The heart of Homans' Exchange Theory lies in propositions based on economic and psychological principles. According to Homans, they are psychological for two reasons: first, because they are usually tested on people who call themselves psychologists and second, because of the level at which they deal with the individual in society. He believed that a sociology built on his principles would be able to explain all social behavior. Homans said, "An incidental advantage of an exchange theory is that it might bring sociology closer to economics" (Homans 1958:598). Overall, Homans' exchange theory, "can be condensed to a view of the actor as a rational profit seeker."