Computer Science 482: Human–Computer Interaction

Study Guide: Unit 1

Foundations of Human–Computer Interaction

In Unit 1 we introduce the field of human–computer interaction (HCI) and provide an overview of topics covered in the course. Human–computer interaction is a complex interdisciplinary area of study that has applications in computing and information systems.

Section 1 introduces human capabilities from an information-processing viewpoint. Section 2 provides an overview of computing technology from an HCI perspective. Section 3 focuses on the interaction of the person with the computer. Section 4 provides a historical view of interface design.

Section 1: Human Capabilities

In this section you will look at basic human capabilities, primarily from the viewpoint of human information systems processing.

Learning Objective 1

Give an overview of the study of HCI and its relevance to cognitive psychology and human physiology.

Required Reading

1. Read pages 1 to 7 and 12 to 13 of HCI.
2. Read the following notes on human information systems processing.

Human Information Systems Processing

As a place to begin our study of human factors, let us consider a single universal information system. It consists of a series of smaller systems (or sub-systems), including an automated information system, the human being, the organization, and the larger cultural context. The philosophical question of whether the entire person should be included within this universal system is beyond the scope of this course.

Information systems contain several components: inputs, outputs, feedback loops, and processes. We can consider each component as a “black box”—the outside world cannot see what goes on inside it. Furthermore, we can say that automated information systems function the same way the human cognitive system does—storing, organizing, and processing information and making it available for later reference and use.

The information-processing school of psychology has argued since the 1950s that the processing that takes place in human beings is analogous to the processing that occurs in automated information systems. Therefore, inferences can be made about the nature of the processing from patterns of input and output. This approach provides a good framework for our study of HCI.

In the information-processing model, input is received from the sensory system, processed by the perceptual system, and then processed by other higher-level systems. Output is through the motor system. The personality and social persona are the total interaction of the various subsystems, as interpreted by other people or the societal system as a whole. This model is obviously simplistic—it does not deal with non-motor outputs, such as pheromones. Furthermore, it is unclear whether the human subsystems are as clearly differentiated as the model implies, or if a more global, holistic system can be emulated using appropriate feedback loops.

Perhaps the most successful application of the information-processing approach is in studies of human memory. In the generic model, memory is broken down into a sensory memory buffer, a short-term working memory, and a long-term memory. Input is held briefly in the sensory buffer, and is then loaded into working memory before being stored in long-term memory. Input may also come into working memory from long-term memory. This model of memory is supported by a great deal of empirical evidence, and research has also identified some of the constraints, that is, the human factors that influence the working of the system.

However simplistic, this model of the human system can be used to generate useful ergonomic principles and guidelines for information systems development. The information-processing approach to psychology uses this model as an explanatory framework for more detailed aspects of human psychology (see, for example, Neisser, 1967). As Newell and Simon (1972) pointed out in their physical symbol hypothesis, cognition and information processing in both humans and machines can be conceptualized in terms of the manipulation of abstract tokens or symbols that represent physical objects. This “symbol processing” metaphor for human thought has proven productive for computer simulations of certain aspects of formal reasoning. The metaphor has inspired a whole approach to artificial intelligence, while supporting a parallel theoretical approach to human psychology. Several of the papers in the volume edited by Baecker et al. (1995) explore this approach more fully.

Interested readers can also look at references for holographic and distributed models (see, for example, Rumelhart & McClelland, 1986) and gestalt models (see Borchers, Deussen, and Knorzer’s 1995 application of gestalt principles to HCI). In the rest of this unit, we will consider how a basic information-processing model can be used as an explanatory framework for aspects of human memory and cognition.

We shall also use this explanatory framework, along with other approaches in later units, as the basis for our descriptions of and recommendations about user interfaces for information systems.

Exercise

You may want to use the Online Workspace to answer the following question:

• What are the five principles of the EC Directive 90/270/EEC? (p. 3 in HCI)

Learning Objective 2

Describe the human IO (input/output) system.

Required Reading

1. Read pages 13 to 27 of HCI.
2. Read the notes below on input and output.

Input and Output

In this section, the chapter discusses input and output from the perspective of the information-processing metaphor. Other metaphors, such as holography or gestalt, may also be appropriate in the final understanding of human psychology. The information-processing approach has generally been characterized by a view of information flowing through a series of stages in input, processing, and output, for example, sensory input and sensory memory in input (Neisser, 1967).

