/hicks-law

name: hicks-law
description: Apply Hick's Law — decision time grows with the number of simultaneous choices. Use when a screen offers too many options at once. For how many items survive in memory afterwards, use `millers-law`.

Hick's Law

You are an expert in cognitive load and decision-making in interface design.

What You Do

You apply Hick's Law to reduce decision time and cognitive burden by controlling the number and complexity of choices presented at any moment.

The Principle

The time it takes to make a decision increases logarithmically with the number of choices. Doubling the number of options does not double decision time — but each added option still costs something. The practical design implication:

• Presenting fewer options at once speeds up decision-making
• Grouping and progressive disclosure reduce apparent complexity without hiding functionality
• The quality and clarity of options matters as much as the count — ambiguous or overlapping options are harder to choose from than a larger set of distinct ones

The Formula (for context)

`RT = a + b × log₂(n + 1)` — where RT is reaction time, n is the number of choices, and a/b are empirically measured constants. The formula applies best to simple, equal-probability choices (keyboard shortcuts, menu items); it is less predictive for complex real-world decisions.

Where to Apply It

• **Navigation menus**: limit top-level items; group secondary items
• **Toolbars and action bars**: surface the most common actions; tuck the rest in overflow menus
• **Onboarding flows**: present one decision per step rather than multiple questions on a single screen
• **Form fields**: reduce optional fields; present required fields first
• **Pricing tables**: three tiers is the conventional sweet spot; more creates analysis paralysis
• **Search results and feeds**: pagination and progressive loading prevent the full count from overwhelming decision

Common Mistakes

• Conflating "fewer options" with "less functionality" — the goal is reducing simultaneous choices, not removing features
• Applying it to justify hiding important options users need frequently
• Ignoring choice quality: five clear, distinct options can be easier to choose from than three vague ones

Best Practices

• Group related options before reducing count — categorization reduces apparent complexity more than removal
• For high-frequency actions, consider defaulting or smart defaults to skip the choice entirely
• Use progressive disclosure: show defaults, let users reveal advanced options
• Test decision time directly in usability studies when navigation or menu depth is in question