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Section 1: Introduction to Psychology
Section
2: Influence of Research on Psychology
Section
3: Experimental Research
Section
4: Types of Research
Experimental Methods
Starting from the general and moving to the
more specific, the first concept we need to discuss is
Theory.
A theory can be defined as a "general principle proposed to explain how
a number of separate facts are related." In other words, a theory is an
"idea about a relationship." In order to test whether
a theory is correct or not, we need to do research. Theories are stated in
general terms, so we need to define more accurately what we will be doing in
our experiment.
To do this, we need to define the
variables
in our theory so that they are testable, and every experiment has two types
of variables:
o
Independent
Variable (IV) – the variable
that is manipulated by the experimenter (input
variable)
o
Dependent
Variable (DV) – the outcome
variable (results of the
experiment)
By defining our variables that we will use to
test our theory we derive at our
Hypothesis,
which is a testable form of a theory.
As an example of this, lets say that we have
a theory that people who drive sports cars are more aggressive in theory
interactions with others. Our independent variable would be the type of car
you drive (sports, sedan, SUV, etc.). Our dependent variables, the outcome
of our research, would be aggression. We would need to further define
aggression so that it is something we can test such as speeding or cutting
other people off in traffic. We now have the basics of our very simple
experiment and can write our Hypothesis: People who drive sports cars drive
over the speed limit more frequently than people who drive other types of
cars.
Research Biases
Now
we’ve got a hypothesis which is the first step in
doing an experiment. Before we can continue, however,
we need to be aware of some aspects of research
that can contaminate our results. In other words,
what could get in the way of our results in this
study being accurate. These aspects are called research
biases, and there are basically three main biases
we need to be concerned with.
·
Selection
Bias – occurs when
differences between groups are present at the
beginning of the experiment.
·
Placebo
Effect – involves
the influencing of performance due to the subject’s
belief about the results. In other words, if I
believe the new medication will help me feel better,
I may feel better even if the new medication is
only a sugar pill. This demonstrates the power
of the mind to change a person’s perceptions of
reality.
·
Experimenter
Bias – The same
way a person’s belief’s can influence his or her
perception, so can the belief of the experimenter.
If I’m doing an experiment, and really believe
my treatment works, or I really want the treatment
to work because it will mean big bucks for me,
I might behave in a manner that will influence
the subject.
Controlling for Biases
After carefully reviewing our study and determining what might effect our
results that are not part of the experiment, we need to control for these
biases. To control for selection bias, most experiments use what’s called
Random
Assignment, which means assigning the subjects to each group based
on chance rather than human decision. To control for the placebo effect,
subjects are often not informed of the purpose of the experiment. This is
called a
Blind
study, because the subjects are blind to the expected results. To control
for experimenter biases, we can utilize a
Double-Blind
study, which means that both the experimenter and the subjects are blind to
the purpose and anticipated results of the study.
Standardization
We have our hypothesis, and we know what our subject pool is, the next
thing we have to do is
standardize
the experiment. Standardization refers to a specific set of instructions.
The reason we want the experiment to be standardized is twofold.
First, we want to make sure all subjects are given the same instructions,
presented with the experiment in the same manner, and that all of the data
is collected exactly the same or all subjects. Second, single experiments
cannot typically stand on their own. To really show that are results are
valid, experiments need to be replicated by other experimenters with
different subjects. To do this, the experimenters need to know exactly what
we did so they can replicate it.
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