SCEA Ex. 1043 Page 1
`
`

`
`Many of the designations used by manufacturers and sellers to distinguish their
`products are claimed as trademarks. Where those designations appear in this
`book, and Addison-Wesley was aware of a trademark claim, the designations
`have been printed in initial caps or all caps.
`
`Library of Congress Cataloging-in-Publication Data
`Shneiderman, Ben.
`Designing the user interface : strategies for effective human
`-computer-interaction I Ben Shneiderman. -- 3rd ed.
`p.
`em.
`Includes bibliographical references and index.
`ISBN 0-201-69497-2
`1. Human-computer interaction.
`I. Title.
`systems)
`QA76.9.H85S54 1998
`004' .01 '9-dc21
`
`2. User interfaces (Computer
`
`96-37974
`CIP
`
`Access the latest information about Addison-Wesley titles from our World Wide
`Web site: http:/ /www.awl.com/cseng
`
`Chapter opener illustrations from art provided by Mark Kostabi. Reproduced
`with permission.
`
`Cover art © Boris Lyubner / SIS
`
`Copyright© 1998 by Addison Wesley Longman, Inc.
`
`Reprinted with corrections, March 1998.
`
`All rights reserved. No part of this publication may be reproduced, stored in a
`retrieval system, or transmitted, in any form or by any means, electronic,
`mechanical, photocopying, recording, or otherwise, without the prior written
`permission of the publisher. Printed in the United States of America.
`
`13-MA-02
`
`Prefac
`
`Designing th
`and evaluate
`ing, implem
`interface of i
`human-<:om
`human perf,
`background
`science, bus.
`neering; all
`with machii
`this book. I
`
`set aside
`the World
`and then
`mg point
`Tbewurk
`
`my~isiot
`
`SCEA Ex. 1043 Page 2
`
`

`
`Contents
`
`CHAPTER 1 HUMAN FACTORS OF INTERACTIVE SOFTWARE 3
`1.1
`Introduction 4
`1.2 Goals of System Engineering 9
`1.2.1 Proper functionality 11
`1.2.2 Reliability, availability, security, and data integrity 12
`1.2.3 Standardization, integration, consistency, and portability 13
`1.2.4 Schedules and budgets 14
`1.3 Goals of User-Interface Design 14
`1.4 Motivations for Human Factors in Design 16
`1.4.1 Life-critical systems 16
`Industrial and commercial uses 16
`1.4.2
`1.4.3 Office, home, and entertainment applications 17
`1.4.4 Exploratory, creative, and cooperative systems 17
`1.5 Accommodation of Human Diversity 18
`1.5.1 Physical abilities and physical workplaces 18
`1.5.2 Cognitive and perceptual abilities 20
`1.5.3 Personality differences 21
`1.5.4 Cultural and international diversity 23
`1.5.5 Users with disabilities 24
`1.5.6 Elderly users 26
`1.6 Goals for Our Profession 28
`Influencing academic and industrial researchers 28
`1.6.1
`1.6.2 Providing tools, techniques, and knowledge for systems
`implementers 31
`1.6.3 Raising the computer consciousness of the general public 31
`1.7 Practitioner's Summary 32
`1.8 Researcher's Agenda 32
`
`CHAPTER 2 THEORIES, PRINCIPLES, AND GUIDELINES 51
`2.1
`Introduction 52
`2.2 High-Level Theories 53
`2.2.1 Conceptual, semantic, syntactic, and lexical model 54
`2.2.2 GOMS and the keystroke-level model 55
`2.2.3 Stages of action models 57
`2.2.4 Consistency through grammars 58
`2.2.5 Widget-level theories 60
`2.3 Object-Action Interface Model 61
`2.3.1 Task hierarchies of objects and actions 63
`
`SCEA Ex. 1043 Page 3
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`

