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)
3: Sex, Hormones, and AIDS
Race differences exist in sexual behavior. The races differ in how often they like to have sexual intercourse. This affects rates of sexually transmitted diseases. On all the counts, Orientals are the least sexually active, Blacks the most, and Whites are in between. The races also differ in the number of twins and multiple births, in hormone levels, in sexual attitudes, and even in their sexual anatomy.
The races differ in their level of sex hormones. Hormone levels are highest in Blacks and the lowest in Orientals. This may tell us why Black women have premenstrual syndrome (PMS) the most and Orientals the least.
The races also differ in testosterone level which helps to explain men’s behavior. In one study of college students, testosterone levels were 10 to 20% higher in Blacks than in Whites. For an older sample of U.S. military veterans, Blacks had levels 3% higher than Whites (see the 1992 issue of Steroids). In a study of university students, Black. Americans had 10 to 15% higher levels than White Americans. The Japanese (in Japan) had even lower levels.
Testosterone acts as a “master switch.” It affects things like self-concept, aggression, altruism, crime, and sexuality, not just in men, but in women too. Testosterone also controls things like muscle mass and the deepening of the voice in the teenage years.
Sexual Behavior and Attitudes
Blacks are sexually active at an earlier age than Whites. Whites, in turn, are sexually active earlier than Orientals. Surveys from the World Health Organization show this three-way racial pattern to be true around the world. National surveys from Britain and the United States produce the same findings.
A Los Angeles study found that the age of first sexual activity in high school students was 16.4 years for Orientals, 14.4 years for Blacks, with Whites in the middle. The percentage of students who were sexually active was 32% for Orientals but 81% for Blacks. Whites again fell between the two other races. A Canadian study found Orientals to be more restrained, even in fantasy and masturbation. Orientals born in Canada were just as restrained as recent Asian immigrants.
Around the world, sexual activity for married couples follows the three-way pattern. A 1951 survey asked people how often they had sex. Pacific Islanders and Native Americans said from 1 to 4 times per week, U.S. Whites answered 2 to 4 times per week, while Africans said they had sex 3 to 10 times per week. Later surveys have confirmed these findings. The average frequency of intercourse per week for married couples in their twenties is 2.5 for the Japanese and Chinese in Asia. It is 4 for American Whites. For American Blacks it is 5.
Racial differences are found in sexual permissiveness, thinking about sex, and even in levels of sex guilt. In one study, three generations of Japanese Americans and Japanese students in Japan had less interest in sex than European students. Yet each generation of Japanese Americans had more sex guilt than White Americans their age. In another study, British men and women said they had three times as many sexual fantasies as Japanese men and women. Orientals were the most likely to say that sex has a weakening effect. Blacks said they had casual intercourse more and felt less concern about it than whites did.
Sexual Physiology and Anatomy
Ovulation rates differ by race, as does the frequency of twins. Black women tend to have shorter cycles than do White women. They often produce two eggs in a single cycle. This makes them more fertile.
The rate of two-egg twins is less than 4 in every 1,000 births for Orientals. It is 8 for Whites, but for Blacks it is 16 or greater. Triplets and quadruplets are very rare in all groups, but they show the same three-way order — Blacks have the most, then Whites, and Orientals the least.
From the 8th to the 16th centuries, Arab Islamic literature showed Black Africans, both men and women, as having high sexual potency and large organs. Nineteenth century European anthropologists reported on the position of female genitals (Orientals highest, Blacks lowest, Whites intermediate) and the angle of the male erection (Orientals parallel to the body, Blacks at right angles). They claimed Orientals also had the least secondary sex characteristics (visible muscles, buttocks, and breasts), Blacks the most. Other early anthropologists also reported that people of mixed race tended to fall in between.
