Usability and user experience (UX) design apply cognitive psychology principles to create products and systems that people can use effectively, efficiently, and with satisfaction. Usability focuses on whether users can accomplish their goals (effectiveness), how much effort it requires (efficiency), and how many errors occur (error rate). UX encompasses the broader experience including emotional responses, aesthetic judgments, and overall satisfaction. Both draw heavily on cognitive psychology research.
Cognitive Principles in Design
Recognition over recall: interfaces should present options for users to recognize rather than requiring them to remember commands (menus over command lines). Consistency: similar actions should produce similar results, leveraging procedural memory and reducing learning demands. Feedback: systems should provide immediate, clear feedback about the effects of user actions, supporting the action-perception cycle. Progressive disclosure: presenting information in layers of increasing detail manages cognitive load. Chunking: grouping related information helps users organize and remember interface elements.
Cognitive psychology research methods are central to UX: think-aloud protocols reveal users' mental models and confusion points; eye tracking shows where attention is directed and what is missed; A/B testing provides controlled experimental evidence for design decisions; cognitive walkthroughs simulate the problem-solving process users follow; card sorting reveals how users categorize information (informing information architecture); and surveys measure subjective satisfaction and perceived ease of use.
Cognitive Ergonomics
Cognitive ergonomics extends usability to high-stakes domains (aviation, medicine, nuclear power) where interface failures can have catastrophic consequences. It addresses situation awareness, decision support systems, alarm design, and error-resistant interface design. The Swiss cheese model of error analysis recognizes that catastrophic failures result from the alignment of multiple system weaknesses, and interface design is a critical layer of defense.