Gestalt Principles and the Laws of UX: Miller’s Law

The scientific principles I use every day designing in tools like Figma were predominantly researched and documented between 1912 and 1960 - before the invention of computers and mobile phones or the gurus of UX at NNG.

Technology changes and evolves at a much faster rate than human behaviour. These principles and laws that govern our behaviour and interactions which have been researched over the last 100+ years are still relevant today when designing an app interface, website navigation or a software feature.

I find it fascinating that we digest information on a screen using our eyes, ears and inputs, our brain interprets the information and makes decisions with it and that it is all predictable with 100 science from before the technology existed.

The documentation of these principles began in 1912 - Gestalt Physcology.

Gestalt Principles

Gestalt principles emerged in Germany in the early 20th century when some bright minds like Max Wertheimer and others were curious about how our brains perceive the world. They figured out that our minds tend to group things together and make sense of patterns, often seeing the whole picture as more important than its individual pieces. These ideas have since been used in various areas, like design and psychology, to help people understand and interact with information and visuals more easily.

These principles tell us things like:

• Similar things belong together
• Things that are close are connected
• We see tack patterns and continuity instinctively

Laws

As well as the Gestalt principles, there are Behavioural Laws that can also provide us guidance in User Experience. Many of these Laws are well known - Occum’s Razor for example - simpler solutions are preferable to more complex ones.

Each week I am going to release a new Law of UX. Don't want to wait? You can read my take on 9 Laws of UX in the full post on my website.

Miller’s Law

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

Another key principle is Miller’s Law, which predicts that the average person can only keep 7 (± 2) items in their working memory. It originates from a paper published in 1956 by cognitive psychologist George Miller, who discussed the limits of short-term memory and memory span.

Imagine juggling balls. As you get to 5, it becomes difficult to follow, at 7 balls you can just manage and at 9 balls they come crashing down.

Miller also asserted that we can “chunk” information to help us memorise. A simple example of this today is phone numbers which are chunked to help us memorise them. Have you ever noticed if someone gives you a mobile number in the wrong chunks, it is very difficult to remember.

• Australian mobile number: 0401 123 456
• Incorrect chunking: 04 012 3456

Miller’s Law is very relevant in todays UI/UX design. A great example is the Netflix home page on your TV or browser. You will notice the screen is split into chunks / rows and there is never more than 6-7 items in a chunk:

Miller’s Law takeaways

1. The average person can hold 5–9 items in their working memory at a time.
2. Chunking information helps users process and remember complex data more easily.
3. Limiting choices to 7 (± 2) items reduces cognitive overload and improves usability.
4. Clear organisation of information ensures a more intuitive and enjoyable user experience.

Further reading:

• The Laws of UX website: lawsofux.com
• Steve Krug’s Don’t Make Me Think
• Interaction Design Foundation IxDF: The Gestalt Principles

References:

Home | Laws of UX

Gestalt psychology