[Paleopsych] J. Philippe Rushton: Ethnic nationalism, evolutionary psychology and Genetic Similarity Theory

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J. Philippe Rushton: Ethnic nationalism, evolutionary psychology and Genetic 
Similarity Theory

Nations and Nationalism 11 (4), 2005, 489-507. r ASEN 2005

Department of Psychology, University of Western Ontario, London, Ontario, 
Canada

This article builds on a paper prepared for the American Psychological 
Association (APA) and the Canadian Psychological Association (CPA) joint 
'Initiative on Ethno-Political Warfare' (APA/CPA, 1997). I thank Aurelio J. 
Figueredo, Henry Harpending, Frank Salter and Pierre L. van den Berghe for 
comments on an earlier draft.


ABSTRACT. Genetic Similarity Theory extends Anthony D. Smith’s theory of 
ethno-symbolism by anchoring ethnic nepotism in the evolutionary psychology of 
altruism. Altruism toward kin and similar others evolved in order to help 
replicate shared genes. Since ethnic groups are repositories of shared genes, 
xenophobia is the 'dark side' of human altruism. A review of the literature 
demonstrates the pull of genetic similarity in dyads such as marriage partners 
and friendships, and even large groups, both national and international. The 
evidence that genes incline people to prefer others who are genetically similar 
to themselves comes from studies of social assortment, differential 
heritabilities, the comparison of identical and fraternal twins, blood tests, 
and family bereavements. DNA sequencing studies confirm some origin myths and 
disconfirm others; they also show that in comparison to the total genetic 
variance around the world, random co-ethnics are related to each other on the 
order of first cousins.

Introduction

Most theories of ethno-political conflict and nationalism focus on cultural, 
cognitive and economic factors, often with the assumption that modernisation 
will gradually reduce the effect of local antagonisms and promote the growth of 
more universalistic societies (Smith 1998). However, purely socio-economic 
explanations seem inadequate to account for the rapid rise of nationalism in 
the former Soviet Bloc and too weak to explain the lethality of the conflicts 
between Tutsis and Hutus in Rwanda, Hindus, Muslims and Sikhs in the Indian 
subcontinent, and Croats, Serbs, Bosnians and Albanians in the former 
Yugoslavia, or even the level of animosity between Blacks, Whites and Hispanics 
in the US. Typically, analysts have also failed to consider the ethno-political 
repercussions of the unprecedented movement of peoples taking place in the 
world today (van den Berghe 2002).

One of the hallmarks of true science is what Edward O. Wilson (1998) termed the 
unity of knowledge through the principle of consilience, in which the 
explanations of phenomena at one level are grounded in those at a lower level. 
Two prominent examples are the understanding of genetics in terms of 
biochemistry once the structure of the DNA molecule was worked out and, in 
turn, of chemistry in terms of atomic physics. Anthony D. Smith's theory of 
ethno-symbolism unifies knowledge in the consilient manner through its 
integration of history and psychology, thereby solving the problem that 
nationalism poses for purely socio-economic theories - the phenomena of mass 
devotion and the belief that one's own group is favourably unique, even 
'chosen' (e.g. Smith 2000 and 2004; Guibernau and Hutchinson 2004; Hutchinson 
2000). With its emphasis on a group's preexisting kinship, religious and belief 
systems fashioned into a sense of common identity and shared culture, however 
mythologised, Smith's theory explains what purely socio-economic theories do 
not, why the 'glorious dead' fought and died for their country. It is more 
robust than other theories because its research analyses show that myths, 
memories and especially symbols, foment and maintain a sense of common identity 
among the people unified in a nation.

The ethno-symbolic perspective further unifies knowledge by highlighting 
interactions between ethnicity and nationhood. For example, Hutchinson (2000) 
described the episodic element in the history of countries as when national 
pride is augmented by events such as sudden new archaeological discoveries. By 
studying the ethnic character of modern nations over the long term, it is 
possible to identify recurring causes of national revivals, the role of 
cultural differences within nations, and the salience of national identities 
with respect to other allegiances.

The current article presents 'Genetic Similarity Theory' to explain ethnic 
nepotism and people's need to identify and be with their 'own kind' (Rushton et 
al. 1984 and 1986; Rushton 1989a, 1995, 2004; Rushton and Bons 2005). 
Nationalists often claim that their nation has organic continuity and 'ties of 
blood' that make them 'special' and different from outsiders, a view not fully 
explained by ethno-symbolism. Although the term 'ethnicity' is recent, the 
sense of kinship, group solidarity and common culture to which it refers is 
often as old as the historical record (Hutchinson and Smith 1996). Genetic 
Similarity Theory extends Smith's theory and the unity of knowledge by 
providing the next link, the necessary biological mooring.

Patriotism is almost always seen as a virtue and extension of family loyalty 
and is typically preached using kinship terms. Countries are called the 
'motherland' or the 'fatherland'. Ethnic identity builds on real as well as 
putative similarity. At the core of human nature, people are genetically 
motivated to prefer others genetically similar to themselves. I will support 
this contention with current findings from evolutionary psychology and 
population genetics.

The evolutionary background

Starting with Charles Darwin's The Origin of Species (1859) and The Descent of 
Man (1871), evolutionary explanations of the moral sentiments have been offered 
for both humans and other animals. Nineteenth century evolutionists such as 
Herbert Spencer and William Graham Sumner built on the concepts of 
in-group-amity and out-group-enmity, group competition and group replacement. 
Tribes, ethnic groups, even nations were seen as extended families (see van der 
Dennen 1987, for a review). However, evolutionary explanations went out of 
favour during the 1920s and 1930s with the rise of fascism in Europe, largely 
because they were seen as providing a justification for racially based politics 
(Degler 1991). During the 1960s and 1970s, most biologists eschewed theories of 
group competition in favour of the mathematically 'cleaner' theories of 
individual adaptation, since the genetic mechanisms necessary for ethnocentrism 
to evolve remained quantitatively problematic. After several decades of 
neglect, evolutionary psychology has now regained scientific respectability 
(e.g. Badcock 2000; Buss 2003; Pinker 2002; Wilson 1998).

In The Descent of Man (1871: 489-90), Darwin proposed the radical and 
far-reaching hypothesis that human morality rested on the same evolutionary 
basis as did the behaviour of other animals - reproductive success - described 
as the 'general good':

The term, general good, may be defined as the rearing of the greatest number of 
individuals in full vigour and health, with all their faculties perfect, under 
the conditions to which they are subjected. As the social instincts both of man 
and the lower animals have no doubt been developed by nearly the same steps, it 
would be advisable, if found practicable, to use the same definition in both 
cases, and to take as the standard of morality, the general good or welfare of 
the community, rather than the general happiness; but this definition would 
perhaps require some limitation on account of political ethics.

