Magical Number 7

In 1956, cognitive psychologist George A. Miller published a paper in Psychological Review that has since become one of the most cited papers in psychology. Miller’s Law, as it’s commonly known, states that the average person can only hold about seven (plus or minus two) items in their working memory.

The number of objects an average person can hold in working memory is about seven, also known as The Magical Number Seven, Plus or Minus Two.
— Miller’s Law

Why is it important?

If we want users to process, understand, and remember information easily, we need to organize it into smaller, more meaningful chunks. When content is chunked, it becomes easier to comprehend and remember, and users can better understand the relationship between different pieces of information.

For example, if we ask someone to memorize a string of numbers, they might struggle.

But if we chunk those numbers into groups of three or four, they become much easier to remember.

Chunking also helps users understand the relationship between content elements and information hierarchy.

How does the “magical number 7” impact UX design?

Miller’s Law is particularly relevant in form design where options need to be presented for users to choose from. When the number of options exceeds 7, it’s recommended to group them into categories or chunks to aid the user’s processing and memory. It’s important to understand that Miller’s Law does not imply a strict limit of 7 items in every design element, but rather emphasizes the importance of organizing information into meaningful and manageable chunks. This approach can lead to better user experience, lesser cognitive load, and improved retention of information.