A comprehensive essay on the biological concept of race and its theoretical and practical viability. Texto de Bernardo Guerra Machado. Revisão de João N.S. Almeida. Imagem: Marco Scarangella.
Older it may seem, the discussion about the use of racial categorization in our species is ongoing. Such is, to a great extent, due to the lack of objectivity of race as a concept and the need for a holistic approach to examine it. Even if no definite answer may be provided on whether its appliance is legitimate or not, an alternative approach can be advanced: seek to better inform about the fascinating diversity existent within our species, and the difficulties our cognitive system faces when processing it. The race for humanity is an essay in which the reader is invited to take this path and formulate an opinion even beyond that expressed by the author.
Part I: Race as a social construct
Introduction
The main problem in the following debate starts from its very premises: the definition of race. I propose two perspectives that can be followed: one, race as a social construct; another, following contemporary taxonomy, race as a synonym of subspecies. This first, which I will try to describe in this part of the essay, is a derivative of traditional delineations of animal breeds, which are largely transmitted by teaching. Usually, it is mostly based on phenotypical aspects, established according to similarities of external traits and which may include behavioural cues as well.
A psychological analysis of our cognitive system and its categorisation processes will be necessary to approach this perspective in order to answer the following questions and determine the trustability of race as a biological category or as a social construct. How is this mechanism of categorization built in our minds? Can we trust our cognitive system regarding this aspect? Are there any behavioural and psychological differences between human groups which can sustain a robust biological racial classification?
Unraveling the machinery of prejudice?
For many years, race encoding was thought to be automatic and mandatory; a primary dimension of human categorization, just like sex [1]; this was partially due to the researchers not being able to reduce racial categorization through context manipulations [2]. However, it was later argued that race categorization could be merely a by-product of some cognitive mechanism, and so three main hypothesis were laid out: that race encoding is part of a domain-general correlational system affecting our perception, which fails to explain why attributing membership into a racial category through observed phenotypical features frequently ends up being a basis for making behavioural inferences, and empirical data has shown that race is not trivially processed as colour or shape [3]. Second, that race encoding is a consequence of our essentialist inference system, but there are reasonable anthropological accounts supporting we perceive races as natural-kinds, to which we tend to ascribe a certain essence [4]. Third, that race encoding was a side-effect of our coalitional psychology [3], which is based on convincing empirical evidence: for instance, in a recall task, by manipulating basketball teams’ jersey colours as coalitional cues, the race effect was, at last, significantly reduced – suggesting the drive to establish social alliances was the primary factor in the categorization process [5]. Consequently, race codification can be seen as part of a set of tools, a cognitive shortcut, to elaborate quick, a priori inferences about with whom is safe to interact with. It doesn’t comes as an evolutionary surprise that such characteristics were selected in an extremely social species. Racial categorization seems to be, after all, a dynamic process whose function is rather specific. Therefore, despite of also consisting in assigning essences to the perceived races, it may not be merely a consequence of a general essentialist inference system.
How fine-grained are these strange engines?
The bias towards faces perceived as belonging to the same race is a widely studied phenomena, observed even in children with 3 months [6]; studies have shown that faces from allegedly different races require higher efforts to be processed [7]. Similarly, brain activation research [8] points that this bias is related with a cognitive deficit, although when participants are aware of the bias and elicited to overcome it [9], as well as when they are trained to individuate a wider range of faces [10].
Interestingly, eliciting a group context with people sharing the same ethnicity is enough to produce a face recognition deficit towards those supposedly belonging to an out-group [11]. If so, it may be that we focus only in faces from individuals we a priori feel to be safe to interact with – as it were a deeper search for signs of trust. An example, using a specific trait: music from other cultural traditions tend to be judged as more cognitively demanding and tense [12]. When exposed to a certain music genre one is not at all familiar with, isn’t it common to feel that “it sounds all the same”? Stereotyping is told to work likewise – as the brain’s response to social stimuli anticipated to be somehow potentially overwhelming [1].
Another phenomenon to account for is racial innumeracy. Semyonov et al.’s [13] study in Germany provided revealing results: natives perceived the relative size of the immigrant population significantly higher than its actual size, usually the double, across several districts. And it was the agents’ estimation, not the objective size, that was positively correlated with the perceived threat from out-groups – which by its turn, related with discriminatory behaviours. Additionally, racial innumeracy includes the underestimation of the majority as well [14]. Hence, on one hand, we tend to produce artificial categories when facing cognitively demanding judgements; on the other, it seems they become exaggeratedly salient from those we are familiar with [1]. In conclusion, the answer to this section’s question, as non-scientific as it may seem, would be that this strange engines of acknowledgment are quite poorly fine-grained across many aspects.
Can we classify humans using behavioural and psychological criteria?
Human groups differ behaviourally, otherwise there would be no cultural diversity. There is a potential culture-behaviour-brain loop ocurring: culture shapes behaviour; this affects the brain; which, by its turn, impacts behaviour; and so on [15]. For example, distinct language systems may not recruit exactly the same neural networks [16], thus differently tuning the brain [17]. In addition, Park and Huang [18] reviewed studies comparing Western and East Asian cultures, providing evidences that individuals from the latter were biased to process context, recur less to categorizations, and rely more on intuitive reasoning. Accompanying such behavioural differences, there were contrasting eye-fixation patterns emerging across several tasks; plus disparities in brain activation, brain structure, and aging. Despite admitting other factors can also play a role in these results, the authors advocated they are to a great extent due to cultural wiring of the brain.
Conversely, other types of explanations have been advanced in one of the most sensitive contrasts studied: the intelligence coefficient (IQ). As represented in Figure 2, disparities in mean scores across human populations have been detected with considerable consistency [19], and there are researchers attributing them partially to genetic factors [20]. Such claims tend to raise a wave of indignation and aggressiveness [21] – but, ironically, that stance can be considered ethnocentric in itself, because the IQ, perhaps similarly to race, is a social construct: a cultural conception of intelligence based on some objective data, not by any means determinant of comprehensive human value. The IQ scale may be valid, reliable, and applicable across human populations [22], but it does no more than providing a score to intelligence as it is conceived by a very small fraction of humanity, focused in measuring components which are fundamental within the so-called Western societies; but considered useless elsewhere. Rather than a question of objective vs subjective, it is a question of Human imperfection and difficulty in producing truly comprehensive scales. Maybe it would be of great importance to measure the capacity to adapt to novelty, according to what will be proposed in the next paragraph.
So, for the sake of the argument, here intelligence is proposed to be defined as the capacity to efficiently navigate into the world surrounding us. Lets continue by considering the accounts Henrich [23] gathered, of European explorers getting lost during expeditions in other continents, and depending on the cumulative cultural knowledge of their native populations to survive. No test needed to be administered by the locals to conclude that these visitors, at that particular place and time point, could be easily be classified as deeply dumb. This to say that intelligence is quite a relative and fluid concept.