Historian Carl Degler (1991) observed that Darwin's equating of human and 
animal morality with the reproductive success of the community had the effect 
of biologising ethics. Suddenly, far-flung notions of economics, demographics, 
politics and philosophy, some of which had been centuries in the making, now 
revolved around a Darwinian centre, capturing the nineteenth century 
imagination and inspiring new analyses of the way society worked. The 
philosophy termed 'Social Darwinism', with its emphasis on the reproductive 
success of groups as well as of individuals, was taken up at every point along 
the political spectrum - from laissez-faire capitalism to communist 
collectivism to National Socialism (again see van der Dennen 1987, for a 
review).

It was crucial for Darwin to emphasise the moral continuity between humans and 
other animals because the opponents of human evolution had argued for their 
discontinuity in both the moral and the intellectual spheres. Darwin departed 
from utilitarian philosophers such as John Stuart Mill and Jeremy Bentham who 
believed that human morality was based on making informed choices about the 
greatest happiness for the greatest number. As Darwin pointedly observed, that 
basis was rational rather than instinctive. Since human beings alone were said 
to follow it, Darwin took exception to it.

In The Descent, Darwin provided numerous examples of how animal morality led to 
reproductive success. All animals fight by nature in some circumstances but are 
altruistic in others. Acts of altruism include parental care, mutual defence, 
rescue behaviour, co-operative hunting, food sharing and self-sacrificial 
altruism. Darwin described how leaders of monkey troops act as sentinels and 
utter cries of danger or safety to their fellows; how even male chimpanzees 
might rush to the aid of infants that cried out under attack, even though the 
infants were not their own.

Animal altruism - even to the point of self-sacrifice - has been massively 
confirmed since Darwin wrote The Descent (see E. O. Wilson 1975, for extended 
discussion). Altruism involves self-sacrifice. Sometimes the altruist dies. For 
example, 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 leaving the soldiers outside to die in the process.

Human warfare appears to be rooted in the evolved behaviour of our nearest 
primate relatives. Male chimpanzees patrol their territories in groups to keep 
the peace within the group and to repel invaders. Such patrols, of up to twenty 
bonded males at a time, raid rival groups, kidnap females and annex territory, 
sometimes fighting pitched battles in the process (Wrangham and Peterson 1996).

Solving the paradox of altruism

In The Origin, Darwin (1859) saw that altruism posed a major enigma for his 
theory of evolution. How could altruism evolve through 'survival of the 
fittest' if altruism means self-sacrifice? If the most altruistic members of a 
group sacrifice themselves for others, they will have fewer offspring to pass 
on the genes that made them altruistic. Altruism should not evolve, but 
selfishness should. Darwin was unable to resolve the paradox of altruism to his 
satisfaction because to do so required greater knowledge of how heredity worked 
than he had available (the word 'genetics' was not coined until 1905). 
Nonetheless, in The Descent, Darwin (1871) intuited the solution when he wrote, 
'sympathy is directed solely towards members of the same community, and 
therefore towards known, and more or less loved members, but not all the 
individuals of the same species' (Vol. 1: 163).

In 1964, evolutionary biologist William Hamilton finally provided a generally 
accepted solution to the problem of altruism based on the concept of inclusive 
fitness, not just individual fitness. It is the genes that survive and are 
passed on. Some of the individual's most distinctive genes will be found in 
siblings, nephews, cousins and grandchildren as well as in offspring. Siblings 
share fifty per cent, nephews and nieces twenty-five per cent, and cousins 
about twelve and a half per cent of their distinctive genes. So when an 
altruist sacrifices its life for its kin, it ensures the survival of these 
common genes. The vehicle has been sacrificed to preserve copies of its 
precious cargo. 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.

'Hamilton's Rule' states that across all species, altruism (or, conversely, 
reduced aggression) is favoured when rb . c40, where r is the genetic 
relatedness between two individuals, b is the (genetic) fitness benefit to the 
beneficiary, and c is the fitness cost to the altruist. Evolutionary biologists 
have used Hamilton's 'gene's eye' point of view to carry out research on a wide 
range of social interactions including altruism, aggression, selfishness and 
spite. The formulation was dubbed 'kin selection theory' by John Maynard Smith 
(1964) and became widely known through influential books such as The Selfish 
Gene by Richard Dawkins (1976) and Sociobiology: the New Synthesis by Edward O. 
Wilson (1975).

In 1971, Hamilton extended his formulation and hypothesised that altruism would 
result from any degree of genetic relatedness, not just that based on immediate 
kin. Hamilton equated his genetic relatedness variable r to Sewall Wright's FST 
measure of within-group variance (typically r . 2FST), and cited an 
experimental study of semi-isolated groups of mice where even random mating 
produced an FST of 0.18. Hamilton concluded that the within-group mice should 
therefore favour each other over those in the out-group, treating 'the average 
individual encountered as a relative closer than a grandchild (or half-sib) but 
more distant than an offspring (or full-sib)'.

In order to favour near kin over distant kin and distant kin over non- 
relatives, the organism must be able to detect degrees of genetic similarity in 
others. Hamilton (1964 and 1971) proposed several mechanisms by which detection 
could occur: (1) location or proximity to self as in the rule 'if it's in the 
nest, it's yours'; (2) familiarity, which is learning through social 
interaction; (3) similarity-to-self through imprinting on self, parents or nest 
mates as in the rule 'look for physical features that are similar to self' - 
dubbed the 'armpit effect' by Dawkins (1976); and (4) 'recognition alleles' or 
innate feature detectors that allow detection of genetic similarity in 
strangers in the absence of any mechanism of learning - dubbed the 'green beard 
effect' by Dawkins (1976). In this latter, a gene produced two effects: (a) 
creating a unique trait such as a green beard, and (b) preferring others who 
also have that trait. Hamilton and Dawkins both favoured an imprinting 
mechanism, which Hamilton (1971) suggested would be most effective if it 
occurred on the more heritable traits because these best indicate the 
underlying genotype.

There is dramatic evidence that many animal species do detect and then act on 
genetic similarity (Fletcher and Michener 1987; Hauber and Sherman 2001). In a 
classic study of bees, Greenberg (1979) bred for fourteen degrees of closeness 
to a guard bee, which blocks the nest to intruders. Only the more genetically 
similar intruders got through. A classic study of frog tadpoles separated 
before hatching and reared in isolation found the tadpoles moved to the end of 
the tank where their siblings had been placed, even though they had never 
encountered them previously, rather than to the end of the tank with 
non-siblings (Blaustein and O'Hara 1981). Squirrels produce litters that 
contain both full-siblings and half-siblings. Even though they have the same 
mother, share the same womb, and inhabit the same nest, full-siblings fight 
less often than do half-siblings. Full-siblings also come to each other's aid 
more often (Hauber and Sherman 2001).