Control processes operate on the information in the processing stage, and feedback from output is used to modify the system. The literature on cognitive science (e.g., the journals Cognitive Psychology and Cognitive Science) present research at a very detailed level within each of these more global systems (input, processing, output, and feedback), but we are focusing on the global level here and making some direct analogies to the computer model. Note again that we are using this metaphor because it has provided the framework for much of the research into human factors in computing systems (e.g., the “GOMS” model described in several papers in Baecker et al., 1995.

The term output does not really do justice to human expression. The idea of communication as “output from people” is simplistic. For people, adding value is an attribute of explanation, elaboration, tutoring, and various other aspects of human communication. At the simplest level, for example, a teacher might use facial expressions and gestures to illustrate or elaborate on a verbal explanation. Adding value appears to be inherent in the process of teaching (and learning) abstract concepts. For instance, one cannot easily imagine teaching concepts such as honour or freedom without a great many examples, extensive elaboration, and perhaps debate.

Debate itself could be considered analogous to an adaptive computer interface that changes in response to the inferred need of the user. For human beings, adding value can go beyond the physical human “output devices” into various levels of technology. In mathematics, a tutor might explain an abstract function by graphical means, by the manipulation of solid objects, or by complex simulations (perhaps computer based). This approach of “enhancements in tutoring” has been incorporated into computer-based learning.

People may express themselves in isolation, but most often their expression is shaped by immediate or delayed feedback at the sensory-motor level, at the perceptual-cognitive level, and through social feedback. High-level and ill-understood aspects of human expression may ultimately be the critical factors in the design of complex learning systems.

Exercise

You may want to use the Online Workspace to answer the following question:

• List and briefly describe the three functions of visual perception that are relevant to HCI. (pp. 15 to 18 in HCI)

Learning Objective 3

Outline the three main types of human memory.

Required Reading

1. Read pages 27 to 39 of HCI.
2. Read the following notes on memory data models in human memory.

Memory Data Models in Human Memory

Data models within human memory are sometimes referred to as schemas (Bartlett, 1932), scripts (Schank & Abelson, 1977), or more recently, mental models (Genter & Stevens, 1983). These constructs relate to issues of representation and management, but also are critical in the input process.

The terms schema and script have generally been used to refer to episodes and events. For example, going to a restaurant might involve a series of transactions (finding a table, ordering the meal, eating the meal, paying for the meal), and each of these pieces of information might be stored in memory. A person’s schema influences his or her perception of the episode of going to a restaurant.

The term mental model has been used primarily to refer to devices and processes, such as a model of a calculator and the process for using it to determine the product of nine times three. However, at a higher conceptual level, there is really no reason to distinguish between schemas, scripts, and mental models.

In human memory, knowing what to expect makes it easier to process input. The flip side is that when a strong model is in place, violations or unexpected inputs are much harder to process. The computer industry has taken advantage of this aspect of human psychology in producing the “desk top” and other metaphors to help organize input for people along dimensions that are familiar to them. In the short term, this practice seems to facilitate society’s adaptation to a more automated information system. In the long term, it is not clear what new structures may evolve for organizing the user interface. In human memory, data control is probably opportunistic. Remembering a name at a party might be difficult, so we might ask someone else to remind us of a person’s name, or check with the person to see if we got the name right.

People (unlike symbol-processing machines) might encode the information incorrectly or weakly because previously stored information was very similar. A new person might remind them of another acquaintance, and the names could become confused. Having made an error, people often persist in making it, because they remembered the information incorrectly. In a database, an error might arise because the value of a field or attribute in a data record has changed. With people, this type of error happens sometimes when a family member gets married and undergoes a name change. In such cases, it is often hard for older members of the family to get used to the name change (emotional factors might compound the difficulty of updating memory). Changing the information seems to be a gradual process, not an all-or-none switch, as in a computer database. However, effects similar to those described above do occur with connectionist models of memory. Rumelhart & McClelland (1986) have argued cogently for a connectionist model of human cognition and memory.

