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Copyright (C) Te'eni 2000
7/31/2017
1. INTRODUCTION
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Contents
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Human-computer interaction
Method and organizing themes
Scope and structure of the book
Summary and discussion
Bibliography
Synopsis
The introduction describes the scope and the approach taken in this book. It emphasizes the need
to study and practice the design of human-computer interaction in a given context. The context
here is managerial and office work. The designer's goal is to achieve a good fit among the user,
the task and the technology. The presentation uses two organizing themes: a multi-layer
description of human-computer interaction and an analysis of the cognitive and other resources
that are needed for the user activity.
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1.1 Human-computer interaction
This book is about human-computer interaction (HCI) in the context of managerial work.
HCI attempts to understand the process of interactively using computers and to build appropriate
human-computer interfaces. This may seem a very limiting approach to HCI, but it covers the
bulk of the field today and we use it to set the scope of this book. We further limit ourselves to
HCI in the organization, e.g., clerical, managerial, and professional work. This excludes a direct
treatment of exciting areas such as HCI in the cockpit, robotics, battlefield and entertainment.
Yet with all this limited scope, we are still left with a vast body of knowledge.
The interactive use of computers is not new. It has been around for at least two decades,
but it has now become an integral, if not dominant, part of the work life. What is the state of the
art? Are the human-computer interfaces designed well enough to improve work? Improve life?
Can they do better? The small collection of pictures above, besides being rather amusing,
suggests that there is room for improving interface design.
Today, building the human-computer interface consumes 50-70% of development. The
importance of the interface to user acceptance is known. That the interface "makes it or breaks it"
is not a cliché, it is reality for the simple reason that users see the system through the interface.
Users care about what they put in, and more importantly, what they get out of the system. The
special interest group on HCI is the fastest growing group in the Association of Computing,
which itself is the largest association of computing professionals. More journals in the area of
HCI have appeared in the last decade than any other field. Today, there are dedicated journals to
specific topics such as window-based interfaces, multimedia, hardware ergonomics,
psychological aspects of HCI, organizational aspects of HCI, and many more. Advancements in
the technology of human-computer interaction are staggering, speech recognition, touch sensitive
screens, virtual reality devices, devices for the handicapped are just a few of the examples that
are undergoing significant progress. Impressive too is the recent progress in generators of humancomputer interfaces, powerful languages, automated analysis and design of interfaces. And yet all
this activity is not enough to satisfy the ever-growing appetite of the diverse pool of users that
now expects of computers a standard of communication that was never expected of the era before
graphical interfaces. Users are demanding improved interfaces because they know that they can
get them.
But what should we be trying to achieve when we improve the interface? How do we
know that we have or don't have a good HCI design? We will devote a whole chapter to each of
these questions. Ben Shneiderman (1987) reproduced the following standard criteria from the
U.S. Military Standard for Human Engineering Design Criteria:
1. Achieve required performance by operator, control and maintenance personnel.
2. Minimize skill and personnel requirements and training time.
3. Achieve required reliability of person-computer combinations (reliability, availability,
security and data integrity).
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4. Foster design standardization within and among systems (integration, consistency,
portability)
5. Accommodate for human diversity.
To make things even more concrete, here is a common list of measurable goals:
1) Time to learn,
2) Speed of performance,
3) Rate of errors by users,
4) Retention over time,
5) Subjective satisfaction.
Achievement of these goals is no easy task. In fact some goals, such as minimizing the
time to learn and the speed of performance may actually conflict. HCI is aimed at understanding
how the human-computer interface can be designed to further such goals. The following section
talks about how this book is organized to do so.
1.2 Method and organizing themes
This book explains the complex phenomena of HCI by building a view of HCI and then
using it to organize the vast and growing body of pertinent knowledge. For some, HCI is an
interdisciplinary field of applied research. For others, it is a practice of design and
implementation. For many of us it is becoming a productive mixture of both approaches.
Accordingly, the book looks at the basic theories and, going from theory to practice, dives into
representative applications such as the use of graphics and windows. Yet it tries to organize both
theory and application through some common elements, which are the organizing themes
described in this section.
HCI should be designed to achieve a fit between the (human) user, computer and task.
This is our underlying premise. Fit is in reference to task performance. A better fit is expected to
improve performance. Performance can be measured by speed and accuracy of operation,
retention over time, subjective satisfaction and other measures outlined above. Fit, however,
cannot be measured objectively. Fit is sometimes operationalized by some measure of
performance, e.g., the input screen design that leads to the fastest update is said to produce the
best fit. Nevertheless, the concept of fit directs the designer's attention to the process of
matching the HCI design to the user and task. If the order of fields on a screen mathces the order
of receiving information there is a high fit between the design and the task. Even before
measuring performance, the high fit would be considered a superior design. Figure 1.2 shows the
three components that feed into 'fit' and the link between fit and performance.
