44 • CHAPTER 2 Cognitive Neuroscience
that patients with Broca’s aphasia can, under certain
conditions, have difficulty understanding language.
Physiological research, involving both studying brain-
damaged patients and recording the event-related poten-
tial, suggests two processes for language processing, one
involving the form of language and the other involving
meaning.- The idea of distributed processing is that specific func-
tions are processed by many different areas in the brain.
This principle is illustrated by the finding that faces acti-
vate many areas of the brain and by the simpler example
of the rolling red ball, which also activates a number of
areas. - Distributed processing also occurs for other cognitive
functions, such as memory, decision making, and prob-
lem solving. A basic principle of cognition is that differ-
ent cognitive functions often involve similar mechanisms. - Objects and properties of the environment are repre-
sented by electrical signals in the nervous system. - Research indicating that individual neurons in the visual
system fire to specific simple stimuli, such as oriented
bars, led to the idea of feature detectors. This research
suggests that a particular object is represented by the fir-
ing of many neurons, creating a unique “chorus” of elec-
trical signals for that object. The pattern of neural firing
that represents an environmental stimulus is called the
neural code.- Among proposals regarding the nature of the neural
code are specificity theory, which includes the idea of
grandmother cells, and distributed coding. Current
evidence favors the idea of distributed coding. Thus, a
particular face would be represented by the pattern of
firing across a number of neurons. This is similar to the
idea of a neural chorus. - The idea of a distributed neural code also applies to
memory and other cognitive functions. The code for
memory involves stored information. - Computer programs have recently been developed that
can, with a surprising degree of accuracy, use data from
brain imaging, collected as a person is observing pictures
of different objects, to identify from a group of objects
the specific object that a person is seeing.
Think ABOUT IT
- Some cognitive psychologists have called the brain the
mind’s computer. What are computers good at, that the
brain is not? How do you think the brain and the mind
compare in terms of complexity? What advantage does
the brain have over a computer? - People generally feel that they are experiencing their
environment directly, especially when it comes to sensory
experiences such as seeing, hearing, or feeling the texture
of a surface. However, our knowledge of how the ner-
vous system operates indicates that this is not the case.
Why would a physiologist say that all of our experiences
are indirect?
3. When brain activity is being measured in an fMRI scan-
ner, the person’s head is surrounded by an array of mag-
nets and must be kept perfectly still. In addition, the
operation of the machine is very noisy. How do these
characteristics of brain scanners limit the types of behav-
iors that can be studied using brain scanning?
4. It has been argued that we will never be able to fully
understand how the brain operates because doing this
involves using the brain to study itself. What do you
think of this argument?
If You WANT TO KNOW MORE
Brain damage and behavior. There are numerous books that
describe fascinating case studies of people whose behavior
has been affected by brain damage.Farah, M. J., & Feinberg, T. E. (2003). Behavioral neurology
and neuropsychology (2nd ed.). New York: McGraw-Hill.Ramachandran, V. S., & Blakeslee, S. (1998). Phantoms of the
mind: Probing the mysteries of the human mind. New York:
HarperCollins.Sacks, O. (1985). The man who mistook his wife for a hat.
New York: Touchstone.Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part.