Hick-Hyman Law
In practiced choice-reaction tasks, response time tends to grow with the information uncertainty of the possible stimulus-response alternatives.
Direct explanation
What it means
More equally likely alternatives carry more information and often take longer to select. Familiarity, unequal probabilities, grouping, search, and decision stakes can matter more than raw count.
The law offers a quantitative account for constrained response tasks, while its popular simplification often leads teams to hide navigation and create extra memory work.
Research anchor: William E. Hick, 1952
Research and interpretation
What the research found
Choice reaction time rose approximately with the information conveyed by possible signals, including when alternatives had unequal probabilities.
The relationship is foundational in human performance research, with parameters dependent on task, practice, mapping, and model formulation.
Popular advice versus careful use
Common shorthand: Every menu should show as few choices as possible.
Use the law for defined response alternatives; design broader choice systems around meaning, probability, search, and task consequences.
RT = a + b · H, where H = −Σ pᵢ log₂ pᵢChoice reaction lab
Change the number of alternatives
Pick a set size, begin the trial, and select the requested number. Organized familiar choices can behave differently from unfamiliar choices, so read this as a small illustration of uncertainty.
Begin when you are ready
This demonstration reveals the mechanism. A few personal trials are not a controlled experiment and should not be treated as evidence about an individual.
How designers apply it
- 01
Prioritize frequent commands in an emergency action set.
- 02
Use stable grouping and labels in a practiced command menu.
- 03
Offer search when a large known-item set cannot be meaningfully reduced.
Original UI examples
desktop enterprise
Call-center disposition
Frequent, mutually exclusive outcomes appear first with typeahead for the full taxonomy.
Probability and practice shape the response path without deleting valid rare codes.
mobile safety
Emergency alert
Three clearly distinguished actions match rehearsed procedures.
The limited response set supports rapid action because labels, mappings, and training align.
A settings hub
Less effective
Bury twenty settings under unlabeled progressive menus because fewer visible options must be faster.
Better fit
Group by user goal, expose high-frequency destinations, and measure end-to-end find time.
A broad information architecture is not the same task as a reaction-time experiment.
Limits and failure modes
It does not directly model open-ended judgment, preference construction, visual search, or nested navigation costs.
Common mistakes
- Using the formula to claim every extra menu item adds a fixed delay.
- Ignoring probability, practice, visual search, and semantic grouping.
When it should not dominate
- As a universal limit for site navigation.
- For complex value-laden choices that require deliberation.
Responsible use
Accessibility
Keep labels explicit, mappings predictable, and keyboard order stable; reducing options must not hide accessible alternatives or make assistive-technology users traverse extra layers.
On mobile: Avoid compressing a large taxonomy into ambiguous icons; combine a prioritized set with search or clear drill-down.
Ethics and context
Use the principle to reduce unnecessary effort and improve comprehension. Validate the result with representative users rather than treating a general tendency as a universal instruction.
On desktop: Use space for grouped commands and shortcuts while preserving full discoverability.
Designer checklist
- Define the actual response alternatives and probabilities.
- Measure end-to-end selection including search.
- Check whether grouping or familiarity changes the prediction.
Check your understanding
Which statement applies Hick-Hyman Law most carefully?
Practice and continue learning
See ideas in real interfaces
These external interfaces are editorial references, not examples created to demonstrate this principle.
Sources and further reading
- 01Open source
On the Rate of Gain of Information
William E. Hick · 1952 · Quarterly Journal of Experimental Psychology
Primary research · primary or original source
- 02Open source
Stimulus Information as a Determinant of Reaction Time
Ray Hyman · 1953 · Journal of Experimental Psychology
Primary research · primary or original source
Continue the graph
Related principles
effect
Choice Overload
Large or difficult choice sets can reduce decision confidence or action when options are hard to compare and preferences are uncertain.
principle
Stimulus-Response Compatibility
Responses are generally faster and less error-prone when the relationship between a signal and its control matches learned or spatial expectations.
usability heuristic
Progressive Disclosure
Progressive disclosure presents the information and controls needed now, then reveals additional detail when the user asks or the task reaches it.