Too many choices exhaust mental energy and impair decision quality.
Definition
Decision Fatigue refers to the deteriorating quality of decisions made by an individual, after a long session of decision making. It is now understood as one of the causes of irrational trade-offs in decision making.
Do
Limit the number of choices presented at a time
Implement sensible defaults or 'recommended' options
Arrange choices or steps in a process in order of importance or difficulty
Avoid
Overwhelm users with too many options at once
Underestimate the cognitive load of decision-making in your interface
Assume that more choices equate to a better user experience
When to apply
Designing complex interfaces with multiple options