Mnemonics

In one celebrated story from over 2000 years ago, a guest was called outside while a wedding feast occurred. The building collapsed, and everyone inside was killed. The one surviving guest was then able to recall the positions of everyone around the table by using a memory aid or mnemonic, that is, a kind of indexing. In this case, the method most likely used was the method of loci (Yates, 1965), where the memory specialist constructed a familiar sequence of locations as a set of mental boxes. He then “inserted” images into these boxes and was able to “open” the boxes to retrieve the images at will. Since human memory is not good at holding lots of specific information all at once, it is considered to be a dazzling feat of memory when a hundred names can be learned at one time and successfully recalled later. Overall, people have remarkably good memories, but memories must be acquired over time, in relatively small increments.

Representation and Organization

Writings on human memory go back to the ancient Greeks, and the phenomenon has been studied consistently within a modern scientific paradigm since the 19th century. While ancients had a high-level view of memory (the method of loci) modern psychologists reduced it at one point to the study of nonsense syllables. The point of this approach was to study “pure associations” without being confounded by meaning. However, today it is considered that this approach threw out the baby with the bath water. The processes of memory inherently involve meaning, and meaning cannot be extracted to leave “pure association.” In the early part of the 20th century, gestalt psychologists and Bartlett (1932) had already argued this point. More recent debates have centred on how many types of memory there may be, whether short-term memory and long-term memory are separate “boxes,” whether images are stored in analog form or as propositions, whether memory for episodes differs from memory for general knowledge, and whether at its base memory is symbolic or connectionist.

The incorporation of memories into schemata allows summaries of memories to be constructed fairly easily. One of the features of the anecdotes that people relate is that skilled storytellers can often tailor the presentation to the amount of time available, the interests and status of the listener, and so on. It is as if the speaker had a set of basic facts available, and then inserted these facts into different narrative structures, depending on the story-telling environment. Studies of reading suggest that people construct propositional networks to accommodate the facts and ideas presented, and mold them into a meaningful context or structure. This approach to comprehension and reading has been described by Kintsch and van Dijk (1978). Storytelling can be likened to the inverse of reading: in reading, the task is to convert the narrative into a network of propositions; in storytelling, the task is to convert the network of propositions back into a narrative. The idea that memories are stored as propositional accounts, rather than as “taped” experiences that can be played back at will, was reinforced in the 1970s in studies of eye-witness testimony by Kintsch and van Dijk.

Transformations

In giving eye-witness testimony, the witness is expected to tell the story in a summarized and stylized form under the cross-examination of one or more lawyers. In a series of studies, Loftus (1979) showed that memories are extremely susceptible to change in response to the kind of implied assertions made during courtroom questioning.

Computer enhancement of stored materials may be analogous to the creative cognitive processes in people where material is integrated to form new concepts, inferences are made to generate new knowledge, and concepts are transformed to generate new representations (for instance, from a verbal description to a precise mental model for a device or a cognitive map).

Note on the Textbook

When presenting a field as diverse as human psychology in one chapter, it is inevitable that the material is very simplified. For example, although there is evidence for some differences in memory processes supporting episodic and semantic distinction, there is also counterevidence. The consensus among cognitive psychologists is that the two-store model (of long- and short-term memory storage) is a convenient metaphor that simplifies a complex situation.

Exercise

You may want to use the Online Workspace to answer the following questions from your textbook reading:

• Describe the characteristics of the three stores of human memory. (pp. 27 to 39 of HCI)
• Explain the possible relationship between short-term memory and long-term memory. (p. 36 of HCI)

Learning Objective 4

Explain the information-processing approach to human reasoning and thinking.

Required Reading

1. Read pages 39 to 52 of HCI.
2. Read the notes below on thinking and reasoning.

Thinking and Reasoning

As you read this section in the textbook, it is important to remember that the information-processing approach to reasoning and thinking is a convenient model but does not necessarily reflect reality. It presents a way of thinking about human cognition and modeling aspects of it. The important question for you is how it can be applied to HCI principles for designing and building systems.

Similarly, although your text discounts the theoretical significance of Gestalt psychology, it may still be relevant for systems design. Gestalt principles determine how people perceive information in the real world—on paper and on the computer screen.