Similarity detection is also required for assortative mating, which occurs in 
insects, birds, mammals and even plants. Optimal outbreeding in some plants is 
promoted by acceptance of pollen from source plants that are neither too 
similar nor too dissimilar molecularly from the host plant's own pollen (see 
Hauber and Sherman 2001, for review). Even in species that disperse, the 
offspring typically show strong aversion to mating with close relatives. One 
study of wild baboons showed that paternal kin recognition occurs as frequently 
as maternal kin recognition even though identifying paternal kin is much more 
difficult in species where the mother mates with more than one male (Alberts 
1999).

Although in 1975 Hamilton extrapolated his ideas to human warfare, his 
formulations have only seldom been taken beyond immediate kin. In The Selfish 
Gene, Dawkins (1976) argued that the mathematics of kin selection soon made 
coefficients of relatedness, even between kin, vanishingly small. One example 
he offered was that Queen Elizabeth II, while a direct descendant of William 
the Conqueror (1066), is unlikely to share a single one of her ancestor's 
genes. In a 1981 editorial for Nature, Dawkins used similar arguments to rebut 
claims made by Britain's far-right National Front that kin selection theory 
provided a genetic justification for ethnocentrism. Perhaps feeling a moral 
obligation to condemn racism, some evolutionists minimised the theoretical 
possibility of a biological underpinning to ethnic or national favouritism. 
Hamilton himself (1987: 426) pithily commented, 'in civilized cultures, 
nepotism has become an embarrassment'.

These qualifications turn out to have been overstated. Through assortative 
mating and other cultural practices, the selfish gene's capacity to replicate 
itself in combination with those clusters of other genes with which it works 
well may be extended for hundreds of generations, not three. Elizabeth II is 
considerably more genetically similar to William the Conqueror than she is to 
an average person alive today.

Genetic Similarity Theory

In 1984, the current author, along with Robin Russell and Pamela Wells, began 
to apply the Hamiltonian perspective to human dyads, small groups and even 
larger national and international entities (Rushton et al. 1984; Rushton 1986, 
1989a, 2004; Rushton and Bons 2005). We dubbed our approach 'Genetic Similarity 
Theory' and reasoned that if genes produced effects that allowed bearers to 
recognise and favour each other, then altruistic behaviour could evolve well 
beyond 'kin selection'. By matching across the entire genome, people can 
maximise their inclusive fitness by marrying others similar to themselves, and 
like, make friends with and help the most similar of their neighbours, as well 
as engage in ethnic nepotism. As the English language makes clear, 'likeness 
goes with liking'.

Social-assortment studies

Of all the decisions people make that affect their environment, choosing 
friends and spouses are among the most important. Genetic Similarity Theory was 
first applied to assortative mating, which kin-selection theory sensu stricto 
does not readily explain since individuals seldom mate with 'kin'. Yet, the 
evidence for assortative mating is pervasive in other animals as well as in 
humans. For humans, both spouses and best friends are most similar on 
socio-demographic variables such as age, ethnicity and educational level (r 5 
0.60), next most on opinions and attitudes (r 5 0.50), then on cognitive 
ability (r 5 0.40), and least, but still significantly, on personality (r 5 
0.20) and physical traits (r 5 0.20).

Even marrying across ethnic lines 'proves the rule'. In Hawaii, men and women 
who married cross-ethnically were more similar in personality than those 
marrying within their group, suggesting that couples 'make up' for ethnic 
dissimilarity by choosing spouses more similar to themselves in other respects 
(Ahern et al. 1981). Evolution has also set an upper limit on 'like marrying 
like' - incest avoidance (van den Berghe 1983). Too close genetic similarity 
between mates increases the probability of 'double doses' of harmful recessive 
genes. The ideal mate is one who is genetically similar but not a close 
relative.

Several studies have shown that people prefer genetic similarity in social 
partners, and assort on the more heritable components of traits, rather than on 
the most intuitively obvious ones, just as Hamilton (1971) predicted they would 
if genetic mechanisms were involved. This occurs because more heritable 
components better reflect the underlying genotype. These studies have used 
homogeneous sets of anthropometric, cognitive, personality and attitudinal 
traits measured within the same ethnic group. Examples of varying 
heritabilities are: for physical attributes, eighty per cent for middle-finger 
length vs. fifty per cent for upper-arm circumference; for intelligence, eighty 
per cent for the general factor vs. less than fifty per cent for specific 
abilities; for personality items, seventy-six per cent for 'enjoying meeting 
people' vs. twenty per cent for 'enjoying being unattached'; and for social 
attitudes, fifty- one per cent for agreement with the 'death penalty' vs. 
twenty-five per cent for agreement with 'Bible truth'.

In a study of married couples, Russell et al. (1985) found that across thirty- 
six physical traits, spousal similarity was greater on attributes with higher 
heritability such as wrist circumference (seventy-one per cent heritable) than 
it was on attributes with lower heritability such as neck circumference 
(fortyeight per cent heritable). On fifty-four indices of personality and 
leisure time pursuits, Rushton and Russell (1985) found that spousal similarity 
was greater on items such as 'enjoying reading' (forty-one per cent heritable) 
than on items such as 'having many hobbies' (twenty per cent heritable). On 
twenty-six cognitive ability tests, Rushton and Nicholson (1988) found that 
spousal resemblance was greater on more heritable subtests from the Hawaii 
Family Study of Cognition and the Wechsler Adult Intelligence Scale (WAIS). 
When spouses assort on more heritable items, they report greater marital 
satisfaction (Russell and Wells 1991).

In a study of best friends, Rushton (1989b) found that across a wide range of 
anthropometric and social attitude measures, such as agreement with 'military 
drill' (forty per cent heritable) and with 'church authority' (twentyfive per 
cent heritable) the similarity of the friends was more pronounced on the more 
heritable measures. These results were extended to liking in acquaintances by 
Tesser (1993) who manipulated people's beliefs about how similar they were to 
others on attitudes pre-selected as being either high or low in heritability. 
Tesser found that people liked others more when their similarity had been 
chosen (by him) on the more heritable items.

The above results cannot be explained by culturalist theories. Genetic 
Similarity Theory and culturalist theory make opposite predictions about social 
assortment. Cultural theory predicts that phenotype matching by spouses will be 
greater on those traits that spouses have become more similar on through the 
shared experiences that shape attitudes, leisure time activities and waist and 
bicep size (e.g. through diet and exercise). Genetic Similarity Theory, on the 
other hand, predicts greater matching on the more heritable traits (e.g. wrist 
size and middle finger length, not easily changed).

