User Experience

The Most Important Rule in UX Design that Everyone Breaks

Published October 3, 2018 ⚡ Updated on April 3, 2019 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.

A great example of a psychological concept being used in UX is Miller’s Law. It was first described in the famous 1965 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, information should be organized in categories no larger than 9, but preferably 7. The rule can be applied to any aspect of life that involves performing a relatively complex task.

But how does a rule that was generated in 1965 relate to modern UX designs?

Good question.

Many web designers tend to make long lists of items – for example, on e-commerce websites – and it becomes difficult for visitors to mentally nap them. 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 important 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 the point they don’t want to do it anymore. Clearly, doing so is a really bad idea because you ignore the most important law in web design, which is to truly serve the user.

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A Brief History of Miller’s Law

In 1956, a psychologist and a researcher George Miller completed a study in which he found what he thought to be the limit of 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 who were presented with the information for the first time because they haven’t had the time to encode the information into long-time memory.

The 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.

Nevertheless, many websites out there break this law by making lengthy menus, creating large chunks of written content, and bombarding web users with lots of information. Since it’s critical to follow Miller’s law to improve user experience, here’s how you can help your visitors with content processing.

How to Improve UX by using Miller’s Law

Many UX designers misunderstand Miller’s magical number seven by thinking that humans can only process seven chunks of information at a time. As the result, they place unnecessary design limitations for 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 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.” – says Clara Lago, UX Designer at A-writer.

Application of Chunking in Web Design

Simply explained, chunking refers to breaking up content into digestible and distinct pieces of information instead of presenting one, large piece. This term was introduced by Miller in his 1965 paper and it’s actually a popular memorization technique that you also use very often.

For example, to help someone to memorize a phone number (+12628335746), you can break it up 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.

Let’s now review how to apply chunking to multimedia and written content.

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 characteristics.

For example, take a look at how text is organized at Hubspot blog. It follows all the three techniques described above!


Chunking Text Content

Chunking Multimedia Content

Multimedia content is a bit more difficult to chunk than a phone number or a text because it’s essentially a combination of 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 easily distinguish content areas:

  • 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


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 it’s highly recommended to apply chunking to help them scan and memorize content easier. Remember: doing 7 products per page or 7 menu sections isn’t necessary, because your main purpose is to make it easy for users to see products/items, and not make anyone memorize things.


Audrey is a visual content and digital marketing specialist who finds her passion in expressing 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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