Genius is something that is difficult to measure quantitatively since it is a unique quality, although most of us can recognize genius when we see it or hear it. (1){{U}}By contrast intelligence is possibly easier to quantify and like genius is a polygenic character that can be moulded by the environment. {{/U}}Intelligence is a qualitative trait, which does have a genetic component, but we should not assume that it has a single dimension of expression. (2){{U}}There are several limitations in measuring intelligence by a linear scale ranging from dull to bright, since individuals differ greatly in their genotypes.{{/U}} Any number of gene combination may predispose an individual to musical genius, or to painting, or to designing computer programs, etc. The possession of any one of these abilities may or may not be associated with another. Moreover, the same genotype may be expressed in markedly different ways in markedly different environments. (3){{U}}For example, intelligence quotient test scores vary considerably with illness and disease, educational, social and economic levels—even the skin color of the examiner conducting the IQ test may have a significant effect!{{/U}} There is also difficulty in deciding what intelligence should be applied to. Is it the ability to learn? Is it related to the enquiring mind or to motivation? Consequently comparisons between an IQ test given to a University .student and to an Aborigine in Australia will give meaningless results, since the test is most unlikely to measure the same behavior. (4){{U}}Not only are the genotypes and the environments of these two individuals totally different, but their motivations for achievement in particular activities will be different.{{/U}}
Indeed, as some articles which deal with the problems mentioned above show, people who believe they can estimate genetic and environmental contributions to differences in intelligence between races are statistically naive. (5){{U}}If some races or social groups in the human population can be shown to be inferior in intelligence, it opens up the possibility that some segregationists or politicians could bring in legislation or policies to suppress or even eliminate such races or groups in the population.{{/U}} History certainly shows that this suggestion is quite likely when ruthless individuals are in positions of power. Can you see why the false scientific conclusions could become dangerous socially and politically?
Notes:
polymeric: having many genes
mould: to shape or form
linear: of lines
genotypes: types of gene