HUMAN-COMPUTER INTERACTION
SECOND EDITION
HUMAN-COMPUTER INTERACTION
SECOND EDITION
1.3 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 may overlap such groupings.
In order to understand how humans interact with computers, we need to have an understanding of both parties in the interaction. The previous chapter explored aspects of human capabilities and behaviour of which we need to be aware in the context of human--computer interaction; this chapter considers the computer and associated input--output devices and investigates how the technology influences the nature of the interaction and style of the interface.
The first part of this chapter concentrates on the transference of information from the user to the computer and back. We begin by considering a current typical computer interface and the devices it employs (the keyboard and mouse), showing that the design is constrained by and related to the technology used. Since the devices influence the style of interaction, we move on to see the effects of different devices, considering their strong and weak points, and how they might alter the interface and interaction. Then we move on to consider devices that are not in common use, and suggest how they may affect future interfaces.
We then consider the computer itself, its processor and memory devices, noting how the technology drives and empowers the interface. The details of computer processing should largely be irrelevant to the end-user. However, the interface designer needs to be aware of the limitations of storage capacity and computational power; it is no good designing on paper a marvellous new interface, only to find it
Consider a typical computer setup as shown in Figure 2.1. There is the computer 'box' itself, a keyboard, a mouse and a colour screen. The screen layout is shown alongside it. If we examine the interface, we can see how its various characteristics are related to the devices used. The details of the interface itself, its underlying principles and design, are discussed in more depth in Chapter 3; we will simply consider the sorts of things that it allows us to do, and the device that facilitates the required actions. Each is discussed in turn, in conjunction with alternatives that offer a different approach to the same situation. The diversity of devices reflects the fact that there are many different types of data that may have to be entered into and obtained from a system, and there are also many different types of user, each with their own unique requirements.
When we are considering text entry, there are alternative approaches to the keyboard. These will affect the nature of the interface, sometimes in minor ways as adaptations are made to a standard system to cope with the slightly different medium, and sometimes in major ways when the interface is completely redesigned to take full advantage of the different characteristics of the devices.
Some organizer designs have dispensed with a keyboard completely. With such systems one must consider all sorts of other ways to interact with the system that are not character based. For example, we may decide to use drawings to tell the system what to do rather than commands using gesture recognition, for example drawing a line through a word in order to delete it. The important point is that a different input device that was initially considered simply as an alternative to the keyboard opens up a whole host of alternative interface designs and different possibilities for interaction. Pen-based systems that use handwriting recognition often use a special pen-based operating system, which attempts to tackle some of the problems of using a pen-based approach to what is otherwise a standard keyboard and mouse-oriented system, in much the same way as we suggested above, although there are also pen-based versions of standard operating systems.
The touchscreen is very fast, and requires no specialized pointing device. It is especially good for selecting items from menus displayed on the screen. Because the screen acts as an input device as well as an output device, there is no separate hardware to become damaged or destroyed by dirt; this makes touchscreens suitable for use in hostile environments. They are also relatively intuitive to use and have been used successfully as an interface to information systems for the general public.
processed in 0.01 seconds
|
| |
|
HCI Book 3rd Edition || old HCI 2e home page || search
|
|
| feedback to feedback@hcibook.com | hosted by hiraeth mixed media |
|
| |