Cognitive Psychology
Cognitive Psychology
is the scientific study of
cognition. Cognition refers to the process of knowing, and
cognitive
psychology is the study of all mental activities related to acquiring,
storing,
and using knowledge. The domain of cognitive psychology spans the entire
spectrum of conscious and unconscious mental activities: sensation and
perception, learning and memory, thinking and reasoning, attention and
consciousness, imagining and dreaming, decision making, and problem
solving.
Other topics that fascinate cognitive psychologists include creativity,
intelligence, and how people learn, understand, and use language.
Over the years, cognitive
psychologists have
discovered that mental activities that seem simple and natural are, in
fact,
extraordinarily complex. For example, most children have no trouble
learning
language from their parents. But how do young children decode the
meanings of
sounds and grasp the basic rules of grammar? Why do children learn
language
more easily and rapidly than adults? Explaining these puzzles has proven
very
difficult, and attempts to duplicate true language ability in machines
have
failed. Even the most advanced computers have trouble understanding the
meaning
of a simple story or conversation. Cognitive psychologists have found
similar
complexity in other mental processes.
Cognitive psychology is
one field within cognitive
science, an interdisciplinary approach to the study of the human
mind.
Other fields in cognitive science include anthropology, linguistics,
neuroscience (the study of the brain and nervous system), and artificial
intelligence. Cognitive neuroscience, or neurocognition,
combines
cognitive psychology and neuroscience.
Cognitive psychology is
sometimes confused with
cognitive therapy, a type of psychotherapy used to treat depression and
other
mental disorders. Cognitive therapy falls within the realm of clinical
psychology, the branch of psychology devoted to the study and treatment
of
mental disorders. See Psychotherapy: Cognitive Therapies.
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ORIGINS OF
COGNITIVE
PSYCHOLOGY
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Curiosity about the nature
of knowledge and the
mind dates back as far as the first recorded philosophers. The Greek
philosopher Plato held that the seat of knowledge was in the brain, but
his
pupil Aristotle believed that knowledge was located in the heart. Many
others
since have wondered about how we come to know and understand our world,
how we
remember or represent information about the world, and how we arrive at
decisions.
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Early Studies of
Cognition
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Although Renaissance philosophers
and theologians
actively debated the source of knowledge and the nature of sense
perception (see
Epistemology), the scientific study of cognition did not begin until
the
late 19th century. In 1879 German physiologist Wilhelm Wundt founded the
first
psychological laboratory, at the University of Leipzig in Leipzig,
Germany.
Reasoning that people are the best source of information about their own
thoughts, Wundt set about studying consciousness through the method of
introspection. This technique involved asking people to observe and
report what
occurred in their minds as they engaged in various mental tasks. In 1885
German
psychologist Hermann Ebbinghaus conducted the first experiments on
memory and
forgetting. In the United States, psychologist William James used
introspection
to theorize about the structure of memory and consciousness, and in 1890
he
defined psychology as “the science of mental life.” In 1896 American
psychologist Mary Whiton Calkins invented an important technique for
studying
memory retention.
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The Shift to
Behaviorism
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In the early 1900s, however,
with psychology
becoming more distinct from philosophy and physiology, attention shifted
away
from questions about mental life to questions about behavior. This shift
occurred
because many psychologists thought that it was impossible to study
mental life
using scientific methods. For example, critics of introspection labeled
it
subjective and speculative, and even its supporters found that people
were
unable to report on their own mental states in much detail. Behavior, on
the
other hand, could be observed, measured, and documented. American
psychologist
John B. Watson, considered the founder of behaviorism, contended that
all human
behavior could be explained without reference to a person’s thoughts,
feelings,
or mental states. Another leading behaviorist, American psychologist B.
F.
Skinner, was adamant in his belief that even the most advanced forms of
human
learning, such as language acquisition, could be explained in terms of
the
basic principles of conditioning (see Learning).
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Reemergence of
Cognitive
Psychology
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Landmark developments
in the late 1940s and throughout the
1950s revived hope for the scientific study of mental life and fueled a
“cognitive revolution” in psychology. In 1949 Canadian psychologist
Donald O.
