IQ Matters: Understanding Your World So As to Predict the Future
Decades of genetics research have shown...that people are born with different hereditary potentials for intelligence and that these genetic endowments are responsible for much of the variation in mental ability among individuals. Last spring an international team of scientists headed by Robert Plomin of the Institute of Psychiatry in London announced the discovery of the first gene linked to intelligence. Of course, genes have their effects only in interaction with environments, partly by enhancing an individual's exposure or sensitivity to formative experiences. Differences in general intelligence, whether measured as IQ or, more accurately, as g are both genetic and environmental in origin--just as are all other psychological traits and attitudes studied so far, including personality, vocational interests and societal attitudes. This is old news among the experts. The experts have, however, been startled by more recent discoveries.
One is that the heritability of IQ rises with age--that is to say, the extent to which genetics accounts for differences in IQ among individuals increases as people get older. Studies comparing identical and fraternal twins, published in the past decade by a group led by Thomas J. Bouchard, Jr., of the University of Minnesota and other scholars, show that about 40 percent of IQ differences among preschoolers stems from genetic differences but that heritability rises to 60 percent by adolescence and to 80 percent by late adulthood. With age, differences among individuals in their developed intelligence come to mirror more closely their genetic differences. It appears that the effects of environment on intelligence fade rather than grow with time. In hindsight, perhaps this should have come as no surprise. Young children have the circumstances of their lives imposed on them by parents, schools and other agents of society, but as people get older they become more independent and tend to seek out the life niches that are most congenial to their genetic proclivities.
A second big surprise for intelligence experts was the discovery that environments shared by siblings have little to do with IQ. Many people still mistakenly believe that social, psychological and economic differences among families create lasting and marked differences in IQ. Behavioral geneticists refer to such environmental effects as "shared" because they are common to siblings who grow up together. Research has shown that although shared environments do have a modest influence on IQ in childhood, their effects dissipate by adolescence. The IQs of adopted children, for example, lose all resemblance to those of their adoptive family members and become more like the IQs of the biological parents they have never known. Such findings suggest that siblings either do not share influential aspects of the rearing environment or do not experience them in the same way. Much behavioral genetics research currently focuses on the still mysterious processes by which environments make members of a household less alike. _Linda Gottfredson
The table below is a guessing game, where you are to fill in the "country" which matches the continent and the IQ score. The table of national IQs below, should assist you in this task. Notice that African nations are not included in the game, since the national IQ scores in the game do not go below 92.
A more complete table of national IQ scores from Lynn and Vanhanen summarized by Steve Sailer
EvoandProud anthropology site). By comparing the TFRs and national IQs, one can estimate the general trend for global IQ, as a falsifiable hypothesis.
What about the "Flynn Effect?" Unfortunately, the multiple and poorly defined underlying mechanisms behind the "Flynn Effect" are not strong enough to overcome the compounding magic of differential birthrates combined with heritability of IQ.
Hope for the best. Plan for the worst.
More: Here is an extremely optimistic look at the future of commodities, energy resources, and food. The human ingenuity of "the smart fraction" has been pushing back against the forces of depletion -- just as Julian Simon said they would do.
It is crucial to look at as many sides to the story as one can. Nothing in real life is as simple as it seems.