Important Studies – The Magic Number Seven and Memory

Important Studies – The Magic Number Seven and Memory

by Jeffrey L. Mitchell, Head of School Currey Ingram Academy

While each year thousands and thousands of studies are completed in psychology and education, there are a handful that, over the years, have had a lasting impact on education and learning. In a series of Extra Credit articles, I will highlight a number of seminal studies that have had a profound impact on teaching and learning.

The first article in this series is based on experiments conducted by George Miller on the parameters of short-term memory.


My grandfather had a number of go-to one-liners. For example, when he would forget something he would often say…I have a good memory, but it’s short. Well, my grandfather was right, his memory was short. But, if it’s any consolation, the work of George Miller in 1956, and literally thousands of other studies that followed, confirm that all of our memories are short. At least when we’re discussing short-term memory.

As they came to be known, Miller’s Magical Number Seven experiments purport that the number of “chunks” of information an average human can hold in short-term memory is 7 ± 2. That is, human memory capacity typically includes strings of words, digits or concepts ranging from 5-9.

In a typical scenario that Miller used to test the limits of short-term memory, a subject is presented a list of words, random digits, etc., and asked to repeat back the list. The average person can repeat back about seven items without error.

Miller referred to a “chunk” as the largest meaningful unit in the presented material. For instance, a word is a single chunk for a speaker of the language but is many chunks for someone who is totally unfamiliar with the language and sees the word as a collection of unfamiliar symbols.

You can see in this simple graph that the percentage of people who can hold anything beyond nine chunks of information in short-term memory is essentially zero.

It cannot be underestimated how important short-term memory is for learning. Despite its limitations, without it, we don’t learn. It is where information from our experiences gets sorted, parsed and manipulated. Exceptionally quick decisions are made about the importance and relevance of given chunks of information. If the information is deemed important, it gets sent on to long-term memory; if it is deemed unimportant, it quickly decays. In a nutshell, with short-term/working memory, we hold information in our mind for short periods in order to work with it. Peter Doolittle sums it up brilliantly in this TED talk:

What are Specific Examples of the Importance of Short-term or Working Memory in Education?
This first “deck” of memory can cause difficulties for students in school. First, I want to note that the term short-term memory in Miller’s study can often (but not always) be substituted for the more common term “working memory” today. While they are not one in the same, the examples below can relate to both.

Accessing Information
When a teacher reads a word problem in math class, learners need to be able to keep all the numbers in their head, figure out what operation to use, and create a written math problem at the same time. Short-term or working memory is where/how learners latch onto and juggle all that information.

Remembering Instructions
Short-term or working memory helps with what comes next, while a learner is doing what comes now. Students needs to be able to hold multistep instructions in their minds, often, while also manipulating other data in the same memory space, which can be difficult.

Paying Attention
Short-term or working memory is located in the same part of the brain responsible for maintaining focus and concentration. Thus, when doing a long division problem, the learner needs short-term/working memory not only to come up with the answer, but also to concentrate on all of the steps involved in getting there.

Learning to Read
Short-term or working memory is responsible for many components of reading. For example, we must hold on to the sounds letters make long enough to sound out new words. Or, we must remember what words look like so we can recognize them throughout the rest of a sentence. When working effectively, these skills keep learners from having to sound out every word they see.

Difficulty Getting Started on Tasks
A learner’s short-term or working memory can easily get overloaded with all the instructions they receive. Even if the task itself involves only one or two steps, the learner may have also heard a myriad of other information, such as which book to use, how long they have to work on the task, what kinds of pens/pencils to use, and how to start things off.

Slow to Copy Things Down from the Board
The learner may find it hard to remember more than one or two words at a time, so they frequently need to check and recheck the original sentence. A slower speed of copying words is exacerbated in younger children because they will also have to remember the spelling of individual words and may only be able to write a few letters at a time before checking the board again.

Unfortunately, all of the difficulties above can mean that a student falls behind across many different areas of the curriculum. They may suffer from self-esteem issues when they compare themselves to other students and wonder why they’re not sure what they should be doing in the classroom or take a long time to get things done.

What Can Be Done About it?
Several strategies can help learners use their short-term or working memory more efficiently.

1. Rehearse. Repeating the information is the most common strategy.

2. Manage distractions. Tempting as they may be and despite a learner’s claim that they can work better, for example, while listening to music, distractions compete for the precious little space in short-term or working memory.

3. Don’t try to do too many things at once.

4. Use chunking. Reducing the information to meaningful pieces reduces the pressure on our short-term or working memory because we are effectively reducing the number of things we are trying to store. For example, this seemingly random list of letters is better remembered in the second “chunked” array.

5. Use mnemonic strategies and other memory tricks. There are dozens of clever memory strategies that help learners better remember large amounts of information. For example, when committing a long list of items to memory that need to be repeated back without the aid of having them written down, try using the Method of Loci. This technique requires you to mentally associate each item in the list with very familiar vocations. So, if you had a list of eight items that you wanted to remember in a certain order and you could associate each of those items with the eight planets, starting with Mercury and ending with Neptune.

6. Make meaningful connections. When new information is connected to information that is solidly established in long-term memory, learning efficiency goes through the ceiling. This can be as simple as noting that the new idea is associated with the color green and then green is the cue to initiate recall of the concept.

7. Finally, educate. Help learners understand what is going on with their short-term/working memory and why they are having difficulty with certain tasks. This was really helpful with my son. I shared with him that a reason he was having difficulty learning in certain ways was because learning that way required the manipulation of larger amounts of information in short-term or working memory. He became much more proactive about how he managed incoming information.

Despite how amazing the human mind is, all of us have rather pedestrian short-term and working memories. If, however, you are concerned that your child’s short-term/working memory might be below what’s typical, an experienced Educational Psychologist can help. They will be able to directly assess short-term and working memory capacity as part of a comprehensive individual learning profile that would also include specific recommendations to improve your child’s learning in all contexts. We operate a full-service diagnostic center at Currey Ingram Academy that is open to the public, and difficulty with working memory is often at the root of why many children begin struggling in school and then come to us for testing. My sincere hope is that the information above and the suggested strategies will help parent readers know how to help their students with this important cognitive skill.

14354_extra_credit_fhp-300x300-150x150Dr. Jeffrey L. Mitchell is the head of school for Currey Ingram Academy. “Extra Credit” is provided each month by Currey Ingram Academy to help parents at all schools and at all stages of the parenting journey. Currey Ingram Academy is a coed, independent K-12 school in Brentwood for students with learning differences such as dyslexia and ADHD. For more information, click here.

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