Wednesday, July 18, 2012

Pigmentation, aggression and sexuality

Researchers have found that darker-colored individuals had higher levels of aggression and sexuality than lighter colored individuals across three species of mammals (African lion, soay sheep, and white-tailed deer), four species of fish (mosquito fish, guppy, green swordtail, and Arctic char), four species of reptiles (asp viper, adder, fence lizard, and spiny lizard), one amphibian species (spadefoot toad), and 36 species of birds. The researchers believe that increased levels of melanocortin hormones, which determine coloring, are linked with increased testosterone and other steroids that stimulate aggression and sexuality, among other things. This link between coloring and behavior has been confirmed in many other species — even tortoises. In Russia, a 40-year-study bred for tameness in silver foxes and found that lightness coincidentally emerged. After 40 years, the selected foxes were as tame and eager to please as domestic dogs — and the dark coat colors originally evolved as camouflage in the wild had been replaced by piebald. (Piebald coats are often seen among domestic animals — in dogs, cats, sheep, donkeys, horses, pigs, goats, mice, and cattle). Similarly, selecting for tameness over 30 generations of Norway rats caused the proportion of piebald rats to increase rapidly until over 70% had white bellies and about 50% had white feet and ankles —“socks". Dogs, too, show a relationship between coat color and behavior — and dog lovers have figured it out. Shelters have a harder time getting black dogs adopted. Researchers have also found clear evidence that darker pigmentation is indeed associated with higher levels of aggression and sexuality in humans — just as it is in animals. Researchers compared people of African descent with those of European and Asian descent. Worldwide — ever since record keeping began — blacks have averaged higher levels of aggression and sexuality than whites and Asians. In 1996, a government commission in Canada found that blacks were five times more likely than whites to be in jail and ten times more likely than Asians. In 1999, a Home Office report in Britain found that blacks made up 15% of the prison population although they made up only 2% of the general population. In 1999, a large study in the U.S. analyzed the FBI Uniform Crime Statistics and National Crime Victimization Surveys from the U.S. Department of Justice and found that, since record keeping began at the turn of the century, African Americans engaged in proportionately more acts of violence than other groups. It has been found that blacks averaged the highest rates of childhood and adolescent psychopathy and conduct disorder. An analysis of the 1993-1996 INTERPOL Yearbooks and found that the rate of murder, rape, and serious assault was four times higher in African and Caribbean countries than elsewhere in the world. The rate of violent crimes for African countries was 149 per 100,000 people; for European, 42; and for Asian, 35. Blacks are over-represented relative to Asians and Europeans in sexually transmitted diseases (STDs) like syphilis, gonorrhea, herpes, chlamydia, and HIV/AIDS. In 2007, of the more than 1 million people living in the U.S. with HIV/AIDS, almost half (46%) were black. The black-White difference in HIV/AIDS is found worldwide, with especially high rates in sub-Saharan Africa. Thus the rate for Botswana was 24.8%, South Africa was 17.8%, Zambia was 14.6%, and Zimbabwe was 14.3%. A very high rate of HIV/AIDS is also found in the black Caribbean. Recent contact with Africa has been minimal, but the HIV/AIDS rates are as high in the Caribbean today as they were in sub-Saharan Africa 20 years ago: 3.1% in the Bahamas, 2.9% in Haiti, 1.7% in Jamaica. A 2006 study found a remarkably high correlation of 0.92 between skin color and national IQ across 129 countries and within each of the three continents: -0.86 for Africa; -0.55 for Asia; and -0.63 for Europe. The correlations are negative because darker skin color predicted lower IQ scores. In 2008, another study found that, across 129 countries, skin color correlated with IQ (-0.91), birth rate (0.85), infant mortality (0.71), longevity (-0.84), rate of HIV/AIDS (0.53), and GDP (0.60). Subsequently, in a 2009 study , researchers found that skin color also correlated with crime in 113 countries (homicide, 0.34; rape, 0.24: and serious assault, 0.25) as well as with IQ (-0.91), GDP (-0.57), HIV/AIDS (0.56), birth rate (0.87), longevity (-0.85), and infant mortality (0.76). Rates of murder, rape, and serious assault correlated with those of HIV/AIDS (0.48, 0.57, and 0.42, respectively). Finally, in 2011, researchers confirmed the international findings using data from within the 50 U.S. states. Skin color was measured by the percentage of blacks in the state. It correlated with infant mortality (0.41), longevity (-0.66), HIV/AIDS (0.74), birth rate (0.12), murder (0.84), robbery (0.77), assault (0.54), as well as IQ (-0.48) and income (-0.28).

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