GOALS & EVOLUTION OF HUMAN COMPUTER INTERACTION

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Human Computer Interaction (CS408)

Lecture

Lecture 4. Goals & Evolution of Human

Computer Interaction

Learning Goals

As the aim of this lecture is to introduce you the study of Human Computer

Interaction, so that after studying this you will be able to:

Describe the goals of HCI

Define Usability goals

Define User Experience goals

Discuss the History and Evolution of HCI

Definition of HCI

"Human-Computer Interaction is a discipline concerned with the design, evaluation

and implementation of interactive computing systems for human use and with the

study of major phenomena surrounding them"

-ACM/IEEE

4.1 Goals of HCI

The term Human Computer Interaction (HCI) was adopted in the mid-1980s as a

means of describing this new field of study. This term acknowledged that the focus of

interest was broader than just the design of the interface and was concerned with all

those aspects that relate to the interaction between users and computers.

The goals of HCI are to produce usable and safe systems, as well as functional

systems. These goals can be summarized as `to develop or improve the safety, utility,

effectiveness, efficiency and usability of systems that include computers' (Interacting

with computers, 1989). In this context the term `system' derives from systems theory

and it refers not just to the hardware and software but to the entire environment---be it

organization of people at work at, home or engaged in leisure pursuits---that uses or is

affected by the computer technology in question. Utility refers to the functionality of a

system or, in other words, the things it can do. Improving effectiveness and efficiency

are self-evident and ubiquitous objectives. The promotion of safety in relation to

computer systems is of paramount importance in the design of safety-critical systems.

Usability, a key concept in HCI, is concerned with making systems easy to learn and

easy to use. Poorly designed computer system can be extremely annoying to users, as

you can understand from above described incidents. [2]

Part of the process of understanding user's needs, with respect to designing an

interactive system to support them, is to be clear about your primary objective. Is it to

design a very efficient system that will allow users to be highly productive to their

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work, or is to design a system that will be challenging and motivating so that it

supports effective learning, or is it some thing else? We call these talk-level concerns

usability goals and user experience goals. The two differ in terms of how they are

operational zed, i.e., how they can be met and through what means. Usability goals

are concerned with meeting specific usability criteria (e.g., efficiency) and user

experience goals are largely concern with explicating the quality of the user

experience (e.g., to be aesthetically pleasing).

Usability goals

To recap, usability in generally regarded as ensuring that interactive products are easy

to learn, effective to use, and enjoyable from user perspective.

It involves optimizing the interactions people have with interactive product to enable

them to carry out their activities at work, school, and in their everyday life. More

specifically, usability is broken down into the following goals:

· Effective to use (effectiveness)

· Efficient to use (efficiency)

· Safe to use(safety)

· Have good utility (utility)

· Easy to learn (learnability)

· Easy to remember how to use (memorability)

For each goal, we describe it in more detail.

Effectiveness

It is a very general goal and refers to how good a system at doing what it is suppose to

do. [1]

Efficiency

It refers to the way a system supports users in carrying out their tasks. [1]

Safety

It involves protecting the users from dangerous conditions and undesirable situations.

In relation to the first ergonomics aspect, it refers to the external conditions where

people work. For example, where there are hazardous conditions---like x-rays

machines or chemical plants---operators should be able to interact with and control

computer-based system remotely. The second aspect refers to helping any kind of user

in any kind of situation avoid the danger of carrying out unwanted action accidentally.

It also refers to the perceived fears users might have of the consequences of making

errors and how this effects their behavior to make computer-based system safer in this

sense involves:

· Preventing the user from making serious error by reducing the risk of wrong

keys/buttons being mistakenly activated (an example is not placing the quit or

delete-file command right next to the save command on a menu.) and

· Providing users with various means of recovery should they make errors. Save

interactive systems should engender confidence and allow the users the

opportunity to explore the interface to carry out new operations.

Human Computer Interaction (CS408)

Other safety mechanism include undo facilities and confirmatory dialog boxes that

give users another chance to consider their intentions (a well-known used in email

application is the appearance of a dialog box after the user has highlighted the

messages to be deleted, saying: "are you sure you want to delete all these messages?")