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`viii
`
`Contents
`
`Interface hierarchies of objects and actions 64
`2.3.2
`2.3.3 The disappearance of syntax 65
`2.4 Principle 1: Recognize the Diversity 67
`2.4.1 Usage profiles 67
`2.4.2 Task profiles 70
`2.4.3
`Interaction styles 71
`2.5 Principle 2: Use the Eight Golden Rules of Interface Design 74
`2.6 Principle 3: Prevent Errors 76
`2.6.1 Correct matching pairs 77
`2.6.2 Complete sequences 77
`2.6.3 Correct commands 78
`2.7 Guidelines for Data Display 79
`2.7.1 Organizing the display 80
`2.7.2 Getting the user's attention 81
`2.8 Guidelines for Data Entry 82
`2.9 Balance of Automation and Human Control 83
`2.10 Practitioner's Summary 89
`2.11 Researcher's Agenda 90
`
`CHAPTER 3 MANAGING DESIGN PROCESSES 95
`3.1
`Introduction 96
`3.2 Organizational Design to Support Usability 97
`3.3 The Three Pillars of Design 100
`3.3.1 Guidelines documents and processes 100
`3.3.2 User-interface software tools 102
`3.3.3 Expert reviews and usability testing 103
`3.4 Development Methodologies 104
`3.5 Ethnographic Observation 107
`3.6 Participatory Design 109
`3.7 Scenario Development 111
`3.8 Social Impact Statement for Early Design Review 113
`3.9 Legallssues 115
`3.10 Practitioner's Summary 118
`3.11 Researcher's Agenda 118
`
`CHAYfER 4 EXPERT REVIEWS, USABILITY TESTING, SURVEYS, AND
`CONTINUING ASSESSMENTS 123
`Introduction 124
`4.1
`4.2 Expert Reviews 125
`4.3 Usability Testing and Laboratories 127
`4.4 Surveys 132
`
`4.5
`4.6
`
`J
`I
`4.1
`4.1
`4.c
`4.1
`4.1
`4.1
`(
`4.7
`4.8 F
`4.9
`};
`
`CHAPT
`II
`5.1
`5.2 s
`5.2
`5.2
`5.2
`5.2
`5.2
`II
`5.3
`5.3
`5.4 E
`5.5
`5.6 Ri
`
`5.3
`
`In
`6.1
`6.2 EJ
`6.2
`
`6.2
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`SCEA Ex. 1043 Page 4
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`

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`n 74
`
`JRVEYS, AND
`
`Contents
`
`ix
`
`4.5 Acceptance Tests 135
`4.6 Evaluation During Active Use 145
`Interviews and focus-group discussions 145
`4.6.1
`4.6.2 Continuous user-performance data logging 146
`4.6.3 Online or telephone consultants 147
`4.6.4 Online suggestion box or trouble reporting 147
`4.6.5 Online bulletin board or newsgroup 148
`4.6.6 User newsletters and conferences 148
`4.7 Controlled Psychologically Oriented Experiments 149
`4.8 Practitioner's Summary 150
`4.9 Researcher's Agenda 151
`
`CHAPTER 5 SOFIWARE TOOLS 155
`5.1
`Introduction 156
`5.2 Specification Methods 157
`5.2.1 Grammars 158
`5.2.2 Menu-selection and dialog-box trees 160
`5.2.3 Transition diagrams 160
`5.2.4 Statecharts 162
`5.2.5 User-action notation (UAN) 163
`5.3 Interface-Building Tools 166
`5.3.1 Design tools 168
`5.3.2 Software-engineering tools 169
`5.4 Evaluation and Critiquing Tools 177
`5.5 Practitioner's Summary 179
`5.6 Researcher's Agenda 181
`
`CHAPTER 6 DIRECT MANIPULATION AND VIRTUAL
`ENVIRONMENTS 185
`Introduction 186
`6.1
`6.2 Examples of Direct-Manipulation Systems 187
`6.2.1 Command-line versus display editors versus word
`processors 187
`6.2.2 The VisiCalc spreadsheet and its descendants 191
`6.2.3 Spatial data management 192
`6.2.4 Video games 193
`6.2.5 Computer-aided design 197
`6.2.6 Office automation 199
`6.2.7 Further examples of direct manipulation 201
`6.3 Explanations of Direct Manipulation 202
`
`SCEA Ex. 1043 Page 5
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`

