Behavior: Basic Psychology of the User - Foundations for Designing User-Centered Systems - page 78

Chapter 4
Behavior: Basic Psychology of the User
Abstract This chapter examines what are described as user behavioral charac-
teristics. These are characteristics that are related to perception in broad terms. The
chapter starts by defining some behavioral terms and concepts that are used in this
and subsequent chapters. We then describe in detail several aspects of the two
main perceptual systems that are involved in interacting with computer-based
systems: vision and hearing. For each of these aspects we consider some of the
implications they have for system design. We finish by introducing the topic of
motivation to help explain why individual users may behave in a particular way
when carrying out a task.
4.1 Introduction
When we refer to behavioral characteristics we are really talking about things that
are linked to sensation and perception, in general terms. We know that people have
five basic senses: sight, hearing, touch, smell, and taste. Sensation occurs when the
sense organs (eyes, ears, and so on) are stimulated, and they generate some form of
coding of the stimuli. Perception occurs when this coded information is further
interpreted using knowledge of the current context (physical, physiological, psy-
chological, and so on) to add meaning. The process of perception is subjective:
simply presenting designed stimuli in such a way that they will be sensed accu-
rately does not necessarily mean that they will be perceived in the way that the
designer intended.
Sight, hearing, and smell all sense stimuli that appear at some distance from the
body. In other words they detect distant (distal) stimuli. Touch and taste, however,
rely on contact being made with the stimuli. This means that the stimuli have to be
very close to the body, which is why they are described as proximal stimuli.
We need to think about the user's behavioral characteristics when designing
systems because we want to make sure that the system fits the user. A well-designed
system will take into account the user's ability to detect changes in an interface, for
example, and we can use this information to inform the design of screen layouts to