Seven (Plus or Minus Two)

George A. Miller died July 22 at age 92. He was truly a giant in the world of psychology. In 1956 he published an article in Psychological Review entitled “The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information”. His ideas were especially important because they were introduced into the stimulus-response world dominated by behavioral psychology. As he developed his thought he posited an information processing theory of human cognition where behavior resulted from taking in and processing information instead of being the deterministic outcome of conditioned responses to external stimuli that behaviorists believed drove a person’s behavior.

This had paradigm-shifting implications for the field of psychology in general but perhaps the most important to the world of communications was his research showing that, while long term memory capacity was practically unlimited, the short term memory that we use to take in information for processing is essentially limited to seven “chunks”- plus or minus two- hence the title of his article. Any attempt to hold more chunks in short term memory results in loss or degradation in the processing as with objects falling off an overloaded desktop.

In a practical sense we do not have direct access to the unlimited long term memory when we communicate. We are only able to place chunks of information before our “receivers” for reception into short term or “working” memory for processing. Therefore, we need to respect the existence of a short term memory limitation as we chunk our information and organize it for presentation.

There has been a great deal of work suggesting that the limit is different for different kinds of information and that the limit may be lower than seven. Some researchers have suggested four items and some three, but whatever the number there is now broad acceptance of the existence of the limit. For that we must tip our hats to Miller.

The next time we do a presentation we should pause to think of him and heed his work. Do our slides violate the principle of a limited working memory? Does our organization honor the principles behind chunking information for processing? We can all think of violators and their violations of these principles. Perhaps by remembering Miller we can avoid joining those ranks. We may not become slaves to the number three, or four or even seven but we can certainly avoid the numbers 20 and 30 and 50!

As we do so, we thank you George. May you rest in peace.

Leave a Reply