| 1 | Date: Tue, 24 Nov 92 22:25:59 -0500 |
| 2 | From: ben@cs.UMD.EDU (Ben Shneiderman) |
| 3 | To: bam@cs.cmu.edu, ben@cs.umd.edu, callahan@cerc.wvu.wvnet.edu, |
| 4 | hopkins@bongo.garnet.cs.cmu.edu, weiser.pa@xerox.com |
| 5 | Subject: Re: more pie menus! |
| 6 | |
| 7 | I couldn't resist sending you all this latest essay which is |
| 8 | destined for IEEE Software...some readers expect it to generate |
| 9 | some strong responses...Ben |
| 10 | |
| 11 | |
| 12 | Beyond Intelligent Machines: |
| 13 | Designing Predictable and Controllable User Interfaces |
| 14 | |
| 15 | |
| 16 | Ben Shneiderman November 24, 1992 |
| 17 | |
| 18 | University of Maryland, College Park, MD 20742 |
| 19 | |
| 20 | Professor, Department of Computer Science, |
| 21 | Head, Human-Computer Interaction Laboratory at the |
| 22 | Center for Automation Research & |
| 23 | Member, Institute for Systems Research |
| 24 | |
| 25 | |
| 26 | Who's in control? |
| 27 | |
| 28 | An important shift is occurring from the old vision of computers |
| 29 | as 'intelligent' to a new vision based on predictable and controllable |
| 30 | user interfaces that depend on direct manipulation of objects and actions. |
| 31 | Appropriate metaphors and terminology are important since they shape |
| 32 | the thoughts of researchers, designers, managers, congress-people, |
| 33 | journalists, etc. Most of us have learned the importance of gender |
| 34 | neutral terminology and similarly I have been strongly opposed to |
| 35 | suggesting that computers are 'intelligent' or 'smart' for several |
| 36 | reasons: |
| 37 | |
| 38 | 1) Limits to Imagination |
| 39 | |
| 40 | I think we should have much greater ambition than to make a computer |
| 41 | behave like an intelligent butler or other human agent. Computer |
| 42 | supported cooperative work (CSCW), hypertext/hypermedia, multi-media, |
| 43 | information visualization, and virtual realities are powerful |
| 44 | technologies that enable human users to accomplish tasks that no human |
| 45 | has ever done. If we describe computers in human terms then we |
| 46 | run the risk of limiting our ambition and creativity in the design |
| 47 | of future computer capabilities. |
| 48 | |
| 49 | |
| 50 | 2) Predictability and Control are Desirable |
| 51 | |
| 52 | If machines are 'intelligent' or 'adaptive' then they may become less |
| 53 | predictable and controllable. Our usability studies show that users |
| 54 | want feelings of mastery, |
| 55 | competence, and understanding that come from a predictable and |
| 56 | controllable interface. Most users seek a sense of |
| 57 | accomplishment at the end of the day, not the sense that this |
| 58 | 'intelligent' machine magically did their job for them. |
| 59 | |
| 60 | |
| 61 | 3) Human Responsibility |
| 62 | |
| 63 | I am concerned that if designers are successful in convincing the users |
| 64 | that computers are intelligent, then the users will have a reduced sense |
| 65 | of responsibility for failures. The tendency to blame the machine is |
| 66 | already widespread and I think we will be on dangerous grounds if we |
| 67 | encourage this trend. |
| 68 | |
| 69 | |
| 70 | 4) Machines are not People AND People are not Machines |
| 71 | |
| 72 | I have a basic philosophical objection to the suggestion that machines |
| 73 | are, or can ever be, intelligent. I know that many of my colleagues are |
| 74 | quite happy to call machines intelligent and knowledgeable, but I prefer |
| 75 | to treat and think about machines in very different ways from the way I |
| 76 | treat and think about people. |
| 77 | |
| 78 | |
| 79 | The lessons of history |
| 80 | |
| 81 | While some productive work has been done under the banner of |
| 82 | `intelligent', often those who use this term reveal how little they |
| 83 | know about what users want or need. The users's goal is not to |
| 84 | interact with an 'intelligent' machine, but to create, communicate, |
| 85 | explore, plan, draw, compose, design, or learn. Ample evidence |
| 86 | exists of the misguided directions brought by 'intelligent' machines: |
| 87 | |
| 88 | - natural language interaction seems clumsy and slow compared to |
| 89 | direct manipulation and information visualization methods that use |
| 90 | rapid, high-resolution, color displays with pointing devices. Lotus HAL |
| 91 | is gone, AI INTELLECT hangs on but is not catching on. There are some |
| 92 | interesting directions for tools that support human work through |
| 93 | natural language processing: aiding human translators, parsing |
| 94 | texts, and generating reports from structured databases. |
