interacting with the world. The process describes the intermediate steps taken as we form a goal, execute, and evaluate the results. Norman’s process starts with the creation of a goal and then the forming of an intention, which Norman describes as specific statements of action. Next are specifying and executing the action followed by perceiving and interpreting the state of the world and, finally, evaluating the outcome. Norman suggests that products be designed with this process in mind and defines two deficiencies arising when they are not. The Gulf of Execution is the difference between user intentions and allowable actions and indicates whether the product allows the user to perform intended functions natively. The Gulf of Evaluation measures the difficulty the user has in perceiving the physical state of the product. In translating the seven stages to a design aid Norman arrives at a checklist for designers – provide visibility (user can see the state of the product and the actionable options), provide a good conceptual model (presentation of operations and results is consistent and coherent), provide good mappings (correlations exist between actions/results and controls/effects), and provide feedback (full and continuous feedback is provided from actions).