Koehler (1929) summarized the research as “gestalt laws,” and explained why certain patterns are considered to “belong” or “relate” to each other, and thus form an object. Some of the gestalt laws that might apply to HCI are described below:

• Law of Succinctness (Law of Good Shape) This rule states that objects that are seen as having a simple shape are easier to remember. For example, a polygon may be seen as being “almost round.” Associating a new shape with the familiar concept of a circle takes up less storage capacity than remembering the new shape we actually saw.
• Law of Proximity Objects that are closer to each other seem to form a group. This law is important for screen design, as it provides an easy way to indicate that certain pieces of information fit together conceptually.
• Law of Unity Objects that form closed shapes are perceived as a group. Boxes and frames are frequently used in graphical user interfaces; for example, a row of buttons may lead into a more complicated interface component.
• Law of Equality Objects with similar characteristics (e.g., size, shape) are grouped by our perceptual system, as well. This is why buttons arranged in a row should all be the same size.
• Law of Continuity Objects tend to be perceived as continuous with one another, unless they are separated by a discontinuity (such as a key line).
• Law of Experience We attempt to match objects that we perceive to things we already know. For example, user interfaces that rely on well-known, real-world metaphors reduce memory load, and so are more successful than those that impose wholly new information.

Exercise

You may want to use the Online Workspace to answer the following question:

• Describe three types of reasoning. (pp. 40 to 42 of HCI)

Learning Objective 5

Explain how individual differences can be an important HCI issue.

Required Reading

1. Read pages 52 to 53 of HCI.
2. Read the following notes on individual differences and the level of expertise.

Individual Differences and the Level of Expertise

The rapid development of computer interfaces and applications has brought consideration of individual differences to the forefront. Perusal of the Web shows that web page design differs tremendously for different classes of users and that some websites allow tailoring of the site to fit the individual’s needs. One particular area of interest is the level of expertise of the user. The usability of a user interface depends to a great extent on the knowledge and experience of the user. Users may be classified into different levels, depending on their expertise with a software application or user interface. For instance, Schneiderman (1982) classified users along the following scale: parrot, novice, intermediate, expert, master.

Novices know little about the application, and they will frequently be reluctant to ask for assistance, since they lack the vocabulary of concepts and terms necessary to express their concerns (Schneiderman, 1987).

In current menu systems, novices often benefit the most from the availability of menus (Lewis & Norman, 1995). In contrast, occasional users will have mastered some aspects of the system, but through infrequent use or lack of practice will sometimes forget key information. Occasional users tend to forget the details and are impatient with the need to remember arbitrary syntax and the like. Experts or power users know how to operate the product or system and will know a variety of shortcuts for getting tasks done.

How does one accommodate the various levels of expertise? In principle, one can have the system adapt to the first-time user’s expertise level. Casual and novice users can have simpler front ends that restrict their options. Complex options will only become available as their expertise increases. However, this strategy is difficult to implement, and the system must be well designed.

Exercise

You may want to use the Online Workspace to answer the following questions:

• Describe two long-term and two short-term individual differences relevant for HCI. (pp. 52 to 53 of HCI)
• Provide an example of a computer system that would be greatly affected by short-term differences (open question).
• Provide an example of a computer system that would be greatly affected by long-term differences (open question).

Learning Objective 6

Describe the role of psychology in computer interface design.

Required Reading

1. Read pages 53 to 55 of HCI.
2. Read the notes below on the role of psychology in HCI.

The Role of Psychology in HCI

The information-processing theory of cognition assumes that information is processed in stages, from sensory input through higher-level processes to response effectors and resulting action. This approach has provided basic design principles based on human limitations in short-term memory, long-term memory, attention, and users’ mental models.

Miller, Galanter, and Pribram’s (1960) rule of thumb for short-term memory capacity was used to help design screen displays. People seem to be able to retain seven, plus or minus two, items in mind at a time. Hence, interfaces that require users to remember more than five to nine items or menu selections will be very difficult to learn. Research on long-term memory showed that human memory is not good at retaining a great deal of specific information given all at once. Such information must be acquired over time in relatively small increments. Hence, complex interfaces should introduce the user to new information a little at a time.

