Path: utzoo!utgpu!watmath!clyde!att!rutgers!mit-eddie!bloom-beacon!tut.cis.ohio-state.edu!mailrus!ames!lll-tis!helios.ee.lbl.gov!nosc!ucsd!sdics!norman
From: norman@sdics.ucsd.EDU (Donald A Norman-UCSD Cog Sci Dept)
Newsgroups: comp.cog-eng
Subject: Re: subliminal feedback
Keywords: feedback windowing interfaces
Message-ID: <651@sdics.ucsd.EDU>
Date: 17 Nov 88 16:04:52 GMT
References: <318@aratar.UUCP>
Reply-To: norman@sdics.UUCP (Donald A Norman-UCSD Cog Sci Dept)
Organization: UC San Diego Department of Cognitive Science
Lines: 41

A comment on Chuck Clanton's comment on feedback.  The issue arose
from a private set of communicatins he and I had over his earlier
posting of a question about the "focus": problem -- how to specify
which window is active so that the user would not make the (common)
mode error of intending to operate upon the contens of one window, but
because it had not been formally selected, having the actionstake
effect upon another window.

Clanton thought the indicator ought to be subtle and "subliminal."  I
suggested it should be fairly significant and available to conscious
knowledge.  But the signal should not be overwhelming in magnitude,
because:
	1. the signal should not distract (flashing the selected
	  window would be a very poor solution);
	2. The non-selected windows should still be easy to use,
	  because one often is reading from or otherwise using the
	  material in the non-selected windows while working in the
	  selected one.

So, this leads to the very important set of questions Chuck Clanton
just asked in his last contribution.

The goal is to make the properties of the system obvious enough that
the new user can learn them (hence the need for signals that are
consciously available), yet subtle enough that the frequent user does
not have the normal work interfered with, so that the usage is
automatic, and, as a result, the user is not consciously aware of them.
This is a difficult and delicate question: providing just the level of
information that can serve these two different requirements.

A very good topic.

don norman

Donald A. Norman	[ danorman@ucsd.edu   BITNET: danorman@ucsd ]
Department of Cognitive Science C-015
University of California, San Diego
La Jolla, California 92093 USA

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