From: Peter.Gorny@arbi.informatik.uni-oldenburg.de (Peter Gorny)
Subject: Re: GUIs Considered Harmful
Organization: University of Oldenburg, Germany
Distribution: usa
Date: Thu, 10 Sep 1992 10:20:17 GMT

jonke@kong.gsfc.nasa.gov (Stephen Jonke) writes:

>In article <1992Sep6.145944.5828@news.eng.convex.com>, Tom Christiansen <tchrist@convex.COM> writes:
>> 
>> :Oh, the subjects were just basically incompetent in general.  If it
>> :takes as long as *one* second to decide which key to press, I consider
>> :myself "idling".  I type well over 100wpm when I don't have to stop and
>> :decide what I want to type next.  
>> 
>> Indeed.
>> 
>> I've got vi in my wetware now.  I don't *ever* think about switching modes
>> or backspacing.  
>> [...]  I've got a mental model of what I'm
>> typing, and don't even need the characters on the screen to know that my
>> fingers have done the wrong thing.  It's all subsumed: what once required
>> thought now goes incredibly fast.  
>> [...]

>The problem with this argument is that while if you continue to use the
>same programs over and over and over and keep up with it, you will go
>into "automatic", if you let it lie for some time, you soon forget a lot
>of it, except for some very basic core stuff 
>[...]
>More importantly, though, this type of program that requires long periods
>of learning time creates another problem -- stagnation.  It makes people
>not want to change with the times.  On the Macintosh, I never worry about
>switching to the latest word processor or graphics program, or whatever,
>because I know that the learning time is so short and effortless and I
>can quickly get on with the work at hand.
>[...]

This discussion is (though often accompagnied with a lot of emotional comments)
very interesting from the point of view of user interface designers:
There are a lot of users, who belong to the ergonomics categories:
           -  frequent users  (vs one-time users, seldom users etc.)
           -  intensive users (vs shorttime users, (e.g. buying a subway
                              ticket from a machine), medium-time users, etc.. )
           -  regular users   (vs irregular users, i.e. with widely differing
                              intervals between uses)
           -  expert users    (vs. beginners,... etc.)

In principle we have to design special user interfaces according to the 
characteristics of the expected users of the program. Since this would be
to expensive, we try to build adaptible (or adaptive) interfaces, thus
covering a broad range of users.

From work psychology we can learn about their learning models, i.e., how the
process of learning on the cognitive level and controling micromotoric move-
ments (in order to handle a machine, for instance) and how these control
actions go over into quasi automatic micromotoric movements.
These learning models are used to support the learning process (skill acquiring
process) by training through a well-design user interface of application
software.
And it is important to remember (for the designers), that the process is
partly reversible: we also forget - also in regard to "automated actions".

So the adaptivity of a user interface has to support the user in his/her
different stages of knowledge, capability and skill.

(BTW: this kind of automated skills are the cause for that it is practically
impossible to change the QWERTY-keyboard to something less fatiguing for
hands and arms. They force user interface designers to stay with what we call
"user expectation"...)

Peter Gorny




      ________________________________________________________
      Prof. Dr. Peter Gorny
      Informatics Dept. - C. v. Ossietzky University Oldenburg
                 Computer Graphics & Software-Ergonomics Group
.     ________________________________________________________
      Snail-Mail:    P.O.Box 2503 - D-2900 Oldenburg - Germany 
      Voice:            +49-441-798-2901 or -4521 (Fax: -2155)
      E-Mail:     Peter.Gorny@arbi.Informatik.Uni-Oldenburg.DE 
      ________________________________________________________


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