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Figure 1.2 The fit among HCI components leads to performance.
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Figure 1.3 A Multi-layer model of HCI.
For instance, using color to discriminate among objects on the screen may be generally
effective but counter productive for users who are color blind (17% of the male population). This
is the fit between computer and user. The example can be taken one step further. Red and blue
have traditionally been used to depict arteries and veins in biological text books. In fact, in this
particular context, any other color combination would be confusing. This convention is
considered essential in medical texts. This is the fit between computer, user and task.
Note, however, if the task is to train surgeons rather than teach first year medical students,
the whole concept of symbolic colors may be counter productive. The training task at advanced
stages of practice in the operating room is completely different. The red and blue color symbols
may lead to errors in identification of real blood vessels, which in reality are not painted blue
and red. The design of the HCI must fit the task.
Fit is not achieved only by adapting screens. Users can be trained to achive a better fit.
Training is part of creating effective HCI. Moreover, the task can be redesigned, too. Task
analysis is also part of building effective HCI.
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The notion of fit leads to two themes that organize the presentation in this book: multi
layer models of HCI and the analysis of user activity as a function of human resources (e.g.,
memory and attention). User activity is the user’s interaction with the computer to accomploish a
task. Multi-layer models of user activity (Figure 1.3 shows the one used here) can explain how
the task context affects the physical design by showing the transition from psychological
intentions to physical implementation. The example of using red and blue for learning about
blood vessels can be examined at different levels. On one level, we examine the user's goal of
learning the concept of arteries and veins. On another level, we examine the use of colors to
enhance pattern recognition in memory. These are different levels of understanding behavior that
range from the user's goals to the physical aspects of the resources used to achieve these goals.
The goals provide the context for the use of resources. In other words, the higher level provides
the context for the lower level. Designers must be able to discriminate between these levels but
also integrate across them.
Put more formally, we will examine HCI as a multi-layer activity, i.e., user activity is
conceptually viewed at multiple and distinct levels of interaction. Of the several multi-layer
models that exist, we adopt a model with four levels of interaction: task, semantic, syntactic and
lexical (Foley, et al., 1990). The task level pertains to the information requirements that have to
be met, e.g., open a word processing document. It relates to the user's goals most closely. The
semantic level pertains to the set of objects and operations through which the computer becomes
meaningful to the user, e.g., a document that can be opened or saved. It relates to the user's world
of meaning but also to the computer's logical structure. The syntactic level dictates the rules of
combining the semantic objects and operations into correct instructions. For example, a syntactic
rule is that operations must precede objects in all instructions (e.g., COPY filename) . The
syntactic level directs the user how to manipulate the computer system. The lexical level
describes the way specific computer devices are used to implement the syntactic level, e.g., move
a mouse pointer to the document label and click twice to open it. Figure 1.3 shows the four levels
of interaction, each layer provides the context for the layer below it. The upper layer (the task) is
closest to the user's goals. The lower is closest to the resources - computer and human resources that physically implement these goals. Thus, Figure 1.3 depicts the translation of goals to
physical implementation as an activity at different levels of interaction.
The second theme for organizing the material examines the impact of user characteristics
on HCI. We assume that the need to enhance limited cognitive resources (e.g., memory,
attention, learning capabilities etc.) determines the potential roles of HCI. For example, using
windows can enhance cognitive control, reduce demands on memory, and support shared
attention to concurrent information sources. Using graphics can support memory, facilitate
comprehension and enhance cognitive processing for certain tasks such as trend comparison.
Furthermore, many users consider graphics to be more pleasing than numbers. Pleasing is an
affective function, rather than cognitive, which together with motivation and others will be
discussed in more advanced chapters. Figure 1.4 can be used as a template for defining the
possible roles of any interface technique. The list of resources will be developed later. These
resources tend to inhibit performance when pushed to their limits. In general, therefore,
supporting them should enhance user activity.
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User activity =
Memory
Processing
Cognitive management
Attention
Comprehension
Affect & other
Figure 1.4: Human-computer interface techniques can
support cognitive and affective resources and, thereby, enhance
user activity.