Utility

It refers to the extent to which the system provides the right kind of functionality so

that user can do what they need or want to do. An example of a system with high

utility is an accounting software package providing a powerful computational tool that

accountants can use to work out tax returns. An example of a system with low utility

is a software drawing tool that does not allow users to draw free hand but forces them

to use a mouse to create their drawings, using only polygon shapes. [1]

Learnability

It refers to how easy a system is to learn to use. It is well known that people do not

like spending a long time learning how to use a system. They want to get started

straight away and become competent at caring out tasks without to much effort. This

is especially so far interactive products intended for everyday use (for example

interactive TV, email) and those used only infrequently (for example, video

conferencing) to certain extent, people are prepared to spend longer learning more

complex system that provide a wider range of functionality (for example web

authoring tools, word processors) in these situations, CD ROM and online tutorials

can help by providing interactive step by step material with hands-on exercises.

However many people find these tedious and often difficult to relate to the tasks they

want to accomplish. A key concern is determining how much time users are prepared

to spend learning a system. There seems little point in developing a range of

functionality if the majority of users are unable or not prepared to spend time learning

how to use it. [1]

Memorability

It refers to how easy a system is to remember how to use, once learned. This is

especially important for interactive systems that are used infrequently. If users haven't

used a system or an operation for a few months or longer, they should be able to

remember or at least rapidly be reminded how to use it. Users shouldn't have to keep

relearning how to carry out tasks. Unfortunately, this tends to happen when the

operation required to be learning are obscure, illogical, or poorly sequenced. Users

need to be helped to remember how to do tasks. There are many ways of designing

the interaction to support this. For example, users can be helped to remember the

sequence of operations at different stages of a task through meaningful icons,

command names, and menu options. Also, structuring options and icons so they are

placed in relevant categories of options (for example, placing all the drawing tools in

the same place on the screen) can help the user remember where to look to find a

particular tool at a given stage of a task. [1]

"Don't Make me THINK, is the key to a usable product"

User experience goals

The realization that new technologies are offering increasing opportunity for

supporting people in their everyday lives has led researchers and practitioners to

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consider further goals. The emergence of technologies (for example, virtual reality,

the web, mobile computing) in diversity of application areas (e.g., entertainment,

education, home, public areas) has brought about a much wider set of concerns. As

well as focusing primarily on improving efficiency and productivity at work,

interaction design is increasingly concerning itself with creating systems that are:

· Satisfying

· Enjoyable

· Fun

· Entertaining

· Helpful

· Motivating

· Aesthetically pleasing

· Supportive of creativity

· Rewarding

· Emotionally fulfilling

The goals of designing interactive products to be fun, enjoyable, pleasurable,

aesthetically pleasing and so on are concerned primarily with the user experience. By

this we mean what the interaction with the system feels like to the users. This

involves, explicating the nature of the user experience in subjective terms. For

example, a new software package for children to create their own music may be

designed with the primary objectives of being fun and entertaining. Hence, user

experience goals differs from the more objective usability goals in that they are

concerned with how user experience an interactive product from their perspective,

rather than assessing how useful or productive a system is from its own perspective.

The relationship between two is shown in figure.

Recognizing and understanding the trade-offs, between usability and user experience

goals, is important. In particular, this enables designers to become aware of the

consequences of pursuing different combinations of them in relation to fulfilling

different users' needs. Obviously, not all of the usability goals and user experience

goals apply to every interactive product being developed. Some combination will also

be incompatible. For example, it may not be possible or desirable to design a process

control system that is both safe and fun. [1]

Human Computer Interaction (CS408)

Fun

Satisfying

Emotionally

fullfilling

Efficient to

use

enjoyable

Effective

Rewarding

Easy to

to use

remember

Usability

Goals

Supportive of

Easy to

Safe to

creativity

learn

Entertaining

use

Have good

utility

Aesthetically

helpful

pleasing

Motivating

4.2 Evolution of HCI

Figure shows the main topics that make up the discipline of HCI. All HCI takes place

within a social and organizational context. Different kinds of applications are required

for different purposes and care is needed to divide tasks between humans and

machines, making sure that those activities and routine are allocated to machines.

Knowledge of human psychological and physiological abilities and, more important

still their limitations is important.

As shown in figure, this involves knowing about such things as human information

processing, language, communication, interaction and ergonomics. Similarly it is

essential to know about the range of possibilities offered by computer hardware and

software so that knowledge about humans can be mapped on to the technology

appropriately. The main issues for consideration on the technology side involve input

techniques, dialogue technique, dialogue genre or style, computer graphics and

dialogue architecture. This knowledge has to be brought together some how into the

design and development of computer systems with good HCI, as shown at the bottom

of the figure. Tools and techniques are needed to realize systems. Evolution also plays

an important role in this process by enabling designers to check that their ideas really

are what users want.

