Miller’s Law and the Magical Number Seven

7There is definitely some psychology to design. And UX design is definitely about organization. There is a principle of organization that comes psychology that I have seen written about in terms of product and service design. It is Miller’s Law.

It was put forward in 1956 – long before UX and web design was a thing – in a paper by cognitive psychologist George A. Miller. In his well-known paper (at least in psych circles), titled “The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information” he proposed a limit to memory which is now called Miller’s Law.

Miller proposed that the number of perceptual ‘chunks’ an average human can hold in working memory (a component of short-term memory) is 7. He found that memory performance is great five or six different stimuli but declines aft so let’s say 5-9.

If the mind can handle ~7 bits of information when completing a task that requires cognitive effort, then designers need to keep that in mind when designing. That would apply to completing forms and surveys. It applies to lists in menus and lots of other tasks that might be presented to users. What happens when a catalog page shows 15 items?

Miller believed that all of us “chunk” information and that if the information is organized in categories no larger than 9, but preferably ~5 chunks, memory is best served.

A related find – which I learned in a writing course – is about primacy, and recency effect (also known as the serial position effect). These two terms describe how we remember items placed at the beginning and end of an experience, and if we forget some it’s likely they will be in the middle. Combining this with Miller’s Law and you would say that the bigger the number of items, the more middle to be forgotten.

Leave a Comment

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.