Studying the Impact of a Sense of Control on Stress

Discuss the research methods of a psychologist interested in understanding the impact of a sense of control on stress in humans.

The psychologist brings in students from around campus and gives them a number of choices before exposing them to a very difficult math test. She brings in another group of students and does not give them any choices before giving them the math test. She uses the scores earned by the two groups to see if those students given choices before the test do better than the students who did not get choices. Which research method was used? Which basic ideas behind early approaches in psychology most closely align with this method?