So, they set up an experiment with college students to test it. They divided the students into three groups.they took each student to a small buiding. They put him or her in a room with a TV screen that showed another person in a different room in the building; then they left. Students in the first group thought that they were alone in the building. Students in the second group thought that there was one other person in the building. Students in the third group thought that there were four other people in the building.