First of all, you don't have to be so terrified by there being a
gentic base for
intelligence. It's not such a bizarre concept. Of course we must make a great distinction between
racial differences and
individual differences, but I really don't see how the racial issue ever got into this node. It is very difficult to establish racial differences of
traits such as intelligence for various reasons. The most prominent is that <>intelligence must be measured by the tools of the measurer. This is different among cultures, and proved to be a crucial barrier in
cross-cultural intelligence tests. The Western concept of intelligence is radically different from many
tribes in Africa, for example. People without any formal education will not usually score high on Western IQ tests. Several other tests of "intelligence", better suited to 'wild environments' (for example
guess what the snake will do?), prove that African tribes are more intelligent than their Western counterparts.
But enough about racial intelligence, which is not what we are talking about in this node. I don't mean to burst anyone's bubble, but intelligence has been proven, in as much as psychological tests can prove anything, that genetics play a large part, in fact probably the major part, in determining intelligence.
Usually, these psyhcological tests focus on identical (monozygotic) twins, and fraternal (dizygotic) twins. For the layman, identical twins are those which came from the same egg and sperm, and thus have the same genetic material (exactly). Fraternal twins are those which developed from separate eggs and sperms, and thus are related genetically just like any two siblings (roughly a quarter of their genetic material is identical). In all the tests I have heard about, a comparison was made between the intelligence of fraternal twins that live in the same household (so that the effects of the environment on their intelligence are approximately the same, or at least very similar), and identical twins separated at birth. In every test I know of, whatever the method used to measure intelligence, there was a much higher correlation between the identical twins than between the paternal twins, even though the identical twins were brought up apart in (sometimes drastically) different environments.
You are free to make your own deductions. The current opinion of the scientific world is that intelligence is more affected by nature than nurture. I know that this may be an uncomfortable thought to many. But life is not always what we want it to be.