| 95 | |
| 96 | - speech I/O in talking cars and vending machines is gone. |
| 97 | Voice recognition is fine for handicapped users plus special situations, |
| 98 | but doesn't seem to be viable in general office, home, or school |
| 99 | settings. Our recent studies suggest that speech I/O has a greater |
| 100 | interference with short term and working memory than hand-eye |
| 101 | coordination for mouse menu selection. Voice store and forward, |
| 102 | phone-based information retrieval, and voice annotation have great |
| 103 | potential but these are not the 'intelligent' applications. |
| 104 | |
| 105 | - adaptive interfaces are unstable and unpredictable, often leading |
| 106 | users to worry about what will change next. I see only modest chances |
| 107 | for success in user modeling to recognize the level of expertise and |
| 108 | revise the interface accordingly - can anyone point to successful |
| 109 | studies or commercial products? By contrast, user controlled |
| 110 | adaptation through control panels, cruise control for cars, and |
| 111 | remote controls for TV are success stories. While algorithms to |
| 112 | deal with dynamic |
| 113 | issues in network or disk space management are needed, the task domain |
| 114 | and user interface issues of the application program |
| 115 | should generally be under direct user control. |
| 116 | |
| 117 | - Intelligent CAI (Computer Assisted Instruction) only prolonged the |
| 118 | time (compared to traditional CAI) until the users felt they were the |
| 119 | victims of the machine. Newer variations such as Intelligent Tutoring |
| 120 | Systems are giving way to Interactive Learning Environments where |
| 121 | students are in control and actively creating or exploring. |
| 122 | |
| 123 | - intelligent talking robots with five-fingered hands and human facial |
| 124 | features (quaint fantasy that did well in Hollywood but not in Detroit |
| 125 | or elsewhere) are mostly gone in favor of flexible manufacturing systems |
| 126 | that enable supervisors to specify behavior with predictable results. |
| 127 | |
| 128 | |
| 129 | It seems that some designers continue to ignore this historical pattern |
| 130 | and still dream of creating 'intelligent' or 'smart' machines. It is an |
| 131 | ancient and primitive fantasy, and its seems most new technologies must |
| 132 | pass through this child-like animistic phase. Lewis Mumford identified |
| 133 | this pattern (Technics and Civilization, 1934) when he wrote about the |
| 134 | Obstacle of Animism: 'the most ineffective kind of machine is the |
| 135 | realistic mechanical imitation of a man or another animal...for |
| 136 | thousands of years animism has stood in the way of...development.' |
| 137 | |
| 138 | |
| 139 | An alternate vision |
| 140 | |
| 141 | My point in this essay is not merely to counter a popular design |
| 142 | philosophy, but to offer a new vision that is more in harmony with what |
| 143 | users want. I believe that the future will be filled with powerful, but |
| 144 | predictable and controllable computers that genuinely serve human needs |
| 145 | (Designing the User Interface: Strategies for Effective Human-Computer |
| 146 | Interaction, Second Edition, Addison-Wesley Publ. Co., Reading, MA, 1992). |
| 147 | |
| 148 | In this vision of predictable and controllable (PC) computing, |
| 149 | the promising strategies are rapid, |
| 150 | visual, animated, colorful, high resolution interfaces built on |
| 151 | meaningful control panels, appropriate preference boxes, |
| 152 | user-selectable toolbars, rapid menu selection, easy to create macros, |
| 153 | and comprehensible shortcuts. These enable me to specify rapidly, |
| 154 | accurately, and confidently how I want my email filtered, what documents |
| 155 | I want retrieved and in what order, and how my documents will be |
| 156 | formatted. |
| 157 | |
| 158 | |
| 159 | Our Human-Computer Interaction Laboratory has applied these principles |
| 160 | to information visualization methods that give users X-ray vision to see |
| 161 | through their mountains of data. Treemaps enable users to see (and |
| 162 | hear) 2-3000 nodes of hierarchically structured information by utilizing |
| 163 | every pixel on the display. Each node is represented by a rectangle |
| 164 | whose location preserves the logical tree structure and whose area is |
| 165 | proportional to one of its attributes. Color represents a second |
| 166 | attribute and sound a third (B. Johnson & D. Turo, Improving the |
| 167 | Visualization of Hierarchies with Treemaps: Design Issues and |
