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1.2 Good and poor design 5

multimedia applications, virtual-reality environments, speech-based systems, per-
sonal digital assistants and large displays-to name but a few. There are also
many ways of designing the way users can interact with a system (e.g., via the use
of menus, commands, forms, icons, etc.). Furthermore, more and more novel
forms of interaction are appearing that comprise physical devices with embedded
computational power, such as electronic ink, interactive toys, smart fridges, and
networked clothing (See Figure 1.2 on Color Plate 1). What this all amounts to is
a multitude of choices and decisions that confront designers when developing in-
teractive products.
A key question for interaction design is: how do you optimize the users' inter-
actions with a system, environment or product, so that they match the users' activi-
ties that are being supported and extended? One could use intuition and hope for
the best. Alternatively, one can be more principled in deciding which choices to
make by basing them on an understanding of the users. This involves:
taking into account what people are good and bad at
considering what might help people with the way they currently do things
thinking through what might provide quality user experiences
listening to what people want and getting them involved in the design
using "tried and tested" user-based techniques during the design process
The aim of this book is to cover these aspects with the goal of teaching you how to
carry out interaction design. In particular, it focuses on how to identify users'
needs, and from this understanding, move to designing usable, useful, and enjoy-
able systems.

How does making a phone call differ when using:
a public phone box
a cell phone?
How have these devices been designed to take into account (a) the kind of users, (b) type
of activity being supported, and (c) context of use?

Comment (a) Public phones are designed to be used by the general public. Many have Braille em-
bossed on the keys and speaker volume control to enable people who are blind and
hard of hearing to use them.
Cell phones are intended for all user groups, although they can be difficult to use for
people who are blind or have limited manual dexterity.
(b) Most phone boxes are designed with a simple mode of interaction: insert card or
money and key in the phone number. If engaged or unable to connect the money or
card is returned when the receiver is replaced. There is also the option of allowing the
caller to make a follow-on call by pressing a button rather than collecting the money
and reinserting it again. This function enables the making of multiple calls to be more
efficient.