Why might it be appropriate to equate civilization with state control?

Because civilization requires rules, basically. Rules are made by an entity higher than ourself, so first there were cities, and then those cities unite together in a state. The state is the entity who has the authority to set rules in order to mantain  order and peace in the territories under its authority. So, civilization equate state control because without state control we don't have a civilization.

i believe the answer is:   psychological  experiment

in this experiment, wilhelm wundt became the first person that implement scientific method in analyzing the pyschological phenomenon.

due to this result, wilhelm wundt also able to make psychology to be acknowledged as a separate scientific field from biology.