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Research Methods in Social Psychology
Last Time
• psychology relies on empirical methods• theories are general propositions about
causal relationships amongst constructs
• hypotheses are conceptual statements that require operationalization
• science is a process of “conjecture and refutation”
Our Proposition
• Hypothesis: Southern white males are more prone to aggression than are Northern white males. (conjecture)
• We’ll look at different strategies to examine hypotheses. (refutation)
Refutation
• putting theories to the test
• What evidence supports (and, more importantly, disconfirms) our theories?
Descriptive Research
• assesses the amount or average level of a given variable in a population– e.g., public opinion surveys
• not a true test of an hypothesis– What is the white male homicide rate
in the South?
Descriptive Research
• What is the white male homicide rate in the South?
Region
Homicide Rates (White Male Offender Rate)
New England 2.62 Middle Atlantic 1.90 Midwest 2.92 Pacific 4.62 Mountain 4.67 Southwest 5.13 South 8.23
adapted from Nisbett (1993)
Descriptive Research
• critical issues– random sampling– basis of comparison
• informative, but not a hypothesis test– What else could account for the
findings?
Correlational Research
• investigates whether changes in one variable are related to changes in another variable– What is the relationship between
being from the South and aggressive behavior?
Correlational Research
• correlation coefficients– range from +1.00 to -1.00– positive correlation:
increase/decrease in the same direction
Correlational Research
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Correlational Research
• correlation coefficients– range from +1.00 to -1.00– negative correlation:
increase/decrease in opposite directions
Correlational Research
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Correlational Research
• correlation coefficients– range from +1.00 to -1.00– strength of the relationship:
closeness to +1.00/-1.00, not by the valence (+/-)
– Which indicates a stronger correlation: -.74 or +.21?
Correlational Research
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Correlational Research
• What is the relationship between being from the South and aggressive behavior?– Nisbett (1993)
• homicide rate and “southernness”: rs = .37 & .52
– in the social sciences (Cohen, 1992) • r = .50 (strong)• r = .30 (moderate)• r = .10 (small)
Correlational Research
• strengths of this approach– can be a random sample– actual behavior– has good generalizability (i.e.,
external validity)– potential for numerous variables
Correlational Research
• weakness of this approach– cannot infer a cause-effect
relationship
• factors for inferring causality– association -- yes– temporal priority -- no– rule out a spurious relationship -- no
Correlational Research
• temporal priority
southernness
homicide rates
time
Correlational Research
• temporal priority
southernness
homicide rates
homicide rates
southernness
or
time
time
Correlational Research
• temporal priority
• direction of causality problem
southernness
homicide rates
homicide rates
southernness
or
time
time
Correlational Research
• rule out a spurious relationship
southernness
homicide rates
another variable
spurious
Correlational Research
• rule out a spurious relationship
southernness
homicide rates
poverty
rs = .38 & .42
(Nisbett, 1993)
Correlational Research
• rule out a spurious relationship
• 3rd variable problem
southernness
homicide rates
another variable
spurious
Correlational Research
• strengths– potential for numerous variables– good generalizability
• weaknesses– cannot make causal conclusions
• direction of causality• 3rd variable problem
Addressing Problems with Correlational Research
• direction of causality problem– Does “southernness” lead to more
aggression or does a propensity for aggression lead to more “southernness”?
– solution: we cause (i.e., manipulate) one of the variables• insult one group on Southerners, but not
another
Addressing Problems with Correlational Research
• direction of causality problem– if we control who is insulted, then
measure aggressiveness, we know the direction of causality
– but, we still have the 3rd variable problem• SES• poor social skills
Addressing Problems with Correlational Research
• random assignment to condition– if SES or social skills have an effect
on aggression, it should be equal for both groups
– We can address the problems of correlational research by doing experiments.
Experimental Design
• characteristics– manipulation of a variable
• solves the direction of causality problem
– randomly assign to conditions• solves the 3rd variable problem
Experimental Design
• language of experiments– independent variable– dependent variable– operational variable– random assignment
Experimental Design
• testing theory– Does the independent variable cause
changes in the dependent variable?
southernness
aggressioncause
Experimental Design
• the Southern culture of honor hypothesis– Cohen et al. (1996)– 2 (Southern/Northern) X 2 (insult/no
insult)– “chicken”, cortisol, testosterone
Experimental Design
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NorthernSouthern
Insult No Insult
Dis
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t w
hic
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art
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gave
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to c
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fed
era
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inch
es)
Experimental Design
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NorthernSouthern
Insult No Insult
Dis
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t w
hic
h p
art
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gave
way
to c
on
fed
era
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inch
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Experimental Design
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Insult No Insult
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Experimental Design
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Insult No Insult
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Experimental Design
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Experimental Design
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Experimental Design
• strengths– allows for causal conclusions to be
made -- best test of theory
• weaknesses– not all questions are amenable to
experiments– concerns about generalizability
Methodological Challenges
• expectancy effects• demand characteristics of the
situation• social desirability concerns• ethical dilemmas
Summary
• refutation: process of testing theories
• descriptive research is informative, but limited in theory testing
• correlational research is more informative, but does not allow for causal explanations
• experiments are the best test of theories
Next Time
• social cognition– how we think about the social world
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