Exchange theory holds that social relationships are regulated or shaped by the desire of each participant to derive maximum gain or profit at minimum cost or pain. As applied to mate selection, the exchange theory of homogamous mate selection holds that
Within any collectivity of potential mates, a marriageable person will seek out that individual who is perceived as maximizing his rewards.
Individuals with equivalent resources are most likely to maximize each other's rewards.
Pairs with equivalent resources are most likely to possess homogamous characteristics.
Mate selection, therefore, will be homogamous with respect to a given set of characteristics.
Participants