RACE, EVOLUTION, AND BEHAVIOR:
A Life History Perspective
2nd Special Abridged Edition
By Professor J. Philippe Rushton
University of Western Ontario
London, Ontario, Canada N6A 5C2
J. Philippe Rushton is a professor of psychology at the University of Western Ontario, London, Ontario, Canada. Rushton holds two doctorates from the University of London (Ph.D. and D.Sc) and is a Fellow of the John Simon Guggenheim Foundation, the American Association for the Advancement of Science, and the American, British, and Canadian Psychological Associations. He is also a member of the Behavior Genetics Association, the Human Behavior and Evolution Society, and the Society for Neuroscience. Rushton has published six books and nearly 200 articles. In 1992 the Institute for Scientific Information ranked him the 22nd most published psychologist and the 11th most cited. Professor Rushton is listed in Who’s Who in Science and Technology, Who’s Who in International Authors, and Who’s Who in Canada.
1. Race is More Than Skin Deep 7
Race in History
Race in Today’s World
Why Are There Race Differences?
2. Maturation, Crime, and Parenting 13
Personality, Aggression, and Self-Esteem
Parenting and Out-of-Wedlock Births
Longevity and Population Growth
3. Sex, Hormones, and AIDS 18
Sexual Behavior and Attitudes
Sexual Physiology and Anatomy
AIDS and HIV
4. Intelligence and Brain Size 22
Culture Fair Tests
Intelligence and Brain Size
Race Differences in Brain Size
Magnetic Resonance Imaging
Brain Weight at Autopsy
Measuring Skull Size
Measuring Living Heads
Summarizing Brain Size Differences
5. Genes, Environment, or Both? 28
Race and Heritability
Trans-racial Adoption Studies
Heritabilities Predict Racial Differences
Regression to the Average
6. Life History Theory 34
r-K Life History Theory
Race Differences and r-K Strategies
Testosterone — The Master Switch?
7. Out of Africa 39
Geography and Race
8. Questions and Answers 42
Is Race a Useful Concept? (Chapter 1)
Are the Race Differences Real? (Chapters 2 through 5)
Is the Relationship Between Race and Crime Valid? (Chapter 2)
Is the Relationship Between Race and Reproduction Valid? (Chapter 3)
Is the Genetic Evidence Flawed? (Chapter 5)
Is r-K Theory Correct? (Chapter 6)
Aren’t Environmental Explanations Sufficient? (Chapter 5)
Is Race Science Immoral? (Chapter 1)
7: Out of Africa
The latest theory of human origins — Out-of-Africa — provides the final piece to the puzzle. It explains why r-K theory accounts for race differences in body, brain, and behavior. As races moved out of Africa they evolved away from r-type behaviors and toward K-type. Moving out of Africa meant increasing brain size and IQ, but lowering reproduction, aggression and sexual activity.
Based on his theory of evolution, Charles Darwin thought Africa was “the cradle of mankind.” He did not have any fossils from Africa to support his theory but he concluded that humans came from Africa based on watching the chimpanzee and the gorilla. If the African apes were our closest living relatives, it made sense that humans first evolved on the only continent where all three species lived.
Evidence from genetics, the fossil record, and archaeology have since all proved Darwin correct. The human line began with the African fossil species called Australopithecus. Later human ancestors Homo erectus and then Homo sapiens also appeared first in Africa.
Homo sapiens were fully human. They were in Africa less than 200,000 years ago. Moving to the Middle East about 100,000 years ago, they then spread out across the world. They replaced the Neanderthal and Homo erectus groups they met either by fighting or competing for food.
When modern humans left Africa they began to develop the racial traits we see today by adapting to the new regions and climates. The first split in the human line took place about 100,000 years ago between groups that remained in Africa (ancestors to modern Blacks) and those who left Africa. Then about 40,000 years ago the group that left Africa divided once again, into the ancestors of today’s Whites and Orientals.
This history of moving first out of Africa into Europe and then later into East Asia explains why Whites fall in between Orientals and Blacks on the life history variables. The split between Africans and non-Africans happened first, almost twice as early as the split between Orientals and Whites.
The Out of Africa theory explains the good fit between the r-K life history traits and race differences. It is hard to survive in Africa. Africa has unpredictable droughts and deadly diseases that spread quickly. More Africans than Asians or Europeans die young — often from tropical disease. In these African conditions, parental care is a less certain way of making sure a child will survive. A better strategy is simply to have more children. This tilts their life history toward the r-end of the r-K scale. A more r-strategy means not only more offspring and less parental care. It also means less culture is passed from parent to child, and this tends to reduce the intellectual demands needed to function in the culture. And the process continues from one generation to the next.
In contrast, the humans migrating to Eurasia faced entirely new problems — gathering and storing food, providing shelter, making clothes, and raising children during the long winters. These tasks were more mentally demanding. They called for larger brains and slower growth rates. They permitted lower levels of sex hormones, resulting in less sexual potency and aggression and more family stability and longevity. Leaving the tropics for the northern continents meant leaving the r-strategy for the K-strategy — and all that went with it.
How can we know if the Out of Africa theory is true? To answer that question, we have to look at the evidence from genetics, paleontology, and archaeology.
