1. 1 Differential (Casual-comparative) Research Definition – Research design in which behavior is measured in 2 groups that differ on 1 primary variable. The “IV” (not true IV) is the ________ or ______variable Classification variable is not manipulated because it is _______ or ___________  Normal adults vs. psychopaths  history of abuse vs. no history  Males vs. females  heroine abusers vs. polydrug abusers Does Group A differ from Group B on measures of the DV?

2. 2 Intact Group of Participants Measurement of the Dependent Variable Differential (Casual-comparative) Research

3. 3 Does ____ demonstrate a causal relationship There is no guarantee that the two groups will be ______________ in all other ways. There may be ________________ explanations for the observed differences. e.g., kids who play sports vs. those who don’t – compare measures of academic success. Differential (Casual-comparative) Research

4. 4 Conducting differential (causal-comparative research Select groups that vary on __ quantifiable variable  Requires ________ definitions  Matching participants – equate groups on ______________factors  Select _____________ groups – more likely to see difference in variable of interest

5. Two groups that differ on some dimension 10 children w/severe behavior problems 10 children w/no behavior problems Compare the two groups Avg. IQ = 103Avg. IQ = 104 Avg. # hobbies = 4 Avg. # hobbies = 3Avg. # siblings = 4Avg. # siblings = 1History of abuse = 6/10History of abuse = 3/10 Relationship?

6. Two groups that differ on some dimension 20 smokers 20 nonsmokers Compare the two groups Ed. = High school Avg. # drinks/day = 2 Avg. # drink/day = 3 15/20 single 5/20 married 3/20 single 17/20 married Relationship?

7. 7 Developmental Research Designs – study age-related changes in behavior Cross-sectional research design Measure a variable in different ___________ Like a ____________ group design Cannot determine how any ___________ changes Other factors may influence groups other than age (______/_____________ effects) Age group 1 e.g., 2-3 Age group 2 e.g., 4-5 Age group 3 e.g., 6-7