In research, subjects fall into two broad categories: experimental and control groups. The experimental group is subjected to the independent variable—that is, the variable of interest to the experimenter. The control group is treated exactly the same, except that it does not receive the independent variable. When the dependent variables of the experimental and control groups are compared, their differences are attributable to the independent variable. Consider research examining the validity of PDD: one group would be assigned to the innocent condition, and the other to the guilty condition. Since the variable of interest is the detection of deception, the guilty would be the experimental group and commit the mock crime, and the innocent would not commit the mock crime and would be the control group.
