CHAPTER
1 LESSON 3
Physiological Measures: Activities of Brain and Body
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Measurement The assignment of an orderly system of numbers to behaviors or traits. Galvanic skin
response (GSR) Electrical changes in the skin associated with the activity of the
sweat glands. |
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Psychologists are
also interested in the measurement of any physiological characteristics that
have a bearing on behavior. They have found, for example, that certain
abnormal states such as severe depression may be triggered by disturbances in
the chemistry of the brain. They have also shown that the feelings of hunger
are not necessarily caused by activity of the stomach, as popularly believed,
but by measurable changes in the composition of the bloodstream. They have
also shown that the body may respond at times with changes in hormones that
are related to anxiety, although the individual reports feeling no emotion. As described in the
next chapter, new techniques now allow researchers to study the brain
directly-its structure, blood flow, chemistry, and electrical activity-while
the individual is engaged in a variety of activities or while experiencing
unusual states of consciousness such as those produced by sleep, drugs, or
hallucinations. Researchers have measured the activity of the glands that
influence emotions, and the way the arousal of emotions produces changes in
the heart rate, blood pressure, and breathing. They have measured muscle
tension and brain wave activity in states of stress and relaxation. In
identifying some of the chemicals, produced in nerve endings, that transmit
nervous impulses, they have found how irregularities in these chemicals play
a part in mood and behavior. Often it turns out to
be important to use physiological measures in conjunction with other methods
since they may reveal information otherwise unavailable. For example,
individuals suffering certain brain injuries have reported being unable to
recognize familiar persons in photographs. However, when electrodes are
placed on their palms to measure the galvanic skin response (GSR)-that
is, the electrical changes associated with sweating-it is clear that the
photographs of familiar persons do indeed arouse a response (Tranel &
Damasio, 1985). This means that at some deep, unconscious level, recognition
is taking place. |
Measuring
the Differences Among Us
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Individual
differences Variations between members of the same species. Statistics A branch of mathematics that analyzes and summarizes data and then
draws conclusions from that data. Normal curve of
distribution A bell-shaped
curve illustrating that for many events in nature most cases cluster around
the average and decline near either extreme. |
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Psychology's methods
have been particularly helpful in adding to our knowledge of individual
differences among people. Every person is indeed unique, and physical and
psychological traits, from height and muscular strength to intelligence and
emotional sensitivity, vary over a wide range.
In studying individual differences, the science relies heavily on mathematical
techniques known as statistics.
Many human traits, from height and weight to intelligence, fall into a
similar pattern. Regarding height, for example, the measurements for adult
American men range all the way from around 3 feet to around 8 feet. But most
cluster around the average, which is now about 5 feet 9 inches, and the
number found at each point in the range goes down steadily with each inch up
or down from the average. Note the graph below, which shows how IQs as
measured by intelligence tests range from below 40 to above 160-but with the
majority falling close to the average of 100, and only a very few at the
extreme low or high levels.
The pattern shown in below is so typical of the results generally
found in all tests and measurements that it is known as the normal curve
of distribution. The message of the curve is that in many measurable
traits, physical and psychological, most people are average or close to it, some
are a fair distance above or below, and a few are very far above or below.
Those who are about average have a lot of company. Those who are far removed
from the average-in intelligence the geniuses and the mentally retarded, in
height the seven-footers and the four-footers-are rare. The curve of normal
distribution helps explain a great deal about behavior, including the general
similarities displayed by most people and the wide deviations shown by a few
others. The curve applies to performance in school. (Most students have to do
an average amount of struggling; some can make A's without turning a hair;
some cannot handle the work at all.) It applies to musical talent, athletic
skill, and interest or lack of interest in sex- as well as to the intensity
of emotional arousal and the strength of motives for achievement, power, and
friendship. These and many other individual differences are the reason you
cannot generalize about humanity as a whole from your own traits--especially
on a matter in which you happen to fall at an unusually low or high point on
the curve. |
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Individual
differences in IQ The graph was obtained by testing the IQs of a large number of people
in the
upper extremes. Fewer than 1 percent of all people showed IQs under 60
and only 1.33 percent were at 140 or over (Terman & Merrill, 1937).
Correlation:
To What Extent Is "A" Related to "8"?