It has been empirically established that attention span is a limitation in the human cognitive system (see, for example, Neisser, 1967; Lindsay & Norman, 1977; Anderson, 1983). Wickens, Dalezmann, and Eggemeier (1976) expressed the view that the amount that people can attend to at one time may be increased by using different modalities or styles of representation, as in multimedia. However, shifting attention takes time and effort, and can be disruptive, so rapid changes of attention should be kept to a minimum. Card, Moran and Newell’s (1983) classic book provided a theoretical framework based on the information-processing view of human beings.

Research on mental models began to influence psychological theorizing about HCI (Gentner & Stevens, 1983). This approach focuses not on the “objective” external device or system itself, but on the user’s model of that device. Mental models and “cognitive structures” are concerned with the structure of a person’s knowledge (Payne, 1988). In their simplest form, they are beliefs about tasks and systems that guide decisions and behavior. Thus, knowledge about mental models can be used to predict behavior.

Research discussed in Woods, O’Brien, and Hanes (1987); Norman and Draper (1986); and Davies, Lambert, and Findlay (1989) suggests that the structure of the presentation on the display screen greatly influences the subject’s ideas about the structure and functions of the system. The general finding has been that the user’s understanding of the system is diminished when the surface representation is extremely cluttered and disorganized, and when it does not directly match the functions it is trying to represent.

Mental models should conform to the actual workings of the system for the user’s purposes or should show cognitive compatibility (Norman, 1983). For this reason, user interfaces that promote high cognitive compatibility tend to be more usable. Task models should be presented in such a way that their manipulation is constrained and biased by the structure of relations that actually exist in the represented task or system.

Overall, practice has run ahead of scientific theory, and there is no doubt that systems design remains something of an art. In many cases, recent empirical findings are, at best, loosely tied to theory. The Web contains many guidelines for developing web materials, and even notes examples of bad design. As systems have evolved, the ergonomic issues involved in designing those systems have become more complex. Along with older, theoretically derived principles of memory limitations and attention, more empirically discovered heuristic design principles have emerged from the literature on mental models and user expertise. However, these approaches are embryonic, and designing systems for complex tasks involves intuition and heuristics, rather than hard science. Furthermore, as software develops, a principle specific to one piece of software tends to become obsolete; there has been a lack of general principles for more complex interactions (Norman, 1988). Perhaps systems development efforts should be considered real-life laboratories for the development of a new psychology.

Exercise

You may want to use the Online Workspace to answer the following question:

• Describe three ways that psychology contributes to HCI. (pp. 53 to 54 of HCI)

Learning Objective 7

Provide a summary of human capabilities from the viewpoint of human information processing.

Required Reading

1. Read page 55 of HCI.
2. Read pages 101 to 133 of Interaction.
3. Study Table 1, which provides a summary of human capabilities in relation to HCI.

Table 1. Summary of Computer and Human Capabilities

Human Factors in Systems Interactions

Review Exercise

You may want to use the Online Workspace to complete the following exercises:

• Observe skilled and novice operators in a familiar domain: for example, touch and “hunt-and-peck” typists, expert and novice game players, or expert and novice users of a computer application. What differences can you discern between their behaviors?
• From what you have learned about cognitive psychology, devise appropriate guidelines for use by interface designers. You may find it helpful to group these under key headings: for example, visual perception, memory, problem solving, etc., although some guidelines may overlap.

Section 2: The Computer

In this section you will review basic computer capabilities.

Learning Objective 1

Give an overview of the configuration of a computer system.

Required Reading

1. Read pages 60 to 62 of HCI.
2. Read the following note on computer capabilities.

Computer Capabilities

Defining the “computer” in HCI is not a trivial matter. Computer applications, the IO devices and peripherals, and processing capabilities have changed drastically over the years, thereby dramatically changing the nature of HCI. The most recent trend towards special purpose games machines, hand-held personal computational devices, voice interfaces, and Internet “information appliances” will bring further challenges to design based on HCI principles. Some of these issues are addressed more fully in Unit 1, Section 3.

Exercise

• Describe two broad categories of interaction devices. (p. 61 of HCI)

Learning Objective 2

Describe text entry systems.

