Miller’s Law is often used in the wrong context and for the wrong purpose by both clients and designers. Here’s how we should deal with it instead.
In order to create usable and enjoyable products, UX/UI designers are required to understand the human’s brain in all its facets: how it processes cognitive stimuli or how it absorbs and processes information are just a few examples for knowledge that is relevant for UX/UI designers. Hence, in the field of UX/UI design, psychological findings serve as important guidelines for our everyday work.
One of these guidelines is Miller’s Law, which claims that humans can only keep about 7 items (plus or minus 2) in their cognitive working memory. It gives us an idea about how to present information in the interface in a way that allows users to process them effectively. But how exactly can designers draw conclusions from this rule?
In this article, I will explain how information overload has become a major issue in our everyday life, and I will illustrate how we as designers can help to reduce it by making the right decisions in our work. However, we will also learn that it’s less about simple numbers and more about context.
There are many examples of how being overwhelmed by too many options can affect our everyday lives.
Take this one: While I was having lunch with my girlfriend the other day, I asked her if she bought anything while online shopping. She responded: “No, I couldn’t decide what I wanted, there were just too many choices.” This illustrative example shows how an overload of options can actually lead to us making no decision at all.
Or let’s take another example, with which most of us are probably familiar: We’re working on an important project, and suddenly our phone starts vibrating. Usually, we notice it, take a quick look at it, and continue to work. Ten minutes later, the same thing happens. From messages from your friends to push notifications from newspapers, online shops or social media alerts — all these attention seekers try to reach out to you and grab your attention. The result? We become inefficient, unproductive — and most of all: unhappy.
Information Overload: What are we talking about here?
For most of us, these examples have become completely normal situations in our daily life. Why? We live in a world with an exponentially increasing amount of information and attention overload.
But first of all, let’s get some clarity on what we are talking about here. Information Overload can be defined as a situation in which too much information is accessible at one time, so that it cannot be processed properly. The term was coined by Bertram Gross, professor of Political Science, in his 1964 published work, The Managing of Organizations. (1)
While information overload has been a psychological challenge throughout history, the invention of the smartphone and the omnipresent availability of digital data has since increased public access to information more than any other point in time. As a result, the looming issue of information overload is more relevant than ever before. (1)
The consequences? Today, in our daily life, we have to handle so many tasks, and we struggle with processing so much information, that if we don’t organize our daily information intake properly, it ultimately degrades our ability to complete critical tasks for the purpose of survival (e.g. navigation or securing our income). That is why it’s essential to omit items, products, and services that don’t produce quality return on investment. This falls in line with the Pareto Principle, i.e. the idea that 80% of our outcomes is generated from 20% of our invested efforts.
Now, let’s take this a step further. Minimizing information load is especially important for digital interfaces. Here, information overload describes the excess of information available to a person who is trying to complete a task or make a decision. This can impede the decision-making process, resulting in a slow (or even no) decision made by users, like my girlfriend not buying anything while online shopping. When designing digital products (e.g. websites or apps), designers should be especially careful to ensure they prevent information overload in order to have a satisfying user experience. (1)
Sounds a little too theoretical? This practical example may help: With its extensive white space, the search website of Google ensures a clear visual focus on the search bar, while unnecessary information is reduced to an absolute minimum. On the other side, the Yahoo! website includes many distracting items, among them news articles and advertisements, which provide an unnecessary strain. Therefore, using the Yahoo! search causes a much higher cognitive load. Now, that makes it probably quite obvious why Google seems much simpler and more pleasant for us to use.
The lesson for UX/UI designers is clear: A crucial part of our job is to ensure that just the right amount of information appears on a webpage or app screen — enough to make it relevant, but not so much that it causes information overload. In a nutshell: The amount of information displayed can either motivate users to stay on the website or in the app, or drive them to ultimately abandon the product, since users can even get stressed out if there is a lot of irrelevant information displayed that they can actually neglect (information anxiety, Saul Wurman). (6)
So, our job is to display the right amount of information the user needs at that specific moment. However, this is easier said than done. Defining the right amount of information that matches the needs of users requires going through an extensive process of identifying user context and understanding— especially in cases in which we actually must display a lot of information, e.g. because this information is part of the service we provide.
