Hick's Law (Hick-Hyman Law)

By Dnyaneshwar N • 5 min read • William Edmund Hick & Ray Hyman, 1952

When users are bombarded with too many options, decision fatigue sets in. Simplify choices by categorizing, progressive disclosure, and highlighting recommended paths.

Core Principle

The time it takes to make a decision increases logarithmically with the number and complexity of choices presented.

The Hick-Hyman Mathematical Law of Reaction Time

Formulated in 1952 by psychologists William Edmund Hick and Ray Hyman, Hick's Law describes the mathematical relationship between the number of stimulus options and human reaction time.

Expressed as RT = b * log2(n + 1), where n represents the number of equiprobable choices, the formula demonstrates that decision time increases logarithmically rather than linearly as options multiply.

This logarithmic relationship means that adding choices to a small set (increasing from 2 to 4 options) creates a substantial spike in decision latency. However, once options reach 50 or 100, each additional item causes smaller incremental increases in delay, but collective decision fatigue sets in.

Structuring Hierarchies and Menu Depth

In navigation architecture, Hick's Law informs the debate between broad versus deep menu hierarchies. A single flat menu with 40 unorganized items forces users to scan linearly through all 40 options, creating severe cognitive friction.

By categorizing options into 5 logical clusters, designers reduce initial decision options, allowing users to quickly identify the relevant subcategory before scanning specific sub-items.

When users know exactly what they are looking for, high-speed search and autocomplete inputs bypass Hick's Law entirely by eliminating the scanning requirement.

Frequently Asked Questions

Mathematical and structural takeaways on Hick's Law:

What is the Hick-Hyman Law in UX? A psychological law stating that the time it takes to make a decision increases logarithmically with the number and complexity of choices presented.
Does Hick's Law apply when users know their exact choice? No. Hick's Law applies primarily when users must evaluate, compare, or search across unfamiliar options in an interface.
How do designers minimize decision time using Hick's Law? Group options into clear categories, highlight a single recommended action, and use progressive disclosure to hide secondary choices.

When to Apply

Pricing table tiers and feature comparisons
Complex multi-step onboarding and checkout flows
Navigation menus and dropdown hierarchies
Form input fields and filter criteria
Decision architecture in checkout and sign-up funnels (see practical SaaS rules in Hick's Law: Choice Overload in UX).

Recommended Practices

Break complex multi-step processes into progressive disclosure chunks.
Highlight a single recommended default option in pricing or tier matrices.
Use smart search with auto-suggest rather than exhaustive nested mega-menus.
Prevent choice fatigue by chunking large option sets into categories using Miller's Law.

Practices to Avoid

Do not present 10+ equal-weight action buttons on a single landing or dashboard view.
Do not require users to configure 15 settings simultaneously during initial onboarding.
Do not display all available product variants without smart filters.

Diagnostic Checklist

Have secondary or non-critical actions been moved under menus or disclosure toggles?
Is there a distinct visual hierarchy marking the recommended choice?
Can multi-step flows be divided into bite-sized 3-step progressive wizards?
Eliminate extraneous mental friction during product discovery by applying Cognitive Load Theory in Product Design.