Turn-taking was another idea to test whether tamarins were acutely aware of their partner’s actions and the effect on those actions. Lydia Henderson, now in medical school, conducted a senior thesis project on college roommates and tamarin cagemates and played a similar game. Each mate would take a turn and make a choice that would either pay off well for their partner, or less well. They always profited from their choice. The question was whether, in humans and tamarins, selfish behavior begets selfish behavior and sharing or cooperative behavior begets the same. While humans were more likely to share across turns, both species in this study would maintain selfish behavior if their partner did so.