Hick-Hyman Law

This article is a conceptual explanation of the Hick-Hyman Law – including practical rules and exam questions.

In a Nutshell

Hick-Hyman states: Decision time increases with the information quantity of the selection. More options slow down, well-grouped and expectation-compliant options speed up.

Compact Technical Description

Formally:

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

For n equally probable options, approximately H = log2(n).

Important: Hick-Hyman models cognitive selection, not motor targeting (that is Fitts).

Practical UI rules:

• Reduce options (only relevant ones)
• Group meaningfully (chunking)
• Progressive disclosure
• Search/filter/favorites
• For large lists: combobox/search instead of dropdown

Exam-Relevant Key Points

• Basic formula + meaning of H (entropy)
• Weigh breadth vs depth of menus
• Expectation-compliant labels shift probability → faster
• Metrics: time to selection, error rate, SUS/UEQ

Practical Example

Toolbar with 16 actions -> slow
Solution:
- bundle into few groups
- frequent action as favorite directly visible
- add search field

Typical Exam Questions (with Short Answer)

1. What does H stand for? Entropy/information quantity of the selection.
2. Dropdown vs combobox? For large lists, combobox with search is more ergonomic.
3. Hick vs Fitts? Hick = selection time, Fitts = movement time.

Most Important Sources

1. https://de.wikipedia.org/wiki/Hicksches_Gesetz
2. https://www.nngroup.com/articles/hick-hyman-law/