Matt Beran

The Laws of UX

Principles that shape how humans interact with design.

Post the wrong answer
Cunningham's Law

The best way to get the right answer on the internet is not to ask a question; it's to post the wrong answer.

Make things look good
Aesthetic Usability Effect

Users often perceive aesthetically pleasing design as design that's more usable.

Things should move as fast as people
Doherty Threshold

Productivity soars when a computer and its users interact at a pace (around 400ms) that ensures that neither has to wait on the other.

Distance and size matter
Fitt's Law

The time to acquire a target is a function of the distance to and size of the target.

Metrics change behavior
Goodhart's Law

When a measure becomes a target, it ceases to be a good measure.

Reduce complexity
Hick's Law

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

Follow web norms
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.

Group like things with visuals
Law of Common Region

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

Simplest form wins
Law of Pragnanz

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.

Near things group together
Law of Proximity

Objects that are near, or proximate to each other, tend to be grouped together.

Similar things feel connected
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.

Visual connection implies relation
Law of Uniform Connectedness

Elements that are visually connected are perceived as more related than elements with no connection.

Working memory has limits
Miller's Law

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

Fewest assumptions wins
Occam's Razor

Among competing hypotheses that predict equally well, the one with the fewest assumptions should be selected.

80% of effects come from 20% of causes
Pareto Principle

For many events, roughly 80% of the effects come from 20% of the causes.

Work expands to fill time
Parkinson's Law

Any task will inflate until all of the available time is spent.

First and last moments define the experience
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.

Be generous in, precise out
Postel's Law

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

First and last stick
Serial Position Effect

Users have a propensity to best remember the first and last items in a series.

Some complexity can't be removed
Tesler's Law

For any system there is a certain amount of complexity which cannot be removed.

The odd one out is remembered
Von Restorff Effect

When multiple similar items are present, the one that differs the most is most likely to be remembered.

Unfinished things linger
Zeigarnik Effect

People remember uncompleted or interrupted tasks better than completed ones.