PSYCH291 Chapter Notes - Chapter 9-14: Longitudinal Study, Internal Validity, External Validity

• School: University of Waterloo
• Department: Psychology
• Course: PSYCH291
• Professor: Heather Henderson

Document Summary

Knowing about causes allows applied researchers to make interventions. If violent tv does cause aggression, then pediatricians, teachers, or advocacy groups could try to persuade pare(cid:374)ts to li(cid:373)it their (cid:272)hildre(cid:374)"s e(cid:454)posure to (cid:448)iole(cid:374)t sho(cid:449)s. Correlation does not mean causation, but researchers can test for it. These techniques can help researchers search for cause in associations. By experimenting, instead of measuring both variables, they manipulate one variable and measure the other. Lets review the three causal criteria: 1) covariance one variable has to be related to one another. 2) temporal precedence one variable came before the next. 3) internal validity variables have all been controlled. In all three techniques, like all association studies, the variables are measured, that is none are manipulated. These are useful when experiments are not able to be done: longitudinal designs establishing temporal precedence. This can be done by measuring the same variables in the same people at difference points in time.