What is the main function of a control group in a psychological experiment?

The primary role of a control group in a psychological experiment is to serve as a basis for comparison against the experimental group. This allows researchers to evaluate the effect of the treatment or intervention being studied. The control group does not receive the experimental treatment; instead, it is exposed to standard conditions or a placebo. By comparing the results of the control group to those of the experimental group, researchers can determine whether any observed differences in outcomes can be attributed to the treatment rather than other extraneous factors. This comparison is crucial for establishing the validity of the experiment's findings, as it helps to isolate the impact of the independent variable being tested.