Required Reading

1. Read pages 63 to 71 of HCI.
2. Read the notes below on input and output.

Input and Output

Voice input not only offers a convenient method of text entry, it also reduces repetitive motion injuries, a major safety concern with computers. As computers become more widespread, the issues addressed by HCI become more far reaching. Software solutions for injuries is a new research area in HCI.

Exercise

You may want to use the Online Workspace to answer the following question:

• Describe the three broad categories of text entry devices. (pp. 63 to 71 of HCI)

Learning Objective 3

Describe input devices in terms of positioning, pointing, and drawing.

Required Reading

1. Read pages 71 to 78 of HCI.

Exercise

You may want to use the Online Workspace to answer the following question:

• List nine 2D pointing devices. (pp. 71 to 78 of HCI)

Learning Objective 4

Describe common output devices.

Required Reading

1. Read pages 78 to 86 of HCI.

Exercise

You may want to use the Online Workspace to answer the following question:

• What is situated display? Give an example. (p. 85 of HCI)

Learning Objective 5

Describe the capabilities of virtual reality devices and 3D interaction.

Required Reading

1. Read pages 87 to 91 of HCI.

Learning Objective 6

Elaborate on the relationship between electronic and paper representations.

Required Reading

1. Read pages 97 to 105 of HCI.
2. Read the following note on the paperless world.

The Paperless World?

An issue that often arises in our courses is reading text on screen versus on paper. It appears in Athabasca University courses, some students read almost entirely on screen and some almost entirely by printing out the materials, but most read in both modes. It seems that as screen readability improves, the younger generation in particular is doing more and more reading online. There are advantages to both media. Electronic materials can be easily searched and manipulated (and in specific cases, converted to voice output). They are easier to store and can be used without danger of wear and tear. Printed materials remain more portable, although that advantage is already disappearing with the advent of hand-held electronic books.

In SCIS the reading method is a real HCI concern. While some people like to work entirely electronically, cutting and pasting from AU materials and annotating electronically to make their personal study notes, others find it easier to work from the printed materials. SCIS has always considered the printing of course materials as a factor in their design. The first version kept very much to the look and feel of printed materials to make students feel at home and facilitate printing for those who preferred that mode. We kept the wide left-hand margin and tried to control for line length as much as possible (given that the browser itself controls line length and size of the reading window).

Exercise

You may want to use the Online Workspace to answer the following question:

• Outline the problems with preparing a presentation for both print and screen. (pp. 102 to 103 of HCI)

Learning Objective 7

Describe the constraints that computer memory puts on HCI.

Required Reading

1. Read pages 107 to 113 of HCI.
2. Read the following notes on neural networks.

Neural Networks

Another approach to knowledge representation is the connectionist or neural net approach, based on the work of Rosenblatt (1958). A connectionist architecture has a very large number of simple processing units operating in parallel on input; memory is distributed and content addressable. The connectionist approach to modelling human capabilities has a long history (Rosenblatt, 1958), but lost favour after a significant critique was published (Minsky & Papert, 1969) until quite recently. The basis of the model is an extremely simplified view of the behaviour of neurons (hence “neural nets”). Much of the recent revival of interest in this approach results from the fact that these “models” can now be implemented in software and hardware. Such implementations have revealed many interesting behaviours. In fact, this technology has had some remarkable successes in pattern recognition (e.g., Gorman & Sejnowski, 1988).

A simple version of a neural net has a set of input units, processing units, and output units. It assumes the simple processing units share some number of excitatory connections with the input layer, and both inhibitory and excitatory connections among the processing units, as well as excitatory connections from the processing layer to the output layer. The connections between processing units are weighted. The output of a processing unit is a function of all weighted input signals to the neuron. A neural net with this simple architecture can improve by adaptation. For “training,” the network is exposed to a number of (correct) examples of a particular concept, and based on the differences between the correct output and the network’s actual output, the network iteratively adjusts the weights of its connections among its processing units and to its output units, until the correct output is associated with each input pattern. Thus, the representation of the input is distributed in parallel over the entire network, and the input directly accesses the correct output response. Unlike symbol-processing representations, neural networks are inherently good at interpreting incomplete, noisy, or fuzzy (unreliable, probabilistic) input data. Neural networks show graceful gradation of performance, in that the output tends to change gradually in keeping with changing input data. Of course, neural networks are generally implemented in software on a standard computer architecture, but hardware implementations are possible.

