View source for Exogamy

{{Short description|Social arrangement which only allows marriage outside a social group}}
{{Use dmy dates|date=April 2017}}
{{Anthropology of kinship |concepts}}

'''Exogamy''' is the [[social norm]] of mating or marrying outside one's [[social group]]. 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.<ref>''New Zealand Slavonic Journal'', Victoria University of Wellington, 2002, Volumes 35-36, p.81 {{oclc|297663912}}</ref>

In [[social science]], exogamy is viewed as a combination of two related aspects: biological and cultural. Biological exogamy is the marriage of people who are not [[blood relatives]].  This is regulated by [[incest taboo|incest taboos]] and [[Legality of incest|laws against incest]]. Cultural exogamy is marrying outside a specific cultural group; the opposite being [[endogamy]], 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]] as opposed to [[inbreeding]]. This may benefit offspring as it reduces the risk of the offspring inheriting two copies of a defective gene. 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.<ref>{{cite book |vauthors=Thornhill N |date=1993 |title=The Natural History of Inbreeding and Outbreeding: Theoretical and Empirical Perspectives. |publisher=The University of Chicago Press |location=Chicago}}</ref>

In one [[Amish|Old Order Amish]] society, inbreeding increases the risk of "neonatal and postneonatal mortality."<ref>{{cite journal | vauthors = Dorsten LE, Hotchkiss L, King TM | title = The effect of inbreeding on early childhood mortality: twelve generations of an Amish settlement | journal = Demography | volume = 36 | issue = 2 | pages = 263–71 | date = May 1999 | pmid = 10332616 | doi = 10.2307/2648113 | s2cid = 26311145 | jstor = 2648113 | doi-access = free }}</ref> In French populations, the children of first cousins develop [[cystinosis]] at a greater rate than the general population.<ref>{{cite journal | vauthors = Tchen P, Bois E, Feingold J, Feingold N, Kaplan J | title = Inbreeding in recessive diseases | journal = Human Genetics | volume = 38 | issue = 2 | pages = 163–7 | date = September 1977 | pmid = 302820 | doi = 10.1007/BF00527398 | s2cid = 8849012 }}</ref>

== Cultural exogamy ==
{{More citations needed section|date=March 2009}}
Cultural exogamy is the custom of [[marriage|marrying]] outside a specified group of people to which a person belongs. Thus, persons may be expected to marry outside their [[totem]] 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 [[kinship|kin]] emerged with a parental deterrence of [[incest]]. 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 [[zygosity|heterozygosity]], that is having two nonidentical copies of a given gene.
[[J. F. McLennan]]<ref>{{cite journal |title=The Origin of Exogamy |vauthors=McLennan JF |author-link=John Ferguson McLennan |journal=The English Historical Review |volume=3 |pages=94–104 |year=1888 |issue=9 |doi=10.1093/ehr/iii.ix.94 |url=https://zenodo.org/record/1431666}}</ref> 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]]<ref>{{cite book| vauthors = Fraser JG |title=Totemism and Exogamy Vol. IV|year=1910|publisher=Cosimo Inc.|location=New York|pages=100–102|url=https://books.google.com/books?id=QuZdMPF6DCkC&pg=PA100 |isbn=9781605209814}}</ref> derives exogamy from [[totemism]]. 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.

In some forms of [[Hinduism]] such as [[Shaktism]], people can only marry outside their [[gotra]] which is a traditional group of people who may be distantly related but have been living in the same area or have an ancestral home in the same area.

Morgan<ref>{{cite journal | title = Systems of Consanguinity and Affinity of the Human Family | vauthors = Morgan LH | journal = Smithsonian Contributions to Knowledge | volume = 41 | year = 1871 | publisher = Smithsonian Institution | issue = 2 }}</ref> 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<ref>{{cite book| vauthors = Frazer JG |title=Totemism and Exogamy Vol. IV|year=1910|publisher=Cosimo Inc.|location=New York|pages=95|url=https://books.google.com/books?id=4xcT9e883CAC&q=Totemism+and+Exogamy+Vol+IV&pg=PA318|isbn=9781605209791}}</ref> says that exogamy was begun to maintain the survival of family groups, especially when single families became larger political groups.

[[Claude Lévi-Strauss]] introduced the "Alliance Theory" of exogamy,<ref>{{cite web |title=Alliance Theory |url=https://www.britannica.com/topic/kinship/Alliance-theory |publisher=Encyclopædia Britannica |access-date=15 March 2012}}</ref> 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, in which two groups continually intermarry with each other, 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. Some [[Aboriginal Australians|Indigenous Australian Nations]] use groupings often called “skins” or “skin groups” to further structure [[Australian Aboriginal kinship|Kinship Systems]] that guide cultural practices, including marriages. It was historically widespread in the [[Turkic languages|Turkic societies]],<ref>''Turkish Studies Association Bulletin,'' 1982, Volume 6, p.79</ref><ref>{{cite journal | vauthors = Potapov LP | date = 1969 | title = Ethnic Composition and Origin of Altaians | journal = Science | location = Leningrad | page = 44 }}</ref> Taï societies ([[Ivory Coast]]),<ref>{{cite book | publisher = UNESCO | title = Effects of the growth of human activities on the Taï forest of the south-west of the Ivory coast | url = http://unesco.org/images/0003/000309/030983eb.pdf | date = December 2017 }}{{Dead link|date=October 2022 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> [[Eskimo]],<ref>{{cite journal | vauthors = Fainberg L | date = 1967 | title = On the Question of the Eskimo kinship system | journal = Arctic Anthropology | volume = 4 | issue = 1 | page = 244 }}</ref> among [[Ob-Ugrians]]<ref>{{cite journal | vauthors = Golovnev AV | title = From One to Seven: Numerical Symbolism in Khanty Culture | journal = Arctic Anthropology | volume = 31 | issue = 1| pages = 62–71 }}</ref><ref>{{Cite journal |last=Csepregi |first=Márta |date=2009 |title=The very highly connected nodes in the Ob-Ugrian networks |url=https://www.sgr.fi/sust/sust258/sust258_csepregi.pdf |journal=Suomalais-Ugrilaisen Seuran Toimituksia = Mémoires de la Société Finno-Ougrienne |volume=258 |pages=15}}</ref> 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 between speakers of different languages. The custom is common among indigenous groups in the northwest [[Amazon River|Amazon]], such as the [[Tucano people|Tucano]] tribes.<ref>{{cite book | vauthors = Jackson JE | title = The Fish People - Linguistic Exogamy and Tukanoan Identity in Northwest Amazonia | date = 1983 | publisher = Cambridge University Press }}</ref>

== See also ==
* [[Chinese surname#Sociological use of surnames|Chinese surname]]: surname exogamy in China
* [[Emmanuel Todd]], author of several demographic-history textbooks on the impact of exogamy on political-religious ideology
* [[Endogamy]]
* [[Gotra]]: exogamous unit in India
* [[Heterophily]]
* [[Hypergamy]]
* [[Interfaith marriage]]
* [[Interracial marriage]]
* [[Kinship]]
* [[Miscegenation]]

== References ==
{{Reflist}}

== External links ==
* {{Cite EB1911|wstitle=Exogamy|short=x}}

{{Types of marriages|state=autocollapse}}
{{Authority control}}

[[Category:Exogamy| ]]
[[Category:Multiculturalism]]
[[Category:Population genetics]]