Module 26
What Is Intelligence?
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intellectual tasks provides the most accurate measure of intelligence. Consequently,
rather than focusing on the structure of intelligence or its underlying content or
dimensions, information-processing approaches examine the processes involved in
producing intelligent behavior (Hunt, 2005; Neubauer & Fink, 2005; Pressley &
Harris, 2006).
For example, research shows that people with high scores on tests of intelligence
spend more time on the initial encoding stages of problems, identifying the parts of
a problem and retrieving relevant information from long-term memory, than do
people with lower scores. This initial emphasis on recalling relevant information pays
off in the end; those who use this approach are more successful in fi nding solutions
than are those who spend relatively less time on the initial stages (Sternberg, 1990;
Deary & Der, 2005; Hunt, 2005).
Other information-processing approaches examine the sheer speed of processing.
For example, research shows that the speed with which people are able to receive
information from memory is related to verbal intelligence. In general, people with
high scores on measures of intelligence react more quickly on a variety of information-
processing tasks ranging from reactions to fl ashing lights to distinguishing between
letters. The speed of information processing, then, may underlie differences in intel-
ligence (Jensen, 2005; Gontkovsky & Beatty, 2006; Helmbold, Troche, & Rammsayer,
2007; Sheppard & Vernon, 2008).
The Biological Basis
of Intelligence
Using brain-scanning methods, researchers have identifi ed several areas of the brain
that relate to intelligence. For example, the brains of people completing intelligence
test questions in both verbal and spatial domains show activation in a similar loca-
tion: the lateral prefrontal cortex. That area is above the outer edge of the eyebrow
about where people rest their heads in the palms of their hands if they are thinking
hard about a problem. This area of the brain is critical to juggling many pieces of
information simultaneously and solving new problems. In addition, higher intelli-
gence is related to the thickness of the cerebral cortex (Schaer & Eliez, 2007; Karama
et al., 2009; Luders et al., 2009).
Similarly, tasks requiring different types of intelligence involve different areas of
the brain. For instance, as can be seen in Figure 2, when tasks require more general
global intelligence, more areas of the brain are involved than tasks requiring more spe-
cifi c sorts of intelligence (such as fl uid and crystallized intelligence) (Colom et al., 2009).
These fi ndings suggest that there is a global “workspace” in the brain that orga-
nizes and coordinates information, helping to transfer material to other parts of the
brain. In this view, the activity in the workspace represents general intelligence (Gray,
Chabris, & Braver, 2003).
Research using nonhumans has also begun to help us better understand the
biological underpinnings of intelligence. For example, rats raised in enriched envi-
ronments (meaning an environment containing more toys, tunnels, and so on)
develop more complex connections between neurons along with more rapid learning
and better memory. Other studies show differences in metabolism (the rate at which
food is converted to energy and expended by the body) that seem to be related to
intelligence (Rampon et al., 2000; Haier, 2003; Yang et al., 2007).
Ultimately, the search for the biological underpinnings of intelligence will not
lead in a single direction. Rather, the most plausible scenario is that multiple areas
of the brain, as well as multiple kinds of functioning, are related to intelligent
behavior.
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