Exercise

You may want to use the Online Workspace to answer the following question:

• Explain the Von Neumann bottleneck and specify the constraints of the underlying architecture. (pp. 107 to 111 of HCI)

Learning Objective 8

Describe the constraints that computer processing power puts on HCI.

Required Reading

1. Read pages 114 to 119 of HCI.
2. Read the following summary of computer processing capabilities in HCI.

Computer Processing Capabilities in HCI

As Internet connectivity has expanded, users have become ever more vocal in demanding user-friendly software, and the new class of “user as consumer” became a major consideration in software development. The affective system became a more important focus for research. Issues such as gender, age, and other individual differences became relevant as the range of users of information systems broadened. Basic physical considerations such as placement of the monitor (height, angle of view), remained primary concerns, but human factors research expanded to include more psychological considerations, primarily at the sensory-perceptual level (e.g., Borchers, Deussen, & Knorzer, 1995). Guidelines for colour use and screen layout were also a focus for research.

Exercise

You may want to use the Online Workspace to answer the following question:

• Describe four limitations on interactive performance presented in your textbook. (pp. 117 to 118 of HCI)

Learning Objective 9

Provide a summary of computer capabilities from a human information-processing viewpoint.

Required Reading

1. Read pages 120 to 121 of HCI.
2. Review Table 1 in Section 1, Learning Objective 7.

Section 3: The Interaction

This section focuses on the interaction aspect of HCI.

Learning Objective 1

Give two extremes of means of interacting with the computer.

Required Reading

1. Read page 124 of HCI.
2. Read the note below on computer capabilities.

Computer Capabilities

Societal and organizational automated information systems continue to become more complex. Since the advent of computers, ergonomics has gone from being concerned with simple sensory and motor human factors to studying most aspects of users’ affective, cognitive, and social personae. Factors to consider in the design of computer systems may include such things as the user’s age, cognitive skill, gender, style, motivation, motor skills, stress, and various aesthetic and social factors. Special needs groups (e.g., the legally blind) may have special requirements that systems designers need to consider.

Exercise

You may want to use the Online Workspace to answer the following question:

• What are the extremes of interactivity in computer systems? (p. 124 of HCI)

Learning Objective 2

Describe a simple model of a user’s interaction with a computer.

Required Reading

1. Read pages 124 to 130 of HCI.
2. Read the notes below on models of interaction

Models of Interaction

Human factors in computer systems design and HCI are huge and ill-defined fields, with a myriad of research threads and development principles. A survey of the issues in systems design will show that they have increased in scope since the work on GOMS and earlier work on plans and actions by Miller, Galanter, and Pribram (1960). Since the 1960s, human factors principles have moved beyond formal theory to a basis in practice.

Norman’s work (e.g., Norman, 1988) is but one of a number of cognitive-science-based approaches to designing systems (see, for example, Baecker et al., 1995). Norman’s work is well known and widely accepted. We are not endorsing it as “correct” in any absolute sense, but find it well articulated, with solid attempts to put practical advances in the context of a loosely defined theory. Norman, whose original human factors paper may have been prompted by his experience in battling with the UNIX interface as much as by cognitive science theory, espouses a coherent set of principles for human factors in systems design (1988, 1993). His work remains, however, as most systems-development methodologies do, heuristic in nature and based more on empirical findings and validation than on any formally verified theoretical axioms and theorems.

Exercise

You may want to use the Online Workspace to answer the following question:

• Describe the interaction framework outlined in your text. (pp. 127 to 130 of HCI)

Learning Objective 3

Present the ACM framework for HCI.

Required Reading

1. Read pages 130 to 131 of HCI.

Exercise

You may want to use the Online Workspace to answer the following question:

• Describe the ACM framework for HCI. (pp. 130 to 131 of HCI)

Learning Objective 4

Define ergonomics and elaborate on its relationship to HCI.