However, what is of real interest to the present work is to investigate if this variability is indeed governed by genetic factors. Some criticism can be pointed to such position. First, IQ scores were documented to be increasing within populations, similarly to height [22] – which may be much less a consequence of polygenic selection and inheritance as once thought [24]. In fact, despite existing reports that genes regulating our brain size are under positive selection [25], other recent studies have noted that the evolution of the human genome might have been mostly affected by negative selection – sweeping alleles (the different alternative forms concerning a given gene) which reduced the individual’s fitness, rather than the selection of superior novel ones [26]. Second, factors like birth order and socioeconomic status were also associated with test score [27], suggesting there may be confounding variables behind the effect, such as familiarity with these type of tests. Third, several psychological experiments have shown that, by removing stereotypical threat (the fear of corresponding to the negative prejudices attributed to the group you perceive belonging to), the performance in intellectual tests got even between Americans of African and European ancestry [28].
These are good reasons to advocate that we need to be very careful when relating mean differences in IQ with genetic inheritance. Moreover, Figure 2 shows a considerable intra-continental variation, from which further detailed and bordering nonsensical racial categories would be produced, at least in respect to the traditional classification (White, Black, Mongoloid, and Native American). Interestingly, the decays seem to tend to occur from North to South [21]. Additionally, even intra-country inconsistencies have been detected, which were attributed to socioeconomic contrasts [21].
Still within the perspective of race as a social construct, another problem arises from using behavioural and psychological criteria to establish categories, as these characteristics, unlike genes, can be to a considerable extension changeable through horizontal transmission (which refers to exchanges of information between non-related individuals from the same generation). Indeed, bicultural individuals are told to be capable of engaging into cultural frame switching [29], meaning they have disparate behavioural pathways that can be triggered by cues from specific cultures. For instance, this has been documented to occur when distinct cultural primes were presented during aesthetic judgments [30]; and when, by changing the language being used, personality shifts were registered [31]. Also, there is data showing a tendency for migrants to, across generations, approach the host society score level on several traits, such as religiosity, collectivism, self-esteem, trust, and social closeness [32].
Conclusion
From the information provided, regarding race as a social construct, it becomes fair to state that there are very good reasons for not trusting our cognitive system when it starts drawing racial categories – and stereotypes in general. We even know it potentially betrays us for the sake of facilitating our navigation in a dense social environment, in which we are demanded to make quick judgments about whom can we safely interact with. Therefore, despite recognizing the existence of racial categorization as a natural side-effect of well-established mental mechanisms, it is here advocated that humans should be able to prevent it from blinding their intelligence. Above all, the first step is to recognize better our cognitive deficits and misleading tendencies.
Overall, we have seen that the fantastic behavioural and psychological diversity exhibited by our species doesn’t seem to serve as a reliable proxy for establishing a racial classification due to being mutable, highly prone to biases, and having internal inconsistencies. We may still have many miles ahead, but throughout these paragraphs, hopefully, a couple of important steps were given within the race for humanity – which is probably the most interesting social construct that ever came into our minds! Considering humanity a social construct might imply that there isn’t so much a robust biological distinction between us and other species, and that is exactly what I am suggesting: chimpanzees have cultures, ritualistic behaviours, and can build tools; birds have dialects and some can solve complex problems – so there are even many aspects in which some other species are closer to the ideal behaviour than us. Biologically, the only thing extraordinary about us is our endurance running ability (the capacity to pursue a prey until they get tired, instead of just running faster than them) – and, of course, the capacity to accumulate information and successfully transmit it to the next generation.
Part II: Race as a biological construct
Introduction
Between-groups prejudice is, and will always be, a subject of great importance, because we are a species whose natural history and behaviour has been deeply influenced by migration — which explains how we have spread to a virtually global distribution. It hardly matters where one exactly lives: think on how many nomadic groups, throughout history, encountered each other in your region of origin, making war and alliances; on how many empires dominated them before falling; on how many emigration crises have occurred among your close ancestors. Plus, in the case of in countries inserted in former colonizing empires throughout history, it can be added: how many people from different societies living far away were forced to move to your hometown?
Our current concept of nation-state, with well-defined borders, is a very recent one [1]. And migrations have always had an important role on the development of politics, functioning as a vehicle of exchange of ideas and technologies, a mechanism present in the pre-modern history dominated by poly-ethnic empires, such as the Roman and the Greek ones. Demographically, it also helped to spread epidemics dramatic enough to provoke population replacements [1].
So, despite our tendency to define static and well-defined categories of human phenotypes, each individual’s genome and inherited culture is always an admixture of influences from the most unexpected parts of the world. Race is not a formal taxonomic category, but will be here treated as a synonym of subspecies.
Why don’t we start with palaeoanthropology?
Some paleoanthropologists advert that, when examining fossil records from our genus, it is a common mistake to misinterpret intraspecific variation as species diversification [2]. This indicates that our evolutionary history predicts a high within-species morphologic diversity. In fact, despite Neanderthals being estimated to have diverged from the Homo sapiens lineage roughly 350,000 years ago, when they had contact with modern shaped humans, around 270.000 years after, admixture still occurred – with an estimated contribution of 1-4% to the actual genome of non-African populations [3].The same happened with a sister group of Neanderthals, the Denisovans: traces of their posterior contact with our species were found in around 4-6% of the genome of actual Melanesians [4].
Hence, on the one hand, our species has had the potential to exhibit a great morphologic diversity; on the other, it seems to be able to maintain a certain genetic unity, which allowed it to successfully hybridize with other groups within the genus Homo.
How committed is our development?
Hand in hand with such morphological diversity goes an ontogenetic versatility. This is shown by a notable variation of life-history traits – such as body growth, and age of puberty and first occurrence of menstruation – detected across several small-scale societies [5]. Moreover, there are evidences that some traits can change by a standard deviation in a given population over timescales of 2 to 6 decades [6]. Developmental shifts have also been detected in the context of migrations: comparing with non-migrating countrymen, females from developing countries being adopted in Europe had their puberty earlier [7]. Understanding which factors underlie this effect is very complex; but still, this research supports the words of Wells and Stock [8], that we are “the ape that doesn’t commit”, a species with notable biological plasticity. Such is expected to be favoured in organisms adapted to unstable environments or prone to regular migration.
Considering our global colonization, it becomes clear that both factors, being adapted to unstable environments and also being prone to regular migration, must be taken into account. Again, the idea that human diversity is not necessarily embedded in genetic differences remains. Although biological plasticity may enhance differentiation, it doesn’t seem to imply, at the genetic level, neither a marked heterogeneity between populations, nor homogeneity within populations, as one commonly tends to assume.
