When mentioning about HCI, the response of "What is that?" is sure a sign of youth. Or try to be mentioned in another way, think about the interactive products in everyday use. Most of us will think about cell phone, computer, remote control, coffee machine, ATM machine and etc.
Most of the interactive products require users to interact with them to carry out their tasks but have not been necessarily been designed with the users in mind. Typically, they have been engineered as systems to perform set functions. However, it is often at the expense of how the system will be used by real people while they may work effectively from an engineering perspective.
The aim of interaction design is to redress this concern by bringing usability into the design process. From the users' perspective, it is about developing interactive products that are easy, effective, and enjoyable to use.
Chapter 1: What is HCI?
HCI is a term used to mean that human-computer interaction. According to Christine Faulkner (1998), Human-computer interaction is the study of the relationships which exist between human users and the computer systems they use in the performance of their various tasks.
HCI in multiple disciplined fields
In the early days, hardware systems were designed for engineer's usage. One of the biggest challenges at that time was to develop computers that could be accessible and usable by other people instead of only engineers to support tasks involving human cognition. To make this possible, the involvement of HCI practitioners from different background such as computer scientists and psychologists in designing user interface is necessary. People with different background might have different perspectives and ways of seeing a particular thing. This meant that more ideas being generated, new methods being developed and more creative and original designs being produced.
The importance of HCI
Today, computers are widely used by people who may be experts in particular fields such as banking, medicine and etc, but not necessarily computer experts. However, it is not necessarily that there is a need for experts from other field to become computer expert as well. It is possible to produce computer systems that enable user to perform the task without having a detailed knowledge of computer systems. For example, there is no need for people to be telephone engineers before they can use a telephone. Therefore, the aim of HCI is to build computer applications that are easy to use and natural so that the users able to focus on the task but not the computer system.
Usability goals of HCI
Usability goals generally regarded as optimizing the interaction between people and interactive products to ensure that it is easy to learn, effective to use, and enjoyable.
Besides that, it also used to ensure that the system is fit for the purpose for which it was designed.
By 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)
Effectiveness is a general goal that refers how good a system is at doing what it is supposed to do.
Efficiency refers the way a system supports users in carrying out their tasks. For eg: Amazon.com patented a clever mechanism which is one-click option which requires users only to click a single button when they want to make another purchase.
Safety involves protecting the user from dangerous conditions and undesirable situations. This is to avoid the dangers of carrying out unwanted actions accidently. For example, the quit or delete-file command should not be placed right next to the save commands on a menu.
Utility refers to the system provides the right kind of functionality so that users can do what they need or want to do.
Learnability refers to how easy a system is to learn to use. The key concern is determining how much time users are prepared to spend learning a system.
Memorability refers to how easy s system is to remember how to use, once learned. It is to ensure that the users do not have to keep relearning how to carry out tasks. For example, users are able to remember the sequence of operations at different stages of a task through meaningful icons, command names and menu options.
Chapter 2: Understanding users
Cognition is a term that used to describe the interpretation of information from the outside world that is received through the senses. It is about what is going on when we carry out our everyday activities. It involves cognitive processes like thinking, remembering, learning, daydreaming, and decision making, seeing, reading, writing and talking.
Norman (1993) points out it can be distinguished into two general modes: experiential and reflective cognition. Experiential mode is the state of mind which we perceive, act, and react to events around us effectively and effortlessly such as driving a car, reading a book, playing a video games and etc. In contrast, reflective cognition involves thinking, comparing, and decision-making which lead to new ideas and activities. Examples include designing, learning, and writing a book.
Cognition typically involves a range of processes. It is rare for one to occur in isolation.
There are specific kinds of processes that used to describe cognition. The various kinds of processes will be discussed as below.
Attention which is the process of selecting things to concentrate on which involves our auditory and visual senses. Attention allows us to focus on information that is relevant to what we are doing. The way of information being displayed can also affect the difficulties of attending to appropriate pieces of information. The result can be proved in Figure 2.2 and Figure 2.3
Both of the figures above showed the different ways of structuring the same information at the interface. It is cleared that it is easier to find information in Figure 2.2 than Figure 2.3. The main reason is the information is poorly structured in the Figure 2.3 while the information in Figure 2.2 has been ordered into meaningful categories which making it easier to select the necessary information.
Perception refers how information is acquired from the environment via the different sense of organs ( eg. ears, eyes, and fingers) and transformed into experiences of objects, events, sounds, and tastes (Roth, 1986). Therefore it is important to present information in a way that can be read easily. For example, icons can be designed in many ways. The key is to make them easily distinguishable from one another to make it easily recognize what are they intended to present. The Figure 2.4 showed the example of poor bin icon design in OS/2 Warp 4, which is not actually a bin at all but a shredder.
