In The 10,000 Year Explosion: How Civilization Accelerated Human Evolution Gregory Cochran and Henry Harpending argue just that: human evolution is advancing faster and faster. Cochran and Harpending are anthropology professors at the University of Utah.
They present three reasons why human evolution is moving faster. First, during the last 10,000 years the human population has grown from an estimated five million to over six billion.
Other things being equal, a large gene pool will evolve faster than a small gene pool. This is because there is more scope for beneficial mutations.
Second, during the past 10,000 years humans have experienced a very different environment from the one that shaped previous human evolution. This is because of the development of farming and urban living. Farming originated in the Near East 10,000 years ago; civilization began there 5,000 years ago. The life of a stone age hunter is exciting, varied, and dangerous. In order to survive a farmer needs to be self disciplined, and he needs to be able to plan for the future. No matter how hungry he gets, he cannot eat his seed corn, or butcher all of his farm animals. Spending all day, day after day plowing fields or harvesting crops is tedious and exhausting, but it has to be done.
During the six million or so years of uniquely human evolution intelligence was important, or human intelligence would not have reached the level it did 10,000 years ago. Nevertheless, urban living places an even higher premium on superior intelligence. Those who are intelligent enough to become merchants, artists, and government officials live better lives than laborers, and have more children who survive and reproduce.
Moreover, over a period of centuries the criminal justice system of a civilized nation removes those with criminal inclinations from the gene pool. As farmers breed tamer domestic animals, governments breed tamer citizens.
Third, travel has become longer and faster. Even before the invention of steam ships, trains, cars, and planes, horse and camel transportation made it possible for men to travel long distances and spread their genes. Those genes which gave competitive advantages continued to be transmitted. Those which gave competitive disadvantages died out, along with those who inherited them.
All of this should make sense. Nevertheless, the consensus has been what Stephen Jay Gould stated when he wrote, “There’s been no biological change in humans in 40,000 or 50,000 years. Everything we call culture and civilization we’ve build with the same body and brain.”
Why would so many people believe something so counter intuitive?
Political correctness. If one wants to believe that race is a social construct, that “we’re all the same under the skin,” that IQ differences don’t matter, and that there are no significant racial differences in average aptitude and behavior, one needs to believe that little or nothing has changed since the races differentiated 40,000 years ago. If one acknowledges persistent differences in performance and behavior between the races, one has to disagree.
One obvious and not very controversial area in which people have changed during the past 10,000 years is in the spread of lactose tolerance. Most mammals lose the ability to digest milk sugar after they are weaned. At several different times and in several different places individuals had mutations that allowed them to digest lactose all of their lives. By making it possible for adults to drink milk, this gave them an advantage against starvation, so their descendants were much more likely to survive and reproduce. Currently most people who speak an Indo European language, Arabs, Mongolians, and several African tribes who have tended cattle for over a thousand years can drink milk all of their lives. Most humans cannot.
Another rather controversial area where humans have evolved is in the superior intelligence of most Ashkenazic Jews. These have average IQs estimated as 112 to 115. Cochran and Harpending argue, and this is becoming the (quiet) scientific consensus, that they evolved that intelligence because after Europe converted to Christianity they were restricted to professions, like commerce and money lending, that required superior intelligence. Those who could not learn the necessary skills did not survive and reproduce. Cochran and Harpending point out that Jews whose ancestors lived for centuries in places other than Europe do not have higher average IQs, and that during the ancient world Jews were not considered to be especially clever, although Greeks were.
The 10,000 Explosion explains why the longer a population has practiced farming and urban living, the higher its average intelligence is, and the lower its crime rate.
http://www.nationmaster.com/graph/cri_mur_percap-crime-murders-per-capita
Nevertheless, the correlation is not exact. With a nearly all white population, Russia has a much higher murder rate than multi racial United States. Although farming and civilization began in the Far East about two thousand years after they began in the Near East, Orientals have lower crime rates and higher average IQs than Caucasians.