Themes > Science > Life Sciences > Human Races > Biological Aspects of Race


PREAMBLE: As scientists who study human evolution and variation, we believe that we have an obligation to share with other scientists and the general public our current understanding of the structure of human variation from a biological perspective. Nineteenth and early twentieth century categories of race, which today are thought to have little scientific merit, have often been used to support racist doctrines. Yet this concept persists as a social convention that fosters institutional discrimination. The expression of prejudice may or may not undermine material well-being, but it does involve the mistreatment of people and thus it often is psychologically distressing and socially damaging. Scientists should endeavour to prevent the results of their research from being used in a biased way that would serve discriminatory ends.

We offer the following points as revisions of the UNESCO statements on race:

1. All humans living today belong to a single species, Homo sapiens, and share a common descent. All living geographical populations have evolved from that common ancestral group for the same amount of time.

Much of the biological variation among populations involves modest degrees of variation in the frequency of shared traits. Human populations have at times been isolated, but have never genetically diverged enough to produce any barriers to interbreeding.

2. Biological differences between human beings reflect both hereditary factors and the influence of natural and social environments. In most cases, these differences are due to the interaction of both. The degree to which environment or heredity affects any particular trait varies greatly.

3. There is great genetic diversity within all human populations. Pure races in the sense of genetically homogeneous populations do not exist in the human species, nor is there evidence that they have ever existed in the past history of the human family.

4. There are obvious physical differences between all populations living in different geographical parts of the world. Some of these differences are strongly inherited and others, such as body size and shape, are strongly influenced by nutrition, way of life and other aspects of the environment. Genetic differences between populations commonly consist of differences in the frequency with which the same hereditary characters occur in various populations.

5. For centuries, scholars have sought comprehend patterns in nature by classifying living things The only living species in the human family, Homo sapiens, has become a highly diversified global array of populations. The geographic pattern of genetic variation within this array is complex, and presents no major discontinuity. Humanity cannot be classified into discrete geographic categories. Furthermore, the complexities of human history make it difficult to determine the position of certain groups in classifications. Multiplying sub-categories cannot correct the inadequacies of these classifications. Generally, the traits used to characterize a population either are independently inherited or show only varying degrees of association with one another within each population. Therefore, the combination of these traits in most individuals does not correspond to any typological racial characterizations. This fact renders untenable the idea of discrete races made up chiefly of typical representatives.

6. In humankind as well as in other animals, the genetic composition of each population is subject over time to the modifying influence of diverse factors. These include natural selection, tending towards adaptation to the environment; mutations involving modifications of genetic material; and random changes in the frequencies of genetic characteristics. The human characteristics which have a universal biological value for the survival of the species are not found more frequently in one population than in any other. Therefore it is not possible from the biological point of view to speak in any way whatsoever of a general inferiority or superiority of this or that 'race'.

7. The human species has a past rich in migrations, in territorial expansions and in contractions As a consequence, we are adapted to many of the earth's environments in general but to none in particular. For many millennia, human progress in any field has been based an culture and not on genetic improvement.

Mating between members of different human groups tends to mitigate acquired differences, and has played a very important role in human history. Wherever different human populations have come in contact, they have interbred. The obstacles to such interbreeding have been social and cultural, not biological. The global process of urbanization, coupled with intercontinental migrations, has the potential to reduce the differences among all human populations.

8. Partly as a result of interbreeding, the hereditary characteristics of human populations are in a state of perpetual flux and distinctive local populations are continually coming into and passing out of existence. Such populations cannot in any way be compared to breeds of domestic animals, which have been produced by artificial selection for specific human purposes.

9. It has never been shown that interbreeding has biological disadvantages for humanity as a whole. The biological consequences of a marriage depend only on the individual genetic make-up of the couple and not on their race. Therefore, no biological justification exists for prohibiting intermarriage between persons of different 'racial' classifications.

10. There is no necessary concordance between biological characteristics and culturally defined groups. On every continent, there are diverse populations that differ in language, economy, and culture. There is no national, religious, geographic, linguistic, cultural group, or economic class that constitutes a race. However, human beings who speak the same language and share the same culture frequently select each other as mates, with the result that there is often some degree of correspondence between the distribution of physical traits on the one hand, and that of linguistic and cultural traits on the other. But there is no known causal linkage between these physical and behavioral traits, and therefore it is not justifiable to attribute cultural characteristics to the influence of genetic inheritance.

11. Physical, cultural, and social environments influence the behavioral differences among individuals in society. Although heredity influences the behavioral variability of individuals within a given population, it does not affect the ability of any such population to function in a social setting. The genetic capacity for intellectual development is one of the biological traits of our species essential for its survival. This genetic capacity is known to differ among individuals. The peoples of the world today appear to possess equal biological potential for assimilating any human culture. Hereditary potentials for overall intelligence and cultural development do not appear to differ among modern human populations, and there is no hereditary justification for considering one population superior to another. Racist political doctrines find no foundation in scientific knowledge concerning modern or past human populations.


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