By Kevin MacDonald
This paper integrates several different but mutually consistent evolutionary approaches to ethnicity: genetic similarity theory, social identity theory, individualism/collectivism, an evolved ‘human kinds’ module, and rational choice mechanisms relying on domain general cognitive mechanisms. These theories are consistent with each other, and together they illustrate the interplay of evolved cognitive and motivational systems with mechanisms of rational choice able to choose adaptive strategies in uncertain, novel environments.
This paper develops a pluralistic account of theories underlying ethnocentrism, ethnic identity, and relations between ethnic groups. Ethnicity is not unique in calling for theoretical pluralism. For example, Bowlby’s ethological theory of attachment includes a suite of universal adaptations designed to promote caregiving (e.g., ‘natural clues’ — innate biases that make social interaction pleasurable) and proximity maintenance (e.g., fear innately elicited by mother’s absence or the presence of strangers). Cognitive control systems are required to monitor mother’s whereabouts with respect to a set point’a perimeter in which the child feels secure. Cognitive and learning mechanisms that track mother’s sensitivity and responsiveness are implicated in developing an internal model of relationships’a cognitive model of others’ expected behavior that is resistant to falsifying instances.
Similarly, models of aggression include universal adaptations triggered in specific contexts (e.g., sexual jealousy triggered by signs of infidelity; threat to an ingroup; aversive stimulation) (Berkowitz, 1982; Buss, 1999; MacDonald, 1998a). However, we also need theories of sex differences, individual differences, and group differences in aggression. These imply the importance of genetic and environmental influences on a variety of evolved systems. These include temperament/personality differences in behavioral approach systems, such as sensation seeking, impulsivity, and social dominance, that are psychometrically linked with aggression; also implicated are differences in emotionality, which subsumes variation in the tendency to exhibit anger, a primary emotion of aggression, and sociopathy, which includes variation in sympathy, empathy, and love (MacDonald, 1995). Finally, learning mechanisms, such as being exposed to successful or unsuccessful models and negative reinforcement, have also been implicated in aggression (Coie & Dodge, 1998).
I propose the relevance of five systems underlying ethnic affiliation.
Genetic similarity theory extends beyond kin recognition by proposing mechanisms that assess phenotypic similarity as a marker for genetic similarity (Rushton, 1989). These proposed mechanisms promote positive attitudes, greater cooperation, and a lower threshold for altruism for similar others. GST is the only way to account for the finding that there is a correlation between the heritability of traits and the degree of positive assortment for those traits by spouses and best friends. The data compiled by Rushton (1999) indicate that people not only assort positively for a wide variety of traits, but they do so most on traits that are more heritable.
GST has important implications for theories of ethnocentrism. The suggestion is that the continuum from phenotypic and genetic similarity to phenotypic and genetic dissimilarity is also an affective continuum, with liking, friendship, marriage, and alliance formation being facilitated by greater phenotypic and genetic similarity. This in turn suggests a genetic basis for xenophobia independent of the theory of groups’i.e., that the liking and disliking of others facilitated by this system is independent of whether the other is a member of a socially designated (culturally constructed) ingroup or outgroup.
It is important to qualify these findings by noting that the relationship between similarity and heritability occurs within category’e.g., within the area of cognitive abilities, there is greater similarity among spouses and friends for general intelligence (h=.8) than for specific cognitive abilities (h=.5). These data also support the importance of resource reciprocity in relationships of marriage and close friendship, since, for example, spouses and best friends are more similar in age, attitudes and religion than they are on physical characteristics even though the latter are more heritable. (Age isn’t heritable at all.) Others who are similar in these ways presumably provide self with more psychological rewards; for example, similar interests and attitudes form the basis of mutual attraction, and similar personality traits such as sensation seeking promote common interests. A common finding in the developmental literature is that friends establish common ground. Children with vastly different interests and attitudes really have nothing to be friends about. Friendship, marriage and other voluntary alliances are fundamentally relationships of reciprocity of valued resources (MacDonald, 1996).
There are therefore two complementary evolutionary theories of similarity in human relationships’one based on attraction to genetic commonality in others and one based on reciprocity in the resource value of others (Lusk, MacDonald, & Newman, 1997). I suggest that relative liking in relationships of friendship, marriage, and alliances does not typically involve altruism’altruism is not the evolutionary cause; i.e., one need not show that evolutionary models would predict greater altruism for genetically similar non-kin for mechanisms sensitive to genetic similarity to evolve. Relationships of marriage, friendship, and ethnic group fundamentally involve reciprocity’self-interest is an obvious component of all of these relationships.
The problem with theoretical arguments that altruism could evolve to be an important cause of assortative mating, friendship and other alliances is that the manifest central tendency of all voluntary mutual relationships with non-relatives is reciprocity. Explanations in terms of self-interest are far more intuitively plausible: Assortative mating increases relatedness to children, so that one receives a greater genetic payoff for the same parenting effort. Successful alliances and successful friendships have a greater payoff to self if genetically similar others succeed when you succeed. Successful alliances of any kind with genetically similar others have a higher threshold for defection: It remains in one’s self-interest to persevere in maintaining the alliance in the face of other self-interested opportunities. These considerations fit well with van den Berghe’s (1999) view that ethnic groups involve represent diluted forms of genetic self-interest.
Consider a situation where one is starting a business (or entering a military or political alliance). All things being equal, the person would be better off doing it with a co-ethnic because from a gene’s eye point of view the alliance, if successful, would result in greater genetic benefit. The alliance would also be relatively less susceptible to defection: The person in the alliance would devalue to some extent opportunities to make alliances with non-co-ethnics. However, all things may not be equal, and one can easily imagine circumstances in which an alliance with a non-co-ethnic would better benefit self’if, for example the non-co-ethnic is highly talented or has unique access to some valued resource. Similarly, a wealthy older man and a young attractive woman might form a marriage alliance that would be in each person’s interest even though they are genetically dissimilar.
In conclusion, there are no theoretical problems with supposing that there could be individual-level natural selection for genetic similarity as a mechanism influencing choice of allies, mates, and friends. Reflecting the general consensus in evolutionary studies (Williams, 1966), there is a presumptive bias in favor of finding arguments that rely on self-interest because natural selection for altruism is theoretically problematic and because self-interest is so massively apparent in human relationships of all kinds, including marriage, friendship, and other voluntary alliances.
Theories, such as GST, based on phenotypic similarity do not address the crucial importance of cultural manipulation of segregative mechanisms as a fundamental characteristic of ethnocentric groups. For example, segregative cultural practices of Judaism have actually resulted in ethnic similarity being of disproportionate importance for Jews in regulating their associations with others (MacDonald, 1994). Because of the cultural barriers between Jews and the gentile world, phenotypic similarity between Jews and gentiles on a wide range of traits was effectively precluded as a mechanism for promoting friendship, business alliances, and marriage between Jews and gentiles, and there was a corresponding hypertrophy of the importance of religious/ethnic affiliation (i.e., group membership) as a criterion of assortment.
Moreover, generalized negative attitudes toward dissimilar others seem insufficient to account for hostility directed against individuals because of their group membership. The mechanisms implied by GST or proposed evolved mechanisms of xenophobia postulate that each individual assesses others on a continuum ranging from very similar to very dissimilar. An important feature of ethnic competition is that there are discontinuities created by ethnic separatism and the consequent hypertrophy of religious/ethnic (i.e., group) status as a criterion of similarity. Fundamentally, what is needed is a theoretical perspective in which group membership per se (rather than other phenotypic characteristics of the individual) is of decisive importance in producing animosity between groups.
