![]() The paper relied on a study of the relationship between head size and latitude showing a clear trend toward larger heads in populations further away from the equator. The relationship between evolved greater intelligence and these new technical innovations is supported by the greater cranial size (and hence brain size) associated with populations that migrated to these northern latitudes. The technical innovations were focused on keeping the cold out and warmth in (to create clothing, shelter, and fuel), on managing time (to conserve limited winter food resources), and on changing the sexual division of labor (to open new roles to women in garment making, shelter building, fire making, pottery design and manufacture, and ornamentation). These innovations included both new technology and changes in social organization. The paper suggested that during the last glacial maximum (about ten thousand years ago), eastern European populations displayed remarkable technical innovations that allowed them to survive the harsh winter conditions of their latitudes. ![]() A recent paper argued for the importance of cold winters in spurring the evolution of intelligence in Eurasians. There is no reason to believe that modern humans did not already possess all the cognitive ability needed to technologically innovate to meet new conditions before they arrived in Eurasia.ĭespite its obvious problems, the idea that climate drove evolution still seems to have some traction. Philippe Rushton and Arthur Jensen in the context of r- and K-selection theory applied to human races. Seventy years later, the winter selection idea was resurrected by J. ![]() This is especially significant in that he spent some time in that work discussing the importance of adaptation to climate as a factor in human evolution. It is notable that Carleton Coon, known for both his racialism and his racism, did not reiterate Huntington’s idea in his work on the origin of the human races. In 1925 Ellsworth Huntington argued that adaptation to the temperate zones caused strong selection for intelligence in Eurasians that was not experienced by sub-Saharan Africans. In 1864 Alfred Russel Wallace (codiscoverer of evolution by means of natural selection) proposed that winter selection would have favored greater intelligence. One convenient answer to this mystery is winter. So we are still left with the question of whether and how there could have been direct selection for greater intelligence as humans migrated into Eurasia. In this model, the benefit of greater cognitive capacity for technical innovation was a by-product of runaway sexual selection, not something directly selected for. Evolutionary psychologist Geoffrey Miller went so far as to propose that the main driving force of this early physical change in brain size was the competition for mates. Sexual selection for a trait differs from natural selection in that it need not lead to greater survivorship of the individual so long as individuals with the trait in question come to have greater numbers of offspring. The seeming disparity between brain growth and lack of technical innovation has led some to propose that sexual selection rather than natural selection might have been at play. Yet something was driving the brain growth (and possibly the intelligence growth). Over this same period the technical sophistication of these hominids was somewhat stagnant. Over the period from 2.5 million to 500,000 years ago the brain size of our hominid ancestors doubled. Many authors also suggest that the primary driving force of all primate intelligence (including our own) is social interactivity. ![]() ![]() Our evolutionary lineage was characterized by increased brain size and complexity along with facial reduction. Why and how should such differences exist? The key adaptation of our species is its greater intelligence compared to other animals. Given the weak differentiation between human populations, those who continue to champion the notion that genomic foundations to racial differences in intelligence must exist are left with a huge elephant in the living room. Available from Basic Books, an imprint of Hachette Book Group, Inc. Excerpted from A Voice in the Wilderness: A Pioneering Biologist Explains How Evolution Can Help Us Solve Our Biggest Problems, by Joseph L. ![]()
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