Cognition: what goes on in our heads when we carry out everyday activities: thinking, remembering, learning, deciding, seeing, reading…

Fast thinking (experiential, automatic) vs. slow thinking (reflective, effortful).

Attention: selecting things to concentrate on; depends on clear goals and how information is displayed.

Perception: how information is acquired through the senses and turned into experiences. Use contrast, white space and grouping.

Recognition is easier than recall: GUIs show options so users recognize rather than remember commands.

Memory trick Menus and icons = recognition; command lines = recall.

Memory load: 7 ± 2 (Miller) is about short-term memory items, NOT a rule for menu length.

Trap Don’t use "7 ± 2" to limit menu items or tabs: the items are visible, so no recall is needed.

Learning: people prefer learning by doing; design for exploration and undo.

Problem solving / planning / reasoning / decision-making: reflective cognition; show information needed for comparisons.

Mental model: a user’s internal model of how a system works; often wrong (turning the thermostat up higher heats faster).

Gulf of execution: gap between what users want to do and what the system lets them do. Gulf of evaluation: gap between the system state and the user’s ability to interpret it.

Information processing: mind as a series of stages: encode → compare → select response → execute.

Distributed cognition: cognition spread across people, tools and the environment (e.g. an air-traffic control team).

External cognition: using external representations (notes, calendars) to reduce memory load and do computational offloading.

Embodied interaction: thinking through the body and physical interaction.