Hebb published pioneering work, based in part on animal studies, that
theorized
about the biological basis of memory and other psychological phenomena.
In 1956
American psychologist George Miller showed that there are limits to the
amount
of information that people can hold in short-term memory at any one
time. In
the late 1950s American linguist Noam Chomsky refuted Skinner’s
behaviorist
explanation of language development as overly simplistic. Chomsky’s
theory,
which proposed that children possess an innate ability to extract
meaning from
speech sounds, stimulated further interest in cognitive psychology.
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Cognition as
Information
Processing
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The development of digital
computers introduced new
metaphors for thinking about human mental operations. Philosophers had
offered
such mechanical metaphors many times before, likening the mind to a
blank slate
(tabula rasa), a black box, and even a mechanical robot. But the
computer
metaphor was more powerful because it provided both a way for
psychologists to
conceptualize their observations and a common language for theorists to
communicate their ideas. Computer terms such as input, output,
processing, information
storage, and information retrieval seemed to resemble
the
“real” mental activities of people. Thus, cognitive psychologists began
describing humans as information processors.
The information-processing
model sees human cognition
as a series of stages through which information passes sequentially. In
this
model, information gets into our brain (is encoded), is retained briefly
or for
longer periods of time (short-term or long-term storage), and is later
reactivated (retrieved) for further processing or use.
With the development of
more-sophisticated computer
systems in the 1980s and 1990s, cognitive psychologists extended the
computer
metaphor to new models of cognition. These models rejected the idea of
information processing as linear and sequential and instead proposed
that the
brain is capable of parallel processing, in which multiple operations
are
carried out simultaneously. One such model, called the parallel
distributed
processing model of cognition, reflects findings in neuroscience
that suggest
linear processing cannot account for the recorded speed of human memory
retrieval.
Although the information-processing
model is a powerful
tool for guiding the study of cognitive processes, many psychologists
argue
that it falls short of capturing the full richness of people’s cognitive
experiences. Describing the act of remembering as a process of storage
and
retrieval, for example, neglects the subjective experience of
remembering.
Another criticism is that information-processing theory may not reflect
how the
brain actually works. Newer models, such as the parallel distributed
processing
model, try to address this criticism by drawing on studies of brain
structure
and function. Psychologists continue to debate the adequacy of the
information-processing model, but its influence likely will last well
into the
21st century.
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METHODS OF
RESEARCH
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Like other psychologists,
cognitive psychologists use a
wide variety of research methods. Methods particularly relevant to
cognitive
psychology can be organized into three general categories: (1)
self-reports, or
people’s descriptions of their experiences; (2) reaction-time
measurements; and
(3) methods that measure biological factors such as brain activity.
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Self-Reports
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One way of researching
cognition is to conduct
experiments in which the participants are asked to report their
experiences.
For example, an experiment on pattern recognition might present people
with
various visual stimuli and ask them to name what they see. An experiment
on
memory ability might require participants to view a list of words, then
either
say what they can remember (recall) or select the words they saw from a
larger
list (recognition). Self-report measures sometimes include people’s
descriptions of their own intuitions about how their minds work. For
example,
people might report on the mental imagery they experience as they listen
to a
story or to music.
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Reaction-Time
Measurements
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One common way that psychologists
study
thinking and other cognitive processes is to measure how fast people can
make
decisions, solve problems, and distinguish between different stimuli. In
typical laboratory studies, people might be asked to name the colors in
which
words are printed, to scan for a special character in an array of
letters, or
to respond as quickly as possible about whether statements are true or
false.
For a demonstration of
how reaction times can
illustrate mental processes, look at the accompanying illustration,
entitled
“Stroop Test.” First, look at the left side of the illustration and,
beginning
with the first column, name aloud each color as fast as you can. Next,
look at
the right side of the illustration and again name the colors in which
the words
are printed as fast as you can. Did you take longer to finish the second
task?
