Miller’s Law — Is there a magical number in UX design?
How much information do you throw on the face of your users?
What’s the origin of Miller’s Law?
Let’s start with a quick exercise. It won’t be wise of me to put some theoretical definition here in the very beginning. I want you to remember this law, and I want you to implement this the next time you are designing.
Your task is to read the numbers from left to right and try to remember it.
7 8 9 6 5 1 2 6 6 5
Now close your eyes and try to recall this number. Can’t do it?
Try doing it again by putting them into groups.
7896 — 512–665
Do you find it easy to remember them now? If no, stop reading this article right now! (I’m kidding 😅)
But isn’t this how you memorize every other phone number?
This process of breaking complex things into groups is called Chunking. And this is what Miller talked about way back in the previous century.
What are chunks?
Valid question! This question might pop in your head and you might want to go deep in detail. But what if I super simplify it for you?
Here it is. Don’t get scared by these numbers 😆.
1, 2, 6, 6, 0
How many bits of information did you mind process?
Yes! These are 5 bits of information. 5 different numbers=5 bits. You can also call them chunks. Now read the numbers below.
(12), 6, 6, 0
Just because you grouped 1 and 2 together, it became 12 and now you have 4 chunks of information. How smartly you reduced the number of chunks! Isn’t it easy?
So, by clustering and chunking, your brain finds it easier to remember and comprehend many complex things.
What was the experiment?
Every research has a proper structure and methods in place which assists researchers to either validate their hypothesis or prove it wrong.
For the sake of simplicity, I would just talk about the experiment in brief and not get into the complexity of it. (It’s not because I don’t trust you :D)
Researchers conducted 5 different sessions over the course of a year and every session had 5 trials. They would read one digit per minute to their subjects and subjects would have to repeat it in the reverse order.
Researcher — (3,5,6,2,3,1)
Subject — (1,3,2,6,5,3)
If you folks want me to talk about the number of subjects, mean, standard deviation, significance, confidence interval, let me know in the comments. If you are interested I wouldn't hesitate to go in detail.
No details but here is the chart for that experiment.
If you look closely at the average results, you would get a good idea of their memory power and how chunking capacity.
What is Miller’s Law?
It’s only fair of you to ask for Miller’s Law in brief now. We have gone through already gone through the basics and now it’s time for the short definition.
George A. Miller first published this in 1956 in Psychological Review.
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
According to Miller, our short term memory and absolute judgment are both limited to number 7 on average.
Number 7 is therefore called the Magic number. Obviously, it’s not a strict number for chunking as the range itself varies from 5 to 9.
Seven(plus or minus 2) is a way of grouping content so that it could be organized better for human comprehension.
How to implement Miller’s Law in UX?
As you scrolled past the quick exercise, many examples must have popped in your big head and you must already be thinking where all you could use this law.
Mobile Numbers
The way we chunk numbers, especially mobile numbers is an excellent usage of the chunking technique.
You might already be using this technique to remember the numbers of those whom you called late in the night 😉
Enter the Card Number
All of us must have faced this huge overwhelming task of entering our card details while making an online transaction.
How many times did we look at our card to enter the correct numbers? It has been simplified a lot these days by chunking them into groups. Thanks to those wise Designers!
Spotify Songs
Look at the clusters of songs below. How many categories do you see in one row?
Do you think it’s easier to make a choice when you see these songs in chunks?
Or would you recommend 20 categories in just one row?
Medium’s Homepage
As chunking is becoming obvious, I’ll leave this you to figure out how Medium used this technique.
Hint: How many articles do you see in one fold? How many options on the right bar?
TL;DR
As you are reading this article, I know that you will become a great UX Designer. You care for your users and you are learning every day.
Miller’s Law could help you ease the lives of your users by keeping a few guidelines in mind.
Miller’s Law states that 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.
- In case your users need to make a choice, don’t give an overwhelming number of choices to them.
- Break down and group information into smaller chunks.
- Try not to rely on the short term memory of users. Use the principle of Recognition over Recall (More about this in the upcoming articles 😉)
Continue Reading
UX Crash Course: Chapter 1
References
Miller, G. A. (1956). “The magical number seven, plus or minus two: Some limits on our capacity for processing information”. Psychological Review.
