Neuroscience Research on Attention
During recent decades, researchers have developed a variety of sophisticated techniques
for examining the biological basis of behavior; Chapter 1 introduced many of these
approaches. Research using these techniques has identified a network of areas through-
out the brain that accomplish various attention tasks (Posner & Rothbart, 2007b).
Several regions of the brain are responsible for attention. In this discussion,
however, we’ll focus on structures in the cerebral cortex, as shown in Figure 3.2. Take
a moment to compare Figure 3.2 with Figure 2.1 (p. 38), which shows the regions of
the cortex that are most relevant in object recognition.
According to Michael Posner and Mary Rothbart, several systems in the cortex
process different aspects of attention (Posner & Rothbart, 2007a, 2007b; Rothbart et
al., 2011; Tang & Posner, 2009). We will discuss two of them, the orienting attention
network and the executive attention network.
The Orienting Attention Network. Imagine that you are searching the area
around your bathroom sink for a lost contact lens. When you are selecting information
from sensory input, your orienting attention network is activated. The orienting
84 CHAPTER 3 Perceptual Processes II: Attention and Consciousness
FIGURE 3.2
A Schematic Drawing of the Cerebral Cortex, as Seen from the Left
Side, Showing the Four Lobes of the Brain and the Regions that Are
Most Important on Attention Tasks.
Parietal lobe
Frontal lobe
Orienting
Attention
Network
Executive
Attention
Network
Occipital lobe
Temporal lobe
attention network is generally responsible for the kind of attention required for
visual search, in which you must shift your attention around to various spatial locations
(Chun & Wolfe, 2001; Posner & Rothbart, 2007b). Figure 3.2 shows that two
important components of the orienting attention network are located in the region of
the cortex known as the parietal lobe (pronounced ‘‘pah-rie-uh-tul’’).
How did researchers identify the parietal cortex as the region of the brain that
we use in visual searches? Several decades ago, the only clue to the organization of
the brain was provided by people with brain lesions (Posner, 2004). The term brain
lesion refers to specific brain damage caused by strokes, accidents, or other traumas.
People who have brain damage in the parietal region of the right hemisphere of
the brain have trouble noticing a visual stimulus that appears on the left side of their
visual field. In contrast, people with damage in the left parietal region have trouble
noticing a visual stimulus on the right side (Luck & Vecera, 2002; Posner & Rothbart,
2007a, 2007b; Styles, 2005). Neurologists use the term unilateral spatial neglect
when a person ignores part of his or her visual field (Gazzaniga et al., 2009).
Explanations for Attention 85
These lesions produce unusual deficits. For instance, a woman with a lesion in the
left parietal region may have trouble noticing the food on the right side of her plate.
She may eat only the food on the left side of her plate, and she might even complain
that she didn’t receive enough food (Farah, 2000; Humphreys & Riddoch, 2001).
Surprisingly, however, she may seem completely unaware of her deficit. In another
study, researchers tested a man with a lesion in his right parietal lobe. They showed
him a figure of an ordinary clock and asked him to draw it. His drawing showed only
half of the clock, with the other half completely empty (Bloom & Lazerson, 1988).
Some of the more recent research on the orienting attention network has used
PET scans. In studies using positron emission tomography (abbreviated PET scan),
the researchers measure blood flow in the brain by injecting the participant with a
radioactive chemical just before he or she performs a cognitive task. As discussed
in Chapter 1, this chemical travels through the blood to the parts of the brain
that are active during the cognitive task. A specialized camera makes an image of
the accumulated chemical. According to PET-scan research, the parietal cortex shows
increased blood flow when people perform visual searches and when they pay attention
to spatial locations (Posner & Rothbart, 2007b).
The orienting network develops during the first year of life. For example, by
about 4 months of age, infants can disengage their attention from an overstimulating
situation, and they can shift this attention to an object such as a new toy (Posner &
Rothbart, 2007a; Rothbart et al., 2011).
The Executive Attention Network. The Stroop task that you tried in Demon-
stration 3.1 relied primarily on your executive attention network. The executive
attention network is responsible for the kind of attention we use when a task focuses
on conflict (Posner & Rothbart, 2007a, 2007b). On the Stroop task, for example, you
need to inhibit your automatic response of reading a word, so that you can name the
color of the ink (Fan et al., 2002).
More generally, the executive attention network inhibits your automatic
responses to stimuli (Stuss et al., 2002). As you can see in Figure 3.2, the prefrontal
portion of the cortex is the region of your brain where the executive attention network
is especially active.
The executive attention network is primarily involved during top-down control of
attention (Farah, 2000). This network begins to develop at about age 3, much later than
the orienting attention network (Posner & Rothbart, 2007a; Rothbart et al., 2011).
Posner and Rothbart (2007b) argue that the executive attention network is extremely
important when you acquire academic skills in school, for example, when you learned
to read. There is also some evidence that adults can enhance their executive attention
network by learning meditation, adopted from traditional Chinese techniques (Tang
& Posner, 2009).
Executive attention also helps you learn new ideas (Posner & Rothbart, 2007a).
For example, as you are reading this passage, your executive attention network has
been actively taking in new information. Ideally, you have also been comparing
this executive attention network with the orienting attention network. This process
of reading and understanding a college-level textbook can be challenging. Not
86 CHAPTER 3 Perceptual Processes II: Attention and Consciousness
surprisingly, the location of the executive attention network overlaps with the areas
of your brain that are related to general intelligence (Duncan et al., 2000; Posner &
Rothbart, 2007b).
In summary, PET scans and other neuroscience techniques have identified one
brain region that is typically active when we are searching for objects (the orienting
attention network). Neuroscience research also show that a different brain region
is typically active when we must inhibit an automatic response and produce a less
obvious response (the executive attention network); this second network is also active
in academic learning.
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