Hick's Law

What it is

Formulated by psychologists William Hick and Ray Hyman in the 1950s (T = b · log2(n + 1)) for reaction-time experiments, the law has been extended into UX contexts by decades of usability research. The behavioural extension — the 'paradox of choice' popularised by Barry Schwartz — adds that beyond decision time, high choice count also reduces satisfaction with whatever gets chosen.

The logarithmic curve is important. Going from 2 to 4 options adds a lot of time; going from 20 to 40 options adds relatively less. But the practical implication is the same at both ends: reduce the choice count wherever meaningful.

Why it matters

Menus with 30 items get scanned incompletely and chosen from suboptimally. Product configurations with too many options paralyse users. Homepages with 20 CTAs get no clicks on any of them. Feature-heavy checkout screens get abandoned mid-flow. Every one of these is a Hick's Law problem — the interface has offered more choice than the user can efficiently process.

When to use it

Any time you're designing a menu, navigation system, feature list, dashboard filter, or moment of user decision. Also any time you're weighing whether to add another option to an existing choice set — the marginal cost of each additional option is real and cumulative.

What it looks like in practice

A primary navigation with 5-7 items outperforms one with 15-20. If more items exist, hide them in a secondary menu, a search, or a sub-nav rather than presenting them all at the top level.

A form field asking 'What's your role?' with 4 grouped categories outperforms the same field with 40 job titles listed alphabetically. Where 40 options must exist, add a search filter so the user's effective choice count at any moment stays small.

A checkout with one clear primary CTA and one clear secondary CTA outperforms a checkout with a save button, a 'save and continue' button, a 'continue as guest' button, and a 'sign in' link all fighting for the same attention.

What people get wrong

• Assuming logarithmic decay means adding one more option is free. It's not — decision time increases, and satisfaction with the chosen option drops.
• Adding options as a way to satisfy stakeholders. Every stakeholder-mandated option imposes Hick cost on every user, forever.
• Ignoring hierarchy. 20 options in a flat list is worse than 20 options grouped into 4 categories of 5, even though the underlying count is identical — because the user's effective choice count at each decision layer is smaller.
• Treating search as a substitute for good IA. Search helps at large scale but doesn't fix a menu that shouldn't have 20 top-level items.

Learn next

Hick's Law works alongside Fitts's Law (movement time to targets) — together they describe the full physical + cognitive cost of navigating a UI. Both are foundational for menu, navigation and form design.

Reviewed 29 September 2026 · Editorial standards