Human Computer Interaction (CS408)

Three systems that provide landmarks along this evolutionary path are the Dynabook,

the Star and the Apple Lisa, predecessor of today's Apple Macintosh machines. An

important unifying theme present in all three computer systems is that they provided a

form of interaction that proved effective and easy for novices and experts alike. They

were also easy to learn, and provided a visual-spatial interface whereby, in general,

objects could be directly manipulated, while the system gave immediate feedback.

Dynabook

Alan Kay designed the first object-oriented programming language in the 1970s.

Called Smalltalk, the programs were the basis for what is now known as windows

technology--the ability to open more than one program at a time on a personal

computer. However, when he first developed the idea, personal computers were only

a concept. In fact, the idea of personal computers and laptops also belongs to Kay. He

envisioned the Dynabook--a notebook-sized computer, with a keyboard on the

bottom and a high-resolution screen at the top.

Star

The Xerox Star was born out of PARC's creative ferment, designing an integrated

system that would bring PARC's new hardware and software ideas into a

commercially viable product for use in office environments. The Star drew on the

ideas that had been developed, and went further in integrating them and in designing

for a class of users who were far less technically knowledgeable than the engineers

Human Computer Interaction (CS408)

who had been both the creators and the prime users of many PARC systems (one of

PARC's favorite mottoes was "Build what you use, use what you build.") The Star

designers were challenged to make the personal computer usable for a community that

did not have previous computer experience.

From today's perspective, the Star screen looks rather unremarkable, and perhaps a bit

clumsy in its graphic design--a boxy model-T when compared to the highly styled

look of today's Taurus or Jaguar. What is notable from a historical perspective, of

course, is how much the Star does look like current screens and how little it looks like

the character-based and vector-drawing screens that preceded it.

The Star (Viewpoint) screen image The Star pioneered the now-familiar constellation

of icons, moveable scrollable windows, and inter-mixed text and graphic images. The

widely used graphic user interfaces (GUIs) of today are all variants of this original

design. (Source: Reprinted by permission from Jeff Johnson et al. Xerox Star, a

retrospective. IEEE Computer 22:9 (September, 1989), p. 13.)

The visible mechanisms on the Star display were backed up with a set of design

principles that grew out of a user-oriented design methodology and by a great deal of

empirical testing. Several principles were central to the Star design:

Direct manipulation

The core concept that distinguished Star (and other Alto programs) from the

conventional computer interfaces of their time was the use of a bitmapped screen to

present the user with direct visual representations of objects. In the Star's desktop

metaphor, documents, printers, folders, collections of folders (file drawers and

cabinets), in and out boxes, and other familiar office objects were depicted on the

screen. To print a document, for example, the user could point (using the mouse) to

the icon for the document and the icon for the printer, while using a key on the

keyboard to indicate a Copy operation.

WYSIWYG (what you see is what you get)

In previously available programs for producing sophisticated graphical output--such

as drawings or page layout with multiple fonts--the user created and edited a

representation that looked like a programming language, and then compiled the

resulting program into a visible form. Alto programs pioneered a new style that Star

unified, in which the user works directly with the desired form, through direct

manipulation. The user makes changes by operating on a direct representation of what

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will appear on the printed page. The Star user could intermix text, tables, graphs,

drawings, and mathematical formulas. In fact, most of the popular microcomputer

applications of today have not yet reached the degree of integration that Star offered

more than a decade ago.

Consistency of commands

Because a single development group developed all Star applications in a unified way,

it was possible to adhere to a coherent and consistent design language. The Star

keyboard embodied a set of generic commands, which were used in a consistent way

across all applications: Move, Copy, Delete, Open, Show Properties, and Same (copy

properties). Evoking one of these commands produced the same behavior whether the

object is being moved or copied, for example, was a word of text, a drawing element,

or a folder of documents. Through the use of property sheets the user could

manipulate the aspects that were specific to each element, such as the font of a text

character, or the brush width of a painted line. The Open command was the basis for

applying a technique of progressive disclosure--showing the user only the relevant

information for a task at hand, and then providing a way to reveal more possibilities,

as they were needed.

