[This piece was submitted to
Foreign Affairs, which rejected it
Z. Muller a
professor at Catholic University, ("Us
March/April 2008, and
July/August 2008) argued that
the power of ethnic nationalism
global politics for generations to come" because it
some enduring propensities of the human spirit,"
which often manifests in the
"need for each
have its own state." His essay provided a
valuable corrective to the position that ethnic identity
is a mere social construction that
globalization will steadily eradicate.
argument would have been strengthened by understanding
why people prefer genetic similarity in others.
since the 1994 publication of The History and Geography of Human Genes by Stanford University
Cavalli-Sforza, it has been possible to measure
genetic distances between population groups in terms of
family equivalents. Anthropologist
Henry Harpending showed that against the background
of worldwide genetic variance, the average similarity
between people within a single population is the same as
that between half-siblings.
Frank Salter calculated that compared to the
Danes, any two random
English people have a kinship of 1/32 of a cousin. Two
English people become the equivalent of 3/8 of a cousin
by comparison with people from the Near East, 1/2 cousin
by comparison with people from
half-siblings by comparison with people from
and like full-siblings compared with people from
the aggregate of genes people share with co-ethnics
dwarfs those shared with extended families. Rather than
being a poor relation of
family nepotism, ethnic nepotism is virtually a
proxy for it.
The pull of genetic
similarity explains why members of ethnic groups
same neighborhoods, join together in clubs and
societies, and are prone to develop ethnocentric
attitudes toward those who differ in dress, dialect, and
other appearance. In The Ethnic Phenomenon (1981), by
Pierre van den Berghe,
a sociology and anthropology at the University Of
Washington, found that even relatively open and
assimilative groups "police"
their boundaries against invasion by strangers using
to mark group membership, such as scarification,
linguistic accent, and clothing style. Another study
calculated coefficients of consanguinity within and
Eskimo tribes in the Hudson`s Bay region of Canada
and found prosocial behavior such as wife exchange, and
anti-social behavior such as genocidal killing during
warfare, followed lines of genetic distance, albeit
mediated by ethnic badging such as dialect and
study in the evolution of ethnocentrism, by
C. J. Irwin, in The Sociobiology of Ethnocentrism, 1987]
evolutionary perspective, the reason why people
construct ethnic identities and engage in ethnic
nepotism is that by doing so they increase the survival
of their genes. Central to discussion is the concept of
explicated in his 1976 book, The Selfish Gene, it is genes that survive and are passed on
across generations. Some of the individual`s most
distinctive genes will be found in fellow ethnics as
well as in offspring, siblings, nephews, cousins, and
grand-children. By benefiting extended kin, people
benefit copies of their genes.
Of course, altruism has always posed a
Darwinism. How could altruism evolve through
of the fittest" if altruism means
self-sacrifice? If the most altruistic members of a
group sacrifice themselves for others, they will leave
fewer offspring to pass on the genes that made them
altruistic. At first glance, it would seem that altruism
could not evolve, while selfishness would.
is common in all animals, even to the point of
self-sacrifice. When bees defend their hive and sting
intruders, the entire stinger is torn from the bee`s
body. Stinging an intruder is an act of altruistic
self-sacrifice. In ants, if nest walls are broken open,
soldiers pour out to combat foragers from other nests;
at the same time, worker ants repair the broken walls,
in the process leaving the soldiers outside to die.
Evolutionary psychology answers the Darwinian
conundrum. From an evolutionary point of view, an
individual organism is only a vehicle, part of an
elaborate device, which ensures the survival and
reproduction of genes with the least possible
biochemical alteration. So even when an altruist
sacrifices its life for its kin, it ensures the survival
of common genes. In this case, the vehicle has been
sacrificed to preserve copies of its precious cargo.
is traditionally seen as a virtue and extension of
family loyalty, typically preached using the terminology
of kinship. Nations are referred to as the
while members call each other
Although ethnic groups and nations appear and disappear,
they break-up and coalesce anchored in the reality of
socially perceived biological descent.
While descent often has an element of
fiction, pure fiction seldom flies. When resources are
plentiful, conflict is minimal. As resources become
scarce, individuals compete more intensely, and they do
so in groups of extended kin.
Ethnic hatred and
warfare are the
of human altruism.