The History and Geography of Human Genes (1994) by Luigi Cavalli-Sforza and his colleagues looks at thousands of genetic DNA comparisons of the races. Geneticists count the number of gene mutations in each group to measure which groups are most closely related and when the groups split from one another. These DNA studies support the Out of Africa theory that the split between Africans and all other groups was the first to take place.
Fossils of prehistoric humans tell us that early steps in our evolution took place in Africa. Homo sapiens lived in Africa between 200,000 and 100,000 years ago, but they only reached the Middle East about 100,000 years ago. Earlier hominids such as the Neanderthals were very different from modern humans. They had faces that jut further forward and they had larger front teeth than any living Europeans, Africans, or East Asians. Neanderthals had denser bones, thicker skulls, and more pronounced brow ridges than any modern humans. By comparison, all living humans are alike, despite our race differences.
Archaeology tells us the same story. The crude, Early Stone Age culture (termed Lower Paleolithic) of Homo erectus, existed more than one million years before Homo sapiens appeared. The Early Stone Age tool kit had hand-axes, choppers, and cleavers, all very similar in shape. However, the Middle Stone Age tool kit of the Neanderthals (termed Middle Paleolithic) included more advanced stone tools and the use of bone.
When modern humans first appeared on the scene 100,000 years ago, things started to change in major ways. The Late Stone Age tool kit (termed Upper Paleolithic) was highly specialized. It consisted of thinner blades struck off of stone cores to make knives, spear barbs, scrapers and cutters. Standardized bone and antler tools appeared in the tool kit for the first time, including needles for sewing fur clothes. The Late Stone Age tool kit contained tools made of several parts tied or glued together. Spear points were set in shafts and ax heads in handles. Rope was used to make nets to trap foxes, rabbits, and other small animals. Advanced weapons like barbed harpoons, darts, spear-throwers, and bows and arrows gave Late Stone Age people the ability to kill animals from a safe distance.
Survival in Northeast Asia about 40,000 years ago also required warm clothing. Archeologists have found needles, cave paintings of parkas, and grave ornaments marking the outlines of shirts and trousers. We know that warm furs were worn. Fox and wolf skeletons missing their paws tell us that these animals were skinned to make fur clothes. Houses were dug into the ground to provide insulation. These large dwellings were marked by post holes and had walls made from mammoth bones. Fireplaces and stone lamps were used to light the long Arctic winter night.
Geography and Race
Africa is warmer than the northern continents, but it is a less stable habitat. Droughts, storms, and diseases from viruses, bacteria, and parasites cause high death rates, even today. Without modern medical care, insuring survival in Africa means having many young (r-strategy). In the more stable environments of Europe and Asia, survival is insured from having fewer young, but caring for them very well (K-strategy).
The environment of Eurasia produced physical differences between the races. Northern Europe’s cloudiness meant less sunshine. This decreased the intake of vitamin D, so lighter skin and hair were needed to let more sunlight get in. As a result, Europeans born with lighter skin and hair were healthier. They had more chance of having children who would survive and reproduce.
East Asia was even colder than North Europe, but with less cloud cover and more sunlight. There a thicker layer of fat helped to insulate against the cold. This gives many Orientals a so-called “yellow” complexion because it reduces the visibility of red blood vessels close to the skin. Meanwhile in Africa melanin gives the skin a black color to protect it from the scorching rays of the sun.
Climate differences also influenced mental abilities. In Africa, food and warmth were available all year round. To survive the cold winters, the populations migrating northwards had to become more inventive. They had to find new sources of food and methods for storing it. They needed to make clothing and shelters to protect against the elements. Without them the people would have died. Both parents had to provide more care to help their young survive in the harsher climates.
Whites and Orientals in Eurasia had to find food and keep warm in the colder climates. In the tropics, plant foods were plentiful all year round. In Europe and Asia they were seasonal and could not be found during many winter and spring months.
To survive the long winters, the ancestors of today’s Whites and Orientals made complex tools and weapons to fish and hunt animals. They made spearheads that could kill big game from a greater distance and knives for cutting and skinning. Fires, clothes and shelters were made for warmth. Bone needles were used to sew animal skins together and shelters were made from large bones and skins.
Making special tools, fires, clothing and shelters called for higher intelligence. Moving “Out of Africa” meant moving into a K-type life-history strategy. That meant higher IQ, larger brains, slower growth, and lower hormone levels. It also meant lower levels of sexuality, aggression, and impulsive behavior. More family stability, advanced planning, self-control, rule-following, and longevity were needed.
Fossil records, archaeology, and genetic DNA studies of the living races support Charles Darwin’s insight that we evolved in Africa. Humans then spread to the Middle East, Europe, Asia, Australia, and then to the Americas. As humans left Africa, their bodies, brains and behavior changed. To deal with the colder winters and scarcer food supply of Europe and Northeast Asia, the Oriental and White races moved away from an r-strategy toward the K-strategy. This meant more parenting and social organization, which required a larger brain size and a higher IQ.
Cavalli-Sforza, L. L., Menozzi, P., & Piazza, A. (1994). The History and Geography of Human Genes. Princeton, NJ: Princeton University Press.
Stringer, C. & McKie, R. (1996). African Exodus. London: Cape.
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