Throughout the evolution of modern science, a popular topic of research and discussion has been the question of whether intelligence is hereditary. Twin studies have suggested a genetic influence on mathematical abilities, but when considered, environmental factors may also have played a role in the development of individuals' intelligence (Pinel, 1). Therefore, the debate remains between nature and nurture: which contributes to an individual's general intelligence and cognitive abilities? Are some people born more intelligent than others, or does everyone, despite a mental disability, have the same chance of acquiring intelligence? Research conducted so far in various studies concludes that both are true; While intelligence is rooted in genetic influence, environmental factors play a crucial role in the extent of this influence. In a study published in 2009 in the Journal of Neuroscience, researchers used a new type of brain imaging scanner in a twin study to show that intelligence is strongly influenced by the quality of the brain's axons, which send signals throughout the brain. The faster the signaling, the faster the brain processes information, and because genes influence the integrity of axons, these genes indirectly play a role in an individual's intelligence. The study suggests that genes appear to influence intelligence by determining the extent to which nerve axons are sheathed in myelin. The correlation with individual intelligence is based on the connection that the faster the myelin, the faster the nerve impulses and therefore the faster the brain's ability to process information. The researchers scanned the brains of 23 pairs of identical twins and 23 pairs of fraternal twins. Using the fact that identical twins share the same genes,...... middle of paper ......enes and general intelligence. The results showed only one nominally significant association, which is less than would be expected by chance alone. The study then followed the methods of the 2011 study and, applying the same procedure in its analysis, estimated that the 630,000 SNPs present in the data jointly accounted for 47% of the variance in general intelligence. The combined results of this study further support the idea that intelligence is a highly polygenic trait. A more recent study published in 2013 in NeuroImage also built on previous twin studies that have long suggested a genetic influence between specific candidate genes and intelligence. . This study examined the heritability of the trait by jointly estimating genetic and environmental contributions with a modified model classically used in twin studies..