Genetic distance studies have
confirmed (and disconfirmed) many ideas about people`s
origins. For example, in the case of both the
Indian caste system and the Jews, traditional views
have been confirmed.
though they have been scattered around the world for two
millennia, Jews from Iraq and Libya share more genes
with Jews from Germany, Poland, and Russia than either
group shares with the non-Jewish populations among whom
they have lived for centuries. Israel is a
new state, yet one which is built on an ancient
tradition of ethnicity and nationhood.
Some Jews have greeted the genetic
positively because it affirms the organic nature of the
Jewish people. It is also recognized as a two-edged
sword that could be invoked to claim
from certain quarters.
Surveys carried out by political scientist
too much ethnic diversity seriously undermines the
trust and social bonds within a community. The more
diverse a community,
the less likely its inhabitants are to
trust others, from next-door neighbors to local
governments. Individuals become more wary even of
members of their own ethnic group, as well as people
from different backgrounds. People like to live within a
"comfort zone" of
others like themselves.
Other surveys show that, in multiethnic countries,
people prefer same-race health providers and perceive
them as more trustworthy. On the positive side, research
with adolescents has shown that ethnic pride helps
teenagers maintain confidence when faced with stress.
The pull of genetic similarity has been demonstrated to
occur not only in large groups, both national and
international, but also in dyads such as
partners and friendships. Of all the decisions
people make that affect their environment, choosing
friends and spouses are among the most important.
Reviews of the literature consistently show that spouses
and best friends are most similar on socio-demographic
variables such as age, ethnicity, and educational level
(r = .60),
next most on opinions and attitudes (r
= .50), then on cognitive ability (r
= .40), and least, but still significantly so, on
personality (r = .20) and physical characteristics (r = .20).
adoptees, and of monozygotic or MZ twins (who share 100%
of their genes) and dizygotic or DZ twins (who share 50%
of their genes), show the
human preference for similarity is heritable.
Psychologist David Rowe
studied similarity between best friends in several
twin pairs. He found not only a genetic contribution
to antisocial behavior, but that adolescents genetically
inclined to delinquency were genetically inclined to
seek each other out as friends.
A study of adopted and non-adopted siblings found that
whereas biological siblings (who share genes as well as
environments) had friends who resembled each other,
adoptive siblings (who share only environments) had
friends who were not at all similar to each other.
2005 study of
at spouses as well as best friends. All the respondents
completed questionnaires measuring their personality and
social attitudes. The results showed: (a) friends and
spouses were about as similar as siblings (r
= .25), a level of similarity not previously recognized;
and (b) MZ twins chose more similar friends and spouses
to their co-twin than did DZ twins. People`s choices
were found to be over 30% heritable.
A genetic contribution to mate choice has been shown by
similarity being more pronounced on the more heritable
attributes within sets of homogeneous traits. In a study
of physical characteristics, people had chosen their
spouses more on the basis of the more heritable features
such as middle-finger length (80% heritable) than on the
less heritable features such as upper-arm circumference
In a study of personality and leisure time pursuits,
spousal similarity was greater on the more heritable
items such as enjoying reading (41% heritable) than on
the less heritable items such as having many different
hobbies (20% heritable).
In a study of cognitive ability, spousal resemblance was
greater on the most heritable of 26 subtests. Other
studies found that degree of genetic matching not only
predicted the occurrence of marriage but also its
stability and happiness.
Even when people marry across ethnic lines, they prove
rather than disprove the rule. One analysis of the large
Hawaii Family Study of Cognition found that spouses
who married across race were more similar to each other
in personality than those marrying within race. The
researchers suggested that couples
"made up" for
their dissimilarity on the racial dimension by choosing
spouses more like themselves in other respects.
Conclusion: the reason people engage
nepotism, as well as marry similar others, and like,
make friends with, and help the most similar of their
neighbors, is that doing so benefits copies of their
The sense of a
common ethnicity remains a major focus of
identification for individuals today. It is no
more likely to diminish in the future than is that of
Genetic similarity theory
J. Philippe Rushton
is a professor of psychology at the University of Western Ontario,
London, Ontario, Canada.
and the author of
Race, Evolution, and Behavior: A Life History Perspective.
His most recent
work on the evolution of ethnonationalism appeared in
Nations and Nationalism
(2005) and the
Journal of the Linnean Society