Hick's Law, Fitts's Law and Miller's Law: Psychology That Fixes Interfaces

Three of the laws in Jon Yablonski’s Laws of UX do most of the heavy lifting in everyday interface work. Master these three and you will diagnose the majority of friction in any product you touch.

How does Hick’s Law fix decision screens?

Hick’s Law states that the time to make a decision increases with the number and complexity of choices. The interface translation: every option you add to a screen taxes the user. Pricing pages with five plans, settings screens with forty toggles, navigation with eleven top-level items. The fix is not deleting features. It is progressive disclosure: show the few choices that matter now, and defer the rest. Onboarding that asks three questions converts better than onboarding that asks twelve, and Hick’s Law tells you why.

How does Fitts’s Law fix buttons?

Fitts’s Law says the time to reach a target is a function of its distance and size. Tiny text links for destructive actions, primary buttons squeezed into corners far from where the eye is working, tap targets smaller than a fingertip: all violations. The practical rules are simple. Make primary actions large. Place them near the content they act on. On mobile, put key controls within thumb reach. The law is fifty years old and mobile screens made it more relevant, not less.

How does Miller’s Law fix content?

Miller’s Law observes that working memory holds roughly seven chunks of information. Interfaces that dump undifferentiated lists on users force them to hold too much at once. The design response is chunking: group related items, label the groups, and use visual hierarchy so the structure does the remembering. A settings page organized into five labeled sections feels simpler than the same forty options in one list, because it is.

Why does Tremoloo share this book?

These three laws appear in our usability test findings constantly, often behind complaints users phrase as “it’s confusing” or “I can’t find things.” Sharing the book helps teams connect that vague feedback to specific, fixable violations.

Want to see these laws tested against real users on your product? Book a usability test.