Now let’s get back to Miller’s Law. To find a way to manage information load in cases in which we actually have to provide lots and lots of information, we have to turn back to the theoretical part of User Experience design.
As we already learned, one of the helpful guidelines for these cases is Miller’s Law, which can be summarized as the following:
The average person can only keep 7 (plus or minus 2) items in their working memory.
This means that when completing a task that requires cognitive effort, the human mind can remember approximately 7 bits of information, which then fade from your brain in about 20–45 seconds.
This number looks quite scary at first glance. However: One of the key concepts behind Miller’s Law is ‘chunking’, which basically means assembling various bits of information into a cohesive group. So don’t bother too much about the number 7, because it’s all about context.
Let’s use another practical example to illustrate how we can make use of chunking: Think about telling someone your mobile number. What are the chunks you have in your head in order to remember it?
Or try to remember the following numbers — which tactic do you think is easier?
14487324534 or 1 (448) 732 4534
Take another example: Have a look at the two different formatting of a user ID, name and Date of Birth (DoB):
Event though the same data is displayed on the left and on the right, chunking the information makes them become processable and memorizable.
What do we learn here? When displaying a lot of information, remember to present the information in a structured way. Chunking is a critical element of UX-friendly information organization.
There are more ways in which chunking can help us with displaying a large amount of information — especially when it comes to improving scanability of our interface. Formatting information in chunks, e.g., when users have to enter their telephone number or zip code, is a popular example for this. However, always keep in mind to provide autoformatting in your input fields (3), so users don’t have to worry about whether or not they have to format their input themselves.
For example, when a user is asked to enter an IBAN, an automatic format to the known structure should be provided for the user, i.e. DE07 1234 1234 1234 1234 12.
Another well known example is date formats, where the user should automatically be provided with the date format, i.e. MM.DD.YYYY. This way, the user is given a clear example of what they must enter, which helps them to fill in the right information with little cognitive effort.
There are a lot of other possibilities, e.g. grouping objects together and adding white space in order to get meaningful chunks of information in the interface, which is naturally connected to the law of proximity (Law of Proximity).
Miller’s Law often leads to common misconceptions, which is very well described in the Article “Short-Term Memory and Web Usability” from the Nielsen Norman Group: For example, that limited short-term memory implies that menus should be similarly limited to 7 items. However, it’s fine to have longer menus (if necessary), because users aren’t required to memorize the full list of menu items. The entire idea of a menu is to rely on recognition rather than recall (one of the basic 10 heuristics for user interface design). There are many other usability issues in menu designs, and shorter menus are certainly faster to scan. But if menus are too short, the choices become overly abstract and obscure. (3,4)
Let’s take a look at an example:
Here you see three menus of major video streaming players. As you can see, they have different approaches of what they wish to display at the first hierarchy:
Let’s have a quick wrap up:
The first and the second menu are clearly labeled and easily meet the expectations of the consumer.
In the third menu, users find a label called “Categories”, which sounds pretty vague. Users must wonder: What does “Categories” mean in this context? Does it mean genres? Or the different types of TV shows or movies? Kids or adults?
Well, actually, it is all of the above.
Even in this trivial example, we can see how abstract wording can make it difficult for users to understand the logic and the organization of the menu. In this case, it would be more efficient to have more than 7 menu entries, thus splitting up the generalized “Category” section into multiple, self-explanatory menu entries.
But short-term memory limitations dictate a whole range of other web design guidelines as well:
Keep this in mind: The brain has a defined method on how to process complex information. This includes the different elements and components within a website or mobile application such as text, colours, images, and animations. The effort required to process all this information is known as cognitive load and it is critical to the success of digital product design. The human brain is not optimized for the abstract thinking and data memorization that websites often demand. Many usability guidelines are derived from cognitive limitations. (7)
Finally, splitting information into different sections, using enough white space and reducing all unnecessary information gives the user the chance to process all the information.
So, always remember: if clients complain that a list or a menu is too long due to containing more than 7 elements, you can now tell them that it’s all about context and structure, not just about 7 items. If we keep this in mind, theoretical principles like Miller’s Law are valuable guidelines that help us to manage the users’ cognitive and psychological needs while at the same time providing them with all the necessary information.