Exogamy is the

social norm Social norms are shared standards of acceptable behavior by groups. Social norms can both be informal understandings that govern the behavior of members of a society, as well as be codified into rules and laws. Social normative influences or soci ...

of marrying outside one's

social group In the social sciences, a social group can be defined as two or more people who interact with one another, share similar characteristics, and collectively have a sense of unity. Regardless, social groups come in a myriad of sizes and varieties ...

. The group defines the scope and extent of exogamy, and the rules and enforcement mechanisms that ensure its continuity. One form of exogamy is dual exogamy, in which two groups continually intermarry with each other. In

social science Social science is one of the branches of science, devoted to the study of societies and the relationships among individuals within those societies. The term was formerly used to refer to the field of sociology, the original "science of s ...

, exogamy is viewed as a combination of two related aspects: biological and cultural. Biological exogamy is marriage of nonblood-related beings, regulated by forms of incest law. Cultural exogamy is marrying outside a specific cultural group; the opposite being

endogamy Endogamy is the practice of marrying within a specific social group, religious denomination, caste, or ethnic group, rejecting those from others as unsuitable for marriage or other close personal relationships. Endogamy is common in many cultu ...

, marriage within a social group.

Biology of exogamy

Exogamy often results in two individuals that are not closely genetically related marrying each other; that is,

outbreeding Out-crossing or out-breeding is the technique of crossing between different breeds. This is the practice of introducing distantly related genetic material into a breeding line, thereby increasing genetic diversity. Outcrossing can be a useful ...

as opposed to

inbreeding Inbreeding is the production of offspring from the mating or breeding of individuals or organisms that are closely related genetically. By analogy, the term is used in human reproduction, but more commonly refers to the genetic disorders a ...

. In moderation, this benefits the offspring as it reduces the risk of the offspring inheriting two copies of a defective gene. Increasing the genetic diversity of the offspring improves the chances of offspring reproducing, up until the fourth-cousin level of relatedness; however, reproduction between individuals on the fourth-cousin level of relatedness decreases evolutionarily fitness. In native populations, exogamy might be detrimental if "the benefits of local adaptation are greater than the cost of inbreeding." However, non-native, "invasive" populations that have "not yet established a pattern of local adaptation" may derive some adaptive benefit from admixture. Nancy Wilmsen Thornhill states that the drive in humans to not reproduce or be attracted to one's immediate family is evolutionarily adaptive, as it reduces the risk of children having genetic defects caused by inbreeding, as a result of inheriting two copies of a deleterious recessive gene. In one

Old Order Amish The Amish (; pdc, Amisch; german: link=no, Amische), formally the Old Order Amish, are a group of traditionalist Anabaptism, Anabaptist Christianity, Christian church fellowships with Swiss German and Alsace, Alsatian origins. They are close ...

society, inbreeding increases the risk of "neonatal and postneonatal mortality." In French populations, people who reproduce with their first cousin develop

cystinosis Cystinosis is a lysosomal storage disease characterized by the abnormal accumulation of cystine, the oxidized dimer of the amino acid cysteine. It is a genetic disorder that follows an autosomal recessive inheritance pattern. It is a rare autosom ...

at a greater rate than the general population.

Cultural exogamy

Cultural exogamy is the custom of marrying outside a specified group of people to which a person belongs. Thus, persons may be expected to marry outside their

totem A totem (from oj, ᑑᑌᒼ, italics=no or '' doodem'') is a spirit being, sacred object, or symbol that serves as an emblem of a group of people, such as a family, clan, lineage, or tribe, such as in the Anishinaabe clan system. While ''the ...

clan(s) or other groups, in addition to outside closer blood relatives. Researchers have proposed different theories to account for the origin of exogamy. Edvard Westermarck said an aversion to marriage between blood relatives or near kin emerged with a parental deterrence of

incest Incest ( ) is human sexual activity between family members or close relatives. This typically includes sexual activity between people in consanguinity (blood relations), and sometimes those related by affinity ( marriage or stepfamily), ado ...

. From a genetic point of view, aversion to breeding with close relatives results in fewer congenital diseases. If one person has a faulty gene, breeding outside his group increases the chances that his partner will have another functional type gene and their child may not suffer the defect. Outbreeding favours the condition of heterozygosity, that is having two nonidentical copies of a given gene. J. F. McLennan holds that exogamy was due originally to a scarcity of women among small bands. Men were obliged to seek wives from other groups, including marriage by capture, and exogamy developed as a cultural custom.

Émile Durkheim David Émile Durkheim ( or ; 15 April 1858 – 15 November 1917) was a French sociologist. Durkheim formally established the academic discipline of sociology and is commonly cited as one of the principal architects of modern social science, al ...

derives exogamy from

totemism A totem (from oj, ᑑᑌᒼ, italics=no or '' doodem'') is a spirit being, sacred object, or symbol that serves as an emblem of a group of people, such as a family, clan, lineage, or tribe, such as in the Anishinaabe clan system. While ''the w ...

. He said that a people had religious respect for the blood of a totemic clan, for the clan totem is a god and is present especially in the blood, a sacred substance. Morgan maintains that exogamy was introduced to prevent marriage between blood relations, especially between brother and sister, which had been common in an earlier state of promiscuity. Frazer says that exogamy was begun to maintain the survival of family groups, especially when single families became larger political groups.

Claude Lévi-Strauss Claude Lévi-Strauss (, ; 28 November 1908 – 30 October 2009) was a French anthropologist and ethnologist whose work was key in the development of the theories of structuralism and structural anthropology. He held the chair of Social Anthr ...

introduced the "Alliance Theory" of exogamy, that is, that small groups must force their members to marry outside so as to build alliances with other groups. According to this theory, groups that engaged in exogamy would flourish, while those that did not would all die, either literally or because they lacked sufficient ties for cultural and economic exchange, leaving them at a disadvantage. The exchange of men or women served as a uniting force between groups.

Dual exogamy

Dual exogamy is a traditional form of arranging marriages in numerous modern societies and in many societies described in classical literature. It can be matrilineal or patrilineal. It is practiced by some Australian tribes, historically widespread in the Turkic societies, Taï societies (

Ivory Coast Ivory Coast, also known as Côte d'Ivoire, officially the Republic of Côte d'Ivoire, is a country on the southern coast of West Africa. Its capital is Yamoussoukro, in the centre of the country, while its largest city and economic centre i ...

Eskimo Eskimo () is an exonym used to refer to two closely related Indigenous peoples: the Inuit (including the Alaska Native Iñupiat, the Greenlandic Inuit, and the Canadian Inuit) and the Yupik (or Yuit) of eastern Siberia and Alaska. A related ...

, among Ugrians and others. In tribal societies, the dual exogamy union lasted for many generations, ultimately uniting the groups initially unrelated by blood or language into a single tribe or nation.

Linguistic exogamy

Linguistic exogamy is a form of cultural exogamy in which marriage occurs only between speakers of different languages. The custom is common among indigenous groups in the northwest

Amazon Amazon most often refers to: * Amazons, a tribe of female warriors in Greek mythology * Amazon rainforest, a rainforest covering most of the Amazon basin * Amazon River, in South America * Amazon (company), an American multinational technolog ...

, such as the Tucano tribes. It is also used to describe families in Atlantic Canada with a

Francophone French became an international language in the Middle Ages, when the power of the Kingdom of France made it the second international language, alongside Latin. This status continued to grow into the 18th century, by which time French was the l ...

and an

Anglophone Speakers of English are also known as Anglophones, and the countries where English is natively spoken by the majority of the population are termed the ''Anglosphere''. Over two billion people speak English , making English the largest language ...

parent.

References

External links