What is Hick's Law?
In 1952 the British psychologist William Edmund Hick measured how long people took to react when one of several lamps lit up and they had to press the matching key. The more lamps there were, the longer the reaction — and the increase followed a logarithmic curve. A year later Ray Hyman confirmed and extended the result, which is why it's also called the Hick–Hyman law.
The Hick's Law formula
RT = a + b · log2(n + 1)
- RT — reaction (decision) time.
- n — number of equally likely choices; the +1 accounts for the decision of whether to respond at all.
- a, b — constants measured for a person and task.
Because the curve is logarithmic, going from 2 to 4 options costs about as much extra time as going from 4 to 8. The first few additions hurt most.
Applying Hick's Law to websites
Keep the main navigation short
Group pages into a handful of clear top-level sections. Lensux flags primary menus with more than 7 links as a practical guideline.
One primary call to action per screen
Two equal buttons force a decision; one highlighted action and one quieter alternative make the choice for the user.
Recommend an option in pricing tables
Marking one plan as recommended reduces the comparison work for most visitors.
Use progressive disclosure
Show the essentials first and reveal advanced settings on demand.
Split long forms into steps
Fewer decisions per screen, with a progress indicator, feel faster than one long form.
Use smart defaults
Pre-select the most common option when it honestly helps the user — never to sneak in extras.
When Hick's Law does not apply
Hick's Law describes choosing between options people already understand. When users search a long, unfamiliar list — a product catalogue, a country selector — they read items one by one, and time grows roughly in proportion to the list length. For those cases, sorting, search and filtering help more than removing items.
Oversimplifying is also a risk: hiding options people need forces extra clicks and searching. Tesler's Law reminds us that complexity can only be moved, not removed.
Lensux counts the links in your primary navigation and flags menus with more than 7 choices, together with the list of items, so you can decide what to group or move to the footer.
Frequently asked questions
What is a simple example of Hick's Law?
A restaurant menu with 100 dishes takes longer to choose from than one with 10. On a website, a menu with 15 equal links slows people down more than one with 5 clear sections.
How many items should a navigation menu have?
There is no magic number, but most usable sites keep the primary navigation to about 5–7 top-level items and group the rest. Lensux uses 7 as its threshold.
What is the difference between Hick's Law and choice overload?
Hick's Law measures decision time for simple choices. Choice overload is a broader effect in which too many options make people less satisfied or less likely to choose at all.