Is There a Biological Basis for Race and Racial Differences?

By J. Philippe Rushton
Department of Psychology
University of Western Ontario
London, Ontario N6A 5C2

Insight, May 28, 2001

Yes: They're scientifically demonstrable, argues J. Philippe Rushton.

No: Such distinctions are socially constructed, counters Joseph L. Graves Jr.

J. Philippe Rushton. Rushton is a professor of psychology at the University of Western Ontario in Canada and is the author of Race, Evolution, and Behavior and more than 200 scientific articles.

Yes: Such differences are real and demonstrated by growing scientific evidence.

For the past 20 years my research has focused on differences between the three major races, commonly termed Orientals (East Asians, Mongoloids), whites (Europeans, Caucasoids), and Blacks (Africans, Negroids). Roughly speaking, Orientals are those who have most of their ancestors from East Asia. Whites have most of their ancestors from Europe. And blacks have most of their ancestors from sub-Saharan Africa. In the main,I have not addressed the many other groups and sub-groups.

What I've found is that in brain size, intelligence, temperament, sexual behavior, fertility, growth rate, life span, crime, and family stability, Orientals fall at one end of the spectrum, blacks fall at the other end and whites fall in between. On average, Orientals are slower to mature, less fertile, and less sexually active, and have larger brains and higher IQ scores. Blacks are at the opposite end in each of these areas. Whites fall in the middle, often close to Orientals.

Of course, these three-way racial differences are averages. Individuals are individuals. However, I've found that this three-way pattern is true over time and across nations. That the same three-way racial pattern occurs repeatedly on some 60 different biological and behavioral variables is profoundly interesting and shows that race is more than "just skin deep." The international data come from the World Health Organization, the United Nations, and Interpol. Recently, I even traveled to South Africa to collect new IQ data.

Let's start with the biological differences in sports, which is something almost everyone observes. Jon Entine's recent book Taboo: Why Black Athletes Dominate Sports and Why We Are Afraid to Talk About It, addresses the old cliché that "white men can't jump" (and the new one that Oriental men jump even less well). Entine shows that in sports, Black men and women have a genetic advantage. Compared to Whites, Blacks have narrower hips, wider shoulders, less body fat, and more muscle.

Blacks also have from 3 to 19% more of the sex hormone testosterone than whites or Orientals. This translates into more explosive energy, which gives Blacks the edge in sports like boxing, basketball, football, and sprinting.

Why is it taboo to say that Blacks are on average better at sports? Because the next question is, "Why do Whites and East Asians have wider hips than Blacks, and so make poorer runners?" The answer is that they give birth to larger brained babies. During evolution, as the head size of newborns increased, women had to have a wider pelvis. The hormones that give Blacks the edge in sports also make them more masculine in general. They are physically more active in school, and this can get them into trouble and even lead to their being diagnosed as hyperactive.

Race differences show up early in life. Black babies are born a week earlier than White babies, yet they mature faster as measured by bone development. By age five or six, Black children excel in the dash, the long jump, and the high jump, all of which require a short burst of power. By the teenage years, Blacks have faster reflexes, as in the famous knee-jerk response.

The biological factors underlying race differences in sports have consequences for educational achievement, crime and sexual behavior. In educational achievement and occupational success, Orientals average slightly ahead of Whites, who average substantially ahead of Blacks. On standardized IQ tests, hundreds of studies show this three-way pattern. Most IQ tests have an average score of 100, with a "normal" range from 85 to 115. Whites average from 100 to 103. Orientals in Asia and the U.S. tend to have higher scores, about 106, even though IQ tests were made for the Euro-American culture. Blacks in the U.S., the Caribbean, Britain and Africa average lower IQs-about 85. The lowest average IQs are found for sub-Saharan Africans-from 70 to 75.

The relation between brain size and intelligence has been shown by dozens of studies, including state-of-the-art magnetic resonance imaging. Orientals average 1 cubic inch more brain matter than Whites, and Whites average a very large 5 cubic inches more than Blacks. Since one cubic inch of brain matter contains millions of brain cells and hundreds of millions of nerve connections, brain size differences help to explain why the races differ in IQ.

Racial differences in brain size show up early in life as well. The U.S. Collaborative Perinatal Project followed more than 50,000 children from birth to seven years. In the 1997 issue of the journal Intelligence, I showed that these Orientals had larger brains than Whites at birth, four months, one year, and seven years; the Whites had larger brains than Blacks at all ages. In the United States, Orientals are seen as a "model minority." They have fewer divorces, out-of-wedlock births, and fewer reports of child abuse than Whites. More Orientals graduate from college and fewer go to prison. Blacks, on the other hand, are 12% of the American population but make up 50% of the prison population.