Are forensic anthropologists about to lose their job?
Sauer [9] wrote a paper with the provocative title “Forensic anthropology and the concept of race: if races don’t exist, why are forensic anthropologists so good at identifying them?”. According to it, forensic anthropologists are capable of attributing to a corpse, with a remarkable success rate, one of the traditional racial categories (White, Black, Mongoloid, and Native American) recurring to a series of cranial measurements. Despite the fact that the method tends to fail when genetic admixture is prominent, it turns out that, at least at the continental level, the internal homogeneity of native populations within each group admits some kind of categorization to be applied – based on a restricted and arbitrary set of characteristics. Nevertheless, the author didn’t defend that these categories correctly represent human diversity as its whole – instead, he treats them as an artificial classification merely useful to help to identify corpses.
It can be posited that it would be only a matter of perfecting technologies and methodologies so to allow origins to be tracked down to the large-scale regional or event to the country-level; though the probability of errors due to admixture would increase more and more. This scenario was raised for the sake of arguing that the borders of our categorization, the point in which we decide to stop “zooming”, will be quite based on preconceived ideas, rather than objective criteria.
Does it run in the genes?
Having discussed phenotypical accounts, the focus shall now be laid on our genes. A relevant initial remark is that our species shows a particularly high degree of genetic unity when compared with other ape species, especially given our vast geographical distribution. On the one hand, some bono and chimpanzee clades show more mitochondrial variability than our entire species [10]; on the other, chimpanzees seem to have more genetic adaptations influenced by directional selection (a type of selection in which a certain phenotype is favoured in relation to others that will become more and more rare) [11], whereas our adaptive evolution appears to occur mostly through subtle alterations of the frequency of the existing alleles [12]. Additionally, many of our traits have a polygenetic basis [13], which contributes to the relaxation of selective pressures on the genome and constrains genetic differentiation, thus partially explaining the maintenance of our genetic unity across so many diverse ecological environments.
How is human genetic diversity distributed?
In a classical study from Lewontin [14], the taxonomic concept of race was dismissed because most genetic diversity was harboured within populations, an average of 85.4%, and between-races differences had a mean of 6.3%. Later, some researchers considered this approach statistically fallacious, as being a unidimensional, arbitrary selection of a small number of loci (these are the fixed positions that specific genes assume in their chromosome) [15]. Rosenberg et al. [16], seeking to address this issue, ended up increasing the debate. On one side, they gave further support to their predecessor, as 93-95% of the genetic diversity was due to within-population differences, and only 3-5% was exclusively due to between-population contrasts. On the other, the genetic data could be clustered with no a priori information into 6 main groups, 5 of them corresponding to the main geographic regions – just like forensic anthropologists could assign origins by examining craniums.
It is tempting to close the case recurring to the conventionalized standards of genetic differentiation (themselves arbitrary to some extension): values superior to 15% imply a significant contrast [17]. However, one study adding a chimpanzee sample into a similar analysis came to challenge all the previous results, as the between-group portion of genetic variability increased only slightly, from 11.9% to 18.3% [18]. Hence, something had to be wrong, and it turned out that the statistic being used (FST) was improper, because it assumed equal within-groups divergence, a principle that our species violates [19]. It turns out that we are diversely diverse.
This paramount piece of information, nonetheless, seemed to be ignored; probably because it was seen as an inconvenient refutation of one of the strongest arguments against the existence of human races. But, assuming so is ignoring the basic functioning of science: evidence is collected to seek support to reject a given null hypothesis, in favour of alternative ones. When discussing the creation of some kind of hierarchical divisions to better describe a species’ diversity, the null hypothesis is obviously that those categories are meaningless. Now, if the statistical tests that would be able to produce such tests do not work, the null hypothesis prevails – and the existence of racial categories remains unconvincing.
Can you hand me the map of human diversity?
Our pattern of genetic diversity can provide further clues about our evolutionary history. Hunley et al. [20] gathered DNA samples of human populations from every habited continent and ran several simulations testing assumptions from the main models trying to explain our gene identity variation. Only after allowing migration between contiguous populations after each region was colonized could the data be accurately comprehended. Conclusion: “the observed pattern of global gene identity variation was produced by a combination of serial population fissions, bottlenecks and long-range migrations associated with the peopling of major geographic regions, and subsequent gene flow between local populations”. According to them, were there to be any possible taxonomic divisions, the traditional geographic groups which have been used to determine races would be assigned in different levels of hierarchical classification, as represented in Figure 1. That is, instead of the classic tree branches structure with which we represent the species and the relation between them, human diversification could be represented as follows:
Non-African populations significantly differ from the sub-Saharian ones, but as the former is nested within the latter, which is the root of human diversity, they cannot be assigned within the same taxonomic unit. The same would happen with the East Asian and Native American populations. Because they are nested within the non-African populations, they should be hypothetically classified as a sub-race. As our species is thought to be originated in Africa, and from there colonized the rest of the world serially, human diversity can be pictured as a matryoshka.
Later, Hunley et al. [21] advanced a study, which was possibly the first identifying a root for the tree of human populations without recurring to a different species as an outer-group. According to it, the Suruí from Brazil, despite being the least diverse population examined, still accounted for 60% of the global species’ diversity. From this, they concluded “that the biological race concept fails (…) because no matter how much variation might exist among human populations under a given model of evolution, human populations are not genetically homogeneous within”.
Notably, there are reports that diversity within certain African populations is greater than between this group as a whole and Eurasians [19]. Still, some disagree that a great intra-group diversity implies the inexistence of races, were there to be a marked genetic discontinuity between the populations [19]. However, Serre and Pääbo [22] provided evidence that human variation is mostly clinal — a continuous, gradual variation in which becomes very hard to draw a line between two given traits, also due to the existence of intermediary forms; and they argued that methods used in some previous studies were actually inflating genetic discontinuities.
What about the future?
Ramachandran et al. [23] stated: “There clearly has not been time to reach equilibrium between the extremes of man’s inhabited range, or even within continents, in the very short evolutionary history of modern humans”. But… will it ever happen?
The main intercontinental migration fluxes of nowadays are represented in Figure 2, though it should be accounted that the greatest flux registered is between Asian countries [24]. 257.7 million people, 3.4% of the world’s population, have been registered as living as international migrants in 2017 [25]. With data from only 11 countries, though gathered in different years, it was possible to very roughly estimate the existence of at least 35 million of illegal, non-accounted migrants. It also should be noticed that there are 700 million people registered as migrating internally in their country of origin [24]. And, not only all these numbers are probably underestimated – due to lack of accuracy of the methods for data collection, and because many countries simply do not gather enough information on their census – as potential genetic inputs of tourists and short-term exchanges in the labour sphere are not being taken into account.
