The Power of Your Working Memory

How much information can you actually hold in your working memory—
what can you deal with on your desktop at one time? Well,
when researchers began studying the working memory, they came
up with some of the findings that are still accepted and incorporated
into models of memory today.
One of these findings is the well-known Magic Number Seven
principle, which was first written about by George Miller in 1956 in
an article titled ‘‘The Magical Number Seven, Plus or Minus Two:
Some Limits on Our Capacity for Processing Information.’’ He suggested
that we can only hold about seven items, give or take two—or
five to nine items—in our short-term memory (which was the term
originally used for the working memory). However, if you group
items together into what Miller calls ‘‘chunks’’—units of short-term
memory composed of several strongly related components—you can
remember more.13 And in Chapter 12 you’ll learn more about how to
do your own chunking to improve your memory capacity.
You can see examples of how this Number Seven principle and
chunking work if you consider your phone number and social security
number. One reason the phone number was originally seven
numbers and divided into two groups of numbers is because of this
principle—then when the area code was added, the phone number
was split up or chunked into three sections. Similarly, your social
security number is divided into three chunks. And when you look at
your bank account, you’ll see that number is chunked up into several
sections. As for memory experts who can reel off long strings of
numbers, they do their own mental chunking so they can remember.
They don’t have a single, very long string of numbers in their mind.
However you chunk it, though, whatever material comes into
your working or short-term memory is frequently forgotten if you
hold it in your memory for less than a minute14—a finding repeatedly
confirmed by hundreds of studies by cognitive psychologists.
That’s why you normally have to do something to make that memory
memorable if you want to retain it.
Yet, while you want to improve your memory for things you
want to remember, you don’t want to try to improve it for everything.
Otherwise your mind would be so hopelessly cluttered, you
would have trouble retrieving what you want. For example, think of
the many activities and thoughts you experience each day, many of
them part of a regular routine. Well, normally, you don’t want to
remember the minutia of all that, lest you drown in an overwhelming
flood of perceptual data. It would be like having an ocean of
memories, where the small memory fish you want to catch easily
slip away and get lost in the vast watery expanses. But if something
unusual happens—say a robber suddenly appears in the bank where
you are about to a make a deposit—then you do want to remember
the event accurately. So that’s when it’s important to focus and pay
attention in order to capture that particular memory, much like reeling
in a targeted fish.
Memory researchers have also found that your short-term or
working memory is affected by when you get information about
something, which is called the ‘‘serial position effect.’’ In general,
whatever type of information you are trying to memorize, you will
better remember what you first learn (called the ‘‘primacy effect’’) or
what you learn most recently (called the ‘‘recency effect’’).15 When
psychologists have tested these effects by giving numerous subjects
lists of words that vary in word length and the number of words, the
results show a similar pattern. Subjects can generally remember two
to seven items and are most likely to remember the most recent
items first. In turn, you can use that principle when you want to
remember a list of anything, from a grocery list to a list of tasks to
do.