Help?? Also ignore my hair lol I was making sure it was focused

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.

answer; reactive is your answer; good luck

answer; longitudinal;

answer; differentiation;