The Laws of Usability: Turning Cognitive Science into Better Design

By Philip Burgess | UX Research Leader

Design is more than just making things look good. It’s about making products easy to use, intuitive, and enjoyable. The key to achieving this lies in understanding how people think and behave. Cognitive science offers valuable insights into human perception, memory, and decision-making. By applying these insights, designers can create interfaces and experiences that feel natural and reduce user frustration. This post explores some of the most important laws of usability, showing how cognitive science shapes better design.

User-friendly touchscreen interface with clear icons and simple layout

Understanding Cognitive Load and Its Impact on Design

Cognitive load refers to the amount of mental effort required to process information. When users face too much information or complex tasks, their cognitive load increases, leading to confusion and errors. Good design minimizes cognitive load by organizing content clearly and limiting distractions.

Example: A website with a cluttered homepage filled with many buttons and ads overwhelms users. Instead, grouping related elements and using whitespace helps users focus on key actions. Google’s homepage is a classic example of low cognitive load design: a simple search bar with minimal distractions.

Hick’s Law: Simplify Choices to Speed Decisions

Hick’s Law states that the time it takes to make a decision increases with the number of options available. When users face too many choices, they hesitate or make poor decisions.

Designers can apply this law by limiting options or grouping them logically. For example, a navigation menu with too many links can confuse users. Instead, categorizing links under clear headings helps users find what they need faster.

Example: Amazon’s filtering system breaks down thousands of products into manageable categories like price, brand, and ratings. This reduces decision time and improves the shopping experience.

Fitts’ Law: Make Targets Easy to Reach

Fitts’ Law predicts that the time to move to a target depends on the distance and size of the target. Larger and closer targets are easier and faster to click or tap.

Designers should make important buttons and links large enough and place them where users can easily reach them, especially on mobile devices. Small buttons or links placed too close together increase errors.

Example: Mobile apps often use large, thumb-friendly buttons at the bottom of the screen where users can easily tap without stretching their fingers.

Miller’s Law: Limit Information to Seven Plus or Minus Two Items

George Miller found that people can hold about 7 (plus or minus 2) items in their working memory. Presenting more information at once overwhelms users.

Designers should chunk information into smaller groups. For example, phone numbers are often broken into segments (123-456-7890) to make them easier to remember.

Example: Menus with too many options can be split into submenus or tabs to avoid overwhelming users.

The Principle of Recognition Over Recall

People find it easier to recognize information than to recall it from memory. Interfaces that rely on recognition reduce user effort.

Designers can use visible options, icons, and labels to help users recognize what to do next instead of forcing them to remember commands or steps.

Example: A form that shows examples of acceptable input formats helps users fill it out correctly without guessing.

Digital dashboard with clear icons and visual cues for easy navigation

Consistency and Standards Build User Confidence

Users expect similar elements to behave the same way across different parts of a product or website. Consistency reduces the learning curve and prevents mistakes.

Designers should follow platform conventions and keep design elements uniform. For example, clickable buttons should look clickable everywhere.

Example: Most websites place the logo in the top-left corner and link it to the homepage. Users expect this and rely on it for navigation.

Feedback Helps Users Understand Their Actions

When users interact with a system, they need immediate feedback to know their actions were successful or if errors occurred.

Designers should provide clear, timely feedback such as highlighting a clicked button, showing loading indicators, or displaying error messages.

Example: When submitting a form, a confirmation message reassures users that their information was received.

Affordance: Design Elements Should Suggest Their Function

Affordance means that the design of an object suggests how it should be used. Buttons should look pressable, sliders should look draggable.

Designers can use shapes, shadows, and textures to indicate interactivity.

Example: Raised buttons with shadows suggest they can be pressed, while flat text labels do not.

Applying Usability Laws in Real Projects

Understanding these laws is one thing, applying them effectively is another. Here are practical steps designers can take:

• Conduct user testing to observe where users struggle and adjust designs accordingly.

• Use wireframes and prototypes to experiment with layout and navigation before final development.

• Prioritize tasks and content based on user goals to reduce unnecessary options.

• Design for accessibility to ensure all users, including those with disabilities, can use the product easily.

  
  

Final Thoughts on Usability and Cognitive Science

Good design respects how people think and process information. The laws of usability provide a roadmap to create products that feel natural and reduce frustration. By simplifying choices, minimizing cognitive load, and providing clear feedback, designers can build experiences that users enjoy and trust.