Twin and adoption studies

Several twin and adoption studies show that the preference for genetic 
similarity is heritable, that is, people are genetically inclined to prefer 
similar partners. In one of these studies, Rowe and Osgood (1984) analysed data 
on delinquency from several hundred adolescent monozygotic (MZ) twin pairs, who 
share one hundred per cent of their genes, and dizygotic (DZ) twin pairs, who 
share fifty per cent of their genes. They found that adolescents genetically 
inclined to delinquency were also genetically inclined to seek out similar 
others as friends. Dovetailing with these results, Daniels and Plomin (1985) 
examined friendships in several hundred pairs of siblings from both adoptive 
and non-adoptive homes, and found that whereas biological siblings (who share 
genes as well as environments) had friends who resembled each other, adoptive 
siblings (who share only their environment) had friends who were not at all 
similar to each other. These results show that shared genes lead to similar 
friends.

Rushton and Bons (2005) analysed a 130-item questionnaire on personality and 
social attitudes gathered from several hundred pairs of identical twins, 
fraternal twins, their spouses and their best friends. They found that: (a) 
spouses and best friends are about as similar as siblings, a level of 
similarity not previously recognised; and (b) identical twins choose more 
similar spouses and best friends to their co-twin than do non-identical twins. 
The preference for similarity is about thirty per cent heritable. Moreover, 
once again, matching for similarity was greater on the more heritable items 
showing that social assortment is based on the underlying genotype. Similarity 
was greater on items such as preferring 'business to science' (heritability 5 
0.60) than on liking to 'travel the world alone' (twenty-four per cent 
heritable).

Blood group studies

Yet another way of testing the hypothesis that humans typically choose mates 
and friends who are genetically similar is to examine blood antigens. In one 
study, Rushton (1988) analysed seven polymorphic marker systems at ten blood 
loci across six chromosomes (ABO, Rhesus [Rh], MNSs, Kell, Duffy [Fy], Kidd 
[Jk] and HLA) in a study of 1,000 cases of disputed paternity, limited to 
people of North European appearance (judged by photographs). Couples who 
produced a child together were fifty-two per cent similar but those that did 
not were only forty-three per cent similar. Subsequently, Rushton (1989b) used 
these blood tests with pairs of male best friends of similar background and 
found the friends were significantly more similar to each other than they were 
to randomly matched pairs from the same database.

Bereavement studies

Within-family bereavement studies show just how fine-tuned human preferences 
for genetic similarity can be. One study of 263 child bereavements found that 
(a) spouses agreed seventy-four per cent of the time on which side of the 
family a child 'took after' the most, their own or that of their spouse, and 
(b) the grief intensity reported by mothers, fathers and grandparents was 
greater for children who resembled their side of the family than it was for 
children who resembled the other side of the family (Littlefield and Rushton 
1986). A study of bereavement in twins found that MZ twins who share one 
hundred per cent of their genes, compared to DZ twins who share fifty per cent 
of their genes: (a) work harder for their co-twin; (b) show more physical 
proximity to their co-twin; (c) express more affection to their co-twin; and 
(d) show greater loss when their co-twin dies (Segal 2000).

Other lines of research

Women prefer the bodily scents of men with genes similar to their own more than 
they do those of men with nearly identical genes or genes totally dissimilar to 
their own (Jacob et al. 2002). Each woman's choice was based upon the human 
leukocyte antigen (HLA) gene sequence - the basis for personal odours and 
olfactory preferences - inherited from her father but not her mother. Another 
study found that both men and women rated versions of their own face as the 
most attractive after they had been computer-morphed into faces of the 
opposite-sex, even though they did not recognise the photos as images of 
themselves (Penton-Voak et al. 1999). Similarly, people whose faces were 
morphed with strange faces trusted others most when they looked like themselves 
(DeBruine 2002). Familiarity was ruled out by using morphs of celebrities; only 
self-resemblance mattered.

The gravity of groups

The pull of genetic similarity does not stop at family and friends. Group 
members move into ethnic neighbourhoods and join together in clubs and 
societies. Since people of the same ethnic group are genetically more similar 
to each other than to members of other groups, they favour members of their own 
group over outsiders.

In his groundbreaking book, The Ethnic Phenomenon, van den Berghe (1981) 
applied kin-selection theory to explain why people everywhere are prone to 
develop ethnocentric attitudes toward those who differ in dress, dialect and 
other appearance, and how even relatively open and assimilative ethnic groups 
'police' their boundaries against invasion by strangers by using 'badges' as 
markers of group membership. Van den Berghe hypothesised that these 'badges' 
would typically be cultural, such as scarification, linguistic accent and 
clothing style rather than physical. He agreed that shared traits of high 
heritability could provide more reliable indicators than cultural, flexible 
ones, but he thought these heritability indices would likely only be relevant 
to modern times when they could be used to discriminate between widely 
differing groups such as the Boers and Xhosa.

The studies I reviewed above on kin recognition in animals and social 
assortment in humans shows that the preference for similarity is fine-tuned. It 
takes place within ethnic groups, even families, and it occurs on the more 
heritable items from sets of homogeneous traits. As such, the process is 
considerably more variegated, subtle and powerful than van den Berghe (1981) 
conjectured. (His 1989 position paper went further toward acknowledging the 
more 'primordial' elements involved.) The reviewed data confirms Hamilton's 
(1971) prediction that kin-recognition systems would use the more heritable 
attributes of others if they were based on mechanisms such as imprinting-onself 
(Dawkins's 'armpit effect') and recognition alleles (Dawkins's 'green beard 
effect'). Detecting degrees of genetic similarity is much more fine-tuned than 
simply determining whether someone is a Boer or a Xhosa. The question is: How 
similar to one is the particular Boer (or Xhosa)?

In his 2003 book On Genetic Interests, Frank Salter, a political ethologist at 
the Max Planck Institute in Munich, extrapolated genetic similarity theory and 
the logic of taking all shared genes into account to also explain ethnic 
nepotism. He showed how Hamilton's (1964, 1971, 1975) coefficient of 
relatedness (r) equated to the FST estimates of genetic variance (on average r 
. 2 FST ) that had become available (e.g. Cavalli-Sforza et al. 1994). Since 
FST provides both a measure of genetic distance between populations and of 
kinship within them, it followed that in comparison to the total genetic 
variance around the world, random members of any one population group are 
related to each other on the order of r . 0.25 or 1/4 or about the same as 
half- siblings. (A general rule would be: If a fellow ethnic looks like you, 
then on average, he or she is genetically equivalent to a cousin.)

