Laws of UX by Jon Jablonski

Aleksei Golovach
6 min readMay 20, 2020

A reference guide for design decisions

Photo courtesy of Jon Jablonski

It is a basic book, but do you remember the base?

I have already known Jon`s webpage “Laws of UX” and used all these laws in practice as an enterprise experience designer. But the curiosity — what could be added to common knowledge — has won.

And I could say, that Jon has done a very good job as the author of the base book for designers.

Sure, if you are only starting the way of the digital designer, everything in this book will be eye-opening to you.

But even if you are an experienced designer, you need a quick and comprehensive guide of the main psychological concepts for your design decisions.

The book is clearly and logically structured, providing for each ‘law’ an overview, key points, origins, examples of use, and conclusion.

Further, I will make a short review of the book’s content.

User Experience laws (quotes by the author):

#1 Jakob’s Law

Users spend most of their time on other sites, and they prefer your site to work the same way as all the other sites they already know.

One of the primary ways designers can remove friction is by leveraging common design patterns and conventions in strategic areas such as page structure, workflows, navigation, and placement of expected elements such as search. When we do this, we ensure people can immediately be productive instead of first having to learn how a website or app works.

#2 Fitts’s Law

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

The time it takes for users to move to and engage with an interactive object is a critical metric. It’s important that designers size and position interactive objects appropriately to ensure they are easily selectable and meet user expectations with regard to the selectable region — a challenge compounded by the differing precision of the range of input methods available today (mouse, finger, etc.).

#3 Hick’s Law

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

What is neither efficient nor elegant is when an interface provides too many
options. This is a clear indication that those who created the product or service do not entirely understand the needs of the user. Complexity extends beyond just the user interface; it can be applied to processes as well. The absence of a distinctive and clear call to action, unclear information architecture, unnecessary steps, too many choices or too much information — all of these can be obstacles to users seeking to perform a specific task.

#4 Miller’s Law

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

This commonly misunderstood heuristic has frequently been cited as justication for design decisions such as “the number of navigation items must be limited to no more than seven” and so forth.While there is value in limiting the number of options available to users …, it is misleading and inaccurate to attribute such dogma to Miller’s law. …

… Miller’s fascination with short-term memory and memory span centered
not on the number seven, but on the concept of chunking and our ability to memorize information accordingly. He found that the size of the chunks did not seem to matter — seven individual words could be held in short-term memory as easily as seven individual letters.

#5 Postel’s Law

Be conservative in what you do, be liberal in what you accept from others.

The first half of Postel’s law states that you should “be conservative in what
you do.” In the context of design, this can be interpreted as stipulating that the output of our efforts, whether that’s an interface or a comprehensive system, should be reliable and accessible. …

… The second half of the principle states that you should “be liberal in what you
accept from others.” In the context of design, this can be taken to mean the acceptance of input from users via any input mechanism and in a variety of possible formats.

#6 Peak — End Rule

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

In other words, we remember each of our life experiences as a series of representative snapshots rather than a comprehensive timeline of events.

Our feelings during the most emotionally intense moments and at the end are averaged in our minds and heavily influence how we assess the overall experience to determine whether we’d be willing to do it again or recommend it to others.

#7 Aesthetic — Usability Effect

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

In other words, an aesthetically pleasing design creates a positive response in
people’s brains and leads them to believe the design actually works better ... We use automatic cognitive processing to determine at a visceral level if something is beautiful very quickly upon first seeing it, and this extends to digital interfaces as well. First impressions do matter.

#8 von Restorff Effect

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

A primary challenge we have as designers is managing what users will focus on in an interface while supporting them in achieving their goals. On the one hand, visual emphasis can be used to guide users toward a goal by capturing their attention. On the other hand, too many points of visual emphasis will compete with one another and make it harder for people to find the information they need. Color, shape, size, position, and motion are all factors that come into play in directing the attention of users, and we must carefully consider each of these when building interfaces.

#9 Tesler’s Law

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

A key objective for designers is to reduce complexity for the people that use the products and services we help to build, yet there is some inherent complexity in every process. Inevitably we reach a point at which complexity cannot be reduced any further but only transferred from one place to another.

#10 Doherty Threshold

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

One of the features that is critical to good user experiences is performance. Emotions can quickly turn to frustration and leave a negative lasting impact when users who are trying to achieve a task are met with slow processing, lack of feedback, or excessive load times. Often overlooked as more a technical best practice, speed should be considered an essential design feature that is core to good user experiences.

#11 Extra valuable content by Jon

Also, you could read short and concise articles on the main concepts of User Experience (UX) like mental models, biases, personas, etc. UX laws are provided with good examples and pictures.

In addition, the reader gets two extra chapters about applying UX laws in practice.

Moreover, Jon reasonably makes an accent on the ethics of design decisions.

Psychology and its application in user experience design plays a critical role in all of this: behaviour design is useful for keeping people “hooked,” but at what cost?

When did “daily active users” or “time on site” become a more meaningful metric than whether a product is actually helping people achieve their goals or facilitating meaningful connections?

Ethics must be an integral part of the design process, because without this check and balance, there may be no one advocating for the end user within the companies and organizations creating technology.

To summarize, this book is a must for novice UX/UI/Experience designers and others, interested in the UX field. It will help to get knowledge of major psychological concepts and behaviour patterns.

Otherwise, the book is obviously good for experienced digital designers — to systemize the fragmented knowledge and to have a quick reference guide under your hand. Also, the content is good for communicating your decisions to the stakeholders.

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