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`x
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`Contents
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`6.3.1 Problems with direct manipulation 204
`6.3.2 The OAI model explanation of direct manipulation 205
`6.4 Visual Thinking and Icons 207
`6.5 Direct-Manipulation Programming 210
`6.6 Home Automation 213
`6.7 Remote Direct Manipulation 217
`6.8 Virtual Environments 221
`6.9 Practitioner's Summary 228
`6.10 Researcher's Agenda 229
`
`CHAPTER 7 MENU SELECTION, FORM FILLIN, AND
`DIALOG BOXES 235
`Introduction 236
`7.1
`7.2 Task-Related Organization 237
`7.2.1 Single menus 238
`7.2.2 Linear sequences and multiple menus 247
`7.2.3 Tree-structured menus 247
`7.2.4 Acyclic and cyclic m~nu networks 252
`Item Presentation Sequence 252
`7.3
`7.4 Response Time and Display Rate 254
`7.5 Fast Movement Through Menus 255
`7.5.1 Menus with typeahead: The BLT approach 255
`7.5.2 Menu names or bookmarks for direct access 256
`7.5.3 Menu macros, custom toolbars, and style sheets 257
`7.6 Menu Layout 257
`7.6.1 Titles 257
`7.6.2 Phrasing of menu items 259
`7.6.3 Graphic layout and design 259
`7.7 Form Fillin 262
`7.7.1 Form-fillin design guidelines 262
`7.7.2 List and combo boxes 265
`7.7.3 Coded fields 266
`7.8 Dialog Boxes 268
`7.9 Practitioner's Summary 270
`7.10 Researcher's Agenda 270
`
`CHAPTER 8 COMMAND AND NATURAL LANGUAGES 275
`Introduction 276
`8.1
`8.2 Functionality to Support Users' Tasks 280
`
`8.3 C01
`8.3.1
`8.3.2
`8.3.3
`8.3.4
`8.4 ThE
`8.4.1
`8.4.2
`8.4.3
`8.5 NaJ
`8.5.1
`8.5.2
`8.5.3
`8.6 Cor
`8.7 Nat
`8.7.1
`8.7.2
`8.7.3
`8.7.4
`8.7.5
`8.8 Pra1
`8.9 Res.
`
`CHAPTER
`Inm
`9.1
`9.2 Key
`9.2.1
`9.2.2
`9.2.3
`9.2.4
`9.3 Poir
`9.3.1
`9.3.2
`9.3.3
`9.3.4
`9.3.5
`9.3.6
`9.4 Spet
`9.4.1
`9.4.2
`9.4.3
`
`SCEA Ex. 1043 Page 6
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`

`
`l 205
`
`'.57
`
`275
`
`Contents
`
`xi
`
`8.3 Command-Organization Strategies 282
`8.3.1 Single command set 282
`8.3.2 Command plus arguments 282
`8.3.3 Command plus options and arguments 284
`8.3.4 Hierarchical command structure 285
`8.4 The Benefits of Structure 285
`8.4.1 Consistent argument ordering 286
`8.4.2 Symbols versus keywords 286
`8.4.3 Hierarchical structure and congruence 287
`8.5 Naming and Abbreviations 289
`8.5.1 Specificity versus generality 289
`8.5.2 Abbreviation strategies 290
`8.5.3 Guidelines for using abbreviations 291
`8.6 Command Menus 292
`8.7 Natural Language in Computing 293
`8.7.1 Natural-language interaction 294
`8.7.2 Natural-language queries 296
`8.7.3 Test-database searching 297
`8.7.4 Natural-language text generation 300
`8.7.5 Adventure and educational games 300
`8.8 Practitioner's Summary 300
`8.9 Researcher's Agenda 301
`
`INTERACTION DEVICES 305
`CHAPTER 9
`9.1
`Introduction 306
`9.2 Keyboards and Function Keys 307
`9.2.1 Keyboard layouts 308
`9 .2.2 Keys 311
`9.2.3 Function keys 312
`9.2.4 Cursor movement keys 313
`9.3 Pointing Devices 315
`9.3.1 Pointing tasks 315
`9.3.2 Direct-control pointing devices 316
`9.3.3
`Indirect-control pointing devices 319
`9.3.4 Comparisons of pointing devices 323
`9.3.5 Fitts' Law 325
`9.3.6 Novel pointing devices 326
`9.4 Speech Recognition, Digitization, and Generation 327
`9.4.1 Discrete-word recognition 328
`9.4.2 Continuous-speech recognition 331
`9.4.3 Speech store and forward 332
`
`SCEA Ex. 1043 Page 7
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`

