You are conducting an experiment on the effects of cartoon viewing on children perceptions of violence. You have two groups of subjects, experimental and control, of 50 children each. Both groups will take a pretest measuring of their perceptions of violence. Then, over the period of a week, the experimental group will be shown six hours of violent cartoons (Ben10, Ninja turtle, star wars etc) films depicting explicit violent activity. About a week after the experimental subjects have seen the films, both groups will be posttested and compared with respect to their changed perceptions of violence. Suggest and explain possible situations which could cause the validity of your research to be threatened by each of the following factors:
1- Selection
2- History
3- Maturation
4- Experimental mortality
5- Instrumentation and testing
6- Regression artifact