Social identity theory offers a promising evolutionary theory of groups (see also van der Dennen, 1999). An early form of social identity theory was stated by William Graham Sumner (1906, 13), who concluded that
Loyalty to the group, sacrifice for it, hatred and contempt for outsiders, brotherhood within, warlikeness without’all grow together, common products of the same situation. It is sanctified by connection with religion. Men of an others-group are outsiders with whose ancestors the ancestors of the we-group waged war…. Each group nourishes its own pride and vanity, boasts itself superior, exalts its own divinities, and looks with contempt on outsiders. Each group thinks its own folkways the only right ones, and if it observes that other groups have other folkways, these excite its scorn.
The classic study of Sherif et al. (1961) found that when randomly chosen groups of boys engaged in between-group competition, group membership became an important aspect of personal identity despite the lack of systematic genetic or phenotypic differences between the groups. The groups developed negative stereotypes of each other and were transformed into groups of ‘wicked, disturbed, and vicious’ children (Sherif 1966, 85). Fear and dislike of strangers are easily developed, and group differences, especially when marked by obvious physical differences such as skin color, are quickly registered in consciousness (Hebb & Thompson, 1964). Levine and Campbell (1972) evaluated theories and anthropological evidence related to the ‘ethnocentric syndrome’ of positive perceptions and behavior toward ingroups and negative perceptions and behavior toward outgroups.
Social identity research shows that people are highly prone to identifying themselves with groups. There is a tendency to conceptualize both ingroups and outgroups as more homogeneous than they really are. The stereotypic behavior and attitudes of the ingroup are positively valued, while outgroup behavior and attitudes are negatively valued (Abrams & Hogg, 1990; Hogg & Abrams, 1987). The result of these categorization processes is behavior that involves discrimination against the outgroup and in favor of the ingroup; beliefs in the superiority of the ingroup and inferiority of the outgroup; and positive affective preference for the ingroup and negative affect directed toward the outgroup. These tendencies toward ingroup cohesiveness and devaluation of the outgroup are exacerbated by real conflicts of interest between groups (see also Triandis 1990, 96).
Nevertheless, ingroup favoritism and discrimination against outgroups occurs even in so-called minimal group experiments, i.e., experiments where groups are constructed with no conflicts of interest, or indeed any social interaction at all. Even when the experimental subjects are aware that the groups are composed randomly, subjects attempt to maximize the difference between the ingroup and the outgroup, even when such a strategy means they would not maximize their own group’s rewards. The important goal seems to be to outcompete the other group. Rather than dismiss the minimal group experiments as not meaningful because of the highly artificial situation, these studies attest to the power of ‘groupness’ in the human mind’the tendency for even the most randomly constructed groups to elicit discrimination against outgroups.
The empirical results of social identity research are highly compatible with supposing that social identity processes are a psychological adaptation designed for between-group competition. Current evidence indicates that the minimal group findings can be generalized across subjects of different ages, nationalities, social classes, and a wide range of dependent variables (Bourhis 1994). Anthropological evidence indicates the universality of the tendency to view one’s own group as superior (Vine 1987). Moreover, social identity processes occur very early in life, prior to explicit knowledge about the outgroup. They also occur among some animal species. Russell (1993, p. 111) notes that ‘chimpanzees, like humans, divide the world into ‘us’ versus ‘them’,’ and van der Dennen (1991, p. 237) proposes, on the basis of his review of the literature on human and animal conflict, that advanced species have ‘extra-strong group delimitations’ based on emotional mechanisms.
Further indicating adaptive design of cognitive mechanisms related to group interactions, Rutherford et al. (!997) found that people weigh individual/group cost/benefit payoffs in an adaptive manner that is inconsistent with rational choice theory but which would be highly adaptive in a context of competing groups. Again, the evidence indicates that perceptions of ingroups and outgroups are the result of adaptive design and that between-group competition is a reality of the human environment of evolutionary adaptedness.
The powerful emotional components of social identity processes are very difficult to explain except as an aspect of the evolved machinery of the human mind. The ingroup develops a positive distinctness, a positive social identity, and increased self-esteem as a result of this process. Within the group there is a great deal of cohesiveness, positive emotional regard, and camaraderie, while relationships outside the group can be hostile and distrustful. As Hogg and Abrams (1987, 73) note, the emotional consequences of ingroup identification cannot be explained in terms of purely cognitive processes, and a learning theory seems hopelessly ad hoc and gratuitous. The tendencies for humans to place themselves in social categories and for these categories to assume powerful emotional and evaluative overtones (involving guilt, empathy, self-esteem, relief at securing a group identity, and distress at losing it) are the best candidates for the biological underpinnings of social identity processes. Clearly, categorization of humans into groups is far more than simply an example of the general process of human categorization.
Social identity processes also are exacerbated in times of resource competition (e.g., Hogg & Abrams, 1987), suggesting that this is an adaptation for between-group conflict. Keeley (1996, pp. 129, 138-141) has found that among pre-state societies, ‘hard times’ and expanding populations are often associated with warfare. As emphasized by Alexander (1979) and Johnson (1995), external threat tends to reduce internal divisions and maximize perceptions of common interest among ingroup members. An evolutionary interpretation of these findings is also supported by results indicating that social identity processes occur among advanced animal species, such as chimpanzees (van den Dennen, 1991). The powerful emotional components of social identity processes are very difficult to explain except as an aspect of the evolved machinery of the human mind. The tendencies for humans to place themselves in social categories and for these categories to assume powerful emotional and evaluative overtones (involving guilt, empathy, self-esteem, relief at securing a group identity, and distress at losing it) are the best candidates for the biological underpinnings of participation in highly cohesive collectivist groups.
The results of social identity theory support the claim that people’s categorization of sets of individuals into groups involves an adaptive distortion of reality in the form of a loss of detail. The perception of the social world as sharply dichotomized between ingroup and outgroup results in some loss of information. People in ingroups are relatively likely to fail to attend to individual differences within groups, with the result that both ingroup members and outgroup members become characterized by the stereotypical traits of their group’positively evaluated traits for members of the ingroup, negatively evaluated traits for members of the outgroup (Hogg & Abrams, 1987). This loss of detail therefore results in sharpening group boundaries, intensifying positive feelings about the ingroup and negative feelings about the outgroup, and discriminating in favor of the ingroup and against the outgroup.
The empirical data derived from social identity theory indicate that perceptions of ingroups and outgroups have been the focus of natural selection, i.e., the mechanism evolved because humans were recurrently exposed to situations in which perceptions of ingroups and outgroups as groups rather than concatenations of individuals were adaptive. Social identity research indicates that people in threatened groups develop a psychological sense of shared fate. The fact that social identity mechanisms appear to be highly sensitive to the presence of external threat to the group is compatible with supposing that people continue to track individual self-interest; in the absence of threat people are more individualistic, and in times of threat, group and individual interests increasingly coincide and group members increasingly have a shared fate.
Shared fate in human groups is likely to occur during situations such as military conflicts and other examples of intense between-group competition in which defection is not individually advantageous or is not an option at all. Warfare is the most likely candidate to meet these conditions. Warfare appears to have been a recurrent phenomenon among pre-state societies. Surveys indicate over 90% of societies engage in warfare, the great majority engaging in military activities at least once per year (Keeley 1996, pp. 27-32). Moreover, ‘whenever modern humans appear on the scene, definitive evidence of homicidal violence becomes more common, given a sufficient number of burials’ (Keeley 1996, 37). Because of its frequency and the seriousness of its consequences, primitive warfare was more deadly than civilized warfare. Most adult males in primitive and pre-historic societies engaged in warfare and ‘saw combat repeatedly in a lifetime’ (Keeley, 1996, p. 174).