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`11
`11
`
`CJ
`
`1
`
`1
`1
`
`(
`1
`1
`
`J
`]
`
`xii
`
`Contents
`
`9.5
`
`9.4.4 Speech generation 333
`9.4.5 Audio tones, audiolization, and music 335
`Image and Video Displays 336
`9.5.1 Display devices 336
`9.5.2 Digital photography and scanners 339
`9.5.3 Digital video 339
`9.5.4 Projectors, heads-up displays, helmet-mounted displays 341
`9.6 Printers 342
`9.7 Practitioner's Summary 343
`9.8 Researcher's Agenda 344
`
`CHAPTER 10 RESPONSE TIME AND DISPLAY RATE 351
`10.1
`Introduction 352
`10.2 Theoretical Foundations 354
`10.2.1 Limitations of short-term and working memory 355
`10.2.2 Sources of errors 356
`10.3 Expectations and Attitudes 358
`10.4 User Productivity 361
`10.4.1 Repetitive tasks 361
`10.4.2 Problem-solving tasks 362
`10.4.3 Summary 364
`10.5 Variability 364
`10.6 Practitioner's Summary 366
`10.7 Researcher's Agenda 367
`
`CHAPTER 11 PRESENTATION STYLES: BALANCING FUNCTION
`AND FASHION 371
`Introduction 372
`11.1
`11.2 Error Messages 373
`11.2.1 Specificity 374
`11.2.2 Constructive guidance and positive tone 375
`11.2.3 User-centered phrasing 376
`11.2.4 Appropriate physical format 376
`11.2.5 Development of effective messages 377
`11.3 Nonanthropomorphic Design 380
`11.4 Display Design 384
`11.4.1 Field layout 387
`11.4.2 Empirical results 389
`11.4.3 Display-complexity metrics 391
`11.5 Color 398
`
`SCEA Ex. 1043 Page 8
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`

`
`ys 341
`
`5
`
`TION
`
`Contents
`
`xiii
`
`11.6 Practitioner's Summary 403
`11.7 Researcher's Agenda 403
`
`CHAPTER U PRINTED MANUALS, ONLINE HELP, AND
`TUTORIALS 409
`Introduction 410
`12.1
`12.2 Reading from Paper versus from Displays 412
`12.3 Preparation of Printed Manuals 414
`12.3.1 Use of the OAI Model to design manuals 415
`12.3.2 Organization and writing style 417
`12.3.3 Nonanthropomorphic descriptions 421
`12.3.4 Development process 423
`12.4 Preparation of Online Facilities 425
`12.4.1 Online manuals 428
`12.4.2 Online tutorials, demonstrations, and animations 434
`12.4.3 Helpful guides 436
`12.5 Practitioner's Summary 437
`12.6 Researcher's Agenda 438
`
`CHAPTER 13 MULTIPLE-WINDOW STRATEGIES 443
`Introduction 444
`13.1
`Individual-Window Design 448
`13.2
`13.3 Multiple-Window Design 455
`13.4 Coordination by Tightly-Coupled Windows 458
`Image Browsing and Tightly-Coupled Windows 462
`13.5
`13.6 Personal Role Management and Elastic Windows 468
`13.7 Practitioner's Summary 472
`13.8 Researcher's Agenda 472
`
`CHAPTER 14 COMPUTER-SUPPORTED COOPERATIVE WORK 477
`Introduction 478
`14.1
`14.2 Goals of Cooperation 479
`14.3 Asynchronous Interactions: Different Time, Different Place 482
`14.3.1 Electronic Mail 483
`14.3.2 Newsgroups and network communities 485
`14.4 Synchronous Distributed: Different Place, Same Time 488
`14.5 Face to Face: Same Place, Same Time 494
`14.6 Applying CSCW to Education 498
`14.7 Practitioner's Summary 502
`14.8 Researcher's Agenda 503
`
`SCEA Ex. 1043 Page 9
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`

