What we know about the genetic and neuro-biological bases of human intelligence and their uses
We are still in deep water as far as knowledge of neurobiology and the genetics of intelligence are concerned. Neuro-scientists interrogate the brain to establish how its structure and activity generate intelligence, or variations in intelligence. Geneticists seek out hereditary factors. A reliable hypothesis is that intelligence is located in specific groups of brain neurons, many of which are situated in the prefrontal and parietal cortex. The structure of these areas, their activity and the connections between them vary from person to person and correlate with cognitive test performance. Recent estimates show that around 25% of individual intelligence variations are explained by polymorphism at the level of the individual genome nucleotide. Overall, the genes identified thus far explain around 11% of individual variability at educational levels.