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Whole fields of science gone awry
ruthlessly enforced the upholding of the false dogma of acquired traits being encoded in the genetic material (with disastrous consequences for the Soviet agronomy).
The heritability of intelligence – a scientific zombie still going strong In astronomy, today a scientific field based on physics, science eventually trumped ideology and today no one doubts the heliocentric view. But in science, where one might think that rational thought should finally prevail, things need not happen like that. And it did not happen in a field where, had science trumped prejudice, disastrous social and political consequences could have been avoided: the controversial issue about the heritability of intelligence. Here the opposite happened: prejudice not only trumped scientific reason in the past, but still does so today. How could something like this happen in a debate deemed to be a scientific one? The treatment of the issue about the heritability of intelligence and other mental traits as it happened in science is one of the crassest and most depressing examples of nonscientific aspects being so dominant as to preclude a consensus about a genuinely scientific problem. More depressing still: the consensus could have been reached by some fundamental and rather simple considerations. Ever since Francis Galton described the regression effect and mistook it for a law of heredity3 around the end of the 19th century, scientists have believed that intelligence is heritable to a substantial degree, somewhere between 50 % and 80 %. When quantitative genetics, the statistical tool for determining the heritability of quantitative traits, had been developed in the 1930s, psychologists applied it to intelligence and still do so today, against the warnings of one of the experts in the field, Douglas Scott Falconer4 (1989). They ended up with heritability estimates between 10 % and 90 %. They also ignored the warnings 3
Galton falsely derived heritability from parent-child regression while this regression is actually affected both by genetic and environmental factors. Regression is not a biological but a statistical law, applicable to all kinds of correlating variables. 4 Quantitative genetics was developed in order to predict breeding success in plants and animals. The preconditions for its use for human mental traits cannot be satisfied due to the lack of experimental control.