`
`xiv
`
`Contents
`
`INFORMATION SEARCH AND VISUALIZATION 509
`CHAPTER 15
`15.1
`Introduction 510
`15.2 Database Query and Phrase Search in Textual Documents 513
`15.3 Multimedia Document Searches 519
`15.4
`Information Visualization 522
`15.5 Advanced Filtering 541
`15.6 Practitioner's Summary 544
`15.7 Researcher's Agenda 544
`
`CHAPTER 16 HYPERMEDIA AND THE WORLD WIDE WEB 551
`16.1
`Introduction 552
`16.2 Hypertext and Hypermedia 556
`16.3 World Wide Web 560
`16.4 Genres and Goals and Designers 562
`16.5 Users and Their Tasks 565
`16.6 Object-Action Interface Model for Web Site Design 567
`16.6.1 Design of task objects and actions 567
`16.6.2 Design of interface objects and actions 569
`16.6.3 Case study with the Library of Congress 571
`16.6.4 Detailed design issues 572
`16.6.5 Web-Page design 575
`16.6.6 Testing and maintenance of web sites 579
`16.7 Practitioner's Summary 580
`16.8 Researcher's Agenda 580
`
`AFTERWORD SOCIETAL AND INDIVIDUAL IMPACT OF
`USER INTERFACES 585
`A.1 Between Hope and Fear 586
`A.2 Ten Plagues of the Information Age 592
`A.3 Prevention of the Plagues 596
`A.4 Overcoming the Obstacle of Animism 597
`A.5
`In the Long Run 600
`A.6 Practitioner's Summary 601
`A.7 Researcher's Agenda 601
`
`Name Index 605
`
`Subject Index 621
`
`De
`us
`
`Str
`Hu
`Int
`Thi
`
`SCEA Ex. 1043 Page 10
`
`

`
`1.2 Goals of System Engineering
`
`13
`
`experience with misleading data or unexpected results will undermine for a
`long time a person's willingness to use a system. The software architecture,
`hardware components, and network support must ensure high availability.
`U the system is not available or introduces errors, then it does not matter
`how well the human interface is designed. Designers also must pay atten(cid:173)
`tion to ensuring privacy, security, and data integrity. Protection must be pro(cid:173)
`vided from unauthorized access, inadvertent destruction of data, or
`malicious tampering.
`
`1.2.3 Standardization, integration, consistency, and portability
`
`As the number of users and software packages increases, the pressures for
`and benefits of standardization grow. Slight differences among systems not
`only increase learning times, but also can lead to annoying and dangerous
`errors. Gross differences among systems require substantial retraining and
`burden users in many ways. Incompatible storage formats, hardware, and
`software versions cause frustration, inefficiency, and delay. Designers must
`decide whether the improvements they offer are useful enough to offset the
`disruption to the users.
`Standardization refers to common user-interface features across multiple
`applications. Apple Computers (1987) successfully developed an early stan(cid:173)
`dard that was widely applied by thousands of developers, enabling users to
`learn multiple applications quickly. IBM's Common User Access (1989, 1991,
`1993) specifications came later; and when the Microsoft Windows (1995)
`interface became standardized, it became a powerful force.
`Integration across application packages and software tools was one of the
`key design principles in Unix. (Portability across hardware platforms was
`another.) The command language was standard from the beginning (with
`some divergences), but there are now competing graphical user interfaces
`(GUls), many built around the X and Motif standards.
`Consistency primarily refers to common action sequences, terms, units,
`layouts, color, typography, and so on within an application program. Consis(cid:173)
`tency is a strong determinant of success of systems. It is naturally extended
`to include compatibility across application programs and compatibility with
`paper or non-computer-based systems. Compatibility across versions is a
`troubling demand, since the desire to accommodate novel functionality or
`improved designs competes with the benefits of consistency.
`Portability refers to the potential to convert data and to share user interfaces
`across multiple software and hardware environments. Arranging for portabil(cid:173)
`ity is a challenge for designers who must contend with different display sizes
`and resolutions, color capabilities, pointing devices, data formats, and so on.
`Some user-interface building tools help by generating code for Macintosh,
`Wmdows, OS/ 2, Unix, and other environments so that the interfaces are simi(cid:173)
`lar in each environment or resemble the style in those environments. Standard
`
`>hack, Tandy
`:k with a one(cid:173)
`word, number,
`
`:iifficul t to dis(cid:173)
`e functionality
`e functionality
`ce is designed.
`s probably the
`nd complexity
`'e diffi cui t.
`
`)mmands must
`;e contents, and
`; is fragile; one
`
`SCEA Ex. 1043 Page 11
`
`