Shared fate would be likely in situations where potential defectors were summarily executed or severely punished by the ingroup, or in situations were survivors were summarily executed by a conquering outgroup or lost access to women and other resources. There is little evidence for high levels of discipline and coercion in pre-state warfare, although it occurred at least in some cases (Turney-High, 1971). Nevertheless, cowards were often shamed and courage was a highly valued trait (Keeley 1996, pp. 42-44; Turney-High, 1971), so that defection from the fighting group did indeed have costs as a result of social pressure.
More important perhaps is that the slaughtering of conquered peoples, especially males, has been a persistent feature of warfare. In their rise to power, the Aztecs probably ‘slaughtered those who opposed them, as all conquerors have always done’ (Keegan (1993, p. 114). In pre-state warfare, while women were often taken as prizes of warfare, immediate death was often the fate of women and children and the certain fate of adult male prisoners: ‘Armed or unarmed, adult males were killed without hesitation in battles, raids, or the routs following battles in the great majority of primitive societies. Surrender was not a practical option for adult tribesmen because survival after capture was unthinkable’ (Keeley 1996, p. 84).
There is reason to suppose, therefore, that situations of intense between-group conflict have recurrently given rise to shared-fate situations. Moreover, Boehm (1997) shows that human hunter-gatherer groups are characterized by an ‘egalitarian ethic’ for an evolutionarily significant period’long enough to have influenced both genetic and cultural evolution. The egalitarian ethic implies that meat and other important resources are shared among the entire group, the power of leaders is circumscribed, free-riders are punished, and virtually all important decisions are made by a consensus process. The egalitarian ethic thus makes it difficult for individuals to increase their fitness at the expense of other individuals in the same group, resulting in relative behavioral uniformity and relatively weak selection pressures within groups. Mild forms of social control, such as gossip and withholding social benefits, are usually sufficient to control would-be dominators, but more extreme measures, such as ostracism and execution, are recorded in the ethnographic literature. By controlling behavioral differences within groups and increasing behavioral differences between groups, Boehm argues that the egalitarian ethic shifted the balance between levels of selection and made selection between groups an important force in human evolution (see also below).
The theory of individualism/collectivism developed by Harry Triandis (1990, 1995) emphasizes individual differences in many of the same tendencies discussed by social identity theory. The theory of individualism/collectivism describes cross-cultural differences in the extent to which emphasis is placed on the goals and needs of the ingroup rather than on individual rights and interests. For individuals highly predisposed to collectivism, ingroup norms and the duty to cooperate and subordinate individual goals to the needs of the group are paramount. Collectivist cultures develop an ‘unquestioned attachment’ to the ingroup, including ‘the perception that ingroup norms are universally valid (a form of ethnocentrism), automatic obedience to ingroup authorities [i.e., authoritarianism], and willingness to fight and die for the ingroup. These characteristics are usually associated with distrust of and unwillingness to cooperate with outgroups’ (Triandis 1990, 55). Like social identity processes, tendencies toward collectivism are exacerbated in times of external threat, again suggesting that the tendency toward collectivism is a facultative response that evolved as a mechanism of between-group conflict.
If there are important individual differences in psychological mechanisms related to developing a sense of shared fate, it would not be surprising to find that some individuals are extremely prone to a sense of shared fate to the point that defecting from the group is not a psychologically available option. There are in fact examples of such people. Especially striking has been the phenomenon of individuals who readily undergo martyrdom or mass suicide rather than abandon the group. We see examples periodically in modern times, and there are many historical examples, ranging from Christian martyrs in ancient times to a great many instances of Jewish martyrdom over a two-thousand-year period. The following emphasizes the ideology and practice of martyrdom in Jewish groups with no implication that Jewish groups are unique in these tendencies. Like many other cultures, Jewish groups are collectivist (Triandis, 1990, p. 57).
One indication of Jewish collectivism is that Jewish groups have had a tendency to retain genetic and cultural separatism even when cut off for centuries from other Jewish groups, and even in the presence of prolonged intense anti-Semitism and enforced crypsis. In the ancient world, Jews alone of all the subject peoples in the Roman Empire engaged in prolonged, even suicidal wars against the government in order to attain national sovereignty. Many authors have noted the religious fanaticism of the Jews in the ancient world and their willingness to die rather than tolerate offenses to Israel or live under foreign domination.
Martyrdom as a response to being required to betray religious law is a recurrent theme of canonical Jewish religious writings, beginning with the ‘binding of Isaac’ in Genesis (i.e., Abraham’s agreement with God’s command to sacrifice his son) and including several stories in the later portions of the Hebrew Bible (Isa:40-55; the story of Shadrach, Meshach, and Abednego in the Book of Daniel), the Apocrypha (e.g., the story of Hannah and her seven sons in IV Maccabees), the writings of Philo and Josephus, Midrashic commentaries, the Mishnah, and the Talmud (Agus 1988; Droge & Tabor 1992). Individual well-being in an afterlife was an important theme of these writings, but there was also an ideology that martyrdom under certain circumstances was critical to the success of the group,: ‘It was through the blood of these righteous ones, and through the expiation of their death, that divine Providence preserved Israel, which had been ill-used (IV Macc. 17:22).
The discussion in the Babylonian Talmud (b. Sanhedrin 74a’75a) provides conflicting opinions, with one group holding that martyrdom is required to avoid committing transgressions involving idolatry, incest, adultery, and murder, while a stricter group held that if a Jew is publicly required to transgress any law no matter how trivial (including the Jewish custom of wearing white shoe straps rather than the black shoe straps worn by the Romans), ‘one must be martyred even for a minor precept rather than violate it.’ Later, Maimonides (b. 1135) held that while heroic defiance of religious persecution was ‘a normative ideal’ and a ‘legitimate and noble act’ for the Jewish community (Halkin & Hartman 1985, 57, 66), transgressions performed to avoid martyrdom were not required except under certain circumscribed conditions and transgressors could remain members of the community despite past sins (Maimonides 1985, 25). Reflecting the collectivist tendencies of Judaism, Maimonides’ criterion for whether martyrdom or transgression was required was whether the community as a whole would be better off with one strategy or the other.
The ideology of martyrdom was not merely theoretical. Josephus, the first-century Jewish historian and apologist, stated that ‘[we face] death on behalf of our laws with a courage which no other nation can equal’ (Against Apion, 2:234). Although not all Jews were willing to die rather than betray the law, ‘story after story reveals that this generalization is true’ (Sanders 1992, 42). ‘No other nation can be shown to have fought so often in defence of its own way of life, and the readiness of Jews to die for their cause is proved by example after example’ (Sanders 1992, p. 239). Jewish political activity against the Romans often included threats of martyrdom if external signs of Roman domination were not removed from Jerusalem and the Temple (Crossan 1991, p. 103ff), as in an incident recounted by Josephus in which Pontius Pilate, the Roman procurator, removed Roman standards from Jerusalem after a large body of Jews who had been threatened with death for protesting the standards ‘fell to the ground in a body and bent their necks, shouting that they were ready to be killed rather than transgress the Law’ (Josephus, 1981, p. 138). Similarly, Philo, in recounting a similar incident during the reign of Caligula records the Jewish delegation as saying that
if we cannot persuade you, we give ourselves for destruction that we may not live to see a calamity worse than death…. We gladly put our throats at your disposal…. We ourselves will conduct the sacrifices, priests of a noble order; wives will be brought to the alter by wife-slayers, brothers and sisters by fratricides, boys and girls in the innocence of their years by child-murderers…. Then standing in the midst of our kinsfolk after bathing ourselves in their blood,… we will mingle our blood with theirs by the crowning slaughter of ourselves (Embassy to Gaius 233-236
In recent times, the members of the Zionist Stern Gang who fought the British for control of Palestine ‘conceived of the final battle with the British as an apocalyptic catharsis out of which they could expect only death’ (Biale 1982, 101).