According to Hartl and Clark [26], genetic drift (random variation of the frequency of certain phenotypes within a population, which can lead to the loss of some variants and the fixation of others) is one of the major forces increasing divergence between populations. They argue that, as an evolutionary process, migration is qualitatively similar to mutation, integrating new alleles into a population; whereas, quantitatively speaking, the migration rate among populations is always greater than the rate of mutation of a gene. In their mathematical analysis, both considering a one-way migration model and a symmetrical island model of migration (the first assumes individuals from large populations migrate to a smaller one, influencing its genetic pool without being affect; whereas the second refers to equal genetic exchanges between two small populations), migration turned out to have a remarkable homogenising effect. Nonetheless, migration does not always lead to an impacting population admixture. In fact, Leonardi et al. (2018) [27], after giving examples of genetic isolates with long-term genealogical continuity, such as Basques, Ogliastra, and Casentino, documented a case of matrilineal continuity across 5000 years in Lucca, Italy. Notably, there are no geographical barriers or any known cultural trait which could justify such a degree of reproductive isolation through the considered centuries. They further suggested that some of the major migration events could consist essentially of males; and that military invasions may not have a remarkable genetic impact in the autochthonous populations, especially in the female lineages.
Nevertheless, with the advance of technology, travelling is getting more easy and accessible. If those changes are to be accompanied by a decrease of nepotism, and inter-marriage becomes more common, it is as if we were shaking the human matryoshka to prepare a cocktail of humanity. If examining race as a biological construct means studying the possibility of creating subspecies of Homo sapiens, then increasing the admixture between populations would definitely undermine the possibility of establishing reasonable criteria to guide further taxonomical divisions. Time brings mutations, genetic drift, and other elements of genetic differentiation between populations; whereas admixture erodes it. As this is a very delicate balance, it is impossible to predict whether our species’ genetic unity is to be continued as a whole – but it is clear that we need to examine not only migration numbers, but also the openness to engage into multicultural relationships.
Conclusion
Rather than unique genetic features, it is the differences in frequency of alleles that changes from population to population [12]. Furthermore, our characteristics frequently have a polygenetic basis [13], which difficults the loss our genetic unity. Thus, the great biological plasticity shown by our species [5,6,7,8] may be less rooted in between-populations contrasts, than in a general ability to respond to changing environments. Recurring to phenotypical [9] and genetic [16] data, the origins of an individual can be assigned with a high success rate, at least at the continental level, but it seems impossible to find reasonable criteria to evidence a coherent pattern of biological race within these continental groups. Because, within each cluster, populations are neither genetically homogeneous [21], nor diverging homogeneously [19]; human variation is clinal, tendentially presenting no marked discontinuities [22]; and the model of human diversity is that of a matryoshka, product of many serial migration events [20]. Additionally, the more technology increases our mobility capacity, greater the admixture of populations – which prevents differentiation from crystalizing [26]. Therefore, the present work argues that there is no ground to establish human subspecies. Notably, not due to lack of human diversity; on the contrary, since the existing diversity is overwhelming for the task of defining rational categories below the species level.
Part III: Thoughts on the marathon
Introduction
Before I express my own opinion about the subject (this time explicitly), there are three things I wish to alert every reader to have in mind whenever a discussion about racial categorization takes place. First of all, there are cultural biases interfering with our perception on the matter, to which surely I am not immune. As pointed in the previous part, the methods chosen to collect genetic data deeply influence how different human populations will group under biological criteria [1]. In fact, Morning [2] pointed out that we can never be sure on how these clusters are a product of an objective genetic analysis, because even the statistical procedures used to process the data are affected by culturally-acquired assumptions about human differences and evolutionary history. In fact, it is erroneous to think that the racial categories one uses are universal. Different cultures produce distinct categorizations, which denounces a considerable degree of arbitrariness. For example, in the United States, before 1790, the socio-political categories present in the census were: free White males, free White females, all other free persons, and slaves; changing, after the civil war, to White, Black, Mulatto, Chinese, Indian; adding after, in accordance with successive migration waves, Mexican (1930), plus Hispanics (1980) [3]. Thus, there was a shift from an apparently hierarchy-oriented division, to one based on the main immigrant groups. Contrastingly, in Brazil, the socio-political categories were simply colour-oriented: Brancos (White), Pardos (grizzly, multiracial), Pretos (Black), Caboclos (descendent of Whites and indigenous), Amarelos (yellow, Asians), and Indigenous [3]. Additionally, I must state that, despite having made a huge effort to be impartial, I probably somehow failed. Indeed, the articles chosen to base this work, and how they were processed, were partially guided by my personal beliefs, which tend to the desire to reject the existence of human races.
Animal breeds and subspecies are no longer established only according to phenotypic criteria, they must be accompanied by a rational genetic basis as well. Which doesn’t seem to exist in our species. When you say Black race, White race, and so on, you are implying the existence of marked differences between them, plus a marked homogeneity within each group – and I would alert: “watch out with the first statement, as it really needs proper contextualization”, and “forget about the second, that doesn’t seem to be the case at all”. In my everyday Life, I use the terms White and Black – as a category, based on skin colour, which is one genetic characteristic out of endless others. I recognize it, but not as a race; and the only rational I give to it is that it allows me to place (a part of) the individuals’ origins, very very broadly, at the continental level. Better would be to use African and European, as it is more direct. But it can be offensive for those who have migrated, as they might feel one is somehow denying their acquired identity. African origins, European origins, then – but… we all have African origins. It’s a never ending story, hence: I take the social categories that exist, but never give them more value than them deserve – and never mix them with scientific constructs such as “subspecies” or “race”. In my opinion, the most rational categorization would be “ethnic groups”, based on culture and identity. This is the most comprehensive categorization system I have come across. An example: I used to work with a Roma community in Greece and I came to understand something quite interesting: they establish divisions (frequently racist as well, by the way) within their group, and one can in fact differentiate some of these sub-groups by skin colour. So are Roma part of the Asian race? Part of the White race? Part of the Roma race? Each sub-group is a race itself? Good luck answering these questions! Wiser to say Roma is an ethnic group that actually comprises several sub-groups that share a common culture but present some differences of identity. The ethnic group categorization has the flexibility to adapt to this chaos, race does not.