Required Reading

1. Read pages 131 to 136 of HCI.
2. Read the note below on ergonomics.

Ergonomics

Ergonomics has traditionally focused on physical factors and has been associated with engineering departments. However, in principle there is no reason that the focus could not be enlarged to include more cognitive/affective aspects of HCI, and some engineering departments have advocated this approach. On the other hand, there is no reason HCI issues should not include physical and emotional health issues, as well as the more traditional measures of system effectiveness.

Exercise

You may want to use the Online Workspace to answer the following question:

• What are five human health issues for HCI to consider? (p. 135 of HCI)

Learning Objective 5

Describe five common interaction styles.

Required Reading

1. Read pages 136 to 144 of HCI.
2. Read pages 81 to 88 of Interaction.

Exercise

You may want to use the Online Workspace to answer the following question:

• List several interface styles and briefly define dialog. (pp. 136 to 137 of HCI)

Learning Objective 6

List the defining characteristics of the WIMP interface.

Required Reading

1. Read pages 145 to 152 of HCI.

Exercise

You may want to use the Online Workspace to answer the following questions:

• Briefly describe eight elements of the WIMP interface. (pp. 145 to 152 of HCI)
• Describe a WIMP interface that you use (open question).

Learning Objective 7

Outline important aspects of interactivity between humans and computers.

Required Reading

1. Read pages 152 to 154 of HCI.

Exercise

You may want to use the Online Workspace to answer the following question:

• Describe the role of pre-emptive components in an interface oriented towards user initialization. (pp. 152 to 154 of HCI)

Learning Objective 8

Explain how context is important for the interaction between the human and the computer.

Required Reading

1. Read pages 154 to 155 of HCI.
2. Read the note below on context for interaction.

Context for Interaction

Part of the context for interaction in the HCI field is recognition that there are whole new categories of users. At one time, users were employees of the company implementing the system (either directly or through a contractor). While the design of the system may have affected users’ motivation, the bottom line was that they were required to use the system and attempt to make it effective. Now users may be customers, clients, students, or learners who likely have diverse expectations and tolerance levels for the “human” interface. Their lack of tolerance may result in a decision not to use or purchase.

Exercise

You may want to use the Online Workspace to answer the following question:

• How can the design of the human–computer interface affect motivation? (pp. 154 to 155 of HCI)

Learning Objective 9

Explain the role of satisfaction, personal experience, engagement, and fun in HCI.

Required Reading

1. Read pages 156 to 160 of HCI.

Exercise

You may want to use the Online Workspace to answer the following question:

• Why do some researchers add the criterion satisfaction to their consideration of usability? (p. 156 of HCI)

Learning Objective 10

Provide a summary of the steps in an interaction.

Required Reading

1. Read pages 160 to 161 from HCI.
2. Read pages 37 to 66 of Interaction.
3. Review Table 1 in Section 1, Learning Objective 7.

Review Exercise

You may want to use the Online Workspace to answer the following questions:

• Do the exercises on page 161 of HCI.

Section 4: Paradigms

In this section you look at basic human capabilities primarily from a human information systems processing viewpoint.

Learning Objective 1

Explain the meaning of the term paradigm with respect to interactive design.

Required Reading

1. Read page 165 of HCI.
2. Read pages 88 to 96 of Interaction.

Exercise

You may want to use the Online Workspace to answer the following questions:

• What are the two open questions for designers of interactive systems? (p. 165 of HCI)
• What does the term paradigm mean in the context of developing an approach to answer these two questions? (p. 165 of HCI)

Learning Objective 2

Describe various historical advances of interactive designs.

Required Reading

1. Read pages 165 to 185 of HCI.

Exercise

You may want to use the Online Workspace to answer the following question:

• List and summarize the 15 paradigms identified by the authors. (pp. 165 to 186 of HCI)
• What are some criticisms of the practice of using metaphors in computer interfaces? (p. 170 of HCI)

Learning Objective 3

Summarize what you have learned about paradigms and interaction metaphors.

Required Reading

1. Read pages 185 to 186 of HCI.

Review Exercise

Choose one of the people mentioned in this chapter, or another important figure in the history of HCI, and create a web page biography on this individual. Try to get at least one picture of your subject, and find out about their life and work, with particular reference to their contribution to HCI.

Acknowledge all information sources used by listing and citing them in APA style.

References