Download Chapter 2 -- Psychology as a Science

Chapter Summary/Lecture Organizer
Chapter 2 — Psychology as a Science
I.
II.
What is a Science?
A.
Science is a philosophy and approach to understanding the world. All science
assumes two core principles:
1.
the universe operates according to certain natural laws; and
2.
these laws are discoverable and testable
B.
Science relies upon the scientific method, a process designed to guard against bias and
based upon inductive reasoning that moves from making controlled, direct
observation to generating progressively broader conclusions. Psychology also
emphasizes empirical (objectively testable) observation and use of the hypotheticodeductive approach in which researchers:
1.
state hypotheses in such a way that they may be proven false (falsification)
2.
create controlled observations in which data are collected to prove or disprove
hypotheses
3.
use results to modify or discard the theory from which the hypotheses were
derived
Is Psychology Really a Science?
A.
The influence of biology during the 19th century, coupled with Darwin’s evolutionary
theory, shifted psychology away from philosophy and closer toward the sciences.
Psychology shares with every science the primary goals of describing, explaining,
predicting, and controlling the objects of study. As a natural science, the goals of
psychology differ somewhat from those of other sciences. For example, the search
for elements of mental processes and behavior is complicated by dynamic individual
and social factors. Also, the basic elements that psychologists study are less directly
observable than some other sciences.
B.
Psychology also shares more similarity with the fields of religion and philosophy than
many sciences do, because psychological findings are more often associated with
values, morality, and personal preference.
C.
Psychology is different from pseudopsychology (“pop psychology”) which does not
the scientific method yet may give the impression of legitimate answers about human
nature and behavior.
III. How Do Psychologists Conduct Research?
A.
Based on their prior observations researchers generate a hypothesis, or prediction
about the relationship between two or more variables (conditions, events, or
situations). A psychologist’s ability to draw conclusions based on his or her study is
strongly influenced by how the variables of interest are operationally defined.
In experiments:
1.
The independent variable is the variable is thought to influence or cause a
change in another variable.
2.
The variables that are changed or influenced by another factor are called
dependent variables.
B.
Researchers select and use a sample, or a small group meant to represent the larger
population of interest. The best method to reduce sampling bias is by using random
selection, a procedure in which everyone in the population has an equal chance of
being selected to be in the sample.
C.
Descriptive research methods include case studies, naturalistic observations, and
surveys.
1.
Case studies are in-depth observations of a single individual. Case studies are
limited due to potential researcher bias and an inability to draw comparisons or
generalize results (since by definition a case study is of a single unit).
2.
Naturalistic observation involves observing people in settings outside of
laboratories, where their behavior occurs naturally.
3.
Surveys may involve interviews or questionnaires and may be conducted in
person, or by telephone, mail, or email. Question wording and subject selfreport bias may affect the results of surveys.
D.
Only experiments allow researchers to draw conclusions about cause and effect
relationships between variables.
1.
Participants are randomly assigned to an experimental or a control group at the
beginning of an experiment. Random assignment equalizes groups on factors
that may influence the dependent variables.
2.
The experimental group is exposed to the independent variable.
3.
The control group is not exposed to manipulation by the independent variable.
4.
The researcher control all other variables in an experiment to insure that any
changes detected are the result of the independent variable.
E.
All researcher methods have advantages for particular uses, and all are subject to
various drawbacks. Researchers must plan carefully to avoid subject bias, researcher
bias, and demand characteristics. Double blind procedures are sometimes used to
minimize the irrelevant influence of either subjects or researchers on the variables of
interest.
IV. How Do Psychologists Make Sense of Research Results?
A.
Psychologists use statistics to summarize data and evaluate similarities and
differences that exist between groups.
V.
B.
Correlations allow us to describe and measure relationships between two variables. A
correlation coefficient tells the direction (positive or negative) and size (ranging from
–1.00 to +1.00) of a correlation.
1.
A positive correlation exists when scores on both variables move in the same
direction with one another.
2.
A negative correlation exists when scores on one variable moves in opposite
direction from scores on the other variable.
3.
Correlation coefficients closer to 1.00 (either positive or negative) signify a
greater strength between the two variables, whereas coefficients approaching
0.00 indicate lower or nonexistent relationship between the two variables.
Researchers use correlational data to make predictions about behavior. Stronger
correlations allow for greater accuracy in prediction.
C.
Researchers use descriptive statistics and inferential statistics in evaluating results of
their studies.
1.
The mean (arithmetic average of all scores in a group) and standard deviation
(average deviation of scores within a group) to describe and summarize their
results.
2.
To compare differences between groups, researchers use probability statistics
such as t-tests and analysis of variance) to determine whether or not there are
reliable differences beween groups. Statistical significance means that the result
of the experiment is not likely to have been caused by chance. Effect size tells
how strong the relationship is between variables.
D.
Replication of experiments and repeated study of the same predictions using different
methods help hypotheses become theories, and later laws.
What Ethical Research Guidelines Do Psychologists Follow?
A.
As egregious ethical breaches came to light in the United States in the 1960s and
1970s, such as the Tuskegee Syphilis Study, people took action to protect the rights of
research participants. Psychologists are bound by a Code of Ethics to “take care to do
not harm.”
B.
Oversight boards called institutional review boards (IRBs) help to protect human
rights and minimize animal discomfort.
C.
Psychological researchers must obtain informed consent from human participants,
protect them from harm and discomfort, protect their confidentiality, and completely
debrief them at the end of their participation.
D.
The use of animal participants in research has also raised key ethical concerns.