Miller’s Law: Designing for Memory Span
Seven plus or Minus two
Do you recall the last time you were frantically trying to remember a phone number while you run across the room to locate your phone? Or that time when you wandered aimlessly in a superstore, feeling overwhelmed by a myriad of products vying for your attention? In situations like these, you’re essentially bumping up against the boundaries of your cognitive capacity. This is where Miller’s Law comes into play.
We are at Day 15 of the series, “30 Days of UX Laws and Principles”. If you are yet to catch Day 14, visit the article before you move ahead. In today’s article, we will look at :
- Understanding Miller’s Law
- Miller’s Law and UX Design
- Miller’s Law in Action
- Real-life highlights of Miller’s Law
- Difficulties and Limitations
Understanding Miller’s Law
Miller’s Law originated from a seminal paper published by cognitive psychologist George A. Miller in 1956, titled “The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information”. The fundamental takeaway from this study is that an average human can hold approximately seven items (plus or minus two) in their working memory.
Miller suggested that the number of objects an average human can hold in their working memory is about seven. This doesn’t mean only seven items in total, but rather seven chunks or units of information. This concept is known as “chunking”. These chunks can be anything — numbers, letters, faces, or even related concepts that can be lumped into a single unit.
For instance, a phone number isn’t just ten separate numbers. It’s divided into chunks: the area code, the first three digits, and the last four digits. This makes the phone number easier to remember. We can apply the same chunking principle to other types of information too.
Miller also noted that this “magical number seven” isn’t a hard and fast rule but rather an average. Some people might be able to hold more, some less. The capacity also depends on other factors, like the type of material (visual, auditory, etc.) and the context in which it is presented.
The paper also posits that our memory and attention aren’t just limited to a set number of chunks, but that this capacity can be affected by how much “cognitive load” we’re under. Cognitive load refers to the total amount of mental effort used in the working memory. When the cognitive load is too high, it becomes harder to process new information.
In other words, most people can comfortably remember seven digits, seven words, or seven objects at a time before the cognitive load becomes overwhelming. Miller’s Law is essentially a guideline for information processing capacity, offering valuable insights into how humans interact with, process, and remember information.
Miller’s Law and UX Design
Let’s consider Miller’s Law in the context of User Experience (UX) design through a familiar scenario. Imagine you’re delving into an intriguing novel. You open it to discover an unbroken wall of text stretching from cover to cover without any paragraphs or chapters. As you read, you find yourself lost in an endless stream of characters, dialogue, and descriptions.
Attempting to retain and comprehend the multitude of events and characters becomes challenging. The lines blur together, making it difficult to remember where one idea ends and the next one begins. You put down the book, your mind reeling from the cognitive overload.
Does this feel overwhelming? That’s what your brain experiences when confronted with cognitive overload, similar to what users may encounter with poorly structured digital content.
Breaking the text into paragraphs, like we break a novel into chapters, applies Miller’s Law. Each paragraph serves as a ‘chunk’ of related ideas, making it easier for the reader to process and understand the content. It provides a mental breather, a pause that enables readers to assimilate what they’ve read before moving on. This chunking not only helps manage cognitive load but also makes the reading experience more enjoyable and the content more digestible.
In the context of UX design, Miller’s Law is not just about reducing the number of items on a page. It’s about reducing the cognitive load — the amount of mental processing power needed to use your product. An interface that respects Miller’s Law is intuitive, reduces cognitive overload, and enhances user satisfaction.
When designing a website or an app, the trick is to present information in small, digestible chunks. For instance, instead of presenting users with a long, complex form to fill out, break it down into smaller steps. This way, users are less likely to feel overwhelmed and more likely to complete the task.
Here are ways in which this Law is useful in the context of UX design :
Navigation Menus:
Websites often limit their main navigation menu to seven items or fewer, as seen on Netflix. This keeps site navigation simple and memorable.
E-commerce Checkouts:
Online stores like ASOS divide their checkout process into multiple stages to avoid overwhelming the customer and improve the shopping experience.
Forms:
Software like TurboTax breaks down lengthy forms into smaller sections, reducing cognitive load and making the process more user-friendly.
Onboarding:
Apps like Slack present onboarding information in easy-to-digest steps, easing new users into the product without overwhelming them.
Information Display:
Platforms like Pinterest present visual content in a grid layout, making it easier for users to process large amounts of information.
Miller’s Law in Action
Let’s look at some real-life examples where brands have successfully applied Miller’s Law.
Apple: Apple’s product pages perfectly embody Miller’s Law. For instance, the homepage for iPhone 13 doesn’t bombard the user with technical specs or feature overloads. Instead, it presents information in easily digestible chunks. Each section highlights a specific feature, reducing cognitive load and making the content more memorable.
Amazon: When you add a product to your Amazon shopping cart, the platform doesn’t navigate you directly to the checkout process. Instead, it shows you an intermediary page where you can review your cart before proceeding. This design respects Miller’s law by breaking down the purchasing process into digestible steps, thereby reducing the cognitive load.
Real-life highlights of Miller’s Law
1. Credit Card Numbers:
The 16-digit numbers on credit cards are broken down into four chunks of four digits each. This division aligns with Miller’s Law, making the long number more manageable and easier to remember.
2. Television and Radio Advertisements:
Have you noticed that phone numbers in commercials are often repeated or set to a catchy tune? This repetition helps chunk the information, making it easier for listeners to recall.
3. Educational Material:
Textbooks and learning resources often break down complex subjects into smaller units or chapters. These chunks facilitate easier understanding and memory retention.
4. Menu Design:
Ever noticed how most restaurant menus are divided into sections like appetizers, mains, desserts, and beverages? This isn’t just for organizations. By chunking the options, customers can process the choices more efficiently.
5. News Broadcasting:
News channels break down their broadcast into smaller segments or stories. This chunking enables viewers to process diverse information effectively without feeling overwhelmed.
6. Google Search Results:
Google does not present you with thousands of results all at once. Instead, it breaks them down into multiple pages with about ten results per page. This makes the information more manageable.
7. Car Dashboards:
Dashboards are designed with a limited number of gauges and indicators to ensure the driver can process the most essential information quickly without cognitive overload.
These examples help underline how prevalent Miller’s Law is in our daily life and how effectively it can be used in various fields to improve comprehension and reduce cognitive load.
Difficulties and Limitations
While Miller’s Law is an influential principle in UX design, it’s not without its limitations:
Subjectivity: The “magic number seven” is average and not applicable to all individuals. Cognitive capacities vary among individuals.
Task complexity: More complex tasks or information could reduce the number of items a person can handle simultaneously.
Contextual factors: Stress, distractions, or multitasking can further limit a person’s capacity to process information.
Conclusion
Miller’s Law is not a one-size-fits-all rule, but it provides a valuable heuristic for designers to create more user-friendly experiences. Remembering that our users are human, with limited cognitive capacity, can guide us towards creating interfaces that are not just visually appealing, but also intuitive and efficient.
Check out: “30 Days of UX Laws and Principles”
Check out Day 14: The Law of Repetition
Weave is a Design Agency focused on building magical experiences through purpose-driven design. Our aim is to create products that people truly love. To know more visit weavedesign.us
