Question

14. Some have proposed that moderate-to-high heritability of IQ scores within populations allows us to infer that differences in IQ scores between populations must be at least partly explained by genetic differences between populations. Explain why this perspective is erroneous (2 points).

Answer 1

Many genes control the brain development.Therefore, many genes are responsible for IQ. Now, mutations happen in populations but there is more chances that one with large effect on the IQ level will reduce the IQ because IQ level of human is quite good as compared to any other animal. If the IQ level is reduced by any mutation that will be removed by natural selection.Therefore, mutation with very small changes may persist.But since many genes contribute to the IQ level, natural selection can’t keep humans free from mutations with small changes all the time. Due to these varied changes in the mutations, any population at any time will carry a varied mixture of mutations that affect the IQ . These will differ between populations, families, and individuals. This continuos mix of genetic variation would work against any long-term rise or fall in intelligence and nullify the effect of genetic IQ differences in populations. That's why the idea that the differences in IQ scores between populations must be atleast partly explained by genetic differences between populations is wrong.