`
`74
`
`2 Theories, Principles, and Guidelines
`
`developers, in spite of limited success thus far. Natural-language interaction
`usually provides little context for issuing the next command, frequently
`requires clarification dialog, and may be slower and more cumbersome than the
`alternatives. Still, where users are knowledgeable about a task domain whose
`scope is limited and where intermittent use inhibits command-language train(cid:173)
`ing, there exist opportunities for natural-language interfaces (discussed at the
`end of Chapter 8).
`Blending several interaction styles may be appropriate when the required
`tasks and users are diverse. Commands can lead the user to a form fillin where
`data entry is required, or menus can be used to control a direct-manipulation
`environment when a suitable visualization of actions cannot be found.
`
`2.5 Principle 2: Use the Eight Golden Rules of
`Interface Design
`
`Later chapters cover constructive guidance for design of direct manipula(cid:173)
`tion, menu selection, comtnand languages, and so on. This section presents
`underlying principles of design that are applicable in most interactive sys(cid:173)
`tems. These underlying principles of interface design, derived heuristically
`from experience, should be validated and refined.
`
`1. Strive for consistency. This rule is the most frequently violated one, but fol(cid:173)
`lowing it can be tricky because there are many forms of consistency. Consis(cid:173)
`tent sequences of actions should be required in similar situations; identical
`terminology should be used in prompts, menus, and help screens; and con(cid:173)
`sistent color, layout, capitalization, fonts, and so on should be employed
`throughout. Exceptions, such as no echoing of passwords or confirmation of
`the delete command, should be comprehensible and limited in number.
`2. Enable frequent users to use shortcuts. As the frequency of use increases, so
`do the user's desires to reduce the number of interactions and to increase
`the pace of interaction. Abbreviations, special keys, hidden commands,
`and macro facilities are appreciated by frequent knowledgeable users.
`Short response times and fast display rates are other attractions for fre(cid:173)
`quent users.
`3. Offer informative feedback. For every user action, there should be system
`feedback. For frequent and minor actions, the response can be modest,
`whereas for infrequent and major actions, the response should be more
`substantial. Visual presentation of the objects of interest provides a con-
`
`VI
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`SCEA Ex. 1043 Page 12
`
`