Furthermore, it is also relevant to think of reasons why to categorize could be useful, other than our impulse to simplify reality by delineating discrete units, of course. Some argue that admitting the existence of human races is necessary to respond to racial gaps, providing better educational and economic support for specific instances [4]. I find this argument worrying, as such response would very probably be embedded in a dangerous paternalistic attitude. Another utility could be within the biomedical frame, so to improve treatments and disease prevention. However, Braun [4] alerted that these genetically-oriented procedures are frequently inefficient, referring that the “narratives of diseases thought to be specific to particular racial groups for reasons of inherited predisposition (…) have been subsequently discredited as changed political, economic, and social conditions allowed a reinterpretation of the science (…).” She continues by affirming that the usual approaches consist of studying genetic susceptibility and collateral effects of cultural practices, and very rarely the interaction between social conditions, power relations, and health is examined. Notably, this critic responds to the previous point. Even if there were consistent contrasts between groups from diverse ancestry, endless potential confounding variables could be underlying the racial effect; as it was argued in the first part.
And on another final aspect, one should reflect on why we tend to approach this theme in such a passionate way. Why are we so sensitive about the possible existence of racial categories in our species? Indeed, it is very difficult to provide an answer: it lies somewhere between the ghosts of past historical traumas, culturally imprinted, the fascination about human diversity, and the conviction that it is incommensurable, so no better groups can be discriminated, plus my internal need for reciprocity, justice, and equality. Also, the idea that our species can get fragmented, differentiating into several others, is mysteriously unbearable, just as if it were a loss of identity; as, for some, is the case of dividing a country into smaller nations. Nevertheless, it must be considered that the existence of races established on the basis of external traits does not necessarily compromises the possibility that a common human nature is shared by all groups.
Why don’t we sum up everything so far?
Throughout this paper it was never denied, by any means, that there are many between-groups differences within our species. On the contrary, one of the biggest points was that human diversity is so chaotic that it becomes impossible to establish borders defining rational categories. Interestingly, even the rate at which each group is diverging shows a great variability [5]. Such is not surprising, for not only populations greatly differ in the degree of geographical isolation, as the tolerance for intermarriage is highly changeable from culture to culture. Another paramount aspect discussed was that psychological contrasts tend to lack consistency and are deeply influenced by socioeconomic aspects [6], not necessarily genetic ones. Moreover, as a species adapted to a wide range of environments, many frequently changing considerably, we have developed an appreciable biological plasticity – which can partially explain some phenotypical distinctions between human groups without requiring genetic differences (see section “How committed is our development?”). [7]. Additionally, the genetic distance between human populations shows a pattern of serial migration phenomena sharing the same origin, rather than a differentiation by isolation [8]. This was described here as a matryoshka distribution of human diversity. So, a significant share of human diversity can be explained by adaptations to changing environmental conditions, socioeconomic aspects, and cultural influences – which are not underlied by genetic contrasts.
Then, we have seen that, when interacting with unknown people, race-encoding was not mandatory, contrarily to sex [9]: it was suggested to be a side-effect of our psychological mechanisms designed to search for coalitional cues [10]. As a highly social species, through our evolutionary history there surely was a marked demand for psychological abilities to highlight potential allies – and once they emerged, it’s not exactly a plot twist that they were accompanied by discriminatory behaviours, as byproducts. Ironically, this means that the inclinations leading us to be cooperative (to whom we judge to deserve) may have the same source as those of nepotism. It all depends on the direction our biases point us in. Thus, it is fair to advance that a philanthropist must face the darker corners of human nature, finding a way to break the chains of prejudice that impair our altruism and re-accommodate a series of psychological artefacts.
Human nature – deal with it?
To face our human nature — a broad term that comprises our seemingly-universal behavioural tendencies, psychological predispositions, genetic-driven characteristics, etc. — is, to a great extent, to re-shape our prejudice machinery. But how? Well, it is probably a matter of education – in which there is no better teacher than our own selves, both with its animal instincts and its capacity for clear individuation and systematization. I aim to depicture prejudice as a set of cognitive biases that should be taken carefully, as they can potentially blind our intelligence. On the other hand, it would be silly not to recognize that our brain, being bombarded with tons of information, frequently requires the shortcuts prejudice offers, and we cannot simply perform a lobotomy and remove them out, neither should we try to suppress them with infinite doses of counter social-constructs such as political correctness. Sometimes, there seems to be little difference between political correctness and religious moral oppression. Moreover, isn’t it common understanding that religious rules may produce docile individuals, albeit not keeping them from being ethically dubious? I advocate for an alternative way: instead of rules-based repression (be them informal or formalized into laws), the emancipation through humour. And this is a very serious joke! Curiosity, personal discovery, the scientific spirit, and artistic experimentation are highly welcomed as well!
I deeply sympathize with a statement made by the contemporary philosopher Slavoj Žižek in several of his videos: We should pay the tribute we have to pay to all the bad tasteness we carry inside. To which I add: Avoiding to hurt those around us; nonetheless, in case it happens, it is not the end of the world, as we can always rely on a very interesting human capacity called peaceful and respectful confrontation. Discuss and solve what is to be solved, assuring that both intervenients finish the conversation as better human beings. Although such doesn’t come easy within some cultures, such as the Anglo-Saxon ones (or maybe these were just some of my personal prejudices taking over the keyboard?), it is worth the effort! Again, rather than norms constraining our prejudices, we need openness to debate them, so we can finally master our less-desired impulses.
Additionally, I would like to propose a re-shaping of prejudice, as represented in Figure 1. In order to do so, I try to channel the prejudice towards social constructs rather than individuals. In other words, I avoid assuming that prejudices act directly into the objective reality. Thus, although I may have a certain set of prejudices for concepts such as the masculine and the feminine, I start by admitting that every individual has a unique combination of characteristics extracted from both constructs. Then, despite recognizing that, according to the sex, the mixture will tend to one side or the other, I try by all means not to let my cognitive system excessively biasing me when confronting the a priori model with reality – the individual, that unique cosmos! The same goes for aspects connected with provenance. Because of climate and historical factors, it is possible to create a series of predictions on how a certain society functions. However, it is commonly accepted that all individuals inside a given society do not have the same behavioural patterns – some even deliberately jump off to join another, according to their personal preferences.
Continuing these ideas with another practical case: I may criticize many cultural aspects of the Anglo-Saxonic way of structuring society – still, what is essential is that this doesn’t mean at all that I tend to dislike people from those origins; to be able to keep the two universes apart. Actually, I take pleasure in seeing the model failing, as if it were a hymn to freewill – because nothing is fully predictable! One final point: We must be careful about the variables we choose our prejudices to work on, focusing strictly on those likely to be informative, while seeking to reject the futile ones! In their potential to provide cues, some can be too vague, like skin colour; others too narrow, such as the day and time of birth. By the way, I would like to classify astrology as an ancient model of prejudice, differing from science (one could think of astrology as somehow based on very long-term, and non-registered, patterns of observation, passing on trough tradition, while science is based on registered information, under systematically well-defined criteria; plus, science does not produces absolute, definite truths – it is always open to modifications and adjustments, or even great changes of paradigm). (Finally, science seeks to produce models with a solid predictive power, which can be verified and are often rejected – and there are many articles that have discarded the predictive power of astrology, as it was not significantly different from the random-chance model. .
