82 • CHAPTER 4 Attention

Is it possible to focus

attention on just one

thing, even when there are

lots of other things going

on at the same time? (83)

Under what conditions

can we pay attention to

more than one thing at a

time? (91)

What does attention

research tell us about the

effect of talking on cell

phones while driving a

car? (94)

Is it true that we are not

paying attention to a

large fraction of the

things that are happening

in our environment? (96)

Some Questions We Will Consider

T

o begin this chapter, let’s revisit Crystal who we sent off on a run

down the beach in Chapter 3. The reason for following Crystal’s run was to

introduce some perceptual phenomena. Perceiving something initially as a piece

of driftwood and then realizing it was an umbrella illustrated the creative,

problem-solving nature of perception. Perceiving the rope as continuous illustrated per-

ceptual organization. Picking up the coffee cup later illustrated the connection between

perception and action.

But Crystal could not have achieved her feats of perception without another cog-

nitive mechanism, attention—the ability to focus on specifi c stimuli or locations. This

idea of focusing is most often associated with selective attention—the focusing of atten-

tion on one specifi c location, object, or message. This is what Crystal was doing when

she was looking at the umbrella, and it is what we are constantly doing as we make

our way through the environment, because we can only deal with a small fraction of

the objects and events that surround us. Think, for example, of all of the stimuli that

are present as you walk down a city street or across campus. There are people, build-

ings, perhaps birds, signs, cars, various sounds, and maybe even a few hundred ants

whose universe is inside a crack in the sidewalk beneath your feet. Because it would

be overwhelming to try to take in all of these stimuli, you focus on what is important

at a particular time and shift where you are looking from one place, object, or sound

source to another.

In the case of visual attention, the process of shifting attention from one place to

another by moving the eyes is called overt attention because the movements of the eyes

provide observable signals of how attention is changing over time. There are other

types of attention as well. There is covert attention, which occurs when attention is

shifted without moving the eyes, commonly referred to as seeing something “out of the

corner of the eye” (as you might do while trying to check someone out without looking

directly at him or her); and divided attention, attending to two or more things at once,

as Crystal might be doing as she looks at the umbrella while also being careful not to

step on any of the rocks that dot the beach. Divided attention can be overt, covert, or a

combination of the two. Looking back and forth between two objects or events (both

overt) would be divided attention; paying attention to something you are looking at

(overt) while at the same time paying attention to something off to the side (covert)

would also be divided attention (● Figure 4.1).

As we discuss these aspects of attention in this chapter, it will become clear that

attention is not just one process. We will show this both with behavioral examples and

by considering the physiology of attention, which involves many different processes

distributed throughout the brain.

We begin the story of attention by focusing on selective attention. We start with

selective attention because this aspect of attention was the primary concern of early

researchers, who, at the beginning of the cognitive revolution that we described

in Chapter 1 (see page 12), did experiments on selective attention to demonstrate

how the information-processing approach can be used to study the operation of

the mind.

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