• humans face loads — ordered by how demanding they are:
  • cognitive (most demanding)
  • visual
  • motor — Fitts's law defines how big objects on screen should be; a relationship between speed, accuracy, and distance between objects; good to minimize motor switching (mouse to keyboard and vice versa)
• mostly we want to reduce loads, but when there's a need for more focus, we should increase them

Mental models

• a collection of thought processes and memories about how something works
• they drive behavior

Attention

• Assume you have at most 7 to 10 minutes of a person's attention.
• If you must hold attention longer than 7–10 minutes, introduce novel information or a break