| 168 | Experimentation, Proc. IEEE Visualization '92). Treemaps have been |
| 169 | applied to Macintosh directory browsing (Figure 1), in which area could |
| 170 | be set to file size, color to application type, and sound to file age |
| 171 | (our TreeViz application is available from the University of Maryland's |
| 172 | Office of Technology Liaison, (301) 405-4210). When users first try |
| 173 | TreeViz they usually discover duplicate or misplaced files, redundant |
| 174 | and chaotic directories, and many useless files or applications. Other |
| 175 | applications include: stock market portfolio management, sales data, |
| 176 | voting patterns, sports (48 statistics on 459 NBA players, in 27 teams, |
| 177 | in four leagues), etc. |
| 178 | |
| 179 | |
| 180 | Dynamic queries allow rapid adjustment of query parameters and immediate |
| 181 | display of updated result sets. These animations enable users to |
| 182 | develop intuitions, discover patterns, spot trends, find exceptions, and |
| 183 | see anomalies. The Dynamic HomeFinder prototype (Figure 2) allows users |
| 184 | to adjust the cost, number of bedrooms, location, etc. and see points of |
| 185 | light come and go on a map to indicate a matching home. Users execute |
| 186 | up to 100 queries/second (rather than one query per 100 seconds) |
| 187 | producing a revealing animated view of where high or low priced homes |
| 188 | are found, and there are no syntax errors. Clicking on a point of |
| 189 | light brings up a description or image (videotape available, or for |
| 190 | an empirical comparison with a natural language system, see |
| 191 | Williamson, C. and Shneiderman, B., The Dynamic HomeFinder: Evaluating |
| 192 | dynamic queries in a real-estate information exploration system, 1992 |
| 193 | ACM SIGIR Proceedings). |
| 194 | |
| 195 | Dynamic queries are very effective when a visual environment such as a |
| 196 | map, calendar, or schematic diagram are available, but they can be |
| 197 | easily applied with standard text file output (Figure 3). Dynamic |
| 198 | queries exemplify the future of interaction; You don't need to |
| 199 | describe your goals, negotiate with an intelligent agent, and wait for |
| 200 | a response, you Just Do It! Furthermore, dynamically seeing the |
| 201 | results enables you to explore and rapidly reformulate your goals in |
| 202 | an engaging videogame-like manner. |
| 203 | |
| 204 | |
| 205 | Open problems in information visualization include screen organization, |
| 206 | widget design, algorithms for rapid search and display, use of color |
| 207 | and sound, and strategies to accommodate human perceptual skills. |
| 208 | We also see promise in expanding macro makers into the graphical |
| 209 | environment with visual triggers based on controlled replay of |
| 210 | desired actions - the |
| 211 | general idea is Programming in the User Interface (PITUI) to |
| 212 | Do-What-I-Did (DWID). |
| 213 | |
| 214 | |
| 215 | I want to encourage the exploration of new metaphors and visions of how |
| 216 | computers can empower people by presenting information, allowing rapid |
| 217 | selection, supporting personally specified automation, and providing |
| 218 | relevant feedback. Metaphors related to controlling tools or machines |
| 219 | such as driving, steering, flying, directing, conducting, piloting, |
| 220 | or operating seem more generative of effective and acceptable |
| 221 | interfaces, than 'intelligent' machines. |
| 222 | |
| 223 | |
| 224 | A scientific approach to user interface research |
| 225 | |
| 226 | Whether you agree with the design philosophy in this essay, and |
| 227 | especially if you disagree, I hope that you will add to our scientific |
| 228 | knowledge by conducting well-designed empirical studies of learning |
| 229 | time, measuring performance time for appropriate tasks, recording error |
| 230 | rates, evaluating human retention of interface features, and assessing |
| 231 | subjective satisfaction. There's much work to be done to make |
| 232 | computing accessible, effective, and enjoyable. |
| 233 | |
| 234 | |
| 235 | Acknowledgements: This essay was prompted by the discussion between |
| 236 | Mark Weiser and Bill Hefley, stimulated by lively email and personal |
| 237 | discussions with Paul Resnick, Tom Malone, and Christopher Fry at MIT, |
| 238 | and refined by comments from Catherine Plaisant, Rick Chimera, Brian |
| 239 | Johnson, David Turo, Richard Huddleston, and Richard Potter at the |
| 240 | Human-Computer Interaction Lab at Univ. of Maryland. I appreciate Bill |
| 241 | Curtis's support for this vision. Thanks to all. |