In conclusion, if prejudice is a part of human Nature that we cannot simply cancel, then, the best solution is to apply the scientific method, transforming it into a model of predictions in constant update; accordingly to the empirical experience. As for the hypotheses rejected along the way, or about to be, the best thing to do is to digest them with humorous enzymes. Now, this does not mean that science is not similar to other endeavours with the world – it is, but the fundamental difference is its character given to constant adaptation and rejection of absolute truths that can’t be disproven by experience. Besides, predictions concern expectations about other people’s behaviour, so I would argue that their outcome is actually a set of a priori ideas. However, this set must be taken as fallible predictions, just as the mental equation behind it should always be ready to accept small updates to be more exact.
The race for humanity?
I will end by doing what I might should have done at the very beginning: To explain what is, for me, the race for humanity. It is something like a marathon, a very long distance to fulfil. The goal is to fit humanity as a whole in our group psychology. Nurturing the true feeling that, first of all, we belong to/support the football club of humanity. In fact, another thing that worries me about political correctness and identity politics is that, instead of seeking to discard irrelevant criteria through which boundaries are commonly built, they actually make them more salient. In my opinion, this is running in the wrong direction. In order to establish more precise roots to my thought, it is worth to bring to the table Edward O. Wilson’s “The Meaning of Human Existence”, in which the author defends that we could try to engage into a New Enlightenment, particularly by bringing much closer natural sciences and humanities. Doing such would, for example, save us from the trouble of analyzing social and biological constructs separately, as the continuous, mutual exchange of information would harmonize them. I personally consider that not a great deal of attention is given to the huge amount of creativity that is needed to design an experiment or a study. On the other hand, a scientist disconnected from society and the art produced by the recent generations can hardly create articles and theories with concrete implications and potential to have an appreciable impact. A discussion about Human races is a very good case to understand the social implications that scientific research can have, and the importance of science looking directly into subjects discussed within humanities – so as to team up in this never ending work of better understanding Human Nature.
A shared sense of belonging to a group called humanity, rooted in a deep appreciation for human diversity, may be a more interesting path, just as we have been doing a huge effort to create an European identity. This investment is worth it, as it enhances cooperation between individuals who previously perceived belonging to different groups. Despite recognizing that it is very hard to bend the dark-side of our group psychology, correct our tendencies for nepotism, rationalize prejudice, and ease the human need for dominance – I think it is a dream worth pursuing! This is not entirely unlike faith; and stands explicitly as an ideal, an outcome worth working for. Whichever are the challenges we have to face, one big hope shall remain: That, in the long run, the best pace one can adopt is to cooperate. Without altruism, life can easily become a prison of endless scheming — and, well, after analysing all other criteria, utility can be a last thing to consider. As a social construct, race is hard to validate or discard – so the same society that created, or adopted, the construct should ask itself: Is it useful to continue applying it? Furthermore, from an evolutionary perspective, it can be argued that the demand for adaptability to multicultural environments – and, consequently, for tolerance – is increasing.
Science, on the other hand, should keep impartially studying the human matryoshka, and how in the past we differentiated from other Homo groups. For instance, it would be paramount to better understand our shared evolutionary history with the Neandertals [11] and Denisovans [12]. As in any other race, one should never forget to warm up first; meaning, to try to neutrally read a wide range of opinions, so to be well informed about the steps to come. The truth is that the concept of subspecies in definition, application, and utility, is not consensual within the scientific community [13]. For example, Kindler and Fritz [14] alerted for its volatility, stating that “(…) subspecies are still fully capable of extensive gene flow and may disappear in the evolutionary process as a consequence of secondary contact.” Therefore, we should be extra-careful about its appliance to our species. While not having any taxonomic utility, an artificial racial categorization could still contribute to deepen the boundaries between human populations, and so I hope to have clarified how it is probably best not to pursue it any further. Although reality tends to be overwhelmingly complex, we shall give our best, producing an accurate representation of it, using all the mental and technological tools at our disposition. After all, society is the sum of the intelligence of each individual, which is the reason why we should never despise our role for the present and future generations. Therefore: get ready, set, go!
References in Part I: Race as a social construct
[1] Taylor, S. E., Fiske, S. T., Etcoff, N. L., & Ruderman, A. J. (1978). Categorical and contextual bases of person memory and stereotyping. Journal of personality and social psychology, 36(7), 778.
[2] Hewstone, M., Hantzi, A., & Johnston, L. (1991). Social categorization and person memory: The pervasiveness of race as an organizing principle. European Journal of Social Psychology, 21(6), 517-528.
[3] Cosmides, L., Tooby, J., & Kurzban, R. (2003). Perceptions of race. Trends in cognitive sciences, 7(4), 173-179.
[4] GilWhite, F., Astuti, R., Atran, S., Banton, M., Boyer, P., Gelman, S. A., … & Laitin, D. D. (2001). Are ethnic groups biological “species” to the human brain? Essentialism in our cognition of some social categories. Current anthropology, 42(4), 515-553.
[5] Kurzban, R., Tooby, J., & Cosmides, L. (2001). Can race be erased? Coalitional computation and social categorization. Proceedings of the National Academy of Sciences, 98(26), 15387-15392.
[6] Kelly, D. J., Liu, S., Ge, L., Quinn, P. C., Slater, A. M., Lee, K., … & Pascalis, O. (2007). Cross-race preferences for same-race faces extend beyond the African versus Caucasian contrast in 3-month-old infants. Infancy, 11(1), 87-95.
[7] Goldinger, S. D., He, Y., & Papesh, M. H. (2009). Deficits in cross-race face learning: insights from eye movements and pupillometry. Journal of Experimental Psychology: Learning, Memory, and Cognition, 35(5), 1105.
[8] Correll, J., Lemoine, C., & Ma, D. S. (2011). Hemispheric asymmetry in cross-race face recognition. Journal of Experimental Social Psychology, 47(6), 1162-1166.
[9] Hugenberg, K., Miller, J., & Claypool, H. M. (2007). Categorization and individuation in the cross-race recognition deficit: Toward a solution to an insidious problem. Journal of Experimental Social Psychology, 43(2), 334-340.
[10] Tanaka, J. W., & Pierce, L. J. (2009). The neural plasticity of other-race face recognition. Cognitive, Affective, & Behavioral Neuroscience, 9(1), 122-131.