Salter's analysis of Cavalli-Sforza's FST data showed that if the world 
population were wholly English then the kinship between any random pair of 
Englishmen would be zero. But if the world population consisted of both English 
people and Germans, then two random English people (or Germans) would have a 
kinship of 0.0044, or that of 1/32 of a cousin. As genetic distances between 
populations become larger, the kinship coefficient between random co-ethnics 
within a population increases. Two English people become the equivalent of 3/8 
cousin by comparison with people from the Near East; 1/ 2 cousin by comparison 
with people from India; half-sibs by comparison with people from China or East 
Africa; and like full-sibs (or children) compared with people from South 
Africa. Since people have many more co-ethnics than relatives, the aggregate of 
genes they share with their fellow ethnics dwarfs those they share with their 
extended families. Rather than being a mere poor relation of family nepotism, 
ethnic nepotism is virtually a proxy for it.

In two other books, Salter (2002 and 2004) and his colleagues found that ethnic 
bonds are central to explaining such diverse phenomena as ethnic mafias, 
minority middlemen networks, heroic freedom fighters, the welfare state, 
generous foreign aid and charity in all its more unstinting manifestations. One 
study examined street beggars in Moscow. Some were ethnic Russians, just like 
the vast majority of the pedestrians. Others were dressed in the distinctive 
garb of Moldova, a small former Soviet republic, ethnically and linguistically 
kin to Romania. Finally, some of the beggars were darker- skinned Roma 
(Gypsies). The Russian pedestrians preferred to give to their fellow Russians, 
with their fellow Eastern European Moldavians, second. The Gypsies were viewed 
so negatively that they had to resort to a wide variety of tactics ranging from 
singing and dancing, to importuning tightwads, to sending out groups of young 
children to beg.

In an earlier study, anthropologist Colin J. Irwin (1987) tested formulations 
of in-group co-operation in inbred populations by calculating coefficients of 
consanguinity within and between various Eskimo tribes and sub- tribes in the 
western Hudson's Bay region of Canada. He found that prosocial behaviour such 
as wife exchange, and anti-social behaviour, such as the genocidal killing of 
women and children during warfare, followed lines of genetic distance, albeit 
mediated by ethnic badging such as dialect and appearance.

Even very young children typically show a clear preference for others of their 
own ethnic heritage (Aboud 1988). In fact, the process of making racial 
groupings has been shown to result from a natural tendency to classify people 
into 'kinds'. Children quickly begin to sort people into 'basic kinds' by sex, 
age, size and occupation. Experiments show that at an early age children 
clearly expect race to run in families (Hirschfield 1996). Very early in life, 
a child knows which race it belongs to, and which ones it doesn't.

The whisper of the genes

The history of the Jewish people provides a well-documented example of how 
genetic similarity theory intersects with Anthony D. Smith's (2000 and 2004) 
ethno-symbolic approach. As shown by Batsheva Bonne-Tamir at Tel Aviv 
University (e.g. 1992; and others, such as Thomas et al. 2002), Jewish groups 
are genetically similar to each other even 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. Although the 
Ethiopian Jews turn out not to be 'genetically Jewish', many other far removed 
Jewish communities share a similar genetic profile despite large geographic 
distances between the communities and the passage of hundreds of years.

Genetic Similarity Theory predicts that many other seemingly purely cultural 
divides are, in fact, rooted in the underlying population genetics. Recent DNA 
sequencing of the ancient Hindu caste system has confirmed that higher castes 
are more genetically related to Europeans than are lower castes who are 
genetically more related to other south Asians (Bamshad et al., 2001). Although 
outlawed in 1960, the caste system continues to be the main feature of Indian 
society, with powerful political repercussions.

Genetic studies can thus confirm (or disconfirm) people's ideas about their 
origins. In the case of Jews and the Indian caste system, traditional views 
have been confirmed. Israel is a new state, yet one which is built on an 
ancient tradition of ethnicity and nationhood. Much recent analysis of Israeli 
society, however, has tended to downplay connections between modern Israel and 
pre-modern Jewish identity, seeing Israel rather as an unambiguously modern 
phenomenon (cf. Smith 2000). Some Jews have greeted the genetic 'validation' 
positively because it affirms the organic nature of the Jewish people. However, 
it is also recognised as a two-edged sword, that could be invoked by claims 
from certain quarters that a 'Jewish Race is working to dominate the world'.

Hindu nationalists have expressed similar mixtures of feelings. While pleased 
to confirm 'Aryan' origins, they fear a backlash over elitism and exclusivity. 
In other cases, genetic evidence refutes origin myths, such as that the Chinese 
gene-pool goes back a quarter of a million years to Beijing Man, or that 
Amerindians have always existed on the American continent rather than being 
only the most ancient of 'immigrants' (Rushton 1995). Genetic distance studies 
are likely to play an increasing role in debates about ancestral custodial 
rights over disputed territory.

People can be predicted to adopt ideologies that work in their genetic self- 
interest. Examples of ideologies that have been shown, on analysis, to increase 
genetic fitness are religious beliefs that regulate dietary habits, sexual 
practices, marital customs, infant care and child rearing (Lumsden and Wilson 
1981). Amerindian tribes that cooked maize with alkali had higher population 
densities and more complex social organisations than tribes that did not, 
partly because alkali releases the most nutritious parts of the cereal, 
enabling more people to grow to reproductive maturity. The Amerindians did not 
know the biochemical reasons for the benefits of alkali cooking but their 
cultural beliefs had evolved for good reason, enabling them to replicate their 
genes more effectively than would otherwise have been the case.

Political interests are typically presented in terms of high ethical standards, 
no matter how transparent these appear to opponents. Consider the competing 
claims of Palestinians and Israelis, or the Afrikaners and the Bantus. 
Psychological explanation is made especially difficult since the rival groups 
construct very different histories of the conflict and all parties tend to see 
themselves as victims whose story has not been told. Because ethnic aspirations 
are rarely openly justified in terms of naked self-interest, analyses need to 
go deeper than surface ideology.

Political issues are especially explosive when survival and reproduction are at 
stake. Consider the growth of Middle Eastern suicide bombers. Polls conducted 
among Palestinian adults from the Gaza Strip and the West Bank show that about 
seventy-five per cent support suicidal attacks, whereas only about twelve per 
cent are opposed (Margalit 2003). Many families state that they are proud of 
their kin who become martyrs.

Most analyses of the motives of suicide bombings emphasise unique aspects such 
as the Palestinian or Iraqi political situation, the teachings of radical 
Islam, or a popular culture saturated with the glorification of martyrs. These 
political factors play an indispensable role but from an evolutionary 
perspective aspiring to universality, people have evolved a 'cognitive module' 
for altruistic self-sacrifice that benefits their gene pool. In an ultimate 
rather than proximate sense, suicide bombing can be viewed as a strategy to 
increase inclusive fitness.