Moreover, both themes, the four layers of HCI and the human resources that determine
the roles of HCI, must be analyzed in context. This book uses the term context at different levels
of abstraction. This is because context consists of multiple layers, like the layers of an onion's
bulb. The outer layer provides the context of the inner layer. Looking at the term context in
relation to a word in a sentence, the word's immediate context is the sentence. The more distant
context is the paragraph and that of the pparagraph is the whole story. Examining HCI requires
an analysis of the immediate context (what the user was doing just before he moved the mouse to
click on a the option 'Save'). It also requires an analysis of the distant context, say of the
particular decision making activity for which the interaction is taking place (e.g., planning the
next budget). The decision making activity itself may need to be understood in the context of a
great time pressure to get the budget out on time. Time pressure may affect the way we act and
therefore the optimal design of the human-computer interface.
The context of HCI in this book is managerial work, obviously a very broad context.
When we get down to building an application, the context must be refined even further. Most of
the examples of HCI will be developed for tasks in a managerial or an office environment.
Learning a wordprocessor in an office at work is not necessarily the same as learning medicine at
college. In business the color red connotes bad news not oxygen.
Not only different situations but different people, too, affect the HCI. Different people
have different styles and preferences (e.g., learning styles, decision styles and verbalizervisualizer orientation). Individual differences can sometimes be accommodated by flexible
systems or individually tailored support. Individual styles will be studied whenever possible to
supplement the more general approach taken in Figure 1.4.
Using the organizing themes in context will prove necessary when we begin to cover the
vast amount of knowledge needed for effective design. We need several sources of knowledge.
One is basic knowledge drawn from the fields of psychology, computer engineering, and the
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relevant domain of the application (i.e. managerial work). The second source is design and
implementation paradigms, which build on the basic knowledge. The multi-layer view of HCI
refers to user goals and their physical implementation. The resources for physical implementation
are human and computer, hence the need for basic knowledge about human capabilities for
information processing and about design possibilities for the computer system. Additionally, the
context for understanding users' goals requires basic knowledge on managerial work and decision
making. However, these three fields are inadequate when treated in isolation. Designers need
methodologies to apply this knowledge in an integrated fashion. They also need heuristics for
thinking about the fit between task, user and components of the human-computer interface
because it is too complex to evaluate all possible design alternatives.
Figure 1.4 is used to organize and apply knowledge of human capabilities and behavior.
For example, if we know that human memory is limited, computerized support should be
designed to reduce the need for memorization. Other human limitations, which should be taken
as opportunities for using technology effectively, include cognitive management, attention, and
comprehension. The upcoming chapters develop this strategy as a sequence of steps that include
defining information processing needs (e.g., memory), using predefined functions that
computerized systems can provide, and matching the appropriate support. Moreover, we will use
this strategy at different levels of interaction. For instance, Chapters 3,4 apply this strategy to
information processing generally and Chapter 5 reapplies it specifically to information processing
in the context of managerial work.
1.3 Scope and structure of the book
The book has three parts: foundations, applications, and beyond. Foundations include
basic knowledge and development paradigms. Chapter 2 surveys specific interactive technologies
such as audio and visual input-output devices, with a section on advanced technologies (virtual
reality etc.). Chapter 3 describes basic knowledge on human information processing within a
simplified model of the cognitive system. Human information processing is described in terms of
memory and processors that accept input from external representations and generate output (see
Figure 1.5). The simplified model provides the designer with a framework for organizing the
knowledge and understanding its implications on design., such as what are the performance
implications of limited short-term memory on interface design?
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Figure 1.5 Human computer interaction as the interface between the
human information processing system and an external representation on
a computer.
The simplified human-information processing system is the basis for Chapter 4, which is
devoted to design methodologies that bridge the gap between the user's cognitive system and the
computerized system. Chapter 4 develops Figures 1.3 and 1.4 into models used in cognitive
engineering. Chapter 5 brings in the context of managerial work by explaining how to understand
support systems for managerial work and decision making.
Chapters 6,7 and 8 expand our knowledge of the user by going beyond the cognitive
paradigm to physiological and affective aspects of design and broadening the discussion to
include learning. Chapter 6 talks about traditional ergonomics, which is concerned with the
design implications of physiological aspects of the human body, e.g., physical stress. Chapter 7
discusses affective issues such as motivation and satisfaction, their implication on the usability of
computerized systems, and their measurement. Finally, Chapter 8 is devoted to issues of learning
and training, issues that are becoming the hallmark of modern organizations. Learning is needed
to achieve fit through change in the user.
The second part of the book deals with applications of basic knowledge and design
methodologies to specific interface techniques such as graphics or windows. The intent is not to
provide a comprehensive list of design guidelines but to demonstrate how the foundations are
applied to representative technologies of interaction. Accordingly all the discussions draw on the
views presented in Figures 1.2, 1.3 and 1.4. Chapter 9 deals with general design guidelines and
the more abstract issues of control, consistency, and the use of metaphors. Chapters 10 to 15 deal
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with several components of the interface such as graphics and color, icons, windows, screen
layout, and multimedia.
