The times must be changing, because a few years ago this book had untied a criticism hurricane and, nevertheless, it has happened relatively unnoticed (or at least a too big candle has not been mounted) the reason? His authors, Cochran and Harpending, open one of the most awesome "melons" of the Biology / psychology, that of the (supposed) cognitive differences between ethnic groups.
But let's start for the beginning. The fundamental thesis of the book is that the human evolution has not stopped in the last milleniums, but on the contrary, it has hastened with the arrival of the civilization and the progress. The authors support that the new living conditions created by the development of the agriculture - first - and for the creation of the states - later - new selective pressures created in the human populations. This idea is not, in itself, himself; what is difficult is to present solid experimental evidence that endorses it. Undoubtedly, the authors do an effort to argue well his thesis although, in my opinion, these are at the moment a hypothesis which empirical assertion stays enough background. It is necessary to admit also that the authors are honored enough in this sense: they say clearly when they are speculating and when his affirmations are well sustained.
Essentially, Cochran and Harpending throw three (risky) ideas to the forum. The first one is that the human beings modern (cro-magnon) that replaced in Europe the neanderthales should have acquired of these some alelos by means of a well-known process like introgresión. The above mentioned genes would have allowed to the cro-magnones to adapt themselves to the hard European conditions during the last glaciation. The idea is not ludicrous. For example, it has been seen that the color of the hair of the wolves of Alaska and Canada owes up to a point to a phenomenon of introgresión (more info). Nevertheless, the genetic information obtained until now shows that cro-magnones and neanderthales they remained genetically separated. It is possible that into the future new information changes the panorama, but in this moment this evidence is nonexistent (see).
The second hypothesis has to do with the appearance of the tolerance to lactose in our species. This topic has been treated other times in this blog (here). The authors go a little further and affirm that the appearance of this mutation that allows to the adults to consume milk, constituted a determinant advantage for the Indo-European peoples up to the point of being the cause of that the Indo-European migration took place. Again, it is possible that it has been like that but the information on which the hypothesis is based is still insufficient.
Finally, we go away to the most controversial hypothesis of all: according to the authors, the Jews ashkenazi turned out to be forced to devote themselves to professions related to the banking and the finance of almost exclusive form during the Middle Age; due to this selective pressure, the ashkenazi would be more intelligent than other ethnic groups. The authors use the number of Nobel Prizes obtained by individuals with this ancestry in the last century.
This type of controversies always supposes a streak species in the sand: it is necessary to be against or in favor. So I am going to define myself: I refuse to accept streaks in the sand. On the one hand, I believe that the arguments used by the authors are insufficient (although they present his case of convincing form). It would be necessary to find alelos clearly tied to the intelligence (understood like IQ, what has a clear limitation) and then to demonstrate that in certain ethnic groups the above mentioned alelos are more frequent than in others. To today, the information is not conclusive not much less.
On the other hand, it seems possible to me that a hypothesis of this type goes so far as to be hard supported by the information some (perhaps there are no populations genetically taller than others?). When that happens, I am ready to allow me to convince, because I believe that the science is much more important and less harmful long-term that the political correction (more on this).
But this day has not come.
PS. On the evolution of the human species at present we will speak another day
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