Should we take these early reports by outsiders on so sensitive a subject seriously? Modern data seem to confirm these early observations. Around the world, public health agencies now give out free condoms to help slow the spread of AIDS and help save lives. Condom size can affect whether one is used, so these agencies take note of penis size when they give out condoms. The World Health Organization Guidelines specify a 49-mm-width condom for Asia, a 52-mm-width for North America and Europe, and a 53-mm-width for Africa. China is now making its own condoms — 49 mm.
Race differences in testicle size have also been measured (Asians = 9 grams, Europeans = 21 g). This is not just because Europeans have a slightly larger body size. The difference is too large. A 1989 article in Nature, the leading British science magazine, said that the difference in testicle size could mean that Whites make two times as many sperm per day as do Orientals. So far, we have no information on the relative size of Blacks.
AIDS and HIV
Race differences in sexual behavior have results in real life. They affect sexually transmitted disease rates. The World Health Organization takes note of sexual diseases like syphilis, gonorrhea, herpes and chlamydia. They report low levels in China and Japan and high levels in Africa. European countries are in the middle.
The racial pattern of these diseases is also true in the U.S. The 1997 syphilis rate among Blacks was 24 times the White rate. The nationwide syphilis rate for Blacks was 22 cases per 100,000 people. It was 0.5 cases per 100,000 for Whites, and even lower for Orientals. A recent report found up to 25% of inner city girls (mainly Black) have chlamydia.
Racial differences also show in the current AIDS crisis. Over 30 million people around the world are living with HIV or AIDS. Many Blacks in the U.S. do get AIDS through drug use, but more get it through sex. At the other extreme, more AIDS sufferers in China and Japan are hemophiliacs. European countries have intermediate HIV infection rates, mostly among homosexual men.
Chart 5 shows the yearly estimates of the HIV infection rate in various parts of the world from the United Nations. The epidemic started in Black Africa in the late 1970s. Today 23 million adults there are living with HIV/AIDS. Over fifty percent of these are female. This shows that transmission is mainly heterosexual. Currently, 8 out of every 100 Africans are infected with the AIDS virus and the epidemic is considered out of control. In some areas the AIDS rate reaches 70%. In South Africa one in 10 adults is living with HIV.
The HIV infection rate is also high in the Black Caribbean. About 2%! Thirty-three percent of the AIDS cases there are women. This high figure among women shows that the spread tends to be from heterosexual intercourse. The high rate of HIV in the 2,000 mile band of Caribbean countries extends from Bermuda to Guyana, and it seems to be the highest in Haiti, with a rate close to 6%. It is the most infected area outside of Black Africa.
Data published by the U.S. Centers for Disease Control and Prevention show that African Americans have HIV rates similar to the Black Caribbean and parts of Black Africa. Three percent of Black men and 1% of Black women in the U.S. are living with HIV (Chart 5). The rate for White Americans is less than 0.1%, while the rate for Asian Americans is less than 0.05%. Rates for Europe and the Pacific Rim are also low. Of course AIDS is a serious public health problem for all racial groups, but it is especially so for Africans and people of African descent.
The three-way pattern of race differences is found in rates of multiple births (two-egg twinning), hormone levels, sexual attitudes, sexual anatomy, frequency of intercourse, and sexually transmitted diseases (STDs). Both male and female sex hormone levels are the highest in Blacks, the lowest in Orientals, with Whites in between. Sex hormones affect not only our bodies, but also the way we act and think. Blacks are the most sexually active, have the most multiple births, and have the most permissive attitudes. Orientals are the least sexually active and show the least sexual fantasy and the most sexual guilt. Whites are in the middle. Sex diseases are most common in Blacks, least so in Orientals, with Whites in between the two. The very high rate of AIDS in Africa, the Black Caribbean and in Black Americans is alarming.
Ellis, L., & Nyborg, H. (1992). Racial/ethnic variations in male testosterone levels: A probable contributor to group differences in health. Steroids, 57, 72-75.
UNAIDS (1999). AIDS epidemic update: December 1999. United Nations Program on HIV/AIDS. New York.
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