The last part of the book is designed to provoke thought beyond the framework discussed
above. It is devoted primarily to organizational and social aspects of HCI. Chapter 16 shows how
organizational issues expand the scope of design. It demonstrates some of these issues in the
design of systems for cooperative work. Chapter 17 takes a more general view and talks about
social impacts of computerization and ethics as dimensions of designing HCI.
A few words about what this book does not do. This book does not provide a list of
exhaustive guidelines on how to design the human-computer interface. Several books provide
such lists and they are listed in the bibliography. The book does describe in detail several HCI
techniques, but this is to demonstrate how to apply the conceptual foundations to practical
applications rather than provide a recipe. Furthermore, the book is concentrates on with design
issues and pays less attention to issues of implementation. Programming issues and User
Interface Management Systems (UIMS) are discussed briefly. The necessary technical knowledge
required to build the recommended design is limited to an Appendix describing elementary
Visual Basic operations and reference to these operations is mentioned occasionally for
demonstration purposes. Usability issues constitute an important part of the book but the
management aspects of development, such as usability centers, are not discussed. Each chapter
provides popular references and advanced readings on topics covered and those relevant but
omitted for lack of space.
The material on HCI is vast and this book does not presume to cover the field or even
mention every hardware device, system or design technique known. When the list of items in any
one context became overwhelming, those that are more relevant, currently or potentially, to
managerial work were chosen. This is not to say that this book is about management support
systems, but it can certainly be regarded as an essential component of any such system.
Furthermore, there is no treatment here of systems analysis, we deal only with design on the basis
of a given set of information requirements. However, the discussion of human limitations in
managerial work (Chapter 5) comes close to a methodology for task analysis.
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Figure 1.6 Human computer interaction is an interdisciplinary field. The fields
listed here have important roles to play in the theory and application. Adapted
from Booth (1989), p. 7.
Another bias in this presentation is the psychological and human-factors approach versus
the many others that exist. Much of this bias is due to the strong influence of behavioral decision
making and organizational behavior bodies of managerial knowledge. These sources are
invaluable for task analysis and tie in nicely with psychological, particularly cognitive, aspects of
HCI. Paul Booth (1989) sketches the various disciplines that play a role in HCI research. An
overall view is presented in Figure 1.5. This figure strongly supports our earlier observation that
HCI is an interdisciplinary field and that a bias towards any one approach, e.g., psychology, is
clearly limiting. For instance, currently there is a strong trend in the HCI field to balance the
contribution of sociology with psychology. Researchers, especially, should find these
contributing disciplines of value to their work. Practitioners too should consider in more depth
those fields that have special relevance to their practice. For example, organizational psychology
may be of greater importance to systems in turbulent organizations.
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1.4 Summary and discussion
The introductory chapter presented a view of HCI that will help organize the material in
later chapters. Figures 1.2, 1.3 and 1.4 depict this view concisely. The notion of levels of
interaction, the task, semantic, syntactic and lexical levels, is a powerful concept that will appear
in nearly every chapter of this book. It is very widely acceptable and yet has not gone without
criticism. In particular, its implicit assumption of a rational and goal oriented user has been
challenged (see for example DeSanctis and Poole, 1993). Like other issues mentioned above,
this limitation is acknowledged. Interested researchers will need to pursue the given references to
lead them on their own individual investigative paths. This is true for other issues that will be
mentioned and referenced but not developed in the short space available.
Below is a list of concepts covered in this chapter. These concepts will be used and
developed further in later chapters. The bibliography includes a list of other texts on HCI. It also
includes advanced readings on specific topics.
Concepts in chapter 1
Human-computer interaction (HCI)
Context of HCI
Managerial work
Human engineering design criteria:
User activity
User resources
Fit
Multi-layer activity:
learning time, performance time, error rate,
retention ofver time, subjective satisfaction
task level, semantic level, syntactic level, lexical
level
1.5 Bibliography
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Texts on human-computer interaction
Booth P A (1989) An introduction to Human-Computer Interaction, Lawrence Erlbaum Assoc.,
Hove & London, UK
Galitz W O (1993) User-Interface screen design, QED Publishing Group, Boston.
Shneiderman B (1992) Designing the User Interface: Strategies for Effective Human-Computer
Interaction, Addison-Wesley, Reading.
Advanced readings
DeSanctis G and Poole M. S. (1993) Capturing the complexity in advanced technology use:
Adaptive structuration theory. Organization Science, 4, 1-36.