EXCHANGE MARRIAGE

form of marriage involving an arranged and reciprocal exchange of spouses between two groups. In societies that associate a doctrine of unilineal descent with a consistent rule of postmarital residence, the symmetry of the alliance is often maintained by a systematic exchange of individuals: whenever group A contracts to give a bride to group B, group B will simultaneously contract to give a bride to group A. Often, as among the Australian Aborigines, the ideal model of any marriage contract is that two men of different groups should marry each other's sisters. When this process is repeated by their children or by kin classified as their children, the second alliance is called marriage of cross-cousins (see cross-cousin). Such marriages, as well as institutions by which a man gives his sister in marriage in exchange for a bride-price (animals, goods, or currency) that he himself then uses to secure a wife, are widespread and constitute the most common types of exchange marriage.