The Magical Number Seven, Plus or Minus Two

The Magical Number Seven, Plus or Minus Two post image

We can fit about seven pieces
of information into our short-term memories…or can we?

It is sometimes said human
beings are nothing more than a collection of memories. Memories for people,
events, places, sounds and sights. Our whole world is funnelled in through our
memories. In fact, they may be our most prized possessions.
The study of memory has always
been central to psychology – this post describes one of its most influential
findings. This is the second nomination for the Top Ten Psychology Studies.
The title of this post is the
same given to a 1956 article by the psychologist George A. Miller in which he
describes the capacity of human memory (Miller, 1956). The article’s opening
has become famous amongst historians of psychology:
“My problem is that I have
been persecuted by an integer. For seven years this number has followed me
around, has intruded in my most private data, and has assaulted me from the
pages of our most public journals. This number assumes a variety of disguises,
being sometimes a little larger and sometimes a little smaller than usual, but
never changing so much as to be unrecognizable.”
It’s not just Miller who was
persecuted by this number though, it’s all of us. What this magical number
represents – 7 plus or minus 2 – is the number of items we can hold in our
short-term memory.
“…memory is a slippery

So while most people can
generally hold around seven numbers in mind for a short period, almost everyone
finds it difficult to hold ten digits in mind.
Remember that memory is a
slippery concept: short-term memory for psychologists refers to things that are
currently being used by your brain right now. For example as you’re reading
this post the words you’ve read go into short-term memory for a very short
period, you extract some meaning (hopefully) and then the meaning is either
stored or discarded. You’ll probably still have some faint memory of this
article tomorrow, but won’t be able to remember most of the actual words.
All sorts of experiments and
theories have followed disputing the 7 items approach to memory. More recent
studies have, for example, shown how we put items together in order to ‘chunk’
data. Still, the basic concept that our immediate short-term memory is
relatively limited is still valid.
If you think seven isn’t much
then be thankful you’re not a six month old infant. Recent research suggests
they can only hold one thing in short-term memory (Kaldy & Leslie, 2005).
Poor little chaps. Perhaps babies are the new goldfish?
About the author

Psychologist, Jeremy Dean, PhD
is the founder and author of PsyBlog. He holds a doctorate in psychology from University
College London and two other advanced degrees in psychology.
He has been writing about
scientific research on PsyBlog since 2004. He is also the author of the book
“Making Habits, Breaking Habits” (Da Capo, 2003) and several ebooks.

Kayode Ojo
Kayode Emmanuel Ojo is the Co-Founder and Managing Director at SHEFFA Limited. He is presently studying Computer Science at the National Open University, Victoria Island, Lagos.