Dominant social classes have often used scientific arguments to explain their privileged status. With the development of intelligence quotient (IQ) tests and the founding of the field of genetics, some researchers explained racial differences in behaviours such as IQ test performance as due to genetic differences. Recent discoveries in molecular genetics have provided evidence that human variation at the deoxyribonucleic acid (DNA) level is slight; much more variation exists within the members of any single group than between two different population groups. However, as the DNA of populations worldwide has been further characterized, some have assumed that racial differences in intelligence or other social behaviours can be ascribed to those slight interracial genetic differences. Scientists must remain vigilant and expose misrepresentations of scientific data that overemphasize the genetics of group differences and that support genetically deterministic explanations for complex behaviours, such as intelligence.

Key Concepts

• Science, through measurements of brain size and IQ test scores, has been misused to support the idea of presumed racial hierarchies in intelligence.
  
• The search for gene variants associated with complex behavioural traits, including intelligence, has been largely unsuccessful.
  
• Environment plays a major role in the manifestation of most genetic traits.
  
• Recent discoveries in molecular genetics have shown that most of the genetic variation that is found among human beings around the world is found in all racial and ethnic groups and only a small amount is found in specific groups.
  
• Using large numbers of genetic variants that differ only slightly in proportion between population groups, researchers can assort individuals into major continental geographic clusters with a high degree of accuracy.
  
• Aside from a small fraction of genes influencing apparent, visible physical features distinguishing people, the distribution of genetic variation does not support a biological basis for the concept of human races.
  
• Preliminary and faulty scientific studies on issues relating to race and intelligence are often rapidly and unjustifiably translated into calls for changes in social policy.
  
• Scientists have a responsibility to help ensure that studies on the genetics of group differences are not misused and misrepresented to support racist theories regarding human behaviours.