The racial pattern of crime in the U.S. is not due to local conditions like "white racism." The same pattern is found worldwide. Interpol Yearbooks show the rate of violent crime (murder, rape, and serious assault) is three times lower in East Asian and Pacific Rim countries than in African and Caribbean countries. Whites in European countries are intermediate. The 1996 Interpol violent crime rates were: East Asian countries, 35 per 100,000 people; European countries, 42; and African and Caribbean countries, 149.

Orientals are the least sexually active, whether measured by age of first intercourse, intercourse frequency, or number of sexual partners. Blacks are the most active on all of these. Once again Whites fall in between. These differences in sexual activity affect the rate of sexually transmitted diseases. In the United States today, 2% of blacks between ages 15 and 49 are living with HIV/AIDS as opposed to 0.4 percent of whites and .05 percent of Asians, according to data from the Centers for Disease Control and Prevention.

Other data make it plain that the race differences in sexuality are biological in nature. For example, the races also differ in rate of ovulation. Not all women produce one egg during the menstrual cycle. When two or more eggs are produced at the same time, pregnancy and the likelihood of producing two-egg twins are more likely. The number of twins born is 16 out of every 1,000 births for blacks, 8 out of every 1,000 births for whites, and 4 or less for Orientals.

Why do whites fall between Orientals and blacks in so many areas? No purely cultural theory can explain this consistent pattern. Genetic and evolutionary theories are required. Genes play a big part in athletic ability, brain size, IQ, and personality. Trans-racial adoption studies, where infants of one race are adopted and reared by parents of a different race, provide some of the strongest evidence. Oriental children, even if malnourished before being adopted by white parents, go on to have IQs above the white average. Black infants adopted into middle-class white families end up with IQs lower than the white average.

These racial patterns make up what is called a "life-history" or "reproductive strategy." The traits evolved together to meet the trials of life-survival, growth, and reproduction. Race differences make sense in terms of human evolution. Modern humans evolved in Africa about 200,000 years ago. Africans and non-Africans then split about 110,000 years ago. Orientals and Whites split about 40,000 years ago.

The further north people went "Out of Africa," the more evolution selected for larger brains, slower growth rates, greater longevity, lower hormone levels, less sexual potency, less aggression, and less impulsivity. Advanced planning, self-control, and rule-following are cultural manifestations of these gene-based evolutionary strategies. Surviving in cold environments required increased intelligence and larger brains. The wider hips of white and Asian women evolved to allow them to give birth to larger brained babies.

What are the implications of this research? One is that we should stop blaming white racism for all society's problems. If blacks are good at certain sports, and Orientals do well in schools, it cannot be because each group is trying to "overcome the prejudice of white society," because each group shows the same pattern of strengths and weaknesses in their countries of origin.

Sometimes it is claimed by those who argue that race is just a social construct that the human genome project shows that because people share roughly 99% of their genes in common, that there are no races. This is silly. Human genes are 98% similar to chimpanzee genes and 90% similar to those in mice, which is why these species make good laboratory animals. But no one claims that mice, chimpanzees, and humans are nearly the same! That would be laughable. Similarly, although men and women are genetically 99% the same, it is foolish to believe that sex is just a "social construction."

Much confusion arises because there are several sets of genetic measures. A much more realistic story comes from looking at the 3.1 billion base pairs that make up the 30,000 genes.

People differ in 1 out of every 1,000 of these base pairs. Each change in a base pair can alter a gene. Technically, base pair differences are called single nucleotide polymorphisms (SNPs). The 99% figure is based on DNA sequences which do not differ between people or even most mammals. These can give the impression that human groups and chimpanzees are almost identical because these genes code for similar internal organs, eyes, hands, and so on. Though humans and mice look very different, any anatomy student can tell you, even their internal bone structures are very similar.

The February 23, issue of Science magazine reported that 2.8 million SNPs were already being sold by Celera Genomics to scientists trying to crack the code of human behavior. Base pair differences are important and SNPs clump together in races. Just one change in the base pair for hemoglobin, for example, causes sickle-cell anemia, from which many Blacks suffer. Other base pair differences affect IQ, aggression, and mental illness. The 3.1 billion base pairs provide plenty of room for large racial differences.

If races did not exist, we would not find the same racial pattern all around the world and over time. The scientific evidence shows that the politically correct mantra "race is just skin deep" is a case of deep denial.