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From: rba@allegra.UUCP
Newsgroups: net.cog-eng
Subject: putting 7+-2 to rest
Message-ID: <1910@allegra.UUCP>
Date: Mon, 24-Oct-83 20:45:19 EDT
Article-I.D.: allegra.1910
Posted: Mon Oct 24 20:45:19 1983
Date-Received: Wed, 26-Oct-83 02:16:57 EDT
Organization: AT&T Bell Laboratories, Murray Hill
Lines: 26

The original citation for the magic number was:
George A. Miller, The magical number seven, plus or minus two:  Some
limits on our capacity for processing information. Psychological
Review, 1956, 63, 81-97.

This was updated a few years ago by Donald Broadbent,
in an article which asserted that the processing limit was closer to five:
D.E. Broadbent.  The magical number seven after fifteen years.
In A. Kennedy and A. Wilkes (Eds.) Studies in long term memory.
Wiley: NY, 1975, 3-18.

However, while most psychologists believe that there is some limit
to short-term memory, almost no serious researcher now takes either of
the magic numbers literally.  (Although there have been many jokes
about the decline in intelligence -- because the magic number dropped
from 7 to 5.  And, there have been other jokes about continuing the
series of magic numbers 7,5,3,1,-1...) Indeed a colleague of mine
(Steve Hanson) told me he talked to George Miller (Steve teaches statistics 
at Princeton where Miller is a professor) and not even Miller accepts 
the 7+-2 model any more.

In any case, as has been pointed out, even if there were a magic
number for STM it isn't clear how that should be related to the number
of items on a distribution list.

Bob Allen, allegra!rba, BTL-CSO