Final answer:
The chief function of the control group in an experiment is to provide a point of reference for comparison with the experimental group's behavior.
Step-by-step explanation:
The chief function of the control group in an experiment is that it provides a point of reference against which the behavior of the experimental group can be compared. The control group serves as a basis for comparison and controls for chance factors that might influence the results of the study. By holding these factors constant across groups, the only difference between the experimental and control groups is the experimental manipulation.