What reasons do suicide bombers themselves give for their action? Many invoke 
the rhetoric of Islam while others appeal to political and economic grievances. 
Mahmoud Ahmed Marmash, a twenty-one-year-old bachelor from Tulkarm who blew 
himself up near Tel Aviv in May 2001 said in a videocassette recorded before he 
went on his mission (cited in Margalit, 2003):

I want to avenge the blood of the Palestinians, especially the blood of the 
women, of the elderly, and of the children, and in particular the blood of the 
baby girl Iman Hejjo, whose death shook me to the core.

Many other national groups have produced suicide warriors. The term 'zealot' 
originates in a Jewish sect that existed for about 70 years in the first 
century CE. According to the classical historian Flavius Josephus (1981), an 
extreme revolutionary faction among them assassinated Romans and Jewish 
collaborators with daggers; this likely reduced their chances of staying alive. 
A group of about 1,000 Zealots, including women and children, chose to commit 
suicide at the fortress of Masada rather than surrender to the Romans. Masada 
today is one of the Jewish people's greatest symbols. Israeli soldiers take an 
oath there: 'Masada shall not fall again'.

Soldier armies - the Japanese kamikaze, or the Iranian basaji - have carried 
out suicide attacks against enemy combatants. Winston Churchill contemplated 
the use of suicide bombers against the Germans if they invaded Britain (see 
Cornwell 2003). Some of the Tamil Tigers of Sri Lanka, who are Hindus, have 
killed themselves in attacks on politicians and army installations, and they 
have done so with utter disregard for the lives of civilians who happened to be 
around.

Genes, of course, typically only 'whisper' their wishes rather than shout. They 
keep cultures on a long rather than a short leash (to use Lumsden and Wilson's 
1981 metaphor). This allows for pragmatism and flexibility in the strategies 
that groups adopt to serve their aspirations. For example, Zubaida (2004) noted 
that the ideological weapons Arabs have employed to further their cause against 
political dominance by the Ottoman Turks (who were fellow Muslims), the Western 
Great Powers, the United States and now Israel have alternated between Islam 
and nationalism, with all the continuities and contradictions in between.

Zubaida (2004) also noted that Turkish, Egyptian and Iranian Islamisms (and 
sometimes anti-Islamisms) have often been national, and often nationalistic. 
Across the Muslim world, Arabs have often seen themselves as the mainstay of 
Islam, and Islam as the national culture of the Arabs. Nationalism became 
unpopular when it failed to satisfy Arab aspirations and is now often seen as 
an import from the West to 'divide and conquer'. Although fundamentalism is 
typically seen as subversive by Arab regimes, ethnic nationalists often 
celebrate it as a demonstration of revolutionary power. The Shi'ite Revolution 
in the non-Arabic but Islamic Republic of Iran, for example, served as an 
example not only for Islamists, but also for many nationalists and leftists in 
the Arab world.

The political pull of ethnic identity and genetic similarity also explains 
voting behaviour. The re-election victory of George W. Bush in the 2004 US 
presidential election was largely attributed to White votes and to the higher 
value placed by these voters on 'values' than on the economy. A closer look at 
the demographics reveals that 'values' may be, at least in part, a proxy for 
ethnic identity and genetic similarity. The majority of White Americans voted 
based on which candidate - and candidate's family - they believed most appeared 
to look, speak and act like them (Brownstein and Rainey 2004).

Another timely example is the growth of Christian fundamentalism in the United 
States. Analyses show that it represents a reaction to what is perceived as the 
moral breakdown of society (Marty and Appleby 1994). Because of trends in the 
mass media and education system, many religious people believe they now live in 
a hostile culture where their core values are under siege. The issue on which 
they are most politically active is opposition to abortion. One hypothesis to 
be investigated is that if estimates of genetic similarity could be obtained, 
fundamentalists would prove close to each other and to the basic Anglo-Saxon 
gene pool. If so, it would be informative to know what percentage of the 
estimated fifty million women who have had legal abortions in the United States 
since 1973 were predominantly of that ethnic background.

Conclusion

Genetic similarity, of course, is only one of many possible influences 
operating on political alliances. Causation is complex and there is no value in 
reducing relationships between ethnic groups to a single factor. Fellow ethnics 
will not always stick together, nor is conflict inevitable between groups any 
more than it is between genetically distinct individuals. In addition to 
reproductive success, individuals also work for motives such as economic 
success. However, as van den Berghe (1981) pointed out, from an evolutionary 
perspective, the ultimate measure of human success is not production but 
reproduction. Behavioural outcomes are always mediated by multiple causes. 
Nonetheless, genetic similarity can be expected to play a clear role in the 
social behaviour of small groups and even of large ones, both national and 
international.

The hypothesis presented here is that because fellow ethnics carry copies of 
the same genes, ethnic consciousness is rooted in the biology of altruism and 
mutual reciprocity. Thus ethnic nationalism, xenophobia and genocide can become 
the 'dark side' of altruism. Moreover, shared genes can govern the degree to 
which an ideology is adopted (e.g. Rushton 1986 and 1989a). Some genes will 
replicate better in some cultures than in others. Religious, political and 
class conflicts become heated because they affect genetic fitness. Karl Marx 
did not take his analysis far enough: ideology may be the servant of economic 
interest, but genes influence both. Since individuals have a greater 
concentration of genetic interest (inclusive fitness) in their own ethnic group 
than they do in other ethnic groups, they can be expected to adopt ideas that 
promote their group over others. Political ethologist Frank Salter (2003) 
refers to ideologies as 'fitness portfolios', and psychologist Kevin MacDonald 
(2001) has described co-ethnics as engaging in 'group evolutionary strategies'.

It is because genetic interests are a powerful force in human affairs that 
ethnic insults so easily lead to violence. Although social scientists and 
historians have been quick to condemn the extent to which political leaders or 
would-be leaders have been able to manipulate ethnic identity, the questions 
they never ask, let alone attempt to answer are, 'Why is it always so easy?' 
and 'Why can a relatively uneducated political outsider set off a riot simply 
by uttering a few well-delivered ethnic epithets?'

Many caveats must be noted to the theoretical approach described here. Thus, 
Salter (2003) concluded that although (a) ethnic bonds can be adaptive because 
they unite people in defence of shared interests, and (b) down-sizing ethnicity 
through multiculturalism might change the competitive advantage of particular 
groups for dominance but is unlikely to eliminate ethnic identity from our 
nature as social beings, nonetheless (c) there are many examples of how 
maladapted modern humans are for defending their ethnic interests due to the 
competing demands of family and immediate kin and the sheer complexity of 
modern societies including the impacts of cultural factors (see his Chapter 6).

