Introducing User Interface Design

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Introducing User Interface Design

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Introduction
1 Why the User Interface Matters
Human–computer interaction (HCI) is the study of how humans interact with computer systems. Many disciplines contribute to HCI, including computer science, psychology, ergonomics, engineering, and graphic design. HCI is a broad term that covers all aspects of the way in which people interact withcomputers. In their daily lives, people are coming into contact with an increasing number of computer-based technologies. Some of these computer systems, such as personal computers, we use directly. We come into contact with other systems less directly — for example, we have all seen cashiers use laser scanners and digital cash registers when we shop. And, as we are all too aware, some systemsare easier to use than others. When users interact with a computer system, they do so via a user interface (UI). This book explores how to design good user interfaces — interfaces that are easy to use and easy to understand, that meet the needs of the intended users, and that support users in the tasks they wish to undertake. In this part of the book, we introduce you to user interface design andevaluation. In particular, we explain why good user interface design is important and highlight the consequences of poor or bad user interface design. More important, we will get you to start thinking about users — and why and how to involve them in the design and evaluation of the user interface.

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Computers Are Ubiquitous
Technology has advanced so much that computer systems areused on an everyday basis by almost everyone. A computer system (or an interactive computer system or just a system) is the combination of hardware and software components that receive input from, and communicate output to, a user in order to support his or her performance of a task (see Figure 1.1). Computer systems may be used directly, as in the case of personal computers (PCs) in use at workor at home. Often, though, we use embedded computer systems where the technology is invisible to us. For

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example, computer-based microchip technology can be found embedded in personal goods such as digital watches and mobile phones, in domestic appliances such as microwave ovens, washing machines, and video recorders, and in the instrument panelsof cars. Again, but less directly, computers are used when we shop; many stores use laser scanners that “swipe” the bar codes on goods to record both the goods we purchase and total the amounts we Figure 1.1 The interface is the part of the computer system spend. Behind the scenes, with which the user interacts in order to use the system and the scanning of goods assists achieve his or her goal.with automated stock control and stock reordering. When we take money from our bank accounts using an automated teller machine (ATM) or when we use ATM debit cards to buy goods electronically, our bank details are accessed via the bank’s computer system. The list of everyday ways in which we use computer-based systems seems endless. Whether we are aware of it or not, computers pervade our life.Computer applications are used either by us, or for us, in some way almost every day. The user interface (or just interface) is that part of the computer system with which a user interacts in order to undertake his or her tasks and achieve his or her goals. The user interface and the ways of interacting with computer-based systems are different for each system. For example, digital watches generallyhave buttons that users press to set the time or use the stopwatch facility. Microwave ovens might have dials to turn or a digital display and a touchpad of buttons to set the cooking time. PCs have a screen, a keyboard, and a mouse (or sometimes a trackball or a joystick) that enable interaction to take place. So each user interface is different. Depending on the design of the interface, each of...