METHODS IN PSYCHOLOGY An Overview

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METHODS IN PSYCHOLOGYAn Overview

• Lawrence R. Gordon
• Psychology Research Methods I

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Something to Start With

• According to 1999 statistics reported on Vermont
  Public Radio, women are not as good at math as
  men are.
• The evidence presented to support this conclusion
  was that the average SAT math score for women was
  40 points lower than the average score for men.

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What do you think about this?

• What is the explanation behind this finding?

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Research questions

• The effects of __________ on _________ ?

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Psychology Research

• Research is the search for the relationships
  between variables.
• Two types of variables
• independent variables
• dependent variables
• Research tries to find the effects of independent
  variables on dependent variables.
• The effects of IV(s) on DV(s) ?

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Independent Variables

• This is the variable of interest because we are
  trying to find its effects (how does it influence
  other (dependent) variables?)
• Called the predictor variable in some analyses
• Can be either manipulated or observed
• Examples

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Dependent Variables

• We are trying to find out how it is affected by
  other (independent) variables
• Called the criterion variable in some analyses
• Always observed
• Examples

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Major Types of Research

• Correlational Research
• independent variable is observed
• dependent variable is observed
• allows you to see if the IV and the DV are
  related
• does NOT allow you to make cause-effect
  statements about the IV and the DV

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Types of Research (cont.)

• Correlational Research (cont.)
• Why no cause-effect conclusions?
• Nature of relationship between IV and DV is
  unclear!
• IV may cause the DV
• DV may cause the IV
• The third variable problem Something else may
  cause them both

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Types of Research (cont.)

• Experimental Research
• independent variable is manipulated
• dependent variable is observed
• all other variables are controlled
• allows you to see if the IV causes DV
• does allow you to make cause-effect statements
  about the IV and the DV
• Example correlational, then experimental

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NPY Disturbances in the Obese Rat

• Williams et al. (1992)
• Lean and obese rats
• The levels of neuropeptide Y (NPY) were measured
  in the rats by radioimmunoassay
• Question
• What is the association between NPY and obesity
  (do obese rats have higher levels of NPY?)

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NPY Disturbances (cont.)

• Results
• Obese rats had higher levels of NPY in the ARC
  than did than lean rats
• What can you conclude?
• Did increased NPY cause the obesity?
• Did obesity cause the increased NPY?
• Did something else cause the increased NPY and
  the obesity?

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NPY Disturbances (cont.)

• Conclusion
• Increased levels of NPY are associated with
  obesity in rats.
• This is correlational research.
• No cause-effect conclusions can be drawn.

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NPY Disturbances (cont.)

• What was the IV?
• How was the IV defined?
• What was the DV?
• How was the DV defined?
• Do you agree with these definitions?
• How could the IV and DV be defined differently,
  yet still ask the same questions?

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Induction of Obesity by NPY Administration in
Normal Rats

• Vettor et al. (1994)
• Lean rats
• 2 conditions
• one group was infused with NPY for seven days
• one group was infused with vehicle saline
  solution for seven days

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NPY Administration (cont.)

• Measured food intake and body weight for 14 days
  (7 infusion days and the 7 following days)
• Questions
• Would the rats with NPY infusions eat more?
• Would the rats with NPY infusions weigh more?
• If so, would this stop when the infusions stopped?

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NPY Administration (cont.)

• Results
• Rats with NPY infusions showed dramatic increases
  in food intake.
• Rats with NPY infusions showed dramatic increases
  in body weight.
• These increases were reversed when the NPY
  infusions stopped.
• Graphic presentations gtgtgtgt

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Food Intake
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Body Weight Increase
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NPY Administration (cont.)

• What can you conclude?
• Did NPY cause the increases in food intake and
  body weight?
• Did the increases in food intake and body weight
  cause the NPY infusions?
• Did a third variable cause both the increases in
  food intake and body weight and the NPY infusions?

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NPY Administration (cont.)

• Conclusion
• NPY infusions caused increases in food intake and
  in body weight in lean rats.
• This is experimental research.
• Cause-effect statements can be made.

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NPY Administration (cont.)

• What was the IV?
• How was the IV defined?
• What was the DV?
• How was the DV defined?
• Do you agree with these definitions?
• How could the IV and DV be defined differently,
  yet still ask the same questions?

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MAJOR RESEARCH METHODS

• Research begins with a question
• The effect(s) of _____ on _____.
• but there are many ways to try to answer it!
• Research also has implicit or explicit
  hypotheses
• If __A__, then __C__.
• A - antecedent, C - consequent
• Falsify A, but Not-C OR Not-C, but A
• Willems (1969) classifies research methods
• by degree of manipulation of antecedents
• by degree of imposition of units on consequents

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Lets simplify

• Major types of research
• Experimental
• Correlational
• Observational
• Well soon start with Experimental and procede
  down the list, because advantages and
  disadvantages of the other two are best discussed
  in reference to it!

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OVERVIEWThe Research Process 8 Steps

• Develop a research question
• Generate a research hypothesis
• Form operational definitions
• Choose a research design
• Evaluate the ethics
• Collect data
• Analyze data and form conclusions
• Report research results