RESEARCH METHODS IN PSYCHOLOGY
Four Goals of Science
Description
Prediction
Explanation
Control
Theories
organize findings
motivates future research
parsimony
I. Descriptive Research
a. Naturalistic Observation
- Behavior may be reactive
- Useful first stage for research
b. Case Study
- Intensive investigation of one person
- Often provide information about things that
could not be studied any other way
Phineas Cage 1868
Multiple Personalities
Natural Disasters
- May not generalize
- Information subject to distortions and
oversights
c. Interviews
- Information gathered through direct questioning
Belson (1978) interviewed 1500 boys to obtain information on their T.V. watching and aggressiveness
d. Surveys
- Sample of opinions from a small proportion
of the population
- Make conclusions about population as a whole
1948 survey concluded Dewey would be
elected over Truman
*biased sample
- Respondents may not answer truthfully
e. Correlational Research
- Correlation coefficient
- Provide information about relationships between variables
Scatterplot
ordinate
abscissa
Pearson’s r
One of several ways to compute correlation
0 to 1.00 indicates the strength
+, - indicates the direction
CORRELATION DOES NOT MEAN CAUSATION
Experimental Research
Experimental method is the only method that can identify a cause-and-effect relationship betweenvariables
Create a situation that allows for controlled observation
Vary some aspect of the situation and hold all other aspects constant
The Structure of Experiments
a. Independent Variable
- manipulated
b. Dependent Variable
- measured
c. Experimental Group
- treatment
d. Control Group
- no treatment
Random Sampling and Assignment
Flaws in Experimental Control
- Confounding Variables
also influence the DV
Confounding Variables
a. Random Variable
factors that cannot be controlled
b. Experimental Design
design must be well thought out
c. Subjects Expectations
Hawthorne Effect
Placebo Effect
d. Experimenter Bias
Clever Hans Effect
double-blind design