20 UX Principles
- Kailin Wang (Unlicensed)
Aesthetic Usability Effect
Users often perceive aesthetically pleasing design as design that’s more usable.
Aesthetically pleasing design can make users more tolerant of minor usability issues.
Aesthetically pleasing design creates a positive response in people’s brains and leads them to believe the design actually works better.
Aesthetically pleasing design can mask usability problems and prevent issues from being discovered during usability testing.
2. Doherty Threshold
Productivity soars when a computer and its users interact at a pace less than 400 milliseconds(<400ms) that ensures that neither has to wait on the other.
Provide system feedback within 400ms in order to keep users’ attention and increase productivity.
Use perceived performance to increase response time and reduce the perception of waiting.
3. Fitt’s Law
The time to acquire a target is a function of the distance to and size of the target.
Touch targets should be large enough for users to both discern what it is and to accurately select them (44 x 44px minimum for Mobile)
Touch targets should have ample spacing between each other.
Touch targets should be placed in areas of an interface that allows them to be easily acquired.
4. Hick’s Law
The time it takes to make a decision increases with the number and complexity of choices.
Simplify choices for the user by breaking down complex tasks into smaller steps.
Avoid overwhelming users by highlighting recommended options.
Use progressive onboarding to minimize cognitive load for new users.
5. Jakob’s Law
Users spend most of their time on other sites. This means that users prefer your site to work the same way as all the other sites they already know.
Users will transfer expectations they have built around one familiar product to another that appears similar.
By leveraging existing mental models, we can create superior user experiences in which the user can focus on their task rather than learning new models.
Minimize discordance by empowering users to continue using a familiar version for a limited time.
6. Law of Common Regions
Elements tend to be perceived into groups if they are sharing an area with a clearly defined boundary.
Adding a border around an element or group of elements is an easy way to create common region.
Common region can be created by defining a background behind an element or group of elements.
7. Law of Prägnanz
People will perceive and interpret ambiguous or complex images as the simplest form possible, because it is the interpretation that requires the least cognitive effort of us.
The human eye likes to find simplicity and order in complex shapes because it prevents us from becoming overwhelmed with information.
Research confirms that people are better able to visually process and remember simple figures than complex figures.
8. Law of Proximity
Objects that are near, or proximate to each other, tend to be grouped together.
Proximity helps to establish a relationship with nearby objects.
Proximity helps users understand and organize information faster and more efficiently.
9. Law of Similarity
The human eye tends to perceive similar elements in a design as a complete picture, shape, or group, even if those elements are separated.
Ensure that links and navigation systems are visually differentiated from normal text elements, and are consistently styled.
10. Law of Uniform Connectedness
Elements that are visually connected are perceived as more related than elements with no connection.
Group functions of a similar nature so they are visually connected via colors, lines, frames, or other shapes.
11. Miller’s Law
The average person can only keep 7 (plus or minus 2) items in their working memory.
Chunking is an effective method of presenting groups of content in a manageable way. Organize content in groups of 5-9 items at a time.
12. Occam’s Razor
Among competing hypotheses that predict equally well, the one with the fewest assumptions should be selected.
Analyze each element and remove as many as possible, without compromising the overall function.
13. Pareto Principle
The Pareto principle states that, for many events, roughly 80% of the effects come from 20% of the causes.
Focus the majority of effort on the areas that will bring the largest benefits to the most users.
14. Parkinson’s Law
Any task will inflate until all of the available time is spent.
15. Peak End-Rule
People judge an experience largely based on how they felt at its peak and at its end, rather than the total sum or average of every moment of the experience.
Pay close attention to the most intense points and the final moments (the “end”) of the user journey.
Identify the moments when your product is most helpful, valuable, or entertaining and design to make those moments even better.
Remember that people recall negative experiences more vividly than positive ones.
16. Postel’s Law
Be liberal in what you accept, and conservative in what you send.
Be empathetic, flexible, and tolerant to any number of actions the user could possibly take. This means accepting variable input from users, translating input to meet the requirements, defining boundaries for input, and providing clear feedback to the user.
17. Serial Position Effect
Users have a propensity to best remember the first and last items in a series.
Placing the least important items in the middle of lists can be helpful because these items tend to be stored less frequently in long-term and working memory.
Positioning key actions on the far left and right within elements such as navigation can increase memorization.
18. Tesler’s Law
Tesler's Law, also known as The Law of Conservation of Complexity, states that for any system there is a certain amount of complexity which cannot be reduced.
19. Von Restorff Effect
The Von Restorff effect, also known as The Isolation Effect, predicts that when multiple similar objects are present, the one that differs from the rest is most likely to be remembered.
Make important information or key actions visually distinctive.
20. Zeigarnik Effect
People remember uncompleted or interrupted tasks better than completed tasks.
Use progress bars for complex tasks to visually indicate when a task is incomplete, and thus increase the likelihood it will be completed.
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