The burden on a person’s short-term memory during complex tasks
When a user is working on a task, relevant information and processes are stored in their working memory. This information must be processed, and the amount of mental resources required to do so is known as cognitive load. As the brain has a limited amount of processing power, too much information delivered in too short a time can increase cognitive load to a point where it overwhelms the user.
Designers can reduce the cognitive load required of their users by reducing extraneous visual elements, building on information or models the user already knows, and performing tasks on their behalf wherever possible.