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Correlation A statistical method examining the |
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Consider a question
that has interested psychologists almost from the beginning of the science:
Do children resemble their parents in intelligence? This question has many
implications for study of the part played by heredity and environment-which,
as you will see a little later, is one of the basic issues in psychology. How
would you try to go about answering it?
A person untrained in the methods of science might jump to conclusions
based on personal experience: "No, obviously not. My neighbors the
Smiths are both smart people-they went to college and have good jobs-but
their two kids are having a terrible time in school." Or,
"Certainly. My neighbors the Joneses are geniuses and their two
daughters are the smartest kids in their school." A
more sophisticated approach would be to look at a much larger sample of
children and parents than provided by just the Smiths or the Joneses-and give
both generations intelligence tests rather than to rely on personal
impressions of how smart they seemed to be. This would be a good start toward
a scientific answer. But the results would be difficult to interpret, because
the tests would show contradictions. One mother and father, both with IQs of
120, turn out to have an only child whose IQ is also 120-but another couple
with the same IQ has an only child with an IQ of 90. One mother at 95 and
father at 85 have an only child with an IQ of 90-but a similar couple has a
child whose IQ is 125. Even in the same family the tests would sometimes show
three children with IQs as far apart as 85, 115, and 135. Without some method
of analyzing and interpreting the test results, any scientific answer to the
question would still be elusive. In this type of situation,
psychologists apply a statistical tool called correlation. This is a
mathematical method used to examine two different measurements (such as the
IQs of parents and the IQs of their children)-and to determine what
relationship, if any, actually exists between the two. The method, computes a coefficient of correlation ranging
from 0.00 (no relationship at all) to 1.00 (a one-to-one or absolutely
perfect relationship.) In the case of parents and children, the coefficient
of correlation between IQs has generally been found to be about
0.50-indicating a fairly high, though by no means perfect, relationship. |
You will find many correlations mentioned throughout this course, but a
word of caution is in order. Correlations reveal
the existence and extent of relationships, but they do not necessarily indicate
cause and effect. Unless
they are carefully interpreted, correlations can be misleading. There is a high
correlation between the number of permanent teeth in children and their ability
to answer increasingly difficult questions on intelligence tests. But this does
not mean that having more teeth causes increased mental ability. The
correlation is high because increasing age accounts for both the new teeth and
the mental development. Usually when two traits are correlated it is because a
third process is the cause of both of them.
VOCABULARY REVIEW
These are vocabulary definitions that you
need to be familiar with the chapter test.
In your notebook, write the term after the given term.
1. Psychology is defined to be
the systematic study of behavior and mental processes-including thought and
emotion-and the factors that influence them. The term "systematic study;'
meaning the use of rigorous and highly disciplined methods of science rather
than relying on judgments based on insufficient evidence or unwarranted
generalities, distinguishes ________
from the views of behavior proposed in philosophy and literature.
2. Psychology studies our physical activities-everything we do from the time we
wake up in the morning until we go back to bed and fall asleep. All these forms
of activities are the _______ that the
science of psychology studies.
3. Psychologists also study the activities that take place inside of us-the
ways we learn, remember, forget, feel hungry, become angry or joyful.
Such, __________ __________ , which include __________ and _______, are also embraced by
the study of psychology.
4. In addition, psychology studies the things and events that influence
behavior and mental processes, including the human brain, sense organs,
chemicals in the bloodstream, heredity, the actions of other people, and so
forth. These _______ that influence behavior and mental processes
are a third category of items studied by psychologists.
5. Psychology, then, is the __________ __________ of ____________ and
__________ _________
-including ________ and ________ and ___________that influence them.
6. The missions of psychology are (1) to understand behavior and mental
processes and (2) to predict their course. For example, psychologists try to
________ why individuals behave as they
do in a classroom or in social situations to ___________ how they would behave in school or in a
social environment.
7. The missions of psychology, similar to the goals of all sciences, are
to _______ behavior and mental processes and to __________ their course.
8. Psychology is one member of a family of sciences often referred to as
the behavioral and social sciences. Subject matter ranging from the
neurochemical basis of memory and mental illness to the dynamics of global
commerce and international conflict constitute the domain of the
____________ and ________ _______.
9. Scientists who study genetics, physiology, anthropology, economics,
linguistics, education, sociology, and
political science are all members of the _________ and _______ __________and
those who study behavior and mental processes in particular are part of the
field of __________.
CHECK
ANSWERS 