[11] Bernstein, M. J., Young, S. G., & Hugenberg, K. (2007). The cross-category effect: Mere social categorization is sufficient to elicit an own-group bias in face recognition. Psychological Science, 18(8), 706-712.
[12] Wong, P. C., Roy, A. K., & Margulis, E. H. (2009). Bimusicalism: The implicit dual enculturation of cognitive and affective systems. Music Perception: An Interdisciplinary Journal, 27(2), 81-88.
[13] Semyonov, M., Raijman, R., Tov, A. Y., & Schmidt, P. (2004). Population size, perceived threat, and exclusion: A multiple-indicators analysis of attitudes toward foreigners in Germany. Social Science Research, 33(4), 681-701.
[14] Wong, C. J. (2007). “Little” and “big” pictures in our heads: Race, local context, and innumeracy about racial groups in the United States. Public Opinion Quarterly, 71(3), 392-412.
[15] Han, S., & Ma, Y. (2015). A culture–behavior–brain loop model of human development. Trends in Cognitive Sciences, 19(11), 666-676.
[16] Bolger, D. J., Perfetti, C. A., & Schneider, W. (2005). Cross‐cultural effect on the brain revisited: Universal structures plus writing system variation. human brain mapping, 25(1), 92-104.
[17] Tan, L. H., Spinks, J. A., Feng, C. M., Siok, W. T., Perfetti, C. A., Xiong, J., … & Gao, J. H. (2003). Neural systems of second language reading are shaped by native language. human brain mapping, 18(3), 158-166.
[18] Park, D. C., & Huang, C. M. (2010). Culture wires the brain: A cognitive neuroscience perspective. Perspectives on Psychological Science, 5(4), 391-400.
[19] Rushton, J. P., & Jensen, A. R. (2005). Thirty years of research on race differences in cognitive ability. Psychology, public policy, and law, 11(2), 235.
[20] Piffer, D. (2019). Evidence for recent polygenic selection on educational attainment and intelligence inferred from Gwas hits: A replication of previous findings using recent data. Psych, 1(1), 55-75.
[21] Lynn, R. (2019). Reflections on Sixty-Eight Years of Research on Race and Intelligence. Psych, 1(1), 123-131.
[22] Carl, N. (2019). The fallacy of equating the hereditarian hypothesis with racism. Psych, 1(1), 262-278.
[23] Henrich, J. (2017). The secret of our success: How culture is driving human evolution, domesticating our species, and making us smarter (pp.22-33). Princeton University Press.
[24] Sohail, M., Maier, R. M., Ganna, A., Bloemendal, A., Martin, A. R., Turchin, M. C., … & Neale, B. (2019). Polygenic adaptation on height is overestimated due to uncorrected stratification in genome-wide association studies. Elife, 8, e39702.
[25] Evans, P. D., Gilbert, S. L., Mekel-Bobrov, N., Vallender, E. J., Anderson, J. R., Vaez-Azizi, L. M., … & Lahn, B. T. (2005). Microcephalin, a gene regulating brain size, continues to evolve adaptively in humans. science, 309(5741), 1717-1720.
[26] Lohmueller, K. E., Albrechtsen, A., Li, Y., Kim, S. Y., Korneliussen, T., Vinckenbosch, N., … & Jørgensen, T. (2011). Natural selection affects multiple aspects of genetic variation at putatively neutral sites across the human genome. PLoS Genet, 7(10), e1002326.
[27] Cottrell, J. M., Newman, D. A., & Roisman, G. I. (2015). Explaining the black–white gap in cognitive test scores: Toward a theory of adverse impact. Journal of Applied Psychology, 100(6), 1713.
[28] Steele, C. M., & Aronson, J. (1995). Stereotype threat and the intellectual test performance of African Americans. Journal of personality and social psychology, 69(5), 797.
[29] Hong, Y. Y., Morris, M. W., Chiu, C. Y., & Benet-Martinez, V. (2000). Multicultural minds: A dynamic constructivist approach to culture and cognition. American psychologist, 55(7), 709.
[30] Chattaraman, V., Rudd, N. A., & Lennon, S. J. (2010). The malleable bicultural consumer: Effects of cultural contexts on aesthetic judgments. Journal of Consumer Behaviour: An International Research Review, 9(1), 18-31.
[31] Chen, S. X., & Bond, M. H. (2010). Two languages, two personalities? Examining language effects on the expression of personality in a bilingual context. Personality and Social Psychology Bulletin, 36(11), 1514-1528.
[32] Mesoudi, A. (2018). Migration, acculturation, and the maintenance of between-group cultural variation. PloS one, 13(10), e0205573.
References in Part II: Race as a biological construct
[1] Koslowski, R. (2002). human migration and the conceptualization of pre-modern world politics. International Studies Quarterly, 46(3), 375-399.
[2] Lordkipanidze, D., de León, M. S. P., Margvelashvili, A., Rak, Y., Rightmire, G. P., Vekua, A., & Zollikofer, C. P. (2013). A complete skull from Dmanisi, Georgia, and the evolutionary biology of early Homo. Science, 342(6156), 326-331.
[3] Green, R. E., Krause, J., Briggs, A. W., Maricic, T., Stenzel, U., Kircher, M., … & Hansen, N. F. (2010). A draft sequence of the Neandertal genome. Science, 328(5979), 710-722.
[4] Reich, D., Green, R. E., Kircher, M., Krause, J., Patterson, N., Durand, E. Y., … & Maricic, T. (2010). Genetic history of an archaic hominin group from Denisova Cave in Siberia. Nature, 468(7327), 1053.
[5] Walker, R., Gurven, M., Hill, K., Migliano, A., Chagnon, N., De Souza, R., … & Kramer, K. (2006). Growth rates and life histories in twenty‐two small‐scale societies. American Journal of human Biology: The Official Journal of the human Biology Association, 18(3), 295-311.
[6] Wells, J. C., & Stock, J. T. (2011). Re-examining heritability: genetics, life history and plasticity. Trends in Endocrinology & Metabolism, 22(10), 421-428.
[7] Parent, A. S., Teilmann, G., Juul, A., Skakkebaek, N. E., Toppari, J., & Bourguignon, J. P. (2003). The timing of normal puberty and the age limits of sexual precocity: variations around the world, secular trends, and changes after migration. Endocrine reviews, 24(5), 668-693.
[8] Wells, J. C., & Stock, J. T. (2012). The biology of human migration: the ape that won’t commit (pp. 21-44). In Crawford, M. H., & Campbell, B. C. (Eds.) (2012). Causes and consequences of human migration: An evolutionary perspective. Cambridge: Cambridge University Press.
[9] Sauer, N. J. (1992). Forensic anthropology and the concept of race: if races don’t exist, why are forensic anthropologists so good at identifying them?. Social Science & Medicine, 34(2), 107-111.