The reputation of Jews as willingly suffering martyrdom rather than deserting the group suggests that among Jews there is a significant critical mass for whom desertion is not a psychologically available option no matter what the consequences to the individual. The response of groups of Ashkenazi Jews to demands to convert during the pogroms surrounding the First Crusade in several areas of Germany in 1096 shows that the ancient threats of martyrdom rather than transgression described by Philo and Josephus were not merely hypothetical: When given the choice of conversion to Christianity or death, a contemporary Jewish chronicler noted, that Jews ‘stretched forth their necks, so that their heads might be cut off in the Name of their Creator…. Indeed fathers also fell with their children, for they were slaughtered together. They slaughtered brethren, relatives, wives, and children. Bridegrooms [slaughtered] their intended and merciful mothers their only children’ (in Chazan 1987, 245).
This sort of martyrdom is theoretically important because it is very difficult to suppose that such people have an algorithm that calculates individual fitness payoffs by balancing the tendency to desert the group with anticipated benefits of continued group membership. The obvious interpretation of such a phenomenon is that these people are obligated to remain in the group no matter what’even to the point of killing their own family members to prevent the possibility of becoming a member of the outgroup. Such examples suggest that there are no conceivable circumstances that would cause such people to abandon the group, go their own way, and become assimilated to the outgroup.
I do not suppose that such an extreme level of self-sacrifice is a pan-human psychological adaptation. As is the case for many other psychological adaptations, there are important individual differences (MacDonald 1991, 1995, 1998b; Wilson 1994). Conceptually, this range of individual differences in personality systems and mechanisms related to social identity and individualism/collectivism may be seen as representing a continuous distribution of phenotypes that matches a continuous distribution of viable strategies. At one extreme end of this variation, it appears that there are a significant number of humans who are so highly prone to developing a sense of shared fate that they do not calculate individual payoffs of group membership and readily suffer martyrdom rather than defect from the group.
It should also be noted that the existence of significant numbers of people for whom desertion of the group is not a psychologically available option shows that between-group selection must be presumed to have occurred among humans. However, the existence of such people is not a necessary condition for groups being a vehicle of selection. Even if all humans were entirely opportunistic and fickle in their group affiliations so that group membership was always contingent on individual self-interest, groups as a vehicle of selection would still be required in order to understand the behavior of coordinated groups (Wilson & Sober, 1998).
It is likely that enduring, bounded discrete gatherings of people have been a common feature of the social environment for many humans (Levine & Campbell, 1972). The phenomenon is important because it would imply that a great many humans have in fact lived in group-structured populations where the status of ingroup and outgroup was highly salient psychologically (see Palmer et al., 1997 for a contrary perspective). Examples that bear investigation include Gypsies, Armenians, Bosnians, Serbs, and Croatians, and a variety of middle-man minority groups (e.g., overseas Chinese groups) occurring in several parts of the world. It is noteworthy that Middle Eastern societies are characterized by anthropologists as ‘segmentary societies’ organized into relatively impermeable groups (e.g., Coon 1958, 153; Eickelman 1981, 157-174). Individuals in these societies have a strong sense of group identity and group boundaries, often accompanied by external markers such as hair style or clothing, and different groups settle in different areas were they retain their homogeneity alongside likewise homogeneous groups. Consider Carlton Coon’s (1958) description of Middle Eastern society:
There the ideal was to emphasize not the uniformity of the citizens of a country as a whole but a uniformity within each special segment, and the greatest possible contrast between segments. The members of each ethnic unit feel the need to identify themselves by some configuration of symbols. If by virtue of their history they possess some racial peculiarity, this they will enhance by special haircuts and the like; in any case they will wear distinctive garments and behave in a distinctive fashion. (Coon, 1958; p. 153)
Between-group conflict often lurked just beneath the surface of these societies. For example, Dumont (1982, 223) describes the increase in anti-Semitism in Turkey in the late 19th century consequent to increased resource competition. In many towns, Jews, Christians, and Muslims lived in a sort of superficial harmony, and even lived in the same areas, ‘but the slightest spark sufficed to ignite the fuse’ (p. 222).
Hirschfeld (1996) finds that young children are very interested in human groupings. ‘This curiosity is shaped by a set of abstract principles that guide the child’s attention toward information relevant to discovering the sorts of intrinsicalities and naturally grounded commonalities that are entrenched in his or her particular cultural environment’ (p. 193). Hirschfeld thus posits an interaction between an innate domain-specific module of intrinsic human kinds combined with cultural input that race is the type of human kind that is intrinsic’that it is inherited and highly relevant to identity’more so even than other types of surface physical characteristics like muscularity. Thus even young children view racial categories as essentialized and natural: ‘Young children’s thinking about race encompasses the defining principles of theory-like conceptual systems, namely an ontology, domain-specific causality, and differentiation of concepts’ (p. 88). ‘But racial kinds are not natural kinds (at least, not as they have classically been conceived), and they certainly are not kinds whose existence is triggered by external reality’ (p. 197).
In other words, humans have a domain-specific module whereby even very young children are prepared to categorize people as belonging to certain groups because of their very nature’they inherit group membership. People may not voluntarily join or leave such a social category. One might speculate that such a module evolved in order to deal with human ethnic groups and ethnic nepotism, as Salter (2000) has suggested.
Combined with social identity theory, the implication is that classification into ingroups and outgroups is easily accompanied by categorization in which both groups are viewed as composed of people who are fundamentally and intrinsically different. Social identity research has indicated that social mobility (i.e., the extent to which group boundaries are permeable) influences ingroup/outgroup attitudes. The perception of permeability reduces perceptions of conflict of interest and reduces the ability of the other group to act in a collective manner, while perceptions of impermeability lead to group strategies involving competition with the other group and negative evaluations of the outgroup. Hirschfeld’s work indicates that people are inclined to view those in outgroups as ‘of a different kind’ and therefore not potential members of one’s one group. This would lead to greater conflict between groups.
Humans possess rational choice mechanisms able to make cost/benefit calculations aimed at adaptively attaining evolutionary goals in novel environments. In psychological terminology, these are domain-general mechanisms, such as the g-factor of intelligence tests and social learning, that enable humans to make rational, adaptive choices in novel, complex, and relatively unpredictable environments (MacDonald, 1991; MacDonald & Geary, 2000). Applied to the issue of group membership, such mechanisms imply that humans are able to opportunistically join or leave groups depending on immediate cost/benefit calculations (see Goetze, 1998). For example, the promise of financial rewards might incline a person to abandon one group for another (e.g., those who converted to Islam during the Turkish occupation of the Balkans), whereas disincentives such as social opprobrium and economic discrimination directed at ethnic group members might be expected to decrease ethnic identification.
There are many historical examples where people have pursued individual interests rather than continue to identify with a particular ethnic group. Informers or traitors to the ingroup are examples. For example, Jewish religious law has highly elaborated regulations on Jews who inform on other Jews or endanger the lives of other Jews; these laws were invoked in a steady stream of cases against Jews who betrayed other Jews, often for personal profit (Shahak & Mezvinsky 1999). There were also many Jews who converted to Christianity or Islam in order to obtain the benefits of Christian religious affiliation during a periods when there were official or unofficial barriers to Jewish advancement. For example, during the 19th century, ‘conversion’ to Christianity was often perceived, in Heinrich Heine’s words, as the ‘entrance ticket to European civilization,’ although in quite a few of these cases the baptized person continued to identify with and associate with members of his former group. There have also been many examples where disparate ethnic groups have been creatively molded into a larger self-identified ethnic group or ethnically-based nation, as in the case of Germany under Bismarck.