Memory involves recalling various kinds of knowledge that allow us to act appropriately. A well-known phenomenon is that people are much better at recognizing things than recalling things. There are certain kinds of information that are easier to recognize than others such as pictures. Instead of requiring users to recall from memory a command name from a possible set of hundreds or even thousands ( see Figure 2.5), GUIs provide visually based options which users can easily recognize and browse through (see Figure 2.6).
Learning can be considered in terms of how to use a computer-based application to understand a given topic. An observation held by Jack Carroll (1990) and his colleagues found that people prefer "learn through doing" than following a set of instructions in a manual. GUI is an example of good environment for supporting this kind of learning. Carroll also suggested another way of helping learners by using a "training-wheels" approach. It helps to make the learning more tractable, helping the learner focus on simple operations before moving on to more complex ones.
Reading, speaking and listening are three forms of language processing. One similarity is that the meaning of sentences and phrases is the same regardless of the mode in which it conveyed. However, there are marks differences between people in their ability to use language. For example, some people prefer writing to listening and vice versa. Many applications such as speech recognition systems and etc have been developed to help support or replace them where they have difficulty with them.
Problem solving, planning, reasoning, decision making are those cognitive processes involving reflective cognition. This includes thinking what to do, what the options are, and what the consequences that might carrying out. For example, when seeking information on the web, people will try to different search engines to find sites that give the best deal or best information. People may also know the pros and cons of different search engines. For example, a student may use a more academically oriented one to search information for their assignments or research.
As well as understanding the cognition of users, it is also needed to examining what the users need to do and know in order to accomplish a task. Therefore, task analysis method has carried out to investigate cognitive processes and physical actions. Hierarchical Task Analysis (HTA) is a widely used technique which was originally designed to identify training needs (Annett and Duncan, 1967). It involves breaking down a task down into subtasks and so on. An example of HTA has been showed in Figure 2.7 which concentrates on the breakdown of high level tasks such as "boil water" into lower level tasks such as "fill kettle"). Several systems may be cut by the tasks and both manual and electronic operations are involved. Other than that, it also focuses on the knowledge required for different parts of a task.
Chapter 3: Interaction Design
Winograd (1997) describes interaction design as "the design of spaces for human communication and interaction." The researchers have shown that redesign of the HCI can make a substantial difference in learning time, performance speed, error rates, and user satisfaction. Therefore, interaction design plays an important role in the design process of a system.
Four basic activities in Interaction Design
There are four basic activities has been identified in interaction design such as below.
- Identifying needs and establishing requirements
- Developing alternative designs
- Building interactive versions of the designs
- Evaluating designs
It is important to know who the targeted users are and what kinds of support can be usefully provided by interactive product. This activity is fundamental to a user-centered approach.
This is the core activity of designing by suggesting ideas to meeting the requirements. This activity can be broken up into two sub activities which are conceptual design that describes what the product should do, behave and look like and physical design that involves colors, sounds, images, menu design and icon design for the product.
It is required that interactive version of the designs to be built. One of the example for achieving "interaction" is paper-based prototypes which quick and cheap to build and are very effective for identifying problems in the early stages of design.
Evaluation is the a process of determining the usability and acceptability of the product or design that is measured by several criteria including the number of errors users make using it, how well it matches the requirements and etc.
Three key characteristics of the interaction design process
There are three characteristics that form a key part of the interaction design process. These include user focus, specific usability criteria, and iteration.
The user focus has been formed as a central plank of view on the interaction design process. The issues should be focused and opportunities for evaluation and user feedback should be provided.
Besides that, specific usability goals should be identified, clearly documented, and agreed upon the beginning of the project. This helped the designers to choose the alternative designs and check on the progress of developing the products.
Iteration allows designs to be refined based on feedback. Gould and Lewis, 1985 points out that iteration is inevitable because designers never get the solution right at the first time. Programming an interface can be a time consuming and difficult business. Making early prototypes is crucial for less precious and easier to throw away. For example, Mock-ups can be quickly constructed by using Visual Basic on the PC.
Lifecycle models show how the activities of interaction being related. Lifecycle models normally served as a management tools or simplified version of reality.
A simple lifecycle for interaction design
Figure 3.1 shows how the four basic activities of interaction design being related.
The waterfall lifecycle model
The waterfall lifecycle was the first model generally known in software engineering. This is a basically a linear model that each step must be completed before moving to the next step (see Figure 3.2).
The Spiral lifecycle model
In 1988, Barry Boehm suggested the spiral model of software development (see Figure 3.3). The important features in spiral models are risk analysis, prototyping, iterative framework that allows ideas and progress can be checked, and explicitly encourages considering alternatives. The spiral model is suitable for large and complex project but not the simple ones.
Rapid Applications development (RAD)
The RAD (see Figure 3.4) approach attempts to take a user-centered view and to minimize the risk caused by requirements changing during the course of the project.
The Star lifecycle model
The Star lifecycle model is suggested by Hartson and Hix (1989) (see Figure 3.5). In this model, evaluation is at central of activities and the ordering of activities does not specified.