Almost all people find that the words interfere with their ability to
name the
colors. People do not need to read color names before naming the printed
colors,
but they seem unable to stop themselves. This test suggests that reading
is an
automatic process and that processing the word meanings interferes with
the
task of color naming.
Computers allow psychologists
to measure reaction time
in very small units, typically in milliseconds (thousandths of a
second). For
example, experiments have shown that people can recognize some faces in
about
300 milliseconds, or less than one-third of a second. Such precise
measurements
allow scientists to test hypotheses about how the brain processes,
stores, and
retrieves information.
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Biological
Methods
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Advances in medical technology
have made possible
some of the most exciting developments in the history of cognitive
psychology.
Prior to the 1970s, it was virtually impossible to measure the activity
of the
living human brain without cutting open the head. The invention of
sophisticated brain imaging techniques means we can now view pictures of
the
brain “in action.” These techniques include computed tomography (CT),
positron
emission tomography (PET), magnetic resonance imaging (MRI), and
functional
magnetic resonance imaging (functional MRI). By observing patterns of
brain
activity as a person engages in various mental activities, researchers
have
gained new insights into memory, perception, language, and other
processes. For
more information about brain imaging techniques, see Brain: Brain
Imaging.
Scientists use a number
of other methods to measure
brain and nervous system activity. Scalp electroencephalography (EEG)
measures
the general electrical activity of the brain by means of electrodes
taped to
the scalp. Researchers have found that certain EEG readings correlate
with
particular states of consciousness, such as arousal, relaxed
wakefulness,
sleep, and deep sleep. Another technique, electrooculography, measures
the
movements of the eyes and is often used in studies of sleep and
dreaming.
Studies of cognitive processes in animals may use invasive research
methods, such
as stimulating parts of the brain with a probe or removing part of the
brain.
For an overview of biological methods used in psychological research, see
Biopsychology:
Methods of Research.
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TOPICS OF STUDY
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One of the broadest branches
of psychology,
cognitive psychology encompasses dozens of topics of study. This article
briefly describes some of the most important areas in the field:
perception,
learning and memory, thinking and reasoning, and language.
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Perception
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Studies in perception
try to understand how people
interpret sensory information to make sense out of their world. The
human sense
organs receive information about the world in the form of physical
energy—for
example, light waves and sound waves. This energy is converted by our
sensory
system into electrical impulses that travel to the brain. Perception is
the
mental process that translates these impulses into things we can
recognize and
understand: people, objects, places, sounds, tastes, and smells.
Perception is such a natural,
effortless
process that most people are not even aware of it. But to cognitive
psychologists, perception is one of the great mysteries of the mind.
They
wonder about questions such as “How do we perceive the world in three
dimensions even though the images projected into the eyes are
two-dimensional?”
“Why do we perceive melodies in music, rather than a series of
disconnected
notes?” “What causes visual illusions?”
One area of study in perception
is
pattern recognition, the ability to recognize familiar forms in a sea of
sensory information. For example, recognizing a friend’s face in a crowd
is a
form of pattern recognition. Another area of interest in perception
concerns
the difference between perceiving and imagining. Some cognitive
psychologists
propose that perceiving and imagining are often quite similar, but
others
disagree with this point of view.
See Perception; Illusion.
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Learning and
Memory
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Many people think of learning
as something
that occurs in a classroom. To psychologists, the word learning
refers
more generally to how we acquire knowledge, develop new behaviors, and
adapt to
life’s challenges. Researchers have discovered many general principles
that
govern basic learning. For example, two common forms of learning are
operant
conditioning (the shaping of behavior through reward and punishment) and
learning through observation. Cognitive psychologists are particularly
interested in complex forms of learning, such as learning languages or
advanced
mathematics.
Learning is tightly interwoven
with memory, the
process of storing and retrieving information in the brain. Memory plays
a
central role in nearly all mental activities. More than just a
fact-retrieval
system, memory allows us to make inferences, solve unfamiliar problems,
and
relate objects and events to prior knowledge. Memory is one of the most
active
areas of research in cognitive psychology. Researchers investigate
questions
such as, What is the capacity of memory? Why do people forget
information? What
parts of the brain are involved in memory? How is knowledge represented
and
organized in memory? What factors influence the accuracy of memories?