The following argues that domain general mechanisms, including the construction of ethnicity and ethnic groups, can be used to attain evolutionary goals. Evolutionary psychology has emphasized the idea that recurrent adaptive challenges of the EEA are optimally solved by domain specific mechanisms specialized to handle specific types of input (Tooby & Cosmides, 1992). However, domain general mechanisms are also important. There is a great deal of evidence that the EEA consists of both recurrent and non-recurrent problems, the latter leading to the evolution of cognitive mechanisms that functionally result in domain-general competencies designed to produce adaptive responses in novel, non-recurrent, and complex (unpredictable) environments.
The human EEA is reasonably construed as consisting of both recurrent and non-recurrent problems. The incredibly rapid radiation of humans resulted in recurrent situations of novelty and complexity (unpredictability) (Potts, 1998). Potts provides evidence that human evolution has been characterized by inconsistent selection pressures resulting from rapidly changing ecological conditions. These shifts were unpredictable and non-repetitive rather than cyclic and included decade-scale fluctuations between glacial and warm conditions and century-long shifts between cold, steppe and warm, forested conditions interspersed with periods of climatic stability. In addition, rapid local change also resulted from volcanic activity, earthquakes, and tectonic activity.
Potts argues that the predominant human response to this environmental uncertainty was to evolve adaptive flexibility via expanding developmental plasticity and developing ‘complex structures or behaviors that are designed to respond to novel and unpredictable adaptive settings’ (p. 85). These traits are proposed to be adaptive responses to a long-term trend of environmental uncertainty resulting in a ‘decoupling of the organism from any one habitat’ (p. 90). A major trend was increasing encephalization, with the largest increase in relative brain size coinciding with the largest environmental oscillations. Larger brain size is also linked with a wider geographic range, also suggesting that the larger brain enabled adaptation to diverse environments. Current evidence indicates a correlation of about 0.4 between brain size and IQ (e.g., Andreason et al., 1994; Rushton, 1997).
Discussions of general intelligence emphasize that intelligence is useful in solving novel problems. From an evolutionary perspective, a critical function is the attainment of evolutionary goals in unfamiliar and novel conditions characterized by a minimal amount of prior knowledge (fluid intelligence): ‘[Fluid intelligence] reasoning abilities consist of strategies, heuristics, and automatized systems that must be used in dealing with ‘novel’ problems, educing relations, and solving inductive, deductive, and conjunctive reasoning tasks’ (Horn & Hofer, 1992, p. 88). Research on intelligence has consistently found that more intelligent people are better at attaining goals in unfamiliar and novel conditions characterized by a minimal amount of prior knowledge. Intelligence is ‘what you use when you don’t know what to do’ (C. Bereiter, in Jensen 1998, p. 111).
This highlights the idea that intelligence taps conscious problem solving in novel situations’situations where past recurrences would be unhelpful except perhaps by analogy or induction to the new situation. Intelligence involves ‘controlled processing is directed at solving novel problems, learning new knowledge or skills, and consciously monitoring an unpredictably changing situation that calls for varied responses all involve controlled processing’ (Jensen 1998, p. 246). On the other hand, domain-specific mechanisms involve rapid, automatic, unconscious processing designed to solve recurrent adaptive problems.
General intelligence involves the ability to respond to novelty and unpredictability by de-contextualizing the social and non-social environment (Stanovich, 1999; Stanovich & West, 2000). General intelligence facilitates decontextualizing and abstracting processes that enable humans to inhibit the operation of highly context-sensitive, domain specific, implicit and automatic heuristics for making inferences, judgments and decisions. IQ researchers are well aware of the centrality of de-contextualizing as central to intelligence.
One of the well-known byproducts of schooling is an increased ability to decontextualize problems. In almost every subject in the school curriculum, pupils learn to discover the general rule that applies to a highly specific situation and to apply a general rule in a wide variety of different contexts. The use of symbols to stand for things in reading (and musical notation); basic arithmetic operations; consistencies in spelling, grammar, and punctuation; regularities and generalizations in history; categorizing, serializing, enumerating, and inferring in science, and so on. Learning to do these things, which are all part of the school curriculum, instills cognitive habits that can be called decontextualization of cognitive skills. The tasks seen in many nonverbal or culture-reduced tests call for no scholastic knowledge per se, but do call for the ability to decontextualize novel situations by discovering rules or regularities and then using them to solve the problem’ (Jensen, 1998, 325).
As Stanovich (1999, 202) points out, contextualization is undoubtedly of adaptive value in many situations. Prior beliefs about the world are a good rule of thumb in many situations, especially if they have worked well in the past. However, prior beliefs can interfere with problem solving because they prevent seeing the problem in its own terms and prevent developing context-independent solutions for the problem. In general, the real world is becoming a place that rewards decontextualized thinking styles. Responding to critics of laboratory experiments based on unfamiliar materials that require decontextualized reasoning, Stanovich (1999, 205) notes that ‘it just seems perverse to argue that the ‘unnaturalness’ of decontextualized reasoning skills when tests of such skills are the gatekeepers for an elite educational system that feeds privileged positions in society.’
Although the emphasis here is on humans, animals also have to deal with environmental uncertainty’situations where past learning or psychological mechanisms that evolved to deal with recurrent environmental challenges are at best an uncertain guide to an adaptive response (i.e., a response that satisfies some evolved goal state), as would occur if, for example, the animal’s usual path to food is blocked. There is considerable evidence for a g factor in rats (Anderson, 1993; Crinella & Yu, 1993). While there is no evidence for reliable individual differences among tests of simple learning, a general factor emerges in tests of problem solving in which information from more than one source had to be combined in order to come up with a solution or in which the correct solution required some adjustments to a previously learned response.
Domain-general mechanisms are therefore important for achieving evolutionary goals in novel, non-recurrent environments. There are in fact a rich set of evolved motivational mechanisms, ranging from children’s curiosity and playfulness to the evolved motivational systems embedded in the five-factor model of personality (e.g., social dominance and social status seeking, sexual gratification, sensation-seeking and risk-taking, love and nurturance, physical safety) (MacDonald, 1995). For example, the types of behaviors that are likely to result in a high social status are highly variable over time and in different cultures. In contemporary Western society, people intent on improving their social status (an evolved motivational system [Buss, 1999]) might attempt to attend good colleges, choose currently lucrative areas of study (e.g., computer science), and study hard. These behaviors would be irrelevant or impossible in many other historical and contemporary societies.
The general model is that human evolved motive dispositions may be attained by a variety of mechanisms. It is often noted by evolutionary psychologists that humans are not designed as generalized fitness maximizers’that our adaptations are geared to solve specific problems in specific past environments (e.g., Tooby & Cosmides, 1992). However, the model adopted here’the model of domain-general mechanisms aimed at attaining evolutionary goals in novel, unpredictable environments’has quite different implications. That is, humans are conceptualized as potentially flexible strategizers in pursuit of evolutionary goals.