In addition to these three key concepts, many specific design features made the Star

unique, including its attention to the communicative aspects of graphic design, its

integration of an end-user scripting language (CUSP), and its underlying mechanisms

for internationalization--from the very beginning, Star versions were developed in

several languages, including non-European languages with large character sets, non

left-to-right orthography, and so on.

Some of the aspects that led to the Star's design quality may have also hampered its

commercial success--in particular Xerox's dependence on development groups within

a single company to produce all the applications software.

Lisa by Apple

The GUI (Graphical User Interface) that started it all. If you are sitting in front of a

computer with a mouse and pull down menus you owe it to this machine. Windows

proponents will tell you that Xerox PARC developed GUIs and Apple stole it from

them, therefore what Mr. Gates has done is okay. Xerox had the core idea, but I've

seen video of the early PARC work. It was advanced but it was not nearly what the

Lisa (and later the Mac) became.

The first Apple Lisa was equipped with dual 5.25 inch floppy drives in addition to a

huge external hard drive (shown here). The Apple Lisa 2/10 moved the hard drive

inside the case. It lost one floppy drive and the Macintosh the newer 3.5-inch floppy

shared the remaining one.

My Lisa is the later variety. In fact I have no way of knowing how mine was sold but

the Lisa was later marketed as the Macintosh XL: a bigger sister to the little

Macintosh. Lisa lacked the ROM toolbox built into every Macintosh so it had to do

Macintosh emulation through a new operating system known as MacWorks. It

allowed Lisa to pretend she was a Macintosh. Why do this when you could just buy a

Human Computer Interaction (CS408)

Mac? Lisa offered more RAM (1 meg) a hard drive (10 meg) and some businesses

had already bought them.

While giving credit to the workers at Xerox it should also be mentioned that much of

the groundwork was done in the 1960s and early 1970s. one influential researcher was

Licklider (1960), who visualized a symbiotic relationship between humans and

computers. He envisaged computers that would be able to do more than simply handle

information: the partnership of computer and human brain would greatly enhance

thinking processes and lead to more creative achievements. Another influential

development was the pioneering work of Sutherland (1963), who developed the

Sketchpad system at MIT. The Sketchpad system introduced a number of powerful

new ideas, including the ability to display, manipulate and copy pictures represented

on the screen and the use of new input devices such as the light pen.

Alongside developments in interactive graphic interface, interactive text processing

systems were also evolving at a rapid rate. Following in the footsteps of line and

display editors was the development of systems that allowed users to create and edit

documents that were represented fully on the screen. The underlying philosophy of

these systems is captured by the term WYSIWYG, which stands for `what you see is

what you get' (pronounced `whizzee-wig'). In other words, the documents were

displayed on the screen exactly as they would look in printed form. This was in stark

contrast to earlier document editors, where commands were embedded in the text and

it was impossible to see what document would look like without printing it.

Interestingly, difference in research and development interests could be discerned on

the two sides of the Atlantic. Pioneers of HCI in the USA were primarily concerned

with how the computer could enrich our lives and make them easier. They foresaw it

as a tool that could facilitate creativity and problem solving. In Europe, in 1980

researchers began to be more concerned with constructing theories of HCI and

developing methods of design which would ensure that the needs of users and their

tasks were taken into account. One of the major contributions from the European side

was an attempt to formalize more fully the concept of usability and to show how it

could be applied to the design of computer systems (Shackel, 1981).

During the technology explosion of the 1970s the notion of user interface, also known

as the Man-Machine Interface (MMI), became a general concern to both system

designers and researchers. Moran defined this term as `those aspects of the system

that the user comes in contact with' (1981, p.4), which in turn means `an input

language for the user, an output language for the machine, and a protocol for

interaction' (Chi, 1985, p.671).

Human Computer Interaction (CS408)

Academic researchers were concerned about how the use of computer might enrich

the work and personal lives of people. In particular, they focused on the capabilities

and limitations of human users, that is, understanding the `people side' of the

interaction with computer systems. At that time this primarily meant understanding

people's psychological processes when interacting with computers. However, as the

field began to develop it soon became clear that other aspects impinge on users and

management and organizational issues and health hazards are all important factors

contributing to the success or failure of using the computer systems. [2]

Reference:

[1] About Face 2.0 the essentials of interaction design by Alan Cooper

[2] Human Computer Interaction by Jenny Preece

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