One way that humans are distinguished from other living creatures by is by our "mental endowment." The mental differences that the human species acquired through evolution allowed for the development and more importantly, the survival of humanity. Therefore, it is not surprising that the concepts of brain, genes, and intelligence gained considerable attention and were extensively studied within the realms of science. .
Emerging in the 1850's, Mendelian genetics dominated the beliefs of the scientific and the general public regarding the theories of intelligence in relation to success in life (Jensen, 2006; Shenk, 2010). "It's in your genes," was a profoundly popular statement that captured the meaning of this theory. Innate intelligence and talent were regarded as limited genetic outcomes, which individuals either possessed or did not possess. In other words, a person's ability, which was equated with genes, was considered to be inherited and fixed. The model of G+E (genes plus environment), held that genes came first and set the grounds for the later arriving environmental influences. From studies based on that model it was concluded that approximately 60 percent of each person's intelligence came directly from his or her genes (Shenk, 2012). .
In the modern world, a slightly different perspective towards the understanding of intelligence and ability has been offered, which rejects the conception of the gene as a sole causal agent. The new theory has been dubbed GxE (genes multiplied by the environment), and as Shenk (2010) states, in GxE everything begins with interaction; there is no genetic foundation that precedes the environment; instead genes express themselves in conformity with environmental influences (p.18). People have not inherited traits from genes in this model, but have 'developed' traits through vibrant gene-environment interactions. This novel information revolutionized the concept of intelligence by promoting the notion that intelligence is not an innate aptitude, but actually a collection of developing skills.