But what evolved motivational systems are relevant to ethnicity? A good place to start is by considering the set of motivations implied in the mechanisms discussed above. People are motivated to establish ingroups and outgroups, to respond to threat by greater collectivism, and to discriminate in favor of similar others. Human groups have used a variety of mechanisms to firm up group boundaries. For example, historical Jewish groups have created boundaries by adopting different religious practices and beliefs, highly elaborated Jewish religious writings (e.g., the Talmud), different language and mannerisms, different clothing and customs (especially the dietary laws), and living in physically separated areas administered by Jews according to Jewish civil and criminal law. Of critical importance for group membership was descent from a Jewish mother, with the result that genealogies were very important for establishing group membership (MacDonald, 1994). Relevant tothe present paper, these cultural practices are conceptualized as aimed at attaining evolutionary goals of social identity (positive emotions elicited by a psychologically salient ingroup) and relative genetic similarity compared to members of surrounding outgroups. (E.g., ingroup alliances of marriage and business would have a greater genetic payoff than similar alliances with outgroup members). These cultural practices are viewed as influenced by domain general mechanisms and aimed ultimately at satisfying these evolved goals. Once constructed, group membership often facilitates attaining other evolved goals, such as social status via ingroup favoritism. For example, Jewish economic behavior was heavily influenced by group membership. Group members in positions of power preferentially employed ingroup members, and economic transactions and ethical standards were deeply influenced by group membership (MacDonald, 1994).
Several theorists have emphasized that ethnic groups are not natural entities but are socially constructed entities typically aimed at achieving the political and economic interests of ethnic leaders (and, I suppose, in at least some cases, their followers). This perspective fits well with the domain-general perspective developed here. Ethnies can indeed appear and disappear; they coalesce and disperse (e.g., Anderson, 1983). Nevertheless, there is every reason to suppose that the coalescing and dispersing reflects evolutionarily comprehensible interests. As van den Berghe (1999, p. 23) notes, ‘Ethnic relations always involve the interplay of the objective reality of biological descent and the subjective perception, definition and manipulation of that objective reality.’
Given the importance of biological descent for understanding human interests and the flexibility provided by domain general mechanisms to achieve those interests, we may ask how one might in general develop a biologically adaptive ethnic group given the evolutionarily novel environment of large states with hundreds of millions of people and with a myriad of genetic fault lines. Designing adaptive strategies is nothing new. The Old Testament is a quite clearly articulated strategy for surviving and prospering economically while maintaining genetic integrity of the ingroup and for specializing in particular economic niches. There are other examples, including the Spartans (MacDonald, 1988, 1994) , and several Christian groups that have emulated aspects of the Old Testament (e.g., Puritans, Mormons, Anabaptists) (Miele, 2000; Wilson, forthcoming).
Ethnic groups are breeding populations; individuals have genetic interests in ethnic groups by virtue of having a greater concentration of inclusive fitness in their own ethnic group than other ethnic groups (Salter, 2000; van den Berghe, 1999). Population genetic studies show that the various European populations are much closer genetically than continentally separated races (Cavalli-Sforza et al., 1994), and that the distances between those populations correspond approximately to what a reasonably well informed historian or demographer or tourist would expect. All things being equal, Scandinavians have greater overlap of genetic interests with other Scandinavians than other Europeans, and Europeans have a greater genetic interest in other Europeans than in Africans (see Figures 1 & 2).
The point is that whatever the fuzziness that characterizes genetic distances, people can creatively decide how best to strategize to promote their genetic interests in the current environment. (See Salter’s  conceptual typology of strategies for advancing genetic ethnic interests.) Reasoning about creating adaptive ethnic groups in the novel environments present in the contemporary world is a problem that is solvable with domain general mechanisms. For example, such a strategizer could look at the map of European genetic distances and decide to promote, organize, and identify with movements of his closest genetic grouping. Thus a Swede might opt for the advancement of the Swedish and Norwegian gene pool, or a Yugoslav might opt for the Yugoslavian and Greek gene pools. Or such a person could look at the larger map and promote, organize, and identify with the Caucasoid group or could promote, organize, and identify with an alliance between Caucasoids and Northeast Asians. How one decides these issues is a pragmatic matter involving optimizing long-term evolutionary interests best achieved via the decontextualizing and abstraction functions characteristic of domain-general mechanisms.
Obviously some groups are already organized effectively to pursue their interests in the modern world. For example, Jewish groups maintain an elaborate network of activist organizations aimed at countering intermarriage, promoting the interests of Israel, advocating self-interested positions on church-state relations, immigration, etc. (MacDonald, 1998b, 1998c). The means utilized to attain ethnic interests in contemporary post-industrial societies utilize domain-general problem solving mechanisms’knowledge of the political process, how to raise money, how to utilize social science research to influence media messages, how to utilize the internet, etc. Groups, such as Jews, with a relatively high IQ — a domain general ability — are able to attain relatively high levels of economic success; they thereby have the resources to fund ethnic activist organizations and influence political parties. Again, domain general abilities are used to advance evolutionary goals.
Given our current knowledge of human genetic distances and human behavior, as well the need to cement powerful alliances able to act effectively on the world stage, some choices are obviously better than others. I suppose that it would be foolish for a Scandinavian-American, e.g., to promote Scandinavian-American interests to the exclusion of larger groupings, because larger groupings would have more political clout, especially in a multi-ethnic context as in the U.S. I suppose the best strategy would be on analogy with the model of inclusive fitness in which people participate in ethnic groups as a function of genetic distance’at the extreme teaming up with all of humanity against an alien invader.
Notice that there is no one natural place on this genetic landscape where it is rational to direct one’s energy. Different contexts demand different responses and even one’s best choices are made under uncertainty. An effective response for a Serbian living in Kosovo might be quite different than for a German-American living in the United States. The former threatened by a cohesive, non-assimilating European ethnic/religious group (the Albanians), while the latter is confronted with a polyglot of many different ethnic and racial groups in which cooperation with larger divisions of European-derived peoples in the United States would seem an obvious choice. But whatever choices are made, domain general problem solving is critical to the choices that are made.
Of these mechanisms, only GST implies a genetically based assessment of genetic distance. Social identity mechanisms and the domain specific categorization module proposed by Hirschfeld imply a categorization process, but the genetic distance of the person or group being categorized from the person doing the categorization is unspecified and irrelevant. Social identity mechanisms are triggered by crowds of ethnically identical people on opposing sides at football games as well as when the outgroup is a different race or ethnic group. Racial classification as proposed by Hirschfeld is independent of whether or not there are real biological race differences. Domain general rational choice mechanisms may be utilized in the service of attaining any number of human goals (e.g., personal social status) rather than maximizing genetic interests by forming optimal coalitions based on current estimates of genetic similarity.
I suggest that the mechanisms underlying ethnocentrism that do not assess genetic distance were adaptive in the EEA because, in general, outgroups were naturally occurring entities whose members were on average less genetically similar than ingroups. That is, members of a given tribe or band were more closely related to other members of their ingroup than they were to other tribes or bands. As a result, mechanisms that result in discrimination in favor of ingroup and against outgroups would also tend to benefit people genetically. There was no need for genetic distance itself to be assessed. Obviously, in multi-racial, multi-ethnic states, social identity mechanisms may often result in maladaptive behavior because ingroups and outgroups can be manipulated by the media, ethnic leaders, and other elites.
Social identity mechanisms, Hirschfeld’s domain-specific categorization mechanism, and rational choice mechanism do not require assessment of real genetic distances. However, even in the modern world ethnic groups seem to be extraordinarily stubborn and non-arbitrary. As van den Berghe (1999, p. 31) notes, many ethnic groupings are remarkably stable; the Flemings and Walloons are ‘almost exactly where their ancestors were when Julius Caesar wrote De Bello Gallica.’ Are mechanisms for assessing genetic distance, as proposed by GST, responsible for this persistence of the ethnic phenomenon. Assessing the degree to which GST processes are important in ethnic conflict is difficult because, in actual cases, ethnic differences coincide with a variety of cultural markers, such as language and religion, that would be expected to trigger social identity mechanisms. As a result, it is difficult to know the extent to which judgments of genetic distance are actually relevant to between-group conflict.
