Developmental psychology.pdf

54 Background and Methods
Survey Method
3. The purpose of the survey is to obtain information from a large number of
subjects in an efficient manner. A questionnaire or inventory, containing
structured or open-ended items, is used to obtain information on a wide
variety of personal traits, and the results provide norms, indicating what is
normal or expected for a certain group.
4. The people to whom the questionnaire is administered constitute a sample,
which is a group of subjects drawn from a larger group called the
population. When a sample accurately reflects the characteristics of a
certain population, it is called a representative sample. As a rule, a large
random sample is more likely to be representative than a small one.
5. If a sample is not representative, generalizations concerning the larger
population are risky. Another limitation of the survey is that the behavior in
question is rarely observed; the investigator studies only what the subjects
say about themselves, not the behavior itself.
Clinical Approach
6. In the clinical approach, used to assist maladjusted individuals, extensive
information is gained through a series of interviews. These conversations
between therapist and patient can vary widely in method; ancillary
techniques can include the use of recordings and group interviews.
7. Psychological tests are also useful in gathering information about people.
Often this information involves idiographic analysis, concerned with
discovering the unique behavior patterns of a given individual. At times,
like the other research methods, it also involves nomothetic research, which
has the purpose of discovering laws of behavior pertaining to people in
general.
8. The case history is a detailed statement of an individual's background and
current circumstances. Developed through tests and interviews, and
emphasizing family life, schooling, and work history, it can be useful in
understanding a specific individual.
Experimental Method
9. The experimental method, involving control or manipulation of variables, is
concerned with the relationships among stimulus (S), organism (O), and
response (R) variables. In the classical experiment the investigator
manipulates an independent variable, usually a stimulus, and notes its
influence on the dependent variable, usually a response.
10. An important consideration in planning an experiment is the method of
controlling disruptive variables. Commonly the subjects are studied under
two conditions, experimental and control, which are equal except that the
independent variable is absent in the control condition. In one method,
called own controls, the same subjects are used for the experimental and
control conditions. In other methods two sets of subjects are used, and they
are placed in comparable groups by matching pairs or by procedures for
randomization.
11. The multiple bases of behavior prompt modern psychologists to study the
influence of several independent variables simultaneously. The multifactor
studies can reveal additive effects, in which the influences are simply
cumulative, and interactive effects, in which the influences are
interdependent.