cunningh@noscvax.UUCP (08/26/83)
"Direct manipulation: a step beyond programming languages" is an article
in the August '83 issue of Computer magazine (the one published by
IEEE Computer Society) by Ben Shneiderman. His main idea is that:
"Direct manipulation systems offer the satisfying experience of
operating on visible objects. The computer becomes transparent,
and users can concentrate on their tasks."
He references a paper by Teresa Roberts at Stanford as having "found
that the overall performance time of display editors is only half
that of line editors ... [and they] also reduce training time."
Besides the display of documents in final form, he also notes several
ways in which users of display editors get immediate feedback from
their actions.
He then goes on to discuss successful features of Visicalc, and various
video games, and claims that most people learn how to use them by
analogy. "A general idea of the game can be gained by watching the
on-line automatic demonstration that runs continuously on the screen,
and the basic principles can be learned in a few minutes by watching
a knowledgeable player. ... Since there is no syntax, there are no
syntax error messages ... [they] are unnecessary because the results
of actions are so obvious and easily reversed. These principles can
be applied to office automation, personal computing, and other
interactive environments."
He then goes on to discuss CAD/CAM [it's an eclectic article, folks]
"The pleasure in using these systems stems from the capacity to
manipulate the object of interest directly and to generate multiple
alternatives rapidly." He goes on to discuss driving a car, programming
industrial robots, using QBE(tm), and the Xerox Star(tm). He even
goes on to discuss drawing pictures to represent mathematical problems,
and draws an analogy with Maria Montessori's teaching methods for children.
He mentions some problems with using direct representation, illustrating
his points that "The wrong information, or a cluttered presentation,
can lead to greater confusion [than using textual descriptions of
the problem to be solved]. ... A graphic icon, although meaningful
to the designer, may require as much -- or more -- learning time
as a word. ... the graphic representation may be misleading. ...
graphic representations may take excessive screen display space.
Shneiderman then goes on to describe his "syntactic/sematic"
cognitive model of user behavior. That's too complicated for me
to review here.
Regardless of where you now stand in the great 'iconic debate' or
even in the 'menu vs. command' debate, if you read this newsgroup,
you should probably check out Shneiderman's article, and some of
the studies he references might be worth looking into also.
reviewed by,
Bob Cunningham ....{ucbvax,philabs}!sdcsvax!noscvax!cunningh