Studies have found that genetics and environment play a role in the level of intelligence of a person.
In the first study, published in the journal Molecular Psychiatry, the research team analyzed thousands of genetic markers in the DNA of 20,000 individuals in search for signals associated with intelligence quotient (IQ).
The study results revealed that the combined effect of rare and common genetic variants accounted for more than half of the difference in intelligence between individuals.
In addition, the research team found that rare genetic variants covered for a disproportionate amount of intelligence in comparison to more common genetic variants.
It was also revealed that environmental factors, such as parenting, nutrition, and exposure to chemicals in the womb affect the intelligence levels of people.
In the other study, published in the journal Psychological Bulletin, an integrative review of recent studies on the nature of human intelligence was conducted to analyze the relationship between intelligence and genes and environment.
The study authors saw that intelligence trait typically rates at 0.8 and is very inheritable, but it can also be as low as 0.3.
They believe that the role of environment also matters when it comes to intelligence.
Both studies show that intelligence can be inherited, but can be affected by environmental factors.
Overall, the findings of the studies indicate that genetics and environment affect the intelligence level of an individual.
William Hill, Ruben Arslan, Charley Xia, Michelle Luciano, Carmen Amador, Pau Navaroo, Carolin Hayward, Reka Nagy, David J. Porteous, Andrew Mcintosh, et al. GENOMIC ANALYSIS OF FAMILY DATA REVEALS ADDITIONAL GENETIC EFFECTS ON INTELLIGENCE AND PERSONALITY. Molecular Psychiatry, 2018; DOI: 10.1038/s41380-017-0005-1
Bruno Sauce, Louis D. Matzel. THE PARADOX OF INTELLIGENCE: HERITABILITY AND MALLEABILITY COEXIST IN HIDDEN GENE-ENVIRONMENT INTERPLAY. Psychological Bulletin, 2018; 144: 26 DOI: http://dx.doi.org/10.1037/bul0000131