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The 9 Laws of UX Design: How to Master Science & Psychology

A straightforward guide to using scientifically proven UX laws and psychology to crush it as a digital product designer

Craig Barber

Senior Product Designer

In the ever-evolving world of digital product design, creating user experiences that captivate, engage, and delight has become paramount.

To achieve this, product designers rely on a set of guiding principles known as the Laws of UX Design.

These laws are rooted in psychology, human behaviour, and cognitive science, and offer valuable insights to enhance the usability and effectiveness of digital products.

In this post, we will explore these laws of UX design, providing an explanation of each one and examples of them in action.

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The 9 Laws of UX Design Explained:

1. Hick's Law: The Paradox of Choice

Laws of UX UI design principles Hicks Law 02

Hick's Law states that the time it takes to make a decision is directly proportional to the number of choices available.

In UX design, this law emphasises the importance of reducing complexity and providing users with clear, concise options.

Reduce options to increase engagement
Laws of UX UI design principles Hicks Law

A great example of applying Hick's Law in your designs would be pricing tables on a website's pricing page.

When you present users with only three options, they are more likely to choose a plan and convert compared to when you provide them with five options.

2. Fitts's Law: Target Size and Distance

Laws of UX UI design principles Fitts Law 01

Fitts's Law states that the time required to move to a target is a function of the target's size and distance from the starting point.

UX designers leverage this law to optimise the placement and size of interactive elements, such as buttons or links, to ensure they are easy to locate and interact with.

Make calls to action large and accessible to improve engagement
Laws of UX UI design principles Fitts Law 02

A great example of this can be seen in landing page designs. When you want a user to sign up for your product or offer, it's best to have a large and clear call to action.

This may seem obvious, but there are still examples out there with small, hidden calls to action that reduce conversions.

3. Jakob's Law: Familiarity Breeds Intuition

Laws of UX UI design principles Jakob's Law 01

Jakob's Law asserts that users' expectations are shaped by their prior experiences with similar products.

Designers should leverage this law by aligning their interfaces with established design patterns and conventions to make them intuitive and familiar.

Use familiar design patterns to improve engagement
Laws of UX UI design principles Jakob's Law 02

A great example of this is the standard video player. The common format involves a triangle play button placed in the middle of the screen, with the controls located at the bottom. Users are familiar with this standardized format and are accustomed to using it.

4. Gestalt Principles: Perception and Visual Organization

Laws of UX UI design principles Gestalt Principles

Gestalt Principles describe how humans perceive and organise visual information. These principles, including proximity and similarity guide designers in creating cohesive and visually pleasing interfaces.

Proximity: Group items together with the same function
Laws of UX UI design principles Gestalt Principles

An example of this can be seen in a website's main navigation. The items within the navigation perform the same function. Therefore, they should be grouped together to indicate to users that these elements have a similar or identical purpose, as they are placed in close proximity to one another.

Similarity: Items with a similar function should look the same
Laws of UX UI design principles Gestalt Principles

An example of this could be the use of uniform toggle switches on an app to enable or disable certain functions. When the design of these elements remains consistent, users can easily recognize that they perform the same function.

5. Miller's Law: Cognitive Limitations

Laws of UX UI design principles Millers Law

Miller's Law proposes that the average person can only hold around seven (plus or minus two) pieces of information in their working memory at once.

UX designers leverage this law by chunking information and breaking it down into manageable, bite-sized pieces.

Limit the number of items to reduce information overload
Laws of UX UI design principles Millers Law

A great example of limiting the number of items on a page can be seen in payment flows on a website.

Instead of bombarding users with all the elements and forms at once, it is important to list a limited number of elements.

This approach prevents overwhelming the user and reduces the likelihood of them dropping off.

6. Parkinson's Law of Triviality: Focus on the Essential

Laws of UX UI design principles Parkinson's Law

Parkinson's Law of Triviality states that people tend to give disproportionate attention to trivial details while neglecting more critical aspects.

In UX design, this law reminds designers to prioritise the essential elements and features, ensuring they receive the necessary attention and focus.

Reduce elements to improve focus and engagement
Laws of UX UI design principles Parkinson's Law

A great example of this is Google's search page. When Google initially launched their search engine, it featured a beautifully simple page with minimal elements. It included a search bar, a button, and minimal text.

In comparison, other sites like Yahoo were considerably more cluttered and failed to emphasise the primary function of the page - searching!

7. Aesthetic-Usability Effect: Beauty Enhances Usability

Laws of UX UI design principles Aesthetic-Usability Effect

The Aesthetic-Usability Effect is a UX law that highlights the positive correlation between aesthetic appeal and perceived usability.

According to this principle, users tend to perceive visually pleasing designs as more intuitive, efficient, and easy to use, even if there is no functional difference compared to less aesthetically pleasing alternatives.

When applied effectively, the Aesthetic-Usability Effect can significantly enhance the overall user experience.

A polished design creates the perception of a good user experience
Laws of UX UI design principles Aesthetic-Usability Effect

Onboarding flows serve as a great example of how aesthetics can enhance the overall experience.

When the onboarding flow is simple, exciting, and beautifully designed, it not only instills a greater sense of value in the product but also encourages increased user engagement.

8. The Doherty Threshold: The Laws of Speed

Laws of UX UI design principles The Doherty Threshold-1

The Doherty Threshold, also known as the "Laws of Speed," is a UX law that states users' perception of system responsiveness affects their engagement and overall satisfaction.

It suggests that when the response time of a system falls below 400 milliseconds, users perceive it as instant, resulting in a seamless and immersive experience.

To keep users engaged, it is essential to ensure fast performance and provide constant feedback
Laws of UX UI design principles The Doherty Threshold

For example, Google's search engine displays search results almost instantly, giving users the perception of immediate feedback and enabling them to navigate and interact with the platform effortlessly.

By designing interfaces that meet or exceed the Doherty Threshold, UX designers can create responsive and engaging experiences that keep users fully immersed in their digital interactions.

9. The Goal Gradient Effect

The Goal Gradient Effect is a UX law that highlights how user motivation increases as they progress towards a goal.

According to this principle, users tend to accelerate their efforts and engagement as they approach the completion of a task or goal.

This effect can be leveraged in UX design to enhance user motivation and drive continued engagement.

Show progress to keep users engaged
Laws of UX UI design principles The Goal Gradient Effect 01

For example, fitness tracking apps often utilise progress bars or milestone trackers to visually depict the user's advancement towards their fitness goals.

As users see themselves nearing their targets, the desire to complete the goal intensifies, leading to increased dedication and persistence in using the app and achieving their desired outcomes.

By incorporating visual cues and progress indicators, designers can tap into the Goal Gradient Effect to fuel user motivation and facilitate successful goal attainment.

Conclusion

Understanding and applying the Laws of UX has a big impact on the success of digital products and how satisfied users are. These guidelines help create experiences that are easy to use, efficient, and visually appealing.

By simplifying things, making targets easy to reach, using familiar elements, organising visuals well, respecting our mental limits, focusing on what's important, and making things look good, designers make user experiences better.

While this list isn't everything, it's important to stay updated, do research, and improve designs as the field of UX evolves.

The Laws of UX are like a guide, helping us create experiences that users will remember and enjoy, and that will set new standards in design.

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Access our database of London-based recruiters looking to place digital product designers like you