UX Design


Laws of

Users generally perceive the aesthetically pleasing design as a more usable design.

Law of aesthetic usability

Productivity increases when a computer and its users interact at a pace (<400ms) that ensures that neither needs to wait for the other.

Doherty threshold

The time to interact with a target is a function of the target's distance and size.

Fitts Law

The time needed to make a decision increases with the number and complexity of the choices.

Hick's Law

Users spend most of their time on other sites. This means that they prefer their website to work the same way as everyone else.

Jakob's Law

Elements tend to be perceived in groups if they are sharing an area with a clearly defined boundary.

Common Region Law

People will perceive and interpret ambiguous or complex images as the simplest form possible, as it is the interpretation that requires the least effort.

Prägnanz Law

Objects close to or close to each other tend to be grouped.

Proximity Law

The human eye tends to perceive similar elements in a design such as an image, shape or complete group, even if these are separate.

Similarity Law

Visually connected elements are perceived to be more related than unconnected elements.

Uniform Connection Law

The average person can only keep 7 (+ or - 2) items in their working memory.

Miller's Law

Among the competing hypotheses that predict equally well, one should select the one with the least number of assumptions.

Occam's razor

The Pareto principle states that, for many events, approximately 80% of the effects come from 20% of the causes.

Pareto principle

Any task will increase up until that all available time is spent.

Parkinson's Law

People judge an experience largely based on how they felt at the height and end, rather than the total or average sum of each moment in the experience.

Endpoint Rule

Be liberal in what you accept and conservative in what you send.

Postel law

Users are more likely to remember the first and last items in a series better.

Serial Position Effect

For any system, there is a certain amount of complexity that cannot be reduced.

Tesler's Law

When several similar objects are present, the one that differs from the rest is more likely to be remembered.

Von Restorff Effect

People remember incomplete or interrupted tasks better than completed tasks.

Zeigarnik effect