Psychology 101: Introductory Psychology--Professor Fong
Handout Accompanying Lectures on Experimental Methods in Psychology
(See Lecture Outline #3)
Examples of Experiments on the Relationship Between Television Violence and
Physical Aggression
Bandura, Ross, and Ross (1961)
Nursery School Children
participate one at a time
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Non Aggressive
(Control *) Condition:
Model plays with tinkertoys
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Aggressive
(Experimental *) Condition:
Model beats up on a Bobo Doll
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|
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Child is taken to a different building
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Child starts playing with wonderful toys
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Experimenter says, "You can't play with
these toys; they are for other children."
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Child is taken to another room, in which
there are other toys, including Bobo Doll
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Dependent variables: physical aggression
and verbal aggression toward Bobo Doll
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_____________________________________________________________________________
* The labels
Control and
Experimental condition are widely used,
although in many studies, they are arbitrary. For example, if you were
interested in the difference between two different training methods for
improving arithmetic skills, which would the control condition be? The labels
don't matter--what
does matter is that the two (or three, or four...)
conditions in your experiment are identical
except for the theoretically
important variable that you are trying to examine in your experiment.
Liebert and Baron (1972)
Children (Ages 5-9)
participate one at a time
|
Watch 2 minutes of commercials warm up: gets
kids watching the TV
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Non Aggressive
Condition: 3.5 minutes of
an exciting sports sequence
|
|
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Aggressive
Condition: 3.5 minutes of
violence--The Untouchables
|
|
Child is taken to another room:
Given the opportunity to either
"help" or "hurt" another child
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Dependent variables:
amount of helping or hurting
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Child is taken to another room with
nonaggressive and aggressive toys
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Dependent variables:
selection of toys
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What Can Experiments Tell Us?
What Can't Experiments Tell Us?
- Experiments can demonstrate that X causes Y. And if we have done a careful
job of establishing both internal and external validity, we can generalize the
results of laboratory experiments to phenomena in everyday life. Typically,
however, no one experiment can do all that. Thus, our conclusions about
application to everyday life are reached over many studies, each with flaws,
but which, when taken together point to a consistent causal relationship
between X and Y.
- Experiments cannot tell us that X is the only cause of Y. Of
course, behavior is multidetermined. No psychologist worth his/her salt
has ever suggested that experiments identify all the causes of a
particular behavior.
- Experiments cannot tell us that X is the most important cause
of Y.
- Experiments can tell us that of all of the possible causes of Y, X is
one of them. And sometimes, it is quite surprising that the set of X's that
have been shown to cause Y contains some counterintuitive causes and do
not contain some causes that would make intuitive sense (recall Lecture
1's demonstration--the Psychology Pre-Test).
Return to Lecture Outline #3
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