Xref: utzoo comp.windows.misc:813 comp.sys.next:1009 comp.sys.mac:24386 comp.cog-eng:733 Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!rutgers!ucsd!cogsci!norman From: norman@cogsci.ucsd.EDU (Donald A Norman-UCSD Cog Sci Dept) Newsgroups: comp.windows.misc,comp.sys.next,comp.sys.mac,comp.cog-eng Subject: Re: replacing the desktop metaphor (Why any metaphor?) Keywords: desktop metaphor, graphical interfaces, computing environments Message-ID: <673@cogsci.ucsd.EDU> Date: 25 Dec 88 17:34:01 GMT References: <850@mtfmi.att.com> Reply-To: norman@cogsci.UUCP (Donald A Norman-UCSD Cog Sci Dept) Organization: UC San Diego Department of Cognitive Science Lines: 71 In article <850@mtfmi.att.com> mel@mtfmi.att.com (M.HAAS) writes: Let's take one step back and see if there is a metaphor or analogy to what we are trying to do ...: I believe that Mel Haas has asked a critical question that should be re-examined. There is much blind faith in the use of metaphor and "consistent mental model" (I know, some of propogated by me), but examination of actual systems and a wide variety of tasks doesn't seem to show much consistent use in actual practice. The Apple (Xerox Star?) desktop metaphor isn't realy one of a desktop. If anything, it is of spatial locations, containers, and movements. Double clicking to "launch" applications and cutting, pasting, copying, and undoing are all invaluable, but don't fit the same metaphor. Moving the disk image into the trash can to ejectthe disk is a violation that bothers many people at first usage, but seems perfectly natural after just one or two uses. The trash can example is one that bothers me a lot (intellectually) because it illustates a real violation of principle that causes no problems in practice. (Some try to save it by redefining ejection of a diskette as a kind of "throwing away" but I think this is a feeble save.) I suspect that metaphors are useful in keeping consistency. But now Jonathan Grudin is about to present a paper in CHI 89 arguing about the foolishness of consistency: systems are often improved by violations. Even the Lisa/Macintosh deliberately violated consistency principles when user testing showed it was better to do so. (One of my favorite examples comes from t he old Tenex operating system (for the DEC PDP-10 and then 20) which kept multiple versions of files around, file operation commands always operated on the latest version: move, copy, rename, print, mail, edit. One command, however, was incosnistsent: delete got rid of the oldest, not the latest version (thank goodness). So much for consistency. Yes, early technoogy almost always copies older ones: early automobiles had tillers, typewriter keys were arranged like piano keyboards (some even had black and white keys), the first plastic items for home and office tried hard to look like wood, etc. But this copying usually gives way to exploitation of the real power of the new technology, which is not to copy. If you examine the way people speak, there is heavy use of metaphor (see Lakoff & Johnson's book, for example). But the metaphors are more often inconsistent and mixed than consistent, yet they cause very little difficulty (except to professors and newspaper columnists who love to cite them as perversities). I do believe that we need overall consistency and a coherent mental model (system image) so we can better remember and derive the appropriate operations and better trouble shoot when things go wrong. The Macintosh is superior in that it is easy to use most programs without any manuals. But most of this results from "visibility": I can examine all the menu items and figure out what to do. Some does result from consistency in the use of editing commands and mouse operations. The main point is that we still understand this suprisingly poorly. Where consistency and mepaphor and consistent system images-mental models help and where they hinder is not yet properly understood. Time for some more research, folks. 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 UNIX: {gatech,rutgers,ucbvax,uunet}!ucsd!danorman [e-mail paths often fail: please give postal address and all e-mail addresses.]