Thus, Stanley Milgram developed a social experiment to test the boundaries of obedience to authority. Volunteers were solicited under the guise of testing memory and learning. Once in Milgram's lab, these volunteers were asked to test the memory of a second participant, the "student" (an actor). With every wrong answer, the volunteer was to administer increasingly painful electrical shocks to the student. Despite shouts of pain and requests to stop, the volunteer was prodded to continue (it was unknown to the volunteer that the shocks were not real) up to a maximum of 450-volts. Surprisingly, 65 percent of participants continued to shock up to the maximum. There were no predictable traits for those who continued to obey. Education or social status had no effect on the final result. As Milgram wrote, "for many persons obedience may be a deeply ingrained behavior tendency, indeed, a prepotent impulse overriding training in ethics, sympathy and moral conduct."