Usability Professionals' Association
2009 International Conference
Bringing Usability to Life
Making everyday things better
UI design rules are not simple recipes to be applied mindlessly. Applying them effectively requires determining their applicability to specific situations, and determining precedence when design rules contradict each other. This tutorial explains the psychology underlying the design rules, enhancing UI designers' and evaluators' ability to interpret and apply rules.
Introduction: User Interface Design Rules: Where do they come from? Presents familiar sets of UI design rules, discusses their similarities, and explains that they are not simply invented out of thin air and that applying them well requires understanding their basis in human perception and cognition.
Section 1: We perceive what we expect. Explains and demonstrates that perception is biased by: past: experience, present: context, and future: goals
Section 2: Our vision is optimized to see structure. Presents the Gestalt principles of visual perception, with visual demonstrations and examples of their application to UI design.
Section 3: Reading is feature & pattern recognition. Explains how our visual system processes symbols to allow us to read.
Section 4: Our color vision is limited. Demonstrates the strengths and limitations of our color vision, with examples of how that affects the optimal design of GUIs.
Section 5: Our peripheral vision is poor. Explains how our vision differs between the central (foveal) and peripheral areas of our visual field.
Section 6: Our attention is limited; our memory is imperfect. Discusses human short- and long-term memory, demonstrates their strengths and limits, and presents examples of computer UIs that do and do not take their limits into account.
Section 7: Recognition is easy; recall is hard. Explains that human recognition is amazingly fast so fast it must be accomplished via massively parallel processing and that recall is slow and error-prone.
Section 8: We think mostly about our tasks, not our tools. Explains that computer users devote very little mental effort to thinking about their tools (e.g., computer software or websites) and instead think mainly about what they are trying to accomplish.
Section 9: We seek, use, and impose structure. Shows that we use structure when it is present in the world, and we create it even when it is absent.
Section 10: Inductive reasoning is easy; deduction is hard. Discusses the difference between inductive and deductive learning/reasoning, and explains that humans do induction easily, without training, but require significant training to perform deduction.
Section 11: Human thought-cycle: goal, execute, evaluate. Explains the normal cycle of human behavior, and how it dictates the optimal design of interactive systems.
Section 12: Many factors affect learning, e.g.: vocabulary, consistency, task-focus.
Section 13: We have real-time requirements. Discusses time-constants of human perception, cognition, and action that affect how people perceive user interfaces.