[10] Gagneux, P., Wills, C., Gerloff, U., Tautz, D., Morin, P. A., Boesch, C., … & Woodruff, D. S. (1999). Mitochondrial sequences show diverse evolutionary histories of African hominoids. Proceedings of the National Academy of Sciences, 96(9), 5077-5082.
[11] Bakewell, M. A., Shi, P., & Zhang, J. (2007). More genes underwent positive selection in chimpanzee evolution than in human evolution. Proceedings of the National Academy of Sciences, 104(18), 7489-7494.
[12] Hancock, A. M., Witonsky, D. B., Ehler, E., Alkorta-Aranburu, G., Beall, C., Gebremedhin, A., … & Di Rienzo, A. (2010). human adaptations to diet, subsistence, and ecoregion are due to subtle shifts in allele frequency. Proceedings of the National Academy of Sciences, 200914625.
[13] Yang, J., Benyamin, B., McEvoy, B. P., Gordon, S., Henders, A. K., Nyholt, D. R., … & Goddard, M. E. (2010). Common SNPs explain a large proportion of the heritability for human height. Nature genetics, 42(7), 565.
[14] Lewontin, R. C. (1972). The apportionment of human diversity. In Evolutionary biology (pp. 381-398). Springer, Boston, MA.
[15] Sesardic, N. (2010). Race: a social destruction of a biological concept. Biology & Philosophy, 25(2), 143-162.
[16] Rosenberg, N. A., Pritchard, J. K., Weber, J. L., Cann, H. M., Kidd, K. K., Zhivotovsky, L. A., & Feldman, M. W. (2002). Genetic structure of human populations. science, 298(5602), 2381-2385
[17] Frankham, R., Ballou, S. E. J. D., Briscoe, D. A., & Ballou, J. D. (2002). Introduction to conservation genetics (p. 326). Cambridge university press.
[18] Long, J. C., & Kittles, R. A. (2009). human genetic diversity and the nonexistence of biological races. human biology, 81(5/6), 777-798.
[19] Long, J. C., Li, J., & Healy, M. E. (2009). human DNA sequences: more variation and less race. American Journal of Physical Anthropology, 139(1), 23-34.
[20] Hunley, K. L., Healy, M. E., & Long, J. C. (2009). The global pattern of gene identity variation reveals a history of long‐range migrations, bottlenecks, and local mate exchange: implications for biological race. American Journal of Physical Anthropology, 139(1), 35-46.
[21] Hunley, K. L., Cabana, G. S., & Long, J. C. (2016). The apportionment of human diversity revisited. American journal of physical anthropology, 160(4), 561-569.
[22] Serre, D., & Pääbo, S. (2004). Evidence for gradients of human genetic diversity within and among continents. Genome research, 14(9), 1679-1685.
[23] Ramachandran, S., Deshpande, O., Roseman, C. C., Rosenberg, N. A., Feldman, M. W., & Cavalli-Sforza, L. L. (2005). Support from the relationship of genetic and geographic distance in human populations for a serial founder effect originating in Africa. Proceedings of the National Academy of Sciences, 102(44), 15942-15947.
[24] International Organization for Migration World Migration Report 2018 (https://publications.iom.int/system/files/pdf/wmr_2018_en.pdf)
[25] IOM’s Migration data portal (https://migrationdataportal.org/data?i=stock_abs_&t=2017)
[26] Hartl, D. L., & Clark, A. G. (1997). Principles of population genetics (pp. 194-196). 3rd ed. Sunderland: Sinauer associates.
[27] Leonardi, M., Sandionigi, A., Conzato, A., Vai, S., Lari, M., Tassi, F., … & Barbujani, G. (2018). The female ancestor’s tale: Long‐term matrilineal continuity in a nonisolated region of Tuscany. American journal of physical anthropology, 167(3), 497-506.
References in the final part of The race for humanity
[1] Serre, D., & Pääbo, S. (2004). Evidence for gradients of human genetic diversity within and among continents. Genome research, 14(9), 1679-1685.
[2] Morning, A. (2014). And you thought we had moved beyond all that: Biological race returns to the social sciences. Ethnic and Racial Studies, 37(10), 1676-1685.
[3] Nobles, M. (2000). Shades of citizenship: Race and the census in modern politics (pp. 28, 44, 104). Stanford University Press.
[4] Braun, L. (2002). Race, ethnicity, and health: can genetics explain disparities?. Perspectives in Biology and Medicine, 45(2), 159-174.
[5] Long, J. C., Li, J., & Healy, M. E. (2009). human DNA sequences: more variation and less race. American Journal of Physical Anthropology, 139(1), 23-34.
[6] Steele, C. M., & Aronson, J. (1995). Stereotype threat and the intellectual test performance of African Americans. Journal of personality and social psychology, 69(5), 797.
[7] Wells, J. C., & Stock, J. T. (2012). The biology of human migration: the ape that won’t commit (pp. 21-44). In Crawford, M. H., & Campbell, B. C. (Eds.) (2012). Causes and consequences of human migration: An evolutionary perspective. Cambridge: Cambridge University Press.
[8] Ramachandran, S., Deshpande, O., Roseman, C. C., Rosenberg, N. A., Feldman, M. W., & Cavalli-Sforza, L. L. (2005). Support from the relationship of genetic and geographic distance in human populations for a serial founder effect originating in Africa. Proceedings of the National Academy of Sciences, 102(44), 15942-15947.
[9] Cosmides, L., Tooby, J., & Kurzban, R. (2003). Perceptions of race. Trends in cognitive sciences, 7(4), 173-179.
[10] Kurzban, R., Tooby, J., & Cosmides, L. (2001). Can race be erased? Coalitional computation and social categorization. Proceedings of the National Academy of Sciences, 98(26), 15387-15392.
[11] Green, R. E., Krause, J., Briggs, A. W., Maricic, T., Stenzel, U., Kircher, M., … & Hansen, N. F. (2010). A draft sequence of the Neandertal genome. Science, 328(5979), 710-722.
[12] Reich, D., Green, R. E., Kircher, M., Krause, J., Patterson, N., Durand, E. Y., … & Maricic, T. (2010). Genetic history of an archaic hominin group from Denisova Cave in Siberia. Nature, 468(7327), 1053.
[13] Braby, M. F., Eastwood, R., & Murray, N. (2012). The subspecies concept in butterflies: has its application in taxonomy and conservation biology outlived its usefulness?. Biological Journal of the Linnean Society, 106(4), 699-716.
[14] Kindler, C., & Fritz, U. (2018). Phylogeography and taxonomy of the barred grass snake (Natrix helvetica), with a discussion of the subspecies category in zoology. Vertebrate Zoology, 68(3), 253-267.
