User Experience

Miller’s Law: The Most Important Rule in UX Design that Everyone Breaks

Published June 9, 2023 ⚡ Updated on June 14, 2023 by Audrey Pilcher
A paper with sketches about rules in UX Design

Psychology and user experience (UX) may be two different branches of knowledge, but they still have a lot in common. In fact, UX gets most of its knowledge from psychology because the latter defines what people perceive to be a good web design and how information should be presented online to maximize the chance of retention. Miller’s Law perfectly demonstrates how Psychology and UX Design combine to create excellent user experiences – unfortunately, everyone breaks this rule. 

Miller’s Law in UX Design

Miller’s Law is an excellent example of a psychological concept applied to UX. It was first described in the famous 1956 article “The magical number seven, plus or minus two: some limits on our capacity for processing information” and theorizes that people can hold up to seven objects in their working memory.

According to this rule, we should organize information in categories no larger than 9, preferably 7. We can apply the Law to any aspect of life involving a relatively complex task.

Miller’s Law and Modern UX Design

But how does an old rule from 1965 relate to modern UX designs? Good question.

Many web designers tend to make long lists of items – for example, on e-commerce websites – making it difficult for visitors to map them mentally. By failing to follow Miller’s Law, they’re running the risk of increasing the bounce rate because visitors simply don’t have all the time in the world to learn where the page they need is.

Nevertheless, many web designers continue to break this vital rule by creating huge lists of items. In other words, instead of showing products to potential customers, they’re making them memorize long lists until they don’t want to do it anymore. Clearly, doing so is a bad idea because you ignore the most important Law in web design: to serve the user.

A Brief History of Miller’s Law

In 1956, psychologist and researcher George Miller completed a study in which he found what he thought to be the limit of the human capacity for processing information. For example, he discovered that most people stored 7 items plus/minus 2 in their short-term memory.

Going beyond this limit made it very difficult for people to memorize information. This was especially important for those presented with the information for the first time because they hadn’t had time to encode the information into long-term memory.

Human short-term memory capabilities are limited; therefore, it’s a good idea for web designers to limit the amount of information for website visitors accordingly. The adherence to Miller’s Law is especially relevant for modern UX designers because web users don’t appreciate information overload.

How to Improve UX Using Miller’s Law

Many UX designers misunderstand Miller’s magical number seven by thinking humans can only process seven chunks of information simultaneously. As a result, they place unnecessary design limitations on websites that undermine their UX and result in negative reviews on company review sites.

For example, a UX designer may create only seven options in a website’s navigation bar to avoid violating Miller’s Law. This is a mistake because the menu is continuously shown on the screen, so there’s no need to keep all the items therein in short-term memory. Therefore, limiting the number of menu sections to seven won’t improve the overall UX of the site.

“The most important thing that UX designers have to understand about Miller’s law is that human short-term memory is fairly limited, so if they want to increase knowledge retention, they should use chunking.” – Clara Lago, UX Designer at A-writer.

Application of Chunking in Web Design

Simply put, chunking refers to breaking up content into digestible and distinct pieces of information instead of presenting one large piece. Miller introduced this term in his 1956 paper, which is still a popular memorization technique you can use daily.

For example, to help someone to memorize a phone number (+12628335746), you can break it down into smaller chunks (+1-262-833-57-46). It’s much easier to scan and remember the second version than the first one because it’s easier to memorize smaller parts.

Chunking Text Content

Do you enjoy reading walls of text? Of course not. No one does. That’s why written content should be divided into smaller, digestible chunks to enable easy scanning and understanding of the main points.

Here are the most commonly used techniques for chunking texts:

  • Short paragraphs containing 2-3 sentences and separated by white space
  • Clear visual hierarchy with headings and subheadings
  • Short lines of text, up to 80 characters.

For example, look at how Hubspot organizes the text in its blogs. It follows all the three techniques described above!


Chunking Text Content

Chunking Multimedia Content

Multimedia content is a bit more challenging to chunk than a phone number or text because it combines text, images, buttons, graphics, and other elements.

There are several ways in which you can achieve chunking of multimedia content while staying true to Miller’s Law and helping your viewers to distinguish content areas easily:

  • Background colors
  • Horizontal cues
  • White space

Here’s a good example of how a website (official Samsung online store) uses chunking techniques – negative space and a background color – to help viewers to distinguish between each chunk (each smartphone). Even though the page displays more than 7 options, the viewers will find it easy to memorize a product because of visual separation. Moreover, they’ll find searching for a smartphone easy because a search option is available.


Chunking Multimedia Content

Conclusion: Miller’s Law and the UX/Psychology Relationship

Evidently, Psychology and UX have a lot in common, and Miller’s Law is an excellent example of that. Breaking this Law results in a poorer experience for web viewers, so applying chunking is highly recommended to help them scan and memorize content easier. Remember: doing 7 products per page or 7 menu sections isn’t necessary because your primary objective is to make it easy for users to see products/items, and not make anyone memorize things.

The Importance of User Testing

To create an effective and user-friendly design, it’s crucial to incorporate user testing throughout the design process. User testing allows you to identify areas for improvement, ensuring your website’s UX aligns with user expectations and follows psychological principles such as Miller’s Law.

Start your Userbrain 14-day free trial now, including 2 free user tests, and optimize your website for a better user experience.


About the author

Audrey is a visual content and digital marketing specialist who finds her passion in expressing her own thoughts as a blogger and currently works at She is a tech-savvy person and likes to write on different topics like social media, web design, mobile apps, online marketing, and much more.

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