Hick-Hyman Law

This article explains Hick-Hyman Law—covering core principles, practical design rules, and common exam questions.

In a Nutshell

Hick-Hyman Law states: decision time increases with the amount of information in your choice set. More options slow selection down; well-organized and predictable options speed it up.

Formal Definition

The law is expressed as:

T = a + b * H
H = Σ (p_i * log2(1/p_i))

For n equally likely options, H ≈ log2(n).

Key distinction: Hick-Hyman models cognitive selection, not motor movement—that’s Fitts’s Law.

Practical UI Guidelines

• Reduce options to only what’s relevant
• Group logically (chunking)
• Progressive disclosure of features
• Search, filter, and favorites to narrow choices
• Combobox or search field instead of dropdown for large lists

Exam Essentials

• The formula and what H represents (entropy/information content)
• Trade-offs between breadth and depth in navigation
• How expectancy shifts probabilities and reduces decision time
• Key metrics: selection time, error rate, SUS/UEQ scores

Real-World Example

Toolbar with 16 actions → slow selection
Solution:
- Group into logical clusters
- Pin the most-used action as a favorite
- Add a search field

Common Exam Questions (Quick Answers)

1. What does H represent? Entropy—the information content of your choice set.

2. Dropdown or combobox for large lists? Combobox with search is more efficient.

3. Hick versus Fitts? Hick covers decision time; Fitts covers movement time.

Key References

1. https://en.wikipedia.org/wiki/Hick%27s_law
2. https://www.nngroup.com/articles/hick-hyman-law/