Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!ucsd!cogsci!norman
From: norman@cogsci.ucsd.edu (Donald A Norman-UCSD Cog Sci Dept)
Newsgroups: comp.cog-eng
Subject: Re: one-finger keyboard
Summary: we need more research
Message-ID: <10068@ucsd.Edu>
Date: 20 Oct 89 23:58:32 GMT
References: <1989Oct6.221013.8269@agate.berkeley.edu> <1259@cbnewsj.ATT.COM> <783@cogsci.ucsd.EDU> <MEF.89Oct13184703@dalek.silvlis.com> <16448@umn-cs.CS.UMN.EDU>
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Reply-To: norman@cogsci (Donald A Norman-UCSD Cog Sci Dept)
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Organization: UC San Diego Department of Cognitive Science
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In my earlier reply, I did not understand the rationale for
one-fingered keyboard, but that was because I did not consider the
problem of the handicapped.  I now see this as a very important area
for study.

Our research group (Gentner, Grudin, LaRochelle, Norman, Rumelhart)
spent considerable time analyzing typing a number of years ago and did
reach a number of conclusions relevant to keyboard design for
10-FINGERED, TOUCH TYPISTS (actually, 9-fingered, because most people
only use one thumb).

Among the conclusions were that the mechanical properties of the
keyboard and hand were the limiting factors for speed for accomplished
typists, whereas mental processing issues were the limiting factors
for beginning typists (Don Gentner has published on this).

QWERTY and DVORAK keyboards are fast because they allow for
alternating hand typing, and typing speds for two-letter pairs are
ranked roughly like this (fastest at the top):
	different hands (as in "is" in the word "this")
	different fingers, same hands) (as in the letters "er")
	repeated letters (as in "ee)
	same finger (as in "mu")

The differences can be huge.  Typists do not type in spurts or
clusters, but there are specific patterns, some determined by
physical factors (as above) and some by learned letter sequences in
the languages (Genter, LaRochelle, and Grudin did a nice study
comparing the typing of dutch and english by typists in the US and the
Netherlands and showed that language patterns did affect typing
speed.)

Dvorak is faster than qwerty because it minimizes movement to the
non-home rows and also maximizes hand alternation.  But it is not much
faster -- say 10% -- and not worth changing millions of keyboards.
Qwerty has a strange and fascinating history, but the same factors
that minimized key jamming with the one handed typists of the time now
cause it to be an efficient keyboard for the touch typists of today.

if you go to one handed typing, the story will change.  And if you go
to one-fingered typing, it will change even more.  However, I would
assume that the same principles would operate for the relevance of
mechanical and mental factors. So, I would predict
that:
	for one handed typing, you want to alternate fingers as much
		as possible, and minimize finger travel.
	for one-fingered typing you want to minimize finger travel

HOWEVER, these have not been studied very well: those commentators who
said we need to study these cases explicitly were correct.  

Finally, Don Gentner and I did a study (unpublished) on simultaneous
keying (2 keys at the same time, as in shift keys of control keys --
or as in chord keyboards).  We found that even expert typists slowed
up with simultaneous keys, so SHIFT-a (capital A) took twice as long
to type as "a")..  That is, even though the keys were to be typed in
parallel, the times were the same as if they had been typed in
serial.

This is one reason, perhaps, that chord keyboards slow down typing.
(Court stenographers are still the fastest typists around, and they
use a chord keyboard, but they type syllables, not letters, so a good
part of the gain is the shorthand transcription method. And they must
practise for years and years to reach those speeds.)


in conclusion: we know a lot about regular expert typing, but very
very little of direct relevance to the handicapped population: we
should learn more about these cases, but this will take specific
research.

Don Norman                         	       INTERNET:  dnorman@ucsd.edu
Department of Cognitive Science D-015	       BITNET:    dnorman@ucsd
University of California, San Diego	       AppleLink: d.norman
La Jolla, California 92093 USA
   [e-mail paths often fail: please give postal address and full e-mail path.]
Don Norman                         	       INTERNET:  dnorman@ucsd.edu
Department of Cognitive Science D-015	       BITNET:    dnorman@ucsd
University of California, San Diego	       AppleLink: d.norman
La Jolla, California 92093 USA