The researchers did experiments with forty male first-year-students. They started by doing a test to determine whether the men had a dominant personality, and then got them to play a computer game. The men had to score points, but someone else – who the test subjects couldn‘t see – could take points away from them. The subjects had a choice in the game: defend themselves against having their points stolen, or take points away from the other. They could choose therefore between an aggressive or defensive game strategy.