Most psychologists distinguish
at least three systems or
components of memory. The first is sensory memory, in which information
is held
by the sensory system for only an instant. Working memory, also called
short-term memory, holds information in consciousness temporarily for
immediate
manipulation and use. Long-term memory is what most people think of as
memory.
It stores immense volumes of information for long periods of time.
See Learning; Memory.
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Thinking and
Reasoning
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Thinking involves the
mental manipulation of information
for the purpose of reasoning, solving problems, making decisions and
judgments,
or simply imagining. Although cognitive psychologists cannot see
thinking
processes, they can make inferences about these processes from behavior.
Cognitive psychologists
have noted that people use a number
of strategies when reasoning about a problem or decision. Often people
employ
deductive reasoning or inductive reasoning, two forms of logic. In
deductive
reasoning, people draw conclusions about specific cases from general
principles
that are assumed to be true. In inductive reasoning, people infer a
general
rule from specific cases. When making judgments or solving problems,
people
also frequently rely on heuristics, rules of thumb that usually
lead to
the correct solution but are not guaranteed to work all of the time.
Many philosophers have
asserted that humans are rational
thinkers who are careful and systematic in their evaluation of
information. But
when cognitive psychologists look carefully at the kinds of decisions
people
make and how they arrive at those decisions, they find that people are
often
less than rational. For example, imagine that you have a serious
tropical
disease and must decide whether to have surgery or take medication. The
medication, while not particularly dangerous, is also not extremely
effective.
The surgery is very effective, but there is 30 percent chance that you
will die
within six months after the surgery. Given this hypothetical scenario,
most
people choose the medication. But when the risk is phrased another
way—that 70
percent of those who select surgery are still alive six months
later—people are
more willing to choose the dangerous procedure. The term framing
effects
refers to the fact that people’s decisions are heavily influenced by the
way
information is framed. One focus of research in decision making is how
to help
people avoid these effects when making difficult or life-threatening
decisions.
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Language
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Of all human abilities,
language is perhaps the
most impressive. In spoken, written, and gestured forms, language is the
primary means of communication among people. Although other animal
species have
evolved sophisticated systems of communication, none of these systems
approaches human language in complexity. With language, we can refer to
events
or ideas in the past or future, talk about abstract concepts such as
morality,
and record the stories of human civilization.
Language is a central
topic of study in cognitive
psychology because it is closely connected with perception, memory,
thinking,
problem solving, and other mental processes. Of particular interest to
psychologists is how children acquire language and why they have an
easier time
mastering language than adults who try to learn a second language. Many
scientists believe the human brain is uniquely “wired” to learn language
during
a critical period in infancy and early childhood. Supporters of this
idea note that
children all over the world achieve specific language milestones at
roughly the
same age. However, scholars continue to debate how much of language
capacity is
inborn.
Another widely debated
question is whether animals other
than humans have the capacity for language. Researchers have tried to
answer
this question by training chimpanzees and gorillas—the closest genetic
relatives of the human species—to use sign language or to press symbols
on a
keyboard. This research has shown that apes can produce and understand
simple
phrases and sentences and even appreciate subtle differences in word
order and
sentence structure. One chimpanzee, Kanzi, has demonstrated the ability
to
understand spoken English sentences at the level of a 2y-year-old child.
Although some scientists remain skeptical of
these findings, most now agree that apes can attain a rudimentary form
of
language.
Other areas of research
include the structure of
language, how language is organized and represented in the mind, how we
process
and understand language, the neurological basis of language, and
language
disorders. Another subject of investigation concerns the relationship
between
language and thought. For example, is thinking merely speech that is not
vocalized, or are other processes involved? How does language influence
the way
we think?
Psycholinguistics is the
interdisciplinary study of the mental processes involved in language
acquisition, production, and comprehension. Specialists in this field
may come
from one of various disciplines, including cognitive psychology,
linguistics,
neuroscience, and anthropology.
Tags
Psychology