Usability engineering lifecycle model
The usability engineering lifecycle model was reported by Deborah Mayhew in 1999 (Mayhew, 1999) (see Figure 3.6). This lifecycle provides the holistic view of usability engineering. It provides the link to software engineering approaches like OOSE (Jacobson et al, 1992). The lifecycle includes the stages of identify requirements, design, evaluate and prototype.
Chapter 4: Evaluation in HCI
Evaluation is a process which the interface is tested against the needs and practices of the user. Without evaluation, designers are unable to make sure that their software is usable or has meets the user's requirement. As well as understanding when, where, why and how the system being evaluated, it will be necessary to find ways of measuring attitudes and obtaining feedback from the users.
When and what to evaluate?
Any testing should be carried out by the design team to produce a system that is satisfying, efficient, effective, and safe. The cost of rectifying errors in the design increases as a design passes through the stages and finally becomes a finished product. Therefore, it is important to test and evaluate at the early stages hopefully it can brings to light only the most minor of problems. The following stages represents the points which the testing should be take places.
System analysis phase
The interface designer should analyze the work that has been done in similar fields whenever possible. For example, get the feedback from users of previously designed systems to help produce scenarios and consider feasibility. It would be economic to use the work that has been done before rather than starting from scratch. Besides that, the change to the system or abandonment of proposal at this stage is the cheapest.
System design phase
At this stage, parts of the system can be tested and simulated. By developing mockups of the system such as prototyping are relatively cheap to produce. The advantages of different types of design can be measured against each other at this stage.
Evaluation can be take place on a larger scale and concentrate on the details of the system when the prototype is complete. Different aspect of design can be evaluated at this stage.
According to Nielson, 1994, there are four basic ways of evaluating system which are automatically (usability measure computed by some programs based on user interface specifications), empirically (usability of interface assessed by users), formally (usability measures calculated by using exact models and formulas), and informally (based on rules of thumb and evaluators experience and skill). However, he suggested that only empirical and informal are very useful while automatic and formal evaluations are problematic. By using Neilson's words, usability evaluation methods can generally be described as empirical or informal. The various methods of informal, formal, and empirical methods will be discussed as below.
Informal or Inspection-based Evaluation
Nielson points out that usability inspection has been used as the generic name for a set of methods that are based on having evaluators inspect the interface. Typically, Usability Inspection Methods are non-empirical methods that used to evaluate user interfaces. It is aimed at finding usability problems in a design.
There are numbers of inspection methods involving heuristic evaluation, cognitive walkthroughs, formal usability inspections, pluralistic walkthroughs, feature inspection, consistency inspection, and standards inspection. The two most commonly used methods are heuristic evaluation (Nielson, 1994) and cognitive walkthroughs (Wharton, Rieman et al. 1994).
Formal or Model-based Evaluation
Model-based evaluation involves how a proposed system might use by human to obtain predicted usability measures by calculation or simulation. A well-known model based evaluation method is GOMS which suggested by Card et al. (1983). GOMS stands for Goals, Operators, Methods, and Selection Rules. Goals are something that the users want to accomplish; operators are basic actions that used to accomplish goals, methods are procedures (sequence) that can accomplish goals, and selection goals determines what methods to use in a circumstances.
Empirical or User-based Evaluation
Empirical evaluation consists of an analysis of user performance in relation to the proposed system. The user-centered evaluations methods consist of verbal reports, walkthroughs, questionnaires, usability testing and think-aloud methods. Usability testing is the most commonly used empirical method.
How Evaluation methods are evaluated
There is a study carried out by Savage, 1996 which compared expert reviews, user reviews and user testing. Expert reviews are the inspection methods that carried out by human factors specialists. User reviews is about getting feedback from the end users through interviews and questionnaires. Usability testing involves measuring typical user's performance on typical, well-defined tasks of a designed system. Results from this study shows that expert reviews are intended to inform user interface issues which needs more research with the users while the other two methods flagged up design issues.
In industry, usability testing is the most commonly used method to measure typical user's performance on typical, well-defined tasks of a designed system (Nielson and Mack 1994). Barnum points out that usability testing are the process of observing users using the product and learn about product's usability. User's performance usually measured in terms of number of errors and times to complete the task. The interactions with software are watched and recorded on the video as the users perform the tasks.
Cognitive Walkthroughs, Heuristic Evaluations and GOMS are more economical because running prototype or actual users are not required. Empirical methods rely on user's performance when testing the user interface, whereas informal evaluations rely on the evaluator's skill and experience.
This chapter addresses about the relationship between design and Human-Computer Interaction (HCI). Fallman points out that HCI has emerged as a design-oriented field of research and it is directed towards innovation, design, and construction of new kinds of information and interaction technology.
1.1 Three Accounts of what is design
1.2 The Role of Design in HCI
2. Critical Evaluation
2.1 How evaluation and design interrelated in HCI
2.2 Design-oriented Research vs. Research-oriented Design