a. Information processing
b. Mental models
c. Learning
d. Skills
e. Individual differences

a. Information processing:

• Our senses collect information, and our brain processes it in two levels: higher (conscious and slow) and lower (rapid, parallel, and unconscious).
• Repetition and learning shift control from the higher to the lower level.
• Both levels function simultaneously, with the higher level doing reasoning, and the lower level perceiving physical information.

b. Mental models:

• Mental models are internal representations of a person’s understanding of something.
• People often can’t describe their mental models, but they influence how we perceive and interact with things.
• When using a new system, people apply their mental models. If the system aligns, it feels intuitive; if not, there may be difficulties.

c. Learning:

• Learning is the process of encoding short-term memory information into long-term memory.
• People can improve performance through learning, but designing overly complex systems underestimates our learning ability.
• Design can enhance learning by providing consistency, feedback, and phased information.

d. Skills:

• Human performance aims for skillful actions.
• Skill involves performing actions in the correct sequence with precision, consistency, and economy of effort.
• Skills are hierarchical, with basic skills integrated to form complex ones.
• System and screen design should support the development of increasingly skillful performance.

e. Individual differences:

• People differ in looks, feelings, abilities, and more.
• Design must accommodate a wide range of characteristics for users to learn and use a task comfortably.
• In the past, designs often catered to the lowest abilities, but technology now allows tailoring tasks to varying skill levels.
• Multiple system versions can be created to meet the needs of different users.