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Science stems from the empirical movement and thus observation, as well as
measurement and description are crucial.
Researchers must measure the phenomenon under study.
The deterministic assumptions of science lead scientists to believe that if they
can understand why a phenomenon occurs, then they will also be able to
predict the conditions under which it will occur again. This gives us the ability
to control our environment.
For example, in studying the effectiveness of muscle relaxation techniques
in reducing anxiety, a psychologist must first develop a means of
measuring anxiety.
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Psychologists form hypotheses about how variables interact. A hypothesis
is a tentative statement about the relationship between 2 or more variables.
Variables are the things that are observed or controlled in a study.
Information gathered by scientists may be of some practical value in helping
to solve problems in schools, businesses, mental health centers, etc.
The purpose of an experiment is to find out how one variable, let’s call it X,
affects another variable, which we’ll call Y.
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Theories are attempts to explain phenomena. They are the product of
inductive logic.
Hypothesis: Students who study over a span of 3 weeks before a test perform better
than those who wait until the night before.
Hypotheses are derived from theories to be applied to a specific, testable
example. They are the product of deductive logic.
Method: Give questionnaire to students on when they study.
Research is a catch-all heading which describes the myriad ways in which
hypotheses can be tested.
Analysis: Correlate questionnaire with test scores.
Data Collection: Collect questionnaires and test scores.
Report the findings: Students who studied over a multiple week period performed better
on tests than those who crammed the night before.
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The independent variable is a condition or event manipulated by experimenter.
An example of experimental research would be the testing of morphine
for effectiveness using analgesia – the absence of pain – as the
dependent variable.
The dependent variable is an aspect of behavior thought to be affected by the
independent variable.
The experimental group consists of participants who receive special treatment.
The control group consists of similar subjects who do not receive treatment given
to experimental group.
The control group allows the researcher to isolate the effects of the
independent variable – since the two groups are alike in every way except
for the variation of the independent variable, any difference between the
groups can be attributed to the independent variable.
Extraneous variables are factors besides independent variables that might affect
the dependent variables, and need to be controlled.
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Which one of these is the dependent variable?
Sometimes, a single group can be used for both experimental and control
conditions…for example, you might study the effects of having the radio on
when people work on an assembly line…you’d collect data from the same
group of workers twice, once with the radio on and once with it off.
Click to see answer.
The amount eaten by the rats is the dependent variable. The caloric content
is food is the independent variable determining the amount eaten by the rats.
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Researchers can also manipulate more than one IV to see what the combined
effect is. Sometimes, the effect of one variable depends on the effect of
another. For example, you might find that having the radio on increases
productivity in workers, but only in the morning. In this example, time of day
interacts with the effects of the radio.
Researchers can also use more than one dependent variable in a single study
to get a more complete picture of the effect of the independent variable. For
example, we might measure not only number of pieces workers finish when the
radio is allowed to be on while they work, but also worker satisfaction,
absenteeism, and attitude. Having 1 day less a month absenteeism might
make up for a slight decrease in productivity.
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The power of the experimental method lies in the ability to draw conclusions about cause-andeffect relationships from an experiment. No other research method has this power.
A positive correlation occurs when two or more variables vary
in the same pattern.
Experimental research does, however, have limitations. Experiments are often artificial;
researchers have to come up with contrived settings so that they have control over
the environment.
An example would be number of cigarettes smoked and blood
pressure reading.
Some experiments cannot be done because of ethical concerns. For example, you would never
want to malnourish infants on purpose to see what the effects are on intelligence.
Others cannot be done because of practical issues – there’s no way we can randomly assign
families to live in urban vs. rural areas so we can determine the effects of city vs. country living.
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A negative correlation occurs when two or more variables show patterns of
variation directly opposite to one another.
The correlation coefficient is a numerical index of the degree of relationship
between two variables.
An example would be amount of cocaine ingested and number of hours slept
in the last 24 hours.
The size of the correlation coefficient varies between zero and plus or minus
one. Its size indicates the strength of the association between two variables.
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Naturalistic observation is when a researcher engages in careful observation of
behavior without intervening directly with the subjects – allowing researchers to
study behavior under conditions that are less artificial than experiments.
A case study is an in-depth and generally highly subjective or impressionistic
report on a single individual that may be based on interviews, psychological
testing, and so on.
It can be particularly useful for studying animals in their natural habitats.
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Surveys use questionnaires or interviews to find out about specific aspects
of people’s backgrounds, attitudes, or opinions.
While descriptive and correlational methods extend the scope of psychological
research, they do not permit scientists to manipulate variables, and therefore a
cause and effect relationship cannot be proved.
Clinical samples are often unrepresentative – drawing inferences about
a population based on a sample only works if the sample is reasonably
representative of the population.
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We already saw how an unrepresentative sample of the population can lead
to inaccuracy – this is called the sampling bias.
Experimenters are fallible, and their research can be affected by a tendency
to see what they want to see. This bias is called experimenter bias.
Another bias is the social desirability bias, which leads people to answer
questions about themselves in a way that fits in with society’s expectations.
Robert Rosenthal’s research on experimenter bias suggests that researchers
may unintentionally influence the behavior of their subjects.
One way to prevent experimenter bias is by conducting a double-blind study one where neither the participants nor the researcher knows which is the
control group and which is the experiment group.
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When individuals are given a medication or are in a treatment condition in an
experiment, their expectations about the treatment may produce a placebo
effect. Placebo effects are especially likely to occur when subjects expect that
the treatment is linked to a change in behavior or reaction.
The advantages of internet research include larger populations, reduced time
and money, and a broader reach into sampling populations.
For example, if someone drinks a virgin margarita and starts acting intoxicated,
they are exhibiting signs of the placebo effect.
A drawback of Internet-mediated research is that typically very few of the
solicited subjects participate, which means that those who do might be an
extreme group, indicating a sampling bias.
In addition, internet studies lack aspects of control found in conventional
studies, and participants may be distracted or intoxicated, for example.
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Deception enables investigation of important issues and empirical evidence
suggests that deception is not harmful to subjects.
Animals are used in research in situations where it is unethical to experiment
on human participants. Such use of animals raises ethical issues about the
nature of non-human animals and the rightful treatment of such animals.
However, deception is inherently immoral and may undermine participants’
trust in others.
Consider this question by Warwick: “If it is all right to use deceit to advance
knowledge, then why not for reasons of national security, for maintaining the
Presidency, or to save one’s own hide?”
Neil Miller argued that, given the amount of abandoned and euthanized
animals each year in the United Status, using animals to research advances
in medical treatment is justified.
When, if ever, do you think deception is justified?
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