One can imagine a thought experiment in which people are stripped entirely of their group identities and one then assesses the extent to which they assort on the basis of genetic distance. The results of GST research indicate that genetically similar others would be preferred as spouses, friends, and as partners in alliances. Such a world is an atomistic world, however; it is insufficient by itself to create ethnic groups. To accomplish that, mechanisms of social identity, including establishing and maintaining group boundaries, are required. The results of social identity research indicate that the boundaries may be drawn in a arbitrary manner and still result in ingroup favoritism and discrimination against outgroups. However, the results of GST predict that such groups would lack the rapport and cohesion of ingroups that are more genetically similar compared to the outgroups they are living among. To provide examples from my work on Jewish groups, there are anecdotal reports of very high levels of rapport and ability to recognize other Jews. For example, As Harvard sociologist Daniel Bell notes, ‘I was born in galut [exile] and I accept’now gladly, though once in pain’the double burden and the double pleasure of my self-consciousness, the outward life of an American and the inward secret of the Jew. I walk with this sign as a frontlet between my eyes, and it is as visible to some secret others as their sign is to me’ (Bell 1961, 477). A writer in the Toronto Globe and Mail (May 11, 1993) commented on the incredible sense of commonality he has with other Jews and his ability to recognize other Jews in public places, a talent he says he has heard called ‘J-dar’. While dining with his prospective gentile wife, he is immediately recognized as Jewish by some other Jews, and there is an immediate ‘bond of brotherhood’ between them that excludes his gentile companion.
To that extent, ethnic groups composed of genetically similar others are indeed natural groups, and it is mechanisms of genetic similarity that account ultimately for the staying power of ethnicity as a human grouping.
Abrams, D., & M. A. Hogg (1990). Social Identity Theory: Constructive and Critical Advances. New York: Springer-Verlag.
Agus, A. R. E. (1988). The Binding of Isaac and Messiah: Law, Martyrdom and Deliverance in Early Rabbinic Religiosity. Albany: SUNY Press.
Alexander, R. (1979). Darwinism and Human Affairs. Seattle: University of Washington Press.
Altemeyer, B. (1994). Reducing prejudice in right-wing authoritarians. In The Psychology of Prejudice: The Ontario Symposium, Volume 7, M. P. Zanna & J. M. Olson (Eds.). Hillsdale, NJ: Erlbaum.
Anderson, Benedict (1983). Imagined Communities. London: Verso.
Anderson, Britt. (1993). Evidence from the rat for a general factor that underlies cognitive performance and that relates to brain size: intelligence? Neuroscience Letters, 153, 98-102.
Andreason, N. C., Flaum, M., Swayze, V., O’Leary, D. S., Alliger, R., Cohen, G., Ehrardt, J., & Yuh, W.T.C. (1993). Intelligence and brain structure in normal individuals. American Journal of Psychiatry 150:130-134.
Bell, D. (1961). Reflections of Jewish identity. Commentary 31(June):471-478.
Berkowitz, L. (1982). Aversive conditions as stimuli to aggression. In Advances in Experimental Social Psychology. Vol. 15, L. Berkowitz (Ed.). New York: Academic Press.
Biale, D. (1982). Gershom Scholem: Kabbalah and Counter-History, 2nd ed. Cambridge: Harvard University Press.
Boehm, C. (1997). Impact of the human egalitarian syndrome on Darwinian selection mechanics. American Naturalist, 150 Supplement, S106’S121.
Bourhis, R. Y. (1994). Power, gender, and intergroup discrimination: Some minimal group experiments. In M. P. Zanna & J. M. Olson (Eds.), The Psychology of Prejudice: The Ontario Symposium, Volume 7. Hillsdale, NJ: Erlbaum, 1994.
Boyd, R., & P. J. Richerson (1992). Punishment allows the evolution of cooperation (or anything else) in sizable groups. Ethology and Sociobiology 13:171-195, 1992.
Buss, D. M. (1999). Evolutionary Psychology. Boston: Allyn & Bacon.
Cavalli-Sforza, L. L., Menozzi, P. & Piazza, A. (1994). The history and geography of human genes. Princeton University Press, Princeton, New Jersey.
Chazan, R. (1987). European Jewry and the First Crusade. Berkeley: University of California Press. San Francisco: HarperSanFrancisco.
Coie, J. D., & Dodge, K. A. (1998). Aggression and antisocial behavior. In N. Eisenberg (Ed.), Handbook of Child Psychology, Vol. 3: Social, Emotional, and Personality Development 779-862. New York: Wiley.
Coon, C. (1958). Caravan: The Story of the Middle East, 2nd ed. New York: Holt, Rinehart, and Winston.
Crinella & Yu: Brain mechanisms in problem-solving and intelligence: A Replication and Extension. Intelligence 21: 225-246.
Crossan, J. D. (1991). The Historical Jesus: The Life of a Mediterranean Jewish Peasant. San Francisco: HarperSanFrancisco.
Deshen, S. (1986). The Jewish family in traditional Morocco. In The Jewish Family: Myths and Reality, S. M. Cohen & P. E. Hyman (Eds.). New York: Holmes & Meier.
Droge, A. J., & Tabor, J. D. (1992). A Noble Death: Suicide and Martyrdom Among Christians and Jews in Antiquity.
Dumont, P. (1982). Jewish communities in Turkey during the last decades of the nineteenth century in light of the archives of the Alliance Israï¿½ï¿½lite Universelle. In Christians and Jews in the Ottoman Empire: The Functioning of a Plural Society, B. Braude & B. Lewis (Eds.). New York: Holmes & Meier Publishers, 1982.
Goetze, D. (1998). Evolution, mobility, and ethnic group formation. Politics and the Life Sciences, 17, 59-71.
Goldstein, A. (1981). Some demographic characteristics of village Jews in Germany: Nonnenweier, 1800-1931. In Modern Jewish Fertility, ed. P. Ritterband. Leiden: E. J. Brill.
Halkin, A., & Hartman, D. (1985). Discussion, in Crisis and Leadership: Epistles of Maimonides, trans. A. Halkin & D. Hartman. Philadelphia: Jewish Publication Society of America.
Hebb, D. O., & Thompson, W. R. (1964). Emotion and society. In War, ed. L. Bramson & G. W. Goethals. New York: Basic Books.
Hirschfeld, L. A. (1996). Race in the making: Cognition, culture, and the child’s construction of human kinds. Cambridge, MA.: MIT Press.
Hogg, M. A., & D. Abrams. (1987). Social Identifications. New York: Routledge.
Horn, J. L., & Hofer, S. M. (1992). Major abilities and development in the adult period. In R. J. Sternberg & C. A. Berg (Eds.), Intellectual Development. New York: Cambridge University Press.
Jensen, A. R. (1998). The g factor: The science of mental ability. Westport, CT: Praeger.
Johnson, G. (1995). The evolutionary origins of government and politics. In J. Losco & A. Somit (eds.), Human Nature and Politics, 243-305. Greenwich: CT: JAI Press.
Josephus, F. (1981). The Jewish Wars, trans. G. A. Williamson. NY: Penguin.
Katz, J. (1986). Jewish Emancipation and Self-Emancipation. Philadelphia: The Jewish Publication Society of America.
Keegan, J. (1993). A History of Warfare. New York: Knopf.
Keeley, L. (1996). War before Civilization. New York: Oxford University Press.
Levine, R. A., & Campbell, D. T. (1972). Ethnocentrism: Theories of Conflict, Ethnic Attitudes and Group Behavior. New York: Wiley.
Lindemann, A. S. (1991). The Jew Accused: Three Anti-Semitic Affairs (Dreyfus, Beilis, Frank) 1894-1915. New York: Cambridge University Press.
