The magical number ...

George S. Miller wrote a paper in 1956 called "The magical number 7 ± 2: Some limits on our capacity to process information." I first came across this paper in the mid-1980s when I was the vice president of education services running the technical training division of a software company.

My associate, Vaughn Frick, and I devised a couple of experiments that we actually repeated many times over the course of a two year period. The experimental results not only confirmed Miller's original hypothesis, but allowed us to push the envelope on the concept even further.

The instigation.

Miller's original report resulted in the now famous American seven digit phone number preceded by a three digit area code. You can even repeat the original experiment yourself. Write down a series of numbers from three digits to 10 digits. it doesn't matter what the numbers are.

You can even use the list below, unless your friends are likely to read this blog and memorize the results! (Wishful thinking.)

you will inevitably find that when the string of digits reaches 10, there was a sharp drop-off in memory. You will find also that there is a much smaller drop-off between five and nine. The difference however in drop-off between the 5/9 range and the 10 and over rate is greater by a factor of five or more.

What this illustrates.

the human brain has a unique, but limited capacity for short-term storage of information. You can call information and remember up to three telephone numbers. Why? Because the telephone number itself is broken down into three smaller groups of numbers: the area code (three digits), the exchange (three digits) and the number (four digits). Some old folks like myself remember the vague and easiness when they first added new area codes. I tracked down that uneasiness to the pattern of numbers used. Originally, the area code and a zero or one as the middle digit. The exchange never had a zero or one.

What does this mean?

it means, basically, that we have an extraordinary capacity to remember information. Think about it. We can remember seven groups of things. Each group of things can have seven elements. Each of the seven elements can be up to seven digits long!

I had a stroke at the end of 2008. It took nearly a year to recover. Even at that, my recovery was not complete -- not back to my pre-stroke self. This knowledge of how the brain uses Miller's magic number in able to me to vastly improve my post stroke of memory.

example data

number list 1

847

2195

64723

539261

3984271

75143268

139624857

4382769150

82734061529

number list 2

203 . 561 . 8947