Off-topic: Magic Number 7 (WAS: Re: XML Editors - Word 2000??)

[Didier PH Martin]

Hi,

The magic seven comes from a well know article form George Miller in 1956
called "The Magical Number Seven, Plus or Minus Two: Some Limits on our
Capacity for Processing Information". In this now famous article, Miller
stated that the short term memory can handle 7 elements plus or minus 2.
This means that gifted people can remember with their short term memory 9
elements and the less gifted 5. The average person can remember 7 and thus,
this is why the number 7 is called the magic seven. it is the "short term
memory register" (kind of) of the average person on this planet.

Bell Labs used the result of this research to design an addressing system
that could be handled by the average person. At Xerox PARC we used the same
principle to design the desktop and the notion of pull down or context
menus. Originally a pull down or context menu has been created to relieve
the long term memory (i.e. a command line based system) and use instead the
short term memory. This is why a menu containing 7 elements (the magic
seven) is better designed than a menu having 10 elements (above the gifted
persons capabilities). From these studies we discovered that the tendency to
chunk data is based on our intuitive knowledge of our magic seven short term
memory limitations. This is why we tend to decompose things in hierarchies
or do a process known as chunking the information universe.

So, the magic seven concept is also known as the Miller principle and you
can find that in the 1956 published paper named "The Magical Number Seven,
Plus or Minus Two: Some Limits on our Capacity for Processing Information"
by George Miller.

regards
Didier PH Martin
mailto:martind at netfolder.com
http://www.netfolder.com


-----Original Message-----
From: owner-xml-dev at ic.ac.uk [mailto:owner-xml-dev at ic.ac.uk]On Behalf Of
John E. Simpson
Sent: Friday, July 02, 1999 8:32 AM
To: XML Developers' List
Subject: Off-topic: Magic Number 7 (WAS: Re: XML Editors - Word 2000??)


At 10:23 AM 7/2/1999 +0100, Philip Nye wrote:
>Rick Jelliffe wrote:
...
>> 1) you have to remember the name, this is difficult if there are more
>> than 7 names in frequent use;
>> 2) if there are more than 7 elements at any one level, there is a
>> selection
>> problem for GUIs: style provides a way to key hierarchy that provides
>> reinforcing feedback;
...
>Incidentally, where does the magic number 7 come from?

When I was at AT&T years ago, there was a company legend (possibly
apocryphal) about the length of US telephone numbers. According to this
legend, Bell Labs had surveyed large numbers of customers and determined
that, on average, people could remember 7 "things," plus or minus 3, about
another "thing." Ergo, a phone number would optimally be made up of: a
4-digit "main portion," sans exchange and area code; a 3-digit exchange;
and a 3-digit area code. This was supposedly in descending order of need to
remember the additional portions, assuming that you'd need primarily to
call people in your own exchange, followed by people in your area code but
outside your exchange, followed by people in other area codes.

I don't know where Rick's magic 7 comes from.

=============================================================
John E. Simpson          | It's no disgrace t'be poor,
simpson at polaris.net      | but it might as well be.
                         |            -- "Kin" Hubbard

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