It would be incorrect to over-generalise findings on genetic similarity and 
reify primordialism or resurrect ideas of organic nationalism. Rather, the 
potential is provided for an even more nuanced ethno-symbolic approach to the 
forces operating both within and between countries, many of which can otherwise 
seem irrational. Although the modern idea of citizenship has replaced the bond 
of ethnicity ('people who look and talk like us') with that of values ('people 
who think and behave like us'), the politics of ethnic identity are 
increasingly replacing the politics of class as the major threat to the 
stability of nations.

Patriotic feeling is much more than a delusion constructed by elites for their 
own purpose. The ethno-symbolic approach anchors the psychology of social 
identity in national identities and in previously existing ethnicities and 
their 'sacred' traditions and customs (e.g. Smith 2000 and 2004). Ethnic 
communities have been present in every period and have played an important role 
in all societies on every continent. The sense of common ethnicity remains a 
major focus of identification for individuals today. Genetic Similarity Theory 
helps to explain why.

References

Aboud, Frances. 1988. Children and Prejudice. London: Blackwell.

Ahern, F. M., R. E. Cole, R. C. Johnson and B. Wong. 1981. 'Personality 
attributes of males and females marrying within vs. across racial/ethnic 
groups', Behavior Genetics 11: 181-94.

Alberts, Susan C. 1999. 'Paternal kin discrimination in wild baboons', 
Proceedings of the Royal Society of London, B 266: 1501-6.

APA/CPA (1997). Ethnopolitical Warfare: Origins, Intervention, and Prevention. 
A Joint Presidential Initiative of the Presidents-Elect of the American 
Psychological Association and the Canadian Psychological Association. 
Washington, DC: American Psychological Association.

Badcock, Christopher. 2000. Evolutionary Psychology: a Critical Introduction. 
Cambridge: Polity Press.

Bamshad, Michael, Toomas Kivisild, W. Scott Watkins, Mary E. Dixon, Chris E. 
Ricker,

Baskara B. Rao, J. Mastan Naidu, B. V. Ravi Prasad, P.Govinda Reddy, Arani 
Rasanayagam, Surinder S. Papiha, Richard Villems, Alan J. Redd, Michael F. 
Hammer, Son V. Nguyen, Marion L. Carroll, Mark A. Batzer and Lynne B. Jorde. 
2001. 'Genetic evidence on the origins of Indian caste populations', Genome 
Research 11(6): 994-1004.

Blaustein, A. R. and R. K. O'Hara. 1981. 'Genetic control for sibling 
recognition?', Nature 290: 246-8.

Bonne-Tamir, Batsheva and Avinoam Adam (eds.). 1992. New Perspectives on 
Genetic Markers and Diseases among Jewish People. Oxford: Oxford University 
Press.

Brownstein, R. and R. Rainey. 2004. 'Bush's huge victory in the fast-growing 
areas beyond the suburbs alters the political map', Los Angeles Times 22 
November: A1, A14-A15.

Buss, David M. 2003. Evolutionary Psychology: the New Science of the Mind. 
Needham Heights, MA: Allyn & Bacon.

Cavalli-Sforza, Luigi L., Paolo Menozzi and Albert Piazza. 1994. The History 
and Geography of Human Genes. Princeton, NJ: Princeton University Press.

Cornwell, John. 2003. Hitler's Scientists: Science, War, and the Devil's Pact. 
New York: Penguin.

Daniels, Denise and Robert Plomin. 1985. 'Differential experience of siblings 
in the same family', Developmental Psychology 21: 747-60.

Darwin, Charles. 1859. The Origin of Species. London: Murray.

Darwin, Charles. 1871. The Descent of Man. London: Murray.

Dawkins, Richard. 1976. The Selfish Gene. Oxford: Oxford University Press.

Dawkins, Richard. 1981. 'Selfish genes in race or politics', Nature 289: 528.

DeBruine, Lisa M. 2002. 'Facial resemblance enhances trust', Proceedings of the 
Royal Society of London, B 269: 1307-12.

Degler, Carl N. 1991. In Search of Human Nature. New York: Oxford.

Fletcher, D. J. C. and C. D. Michener. 1987. Kin Recognition in Animals. New 
York: Wiley.

Greenberg, L. 1979. 'Genetic component of bee odor in kin recognition', Science 
206: 1095-7.

Guibernau, Montserrat and John Hutchinson (eds.). 2004. History and National 
Destiny: Ethnosymbolism and its Critics. London: Blackwell.

Hamilton, William D. 1964. 'The genetical evolution of social behavior. I and 
II', Journal of Theoretical Biology 7: 1-52.

Hamilton, William D. 1971. 'Selection of selfish and altruistic behaviour in 
some extreme models' in J. F. Eisenberg and W. S. Dillon (eds.), Man and Beast: 
Comparative Social Behavior. Washington, DC: Smithsonian Press, 57-91.

Hamilton, William D. 1975. 'Innate social aptitudes of man: an approach from 
evolutionary genetics' in R. Fox (ed.), Biosocial Anthropology. London: Malaby 
Press, 133-55.

Hamilton, William D. 1987. 'Discriminating nepotism: expectable, common, 
overlooked' in D. J. C. Fletcher and C. D. Michener (eds.), Kin Recognition in 
Animals. New York: Wiley, 417-37.

Hauber, Mark E. and Paul W. Sherman. 2001. 'Self-referent phenotype matching: 
theoretical considerations and empirical evidence', Trends in Neuroscience 
24(10): 609-16.

Hirschfield, Lawrence A. 1996. Race in the Making: Cognition, Culture, and the 
Child's Construction of Human Kinds. Cambridge, MA: MIT Press.

Hutchinson, John. 2000. 'Ethnicity and modern nations', Ethnic and Racial 
Studies 23(4): 651-69.

Hutchinson, John and Anthony D. Smith (eds.). 1996. Ethnicity. Oxford: Oxford 
University Press.

Irwin, Colin J. 1987. 'A study in the evolution of ethnocentrism' in V. 
Reynolds, V. S. E. Falger and I. Vine (eds.), The Sociobiology of 
Ethnocentrism: Evolutionary Dimensions of Xenophobia, Discrimination, Racism, 
and Nationalism. London: Croom Helm, 131-56.

Jacob, Suma, Martha K. McLintock, Bethanne Zelano and Carole Ober. 2002. 
'Paternally inherited HLA alleles are associated with women's choice of male 
odor', Nature Genetics 30(2): 175-9.

Josephus, Flavius. 1981. The Jewish War (revised edn by E. M. Smallwood of G. 
A. Williamson translation). New York: Penguin.

