In Race, Ethnicity, and the Genetic Time Bomb I discussed the coming collision between the accumulating body of scientific data regarding human evolution and differentiation, and the PC shibboleth that all men and all populations are exactly equivalent. The corollary to this assumption has become conventional wisdom, ie that any differences in outcome between populations can only be the result of discrimination by the powerful against the weak. Various iterations of this assumption have become so deeply ingrained in science and society that it is considered a career destroyer to publicly question the idea.
In The 10,000 Year Explosion: How Civilization Accelerated Human Evolution Gregory Cochran and Henry Harpending have done an excellent job of collecting much of the data from population genetics (their 227 page book has 177 footnotes and a 14 page bibliography) and presenting their theory that evolution has not only not stagnated or ended with the advent of the modern human, but that civilization itself has caused human evolution to speed up significantly.
The reigning scientific conventional wisdom, adhered to unfailingly and fiercely defended by most of the soft sciences (including Psychology) is described by the authors in the first three pages:
(pps. 2-3) Scientists have long believed that the "great leap forward," some 40,000 to 50,000 years ago in Europe, marked the advent of cultural evolution and the end of significant biological evolution in humans. At this time, the theory goes, humans developed culture, as shown by the sophisticated new tools, art, and forms of personal decoration that emerged in the Upper Paleolithic. Culture then freed the human race from the pressures of natural selection. We made clothes rather than growing fur and built better wagons rather than becoming stronger.
The argument that the advent of behavioral modernity somehow froze human evolution is dependent on the notion of a static environment. In other words, if a population - of humans, wolves, crabgrass, you name it - experiences a stable environment for a long time, it will eventually become genetically well matched to that environment. ...
However, modern humans have experienced a storm of change over the past 50,000 years. We left Africa and settled every continent other than Antarctica. We encountered and displaced archaic humans like Neanderthals - and probably picked up genes from them in the process. An ever-accelerating cultural explosion from the Upper Paleolithic to the Neolithic and beyond led to new technologies and new social forms. Indeed, culture itself has been an increasingly important part of the human environment.
The book is extremely readable and its implications will, just like the beneficial gene alleles they describe, spread throughout the population. Cochran and Harpending, in my view, successfully present their major thesis, though their ancillary arguments are much more speculative. For example, the authors believe that the transition to agriculture led to major evolutionary changes that both depended upon and fostered modernity. Further, populations that were late to agriculture (eg, the Australian aborigine, who adopted agriculture only ~1000 years ago) may be at an impossible disadvantage in the modern world:
(pps. 121-122) The relative ease with which old agricultural civilizations (many of them, anyhow) have managed to adopt complex new technologies and forms of social organization, compared to populations that have had less experience with agriculture and dense hierarchical societies, suggests that biological changes in cognition and personality played a key role in the birth of the industrial and scientific revolutions.
If the root causes of these differences are biological changes affecting cognition and personality traits, changes that are the product of natural selection acting over millenia, conventional solutions to the problem of slow modernization among peoples with shallow experience of farming are highly problematic. And yet, methods based on an understanding of underlying biological causes might be very effective. [Emphasis mine-SW]
The details of their argument, that the advent of agriculture led to an acceleration of evolution, are quite speculative and their evidence is limited; P-ter at Gene Expressions has it mostly correct:
In lieu of a full review of Greg Cochran and Henry Harpending's new book, The 10,000 Year Explosion, I'll keep this short: this book is interesting, well-written, and probably mostly wrong.
In any case, this book is not intended to be "correct", so to speak--it seems to be more intended as an overarching frame of reference for viewing human history, acting as a counterpoint to that presented by authors like Jared Diamond. But if anthropology has a "Guns, Germs, and Steel problem", I just hope population genetics doesn't end up with a "10,000 Year Explosion problem".
Razib liked this book (see the first Amazon review) and I suppose it is a good introduction to this point of view, but overall I didn't come away feeling I obtained a superior understanding of the issues.
The book is fascinating and thought provoking, though there is a good chance that many of its speculative details are incorrect. Sigmund Freud would sympathize. Since Freud first began his studies of the unconscious mind, many of his theories have been shown to be incorrect or exaggerated. For instance, his assertion that the core of female sexuality is penis envy has been superseded by much more careful and deeper work which has shown that female sexuality is far more complex than Freud at first thought and that penis envy is a central issue in rather limited circumstances. Freud's concept of a death instinct, thanatos, has likewise been shown to lack explanatory power or supporting data. Yet, in the largest sense, Freud has been shown to be correct. Modern Neuroscience is continually adding to a body of data supporting such concepts as a dynamic unconscious, the primacy of self and object differentiations in character development, the centrality of attachment, and a host of other psychodynamic concepts.
In much the same way, Cochran and Harpending's most significant idea, that there is increasing evidence that populations of human beings have evolved away from each other, that different populations have different assets and liabilities depending upon the environmental stresses under which they evolved and continue to evolve, and that evolution has been increasing in human beings for the last 10,000 years, will soon be unassailable.
This presents two extremely worrisome dangers.
First, racists (of all colors and ethnicity) will be able to use the data of population genetics to support their twisted views on those they demonize. One race treating another as less than human is a historical fact, just as specific tribes treating non-members as less than human is the default position of homo sapiens.
The second danger is more insidious. For those who adhere most assiduously to Politically Correct-thinking and for that large body of followers for whom PC-thinking is more a posture than a coherent philosophy, the idea that different human populations could have different biological endowments is anathema. The thought-police will need to redouble their efforts to prevent dangerous thoughts in so far as the evidence continues to show that population genetics is a real discipline which is discovering real differences.
In the 1930s Soviet Biology came to a stand still because of the Politically Correct theories of Trofim Lysenko, who developed the theory that acquired traits could be inherited. This fit in perfectly with the Stalinist idea that a "new man" could be molded by the state:
Trofim Denisovich Lysenko (September 29, 1898–November 20, 1976) was an agronomist who was director of Soviet biology under Joseph Stalin. Lysenko rejected Mendelian genetics in favor of the hybridization theories of Russian horticulturist Ivan Vladimirovich Michurin, and adopted them into a powerful political scientific movement termed Lysenkoism. His unorthodox experimental research in improved crop yields earned the support of Soviet leadership, especially following the famine and loss of productivity resulting from forced collectivization in several regions of the Soviet Union in the early 1930s. In 1940 he became director of the Institute of Genetics within the USSR's Academy of Sciences, and Lysenko's anti-Mendelian doctrines were further secured in Soviet science and education by the exercise of political influence and power. Scientific dissent from Lysenko's theories of environmentally acquired inheritance was formally outlawed in 1948, and for the next several years opponents were purged from held positions, and many imprisoned. Lysenko's work was officially discredited in the Soviet Union in 1964, leading to a renewed emphasis there to re-institute Mendelian genetics and orthodox science. [Emphasis mine-SW]
[Interestingly, Biology now accepts that some acquired traits can be inheritable, for example anti-biotic resistance in bacteria, but this knowledge is a small part of our burgeoning understanding of genetics, rather than the central theorem.]
Unless the scientific and political establishment outlaw research on population genetics, the PC belief that all human populations have an equal endowment of assets, equally distributed, will not long stand.
Whenever a new paradigm overturns an older paradigm, the results are destabilizing. When the paradigm that is eclipsed forms the core of a social construct, the destablizing effects cannot be confined to the halls of academe. That is why The 10,000 Year Explosion is a dangerous book.