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From: jones@pyrite.cs.uiowa.edu (Douglas W. Jones,201H MLH,3193350740,3193382879)
Newsgroups: comp.human-factors
Subject: Re: Touchscreens
Message-ID: <6460@ns-mx.uiowa.edu>
Date: 13 Jun 91 14:18:34 GMT
Article-I.D.: ns-mx.6460
References: <8435@awdprime.UUCP>
Sender: news@ns-mx.uiowa.edu
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From article <8435@awdprime.UUCP>, by jon@kitty.austin.ibm.com (Werner):

> Are there any papers written dealing with the use of touchscreens as an
> alternate input device in environments which don not have enough desk 
> space for a keyboard or a mouse? 

I don't know of any papers, but as a long-term touch-panel user, I much
prefer mice, trackballs, or knobs on my keyboard.

I used the U of Illinois Plato touch panels between 1973 and 1980, and
the big problems are:

  1) You have to lift your hand up from the keyboard, perhaps a foot,
      to touch the screen.  This slows you down compared to horizontal
      moves to a mouse.

  2) No matter how good the anti-reflection coating on your screen is,
      fingerprints tend to defeat it.  If you've got a touch panel, you'll
      need to wash it almost daily to keep the glare down.

  3) If you have touch-intensive software, where you spend long periods
      holding your hand up to the screen poking here and there, your arm
      gets tired.  I remember after some sessions debugging a particular
      touch-intensive piece of computer aided instructional material, my
      arm began to ache quite intensely.  I've never experienced that kind
      of reaction to "desktop pointers" like mice.

  4) Touch panels aren't particularly accurate.  Even if you use a modern
      thin-film touch panel, there is a real problem with paralax.  The
      front of a CRT display is quite thick, and the push button size we
      typically use with mice is small enough that it can be very hard to
      find the right spot on the screen to touch to get a particular
      button and not its surrounding area.  The Iowa City Public Library
      on-line card catalog has been touch screen based for a few years
      now, and I've had numerous paralax problems with it, even thoug it
      has nice big on-screen push buttons.

					Doug Jones
					jones@cs.uiowa.edu
      it's