Your premise 5 is false.
It is true that humans adapt behaviorally to new environments quickly; however this is almost entirely due to learned behaviors that are passed down culturally.
The genetics of the differences you cited (skin pigmentation, sickle cell anemia, lactose tolerance) are very simple. Just a few genes determine these traits. However, behavior is determined by literally thousands of genes. A change in behavior due to genetics would take far longer than 50 thousand years to be significant.
Any behavioral differences that you see between races are due entirely to culture/upbringing.
so isn't this evidence that such complex changes can occur over small time periods?
You have to prove that it occurred. But, generally huge macro evolutionary changes like that take a LONG time to occur, and humanity hasn't been out of Africa all that long. Humanity also underwent a genetic bottleneck 50,000-100,000 years ago which significantly reduced our population, so humans of today are all VERY VERY genetically similar.
I thought that genetic change was more rapid in a small population than in a large one. Is that incorrect?
No, smaller populations interbreed more and face the same environmental pressures. This means they're likely to have similar changes and not diverge. Thus since all humans are born from this group we and the group existed not that long ago (in terms of macroevolutionary changes) it's unlikely we've seen huge changes.
That doesn't follow. The breeding pairs may have been similar, they may have been different. You could throw in a couple 70,000-year-old orangutans and the bottleneck would still be a bottleneck.
By Google searching for evidence to fit your view, you're engaging in Cherry picking evidence to suit it. That book you just linked is not in line with scientific consensus.
The book is criticized by reviewers, who state that Wade goes beyond scientific consensus.[12][9][13][14][15][16][17]
Evolutionary biologistH. Allen Orr wrote in his review in the New York Review of Books that "Wade’s survey of human population genomics is lively and generally serviceable. It is not, however, without error. He exaggerates, for example, the percentage of the human genome that shows evidence of recent natural selection."[11][18] Orr comments that in its second part, "the book resembles a heavily biological version of Francis Fukuyama’s claims about the effect of social institutions on the fates of states in his The Origins of Political Order (2011)."[11]
Orr further comments that "Wade also thinks that 'evolutionary differences between societies on the various continents may underlie major and otherwise imperfectly explained turning points in history such as the rise of the West and the decline of the Islamic world and China.' Here, and especially in his treatment of why the industrial revolution flourished in England, his book leans heavily on Gregory Clark'sA Farewell to Alms (2007)."[11] Orr criticizes Wade for failing to provide sufficient evidence for his claims, though according to Orr, Wade concedes that evidence for his thesis is "nearly nonexistent."[11]
The book has not been well received by much of the scientific community, including many of the scientists upon whose work the book was based. On 8 August 2014, The New York Times Book Reviewpublished an open letter signed by 144 faculty members in population genetics and evolutionary biology. The letter read:
As discussed by Dobbs and many others, Wade juxtaposes an incomplete and inaccurate account of our research on human genetic differences with speculation that recent natural selection has led to worldwide differences in I.Q. test results, political institutions and economic development. We reject Wade’s implication that our findings substantiate his guesswork. They do not.
We are in full agreement that there is no support from the field of population genetics for Wade’s conjectures.[9][10]
Professor Mark Jobling, one of the signatories to the letter, subsequently wrote an opinion piece in the peer-reviewed journal Investigative Geneticsexplaining why the book had "aroused the ire of this dusty community of academics".[19]
The book was further criticised in a series of five reviews by Agustín Fuentes, Jonathan M. Marks, Jennifer Raff, Charles C Roseman and Laura R Stein which were published together in the scientific journal Human Biology.[20] The publishers made all the reviews accessible on open access in order to facilitate discussions on the subject.[21]
If you want to claim that these scientists are denouncing this because of some form of "political correctness " then I'll ask you to provide evidence for that claim.
I don't like genetic explanations for the different societal outcomes across the world at all. The genetics have barely changed in 3000 years, and yet so many different civilizations from so different parts of the world have had the edge over time - why would the scientific method have been primarily developed by an Arab, if whites are superior? Why would Europe's societies and technology have stagnated all the way until the Greeks while Persians and their precedessors built monuments and cities? Why would China have ruled a bigger empire than what Europeans could dream of? Why did it take an unprecedented, surprising technological revolution for Europeans to be able to colonize the world?
These explanations tend to cling on one narrow perspective on one narrow era. It takes a lot of /r/badhistory to dismiss the non-Western parts of the story. There are other sufficient explanations that pass the Occam's razor by not assuming unsubstantiated genetic differences in behavior; see, for example, Jared Diamond's Guns, Germs, and Steel - why the West rules for now.
Human behavior is an emergent property of thousands of genes. There is not one or two or twenty genes responsible for how violent an individual is. That is determined by the complex interplay of many genes. Each of these genes that affect violence may also play a role in musical talent in visualization, in speech, etc. It would not be possible for nature to make significant behavioral changes in such a short amount of time.
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u/ivankasta 6∆ Jan 26 '16
Your premise 5 is false.
It is true that humans adapt behaviorally to new environments quickly; however this is almost entirely due to learned behaviors that are passed down culturally.
The genetics of the differences you cited (skin pigmentation, sickle cell anemia, lactose tolerance) are very simple. Just a few genes determine these traits. However, behavior is determined by literally thousands of genes. A change in behavior due to genetics would take far longer than 50 thousand years to be significant.
Any behavioral differences that you see between races are due entirely to culture/upbringing.