Littlefield, Christine H. and J. Philippe Rushton. 1986. 'When a child dies: 
the sociobiology of bereavement', Journal of Personality and Social Psychology 
51: 797-802.

Lumsden, Charles J. and Edward O. Wilson. 1981. Genes, Mind, and Culture: the 
Coevolutionary Process. Cambridge, MA: Harvard University Press.

MacDonald, Kevin. 2001. 'An integrative evolutionary perspective on ethnicity', 
Politics and the Life Sciences 20(1): 67-80.

Margalit, Avishai. 2003. 'The suicide bombers', The New York Review of Books 
50(1, 16 January).

Marty, M. and R. S. Appleby. 1994. Fundamentalism Observed: the Fundamentalism 
Project. Chicago, IL: University of Chicago Press.

Maynard Smith, John. 1964. 'Group selection and kin selection', Nature 201: 
1145-7.

Penton-Voak, I. S., D. I. Perret and J. W. Pierce. 1999. 'Computer graphic 
studies of the role of facial similarity in judgements of attractiveness', 
Current Psychology 18: 104-17.

Pinker, Steven. 2002. The Blank Slate: the Modern Denial of Human Nature. New 
York: Viking.

Rowe, David C. and D. W. Osgood. 1984. 'Heredity and sociological theories of 
delinquency: a reconsideration', American Sociological Review 49: 526-40.

Rushton, J. Philippe. 1986. 'Gene - culture coevolution and genetic similarity 
theory: Implications for ideology, ethnic nepotism, and geopolitics', Politics 
and the Life Sciences 4(2): 144-8.

Rushton, J. Philippe. 1988. 'Genetic similarity, mate choice, and fecundity in 
humans', Ethology and Sociobiology 9(6): 329-33.

Rushton, J. Philippe. 1989a. 'Genetic similarity, human altruism, and group 
selection', Behavioral and Brain Sciences 12(3): 503-59.

Rushton, J. Philippe. 1989b. 'Genetic similarity in male friendships', Ethology 
and Sociobiology 10(5): 361-73.

Rushton, J. Philippe. 1995. Race, Evolution, and Behavior. New Brunswick, NJ: 
Transaction.

Rushton, J. Philippe. 2004. 'Genetic and environmental contributions to 
prosocial attitudes: a twin study of social responsibility', Proceedings of the 
Royal Society of London, B 271: 2583-5.

Rushton, J. Philippe and Trudy A. Bons. 2005. 'Mate choice and friendship in 
twins: evidence for genetic similarity', Psychological Science 16(7): 555-9.

Rushton, J. Philippe and Ian R. Nicholson. 1988. 'Genetic similarity theory, 
intelligence, and human mate choice', Ethology and Sociobiology 9(1): 45-57.

Rushton, J. Philippe and Robin J. H. Russell. 1985. 'Genetic similarity theory: 
a reply to Mealey and new evidence', Behavior Genetics 15: 575-82.

Rushton, J. Philippe, Robin J. H. Russell and Pamela A. Wells. 1984. 'Genetic 
similarity theory: beyond kin selection', Behavior Genetics 14: 179-93.

Rushton, J. Philippe, Christine H. Littlefield and Charles J. Lumsden. 1986. 
'Gene-culture coevolution of complex social behavior: human altruism and mate 
choice', Proceedings of the National Academy of Sciences, USA 83(19): 7340-3.

Russell, Robin J. H and Pamela A. Wells. 1991. 'Personality similarity and 
quality of marriage', Personality and Individual Differences 12: 406-12.

Russell, Robin J. H., Pamela A. Wells and J. Philippe Rushton. 1985. 'Evidence 
for genetic similarity detection in human marriage', Ethology and Sociobiology 
6(3): 183-87.

Salter, Frank. 2002. Risky Transactions: Trust, Kinship and Ethnicity. London: 
Berghahn.

Salter, Frank. 2003. On Genetic Interests: Family, Ethny and Humanity in an Age 
of Mass Migration. Frankfurt, Germany: Peter Lang.

Salter, Frank (ed.). 2004. Welfare, Ethnicity, and Altruism: New Findings and 
Evolutionary Theory. New York: Frank Cass.

Segal, Nancy L. 2000. Entwined Lives: Twins and What They Tell Us About Human 
Behavior. New York: Plume.

Smith, Anthony D. 1998. Nationalism and Modernism: a Critical Survey of Recent 
Theories of Nations and Nationalism. London: Routledge.

Smith, Anthony D. 2000. The Nation in History: Historiographical Debates about 
Ethnicity and Nationalism. Hanover, NH: University Press of New England.

Smith, Anthony D. 2004. Chosen Peoples: Sacred Sources of National Identity. 
Oxford: Oxford University Press.

Tesser, Abraham. 1993. 'The importance of heritability in psychological 
research: the case of attitudes', Psychological Review 93(1): 129-42.

Thomas, Mark G., Michael E. Weale, Abigail L. Jones, Martin Richards, Alice 
Smith, Nicola Redhead, Antonio Torroni, Rosaria Scozzari, Fiona Gratix, Ayele 
Tarakegn, James F. Wilson, Christian Capelli, Neil Bradman and David B. 
Goldstein. 2002. 'Founding mothers of Jewish communities: geographically 
separated Jewish groups were independently founded by very few female 
ancestors', American Journal of Human Genetics 70(6): 1411-20.

van den Berghe, Pierre L. 1981. The Ethnic Phenomenon. New York: Elsevier.

van den Berghe, Pierre L. 1983. 'Human inbreeding avoidance', Behavioral and 
Brain Sciences 6: 91-123.

van den Berghe, Pierre L. 1989. 'Heritable phenotypes and ethnicity', 
Behavioral and Brain Sciences 12: 544-55.

van den Berghe, Pierre L. 2002. 'Multicultural democracy: can it work?', 
Nations and Nationalism 8(4): 433-49.

van der Dennen, Johan M. G. 1987. 'Ethnocentrism and in-group/out-group 
differentiation: a review and interpretation of the literature' in V. Reynolds, 
V. S. E. Falger and I. Vine (eds.), The Sociobiology of Ethnocentrism: 
Evolutionary Dimensions of Xenophobia, Discrimination, Racism, and Nationalism. 
London: Croom Helm, 1-47.

Wilson, Edward O. 1975. Sociobiology: the New Synthesis. Cambridge, MA: Harvard 
University Press.

Wilson, Edward O. 1998. Consilience: the Unity of Knowledge. New York: Knopf.

Wrangham, R. and D. Peterson. 1996. Demonic Males: Apes and the Origins of 
Human Violence. Boston, MA: Houghton Mifflin.

Zubaida, Sami. 2004. 'Islam and nationalism: continuities and contradictions', 
Nations and Nationalism 10(4): 407-20.