Lindemann, A. S. (1997). Esau’s Tears: Modern Anti-Semitism and the Rise of the Jews. New York: Cambridge University Press.
Lusk, J., MacDonald, K., & Newman, J. R. (1998). Resource Appraisals among Self, Friend and Leader: Implications for an Evolutionary Perspective on Individual Differences and a Resource/Reciprocity Perspective on Friendship. Personality and Individual Differences, 24, 685-700.
MacDonald, K. B. (1988). Social and Personality Development: An Evolutionary Synthesis. New York: Plenum.
MacDonald, K. B. (1991). A perspective on Darwinian psychology: The importance of domain-general mechanisms, plasticity, and individual differences. Ethology and Sociobiology, 12, 449-480.
MacDonald, K. B. (1994). A People that Shall Dwell Alone: Judaism as a Group Evolutionary Strategy. Westport, CT: Praeger.
MacDonald, K. (1995). Evolution, the Five Factor Model, and Levels of Personality. Journal of Personality 63:525-567.
MacDonald, K. B. (1996). What do children want? An evolutionary perspective on children’s motivation in the peer group. International Journal of Behavioral Development, 19(1), 53-73
MacDonald, K. (1998a). Separation and Its Discontents: Toward an Evolutionary Theory of Anti-Semitism. Westport, CT: Praeger.
MacDonald, K. (1998b). Evolution, Culture, and the Five-Factor Model. Journal of Cross-Cultural Psychology 29:119-149.
Maimonides, M. (1985). Crisis and Leadership: Epistles of Maimonides, trans. A. Halkin & D. Hartman. Philadelphia: Jewish Publication Society of America.
Miele, F. (2000). To Rule is to Populate: Puritanism as a Group Evolutionary Strategy, the Rise
(and Fall?) of Anglo-America, and the Unifying or Fragging of Knowledge. Paper presented at the American Political Science Association annual meeting, Washington D.C., 2 September, 2000
Palmer, C. T., Fredrickson, E., & Tilley, C. F. (1997). Categories and gatherings: Group selection and the mythology of cultural anthropology. Evolution and Human Behavior 18:291-308.
Potts, R. (1998). Variability selection in Hominid evolution. Evolutionary Anthropology, 7, 81-796.
Richerson, P. J., & R. Boyd. (1971). The evolution of human ultra-sociality. In Ideology, Warfare, and Indoctrinability, I. Eibl-Eibesfeldt & F. Salter., eds. Oxford and Providence: Berghahn Books.
Ritterband, P. (1981). Introduction. In Modern Jewish Fertility, P. Ritterband, (ed.). Leiden: E. J. Brill.
Russell, R. J. (1993). The Lemur’s Legacy: The Evolution of Power, Sex, and Love. New York: Tarcher/Putnam.
Rushton, J. P. (1997). Race, intelligence and the brain: The errors and omissions of the ‘revised’ edition of S. J. Gould’s The Mismeasure of Man. Personality and Individual Differences 23:169-180.
Rushton, J. P. (1999). Genetic similarity theory and the nature of ethnocentrism. In K. Thienpont & R. Cliquet (Eds.) In-group/Out-group Behavior in Modern Societies: An Evolutionary Perspective, pp. 75-107. Th Netherlands: Vlaamse Gemeeschap/CBGS.
Rutherford, M. D., Kurzban, R., Tooby, J., & Cosmides, L. (1997). Cooperation and punishment in groups: Economic trade-offs. Paper presented at the meetings of the Human Behavior and Evolution Society, Tuscon, AZ, June 5.
Salter, F. K. (2000). On genetic ethnic interests. Paper presented at the American Political Science Association annual meeting, Washington D.C., 2 September, 2000.
Sanders, E. P. (1992). Judaism: Practice & Belief 63 BCE-66 CE. London: SCM Press.
Shahak, I., & Mezvinsky, N. (1999). Jewish Fundamentalism In Israel. London: Pluto Press.
Sherif, M., O. Harvey, B. J. White, W. R. Hood, & C. Sherif (1961). Intergroup Conflict and Cooperation: The Robbers’ Cave Experiment. Norman: University of Oklahoma Press.
Sherif, M. (1966). In Common Predicament: The Social Psychology of Intergroup Conflict. Boston: Houghton-Mifflin.
Stanovich, K. E. (1999). Who is rational? Studies of individual differences in reasoning. Mahweh, NJ: Erlbaum.
Stanovich, K. E., & West, R. F. (2000) Individual Differences in Reasoning: Implications for the Rationality Debate? Behavioral and Brain Sciences 22 (5), in press.
Stein, H. F. (1978). Judaism and the Group-Fantasy of Martydom: The Psychodynamic Paradox of Survival Through Persecution. Journal of Psychohistory 6: 151-210.
Sumner, W. G. (1906). Folkways. New York: Ginn.
Tajfel, H. (1981). Human Groups and Social Categories: Studies in Social Psychology. Cambridge: Cambridge University Press.
Triandis, H. C. (1990). Cross-cultural studies of individualism and collectivism. Nebraska Symposium on Motivation 1989: Cross Cultural Perspectives. Lincoln, NE: University of Nebraska Press.
Triandis, H. C. (1991). Cross-cultural differences in assertiveness/competition vs. group loyalty/cohesiveness. In Cooperation and Prosocial Behavior, R. A. Hinde & J. Groebel (eds.), Pp. 78-88. Cambridge, UK: Cambridge University Press.
Triandis, H. C. (1995). Individualism and Collectivism. Boulder, CO: Westview Press.
Tajfel, H. (1981). Human Groups and Social Categories: Studies in Social Psychology. Cambridge: Cambridge University Press.
Tooby, J., & Cosmides, L. (1992). The psychological foundations of culture. In G. Barkow, L. Cosmides, & J. Tooby (Eds.), The Adapted Mind: Evolutionary Psychology and the Generation of Culture (pp. 3-136). New York: Oxford University Press
Turney-High, H. (1971). Primitive War: Its Practice and Concepts (2nd ed.). Columbia, SC: University of South Carolina Press.
van den Berghe, P. L. (1999). Racism, ethnocentrism, and Xenophobia: In our genes or in our memes? In K. Thienpont & R. Vcliquet (Eds.), In-group/Out-group Behavior in Modern Societies, pp. 21-33. The Netherlands: NIDI CBGS Publications.
van der Dennen, J M. G. (1987). Ethnocentrism and in-group/out-group differentiation. A review and interpretation of the literature. In V. Reynolds, V. Falger, & I. Vine (eds.), The Sociobiology of Ethnocentrism. Athens, GA: The University of Georgia Press.
van der Dennen (1991). Studies of conflict. In M. Maxwell (Ed.), The Sociobiological Imagination. Albany: The State University of New York Press.
van der Dennen (1999). Of badges, bonds, and boundaries: In-group/out-group differentiation and ethnocentrism revisited. In K. Thienpont & R. Cliquet (Eds.) In-group/Out-group Behavior in Modern Societies: An Evolutionary Perspective, pp. 37-74. The Netherlands: Vlaamse Gemeeschap/CBGS.
Vine, I. (1987). Inclusive fitness and the self-system. The roles of human nature and sociocultural processes in intergroup discrimination. In V. Reynolds, V. Falger, & I. Vine (eds.), The Sociobiology of Ethnocentrism. Athens, GA: The University of Georgia Press.
Wilson, D. S. (1994). Adaptive genetic variation and human evolutionary psychology. Ethology and Sociobiology 15:219-235.
Wilson, D. S., & Sober, E. (1998). Unto Others: The Evolution and Psychology of Unselfish Behavior. Cambridge, MA: Harvard University Press.