`
`tge interaction
`1d, frequently
`'SOme ilian the
`iomain whose
`mguage train(cid:173)
`scussed at ilie
`
`:1 ilie required
`m fillin where
`manipulation
`found.
`
`'Ct manipula(cid:173)
`tion presents
`teractive sys-
`heuristically
`
`one, but fol(cid:173)
`:ency. Consis(cid:173)
`ons; identical
`ens; and con(cid:173)
`be employed
`nfirmation of
`number.
`increases, so
`d to increase
`commands,
`;eable users.
`tions for fre-
`
`d be system
`1 be modest,
`uld be more
`vides a con-
`
`2.5 Principle 2: Use the Eight Golden Rules of Interface Design
`
`75
`
`venient environment for showing changes explicitly (see discussion of
`direct manipulation in Chapter 6).
`4. Design dialogs to yield closure. Sequences of actions should be organized
`into groups wiili a begirming, middle, and end. The informative feedback
`at the completion of a group of actions gives operators the satisfaction of
`accomplishment, a sense of relief, ilie signal to drop contingency plans
`and options from their minds, and an indication that ilie way is clear to
`prepare for the next group of actions.
`5. Offer error prevention and simple error handling. As much as possible, design
`ilie system such that users cannot make a serious error; for example, prefer
`menu selection to form fi1lin and do not allow alphabetic characters in
`numeric entry fields. If users make an error, ilie system should detect ilie
`error and offer simple, constructive, and specific instructions for recovery.
`For example, users should not have to retype an entire command, but
`railier should need to repair only ilie faulty part. Erroneous actions should
`leave the system state unchanged, or ilie system should give instructions
`about restoring ilie state.
`6. Permit easy reversal of actions. As much as possible, actions should be
`reversible. This feature relieves anxiety, since the user knows that errors
`can be undone, ilius encouraging exploration of unfamiliar options. The
`units of reversibility may be a single action, a data-entry task, or a com(cid:173)
`plete group of actions such as entry of a name and address block.
`7. Support internal locus of control. Experienced operators strongly desire ilie
`sense iliat they are in charge of the system and that the system responds to
`their actions. Surprising system actions, tedious sequences of data entries,
`inability or difficulty in obtaining necessary information, and inability to
`produce the action desired all build anxiety and dissatisfaction. Gaines
`(1981) captured part of this principle with his rule avoid acausality and his
`encouragement to make users ilie initiators of actions railier than the respon(cid:173)
`ders to actions.
`8. Reduce short-term memory load. The limitation of human information pro(cid:173)
`cessing in short-term memory (the rule of thumb is that humans can
`remember "seven-plus or minus-two churtks" of information) requires
`iliat displays be kept simple, multiple page displays be consolidated,
`window-motion frequency be reduced, and sufficient training time be
`allotted for codes, mnemonics, and sequences of actions. Where appro(cid:173)
`priate, online access to command-syntax forms, abbreviations, codes, and
`other information should be provided.
`
`These underlying principles must be interpreted, refined, and extended
`for each environment. The principles presented in the ensuing sections
`
`SCEA Ex. 1043 Page 13
`
`

`
`~esigning t~e ~ser Interface
`StrategiesJor lJjfective Human-Computer Interaction
`Third Edition
`Ben Shneiderman, University qf Maryland
`
`In revising this popular book, Ben Shneiderman again provides a complete, current, and
`authoritative introduction to user-interface design. The user interface is the part of every
`computer system that determines how people control and operate that system. When the
`interface is well designed, it is comprehensible, predictable, and controllable; users feel com(cid:173)
`petent, satisfied, and responsible for their actions. Shneiderman discusses the principles and
`practices needed to design such effective interaction.
`
`Based on 20 years experience, Shneiderman offers readers practical techniques and guide(cid:173)
`lines for interface design. He also takes great care to discuss underlying issues and to sup(cid:173)
`port conclusions with empirical resul~. Interface designers, software engineers, and product
`managers will fmd this book an invaluable resource for creating systems that facilitate rapid
`learning and performance, yield low error rates, and generate high user satisfaction.
`
`Coverage includes the human factors of interactive software (with a new discussion of diverse
`user communities), tested methods to develop and assess interfaces, interaction styles such
`as direct manipulation for graphical user interfaces, and design considerations such as effec(cid:173)
`tive messages, consistent screen design, and appropriate color.
`Hl!;!Ui!;l'l.., -· ~.ue T n.rd LJh.luu:
`
`• New chapters on the World Wide Web, information visualization, and
`computer-supported cooperative work
`
`• Expanded and earlier coverage of development methodologies,
`evaluation techniques, and user-interface-building tools
`
`• Thought-provoking discussion of speech input-output, natural-language
`interaction, anthropomorphic design, virtual environments, and agents
`
`• An associated Web site that provides additional illustrations and examples,
`updates, and links to useful resources: http://www.aw.com /DTUI
`Ben Shneiderman is a professor of computer science at the University of Maryland, where
`he heads the Human-Computer Interaction Laboratory. A pioneer in user-interface design, he
`is known throughout the world for his research and writing. You can learn more about him,
`and about this 6ook, from the DTUI Web site.
`
`!Iiiii I~ IH II I '
`
`XOOOOIII' lHO
`Deaienine the Uae,. Jnterf'ece
`Uaed • Very Good ; ahip •o &N:Al
`
`SCEA Ex. 1043 Page 14