With the exchange of capital, comes Coleman's theories on obligations and expectations. He describes the situation of doing favors for someone as "credit slips." Should an individual need a favor, he is essentially giving someone else a credit slip, which signifies that they will be paid back for their goods and/or services. For an individual to believe that their favor will be reciprocated, Coleman believes that there are two vital conditions. There needs to be a level of trustworthiness in a social environment to be able to believe the obligation will be met. Also, the individual needs to take into account the extent of the obligation.