Angela L. Duckworth
Angela L. Duckworth
Psychologist and Science Author 06 February, 2023

Modern humanity has always been curious about the role of heredity in intelligence. Does intelligence come down to the genes we inherit from our parents or is it something more complex than that? In this article, we’ll explore what science has to say on this subject, and whether or not IQ is only related to our genetic makeup.

It can be said with certainty that heredity plays some role in intelligence. After all, certain genetic conditions and diseases can impact intellectual development, such as fragile X syndrome which is associated with lower IQ scores. But does that mean having a good set of genes guarantees higher IQ scores? The answer is no.

Studies have looked into the connection between genetics and intelligence by examining the similarities between twins, siblings and parents. When comparing fraternal and identical twins reared together (who share 50% or 100% of their DNA respectively), researchers have found that identical twins tend to score more similarly on IQ tests than fraternal twins – leading them to conclude that some level of heritability does indeed exist within intelligence.

However, these studies only measure correlation and cannot determine causation – meaning they don’t prove that one’s genes are actually the cause of any particular trait or ability. Despite popular belief, there is still no solid scientific proof that one’s genetic makeup can accurately predict their intelligence level or IQ score.

Another important factor to consider when looking at intelligence is environment. Studies show that how an individual is raised can affect their cognitive development in significant ways; for instance, children who are consistently exposed to books, music, educational toys etc., versus those raised in environments lacking stimulation tend to fare better on cognitive tests later in life. Not only do traits such as motivation and determination rely heavily on environmental factors but also day-to-day experiences can influence learning abilities which directly affect one’s IQ score: research shows early childhood education accounts for a large portion of the variation seen across different levels of IQ within a given population group.

Not forgetting the importance of experience play too: expertise acquired through practice tests will permanently increase one’s IQ score since problem solving skills increase over time; perhaps explaining why some people perform better than others when taking tests multiple times throughout their lives due solely to increased familiarity with said test material as opposed to actual changes in intellectual abilities themselves.

In conclusion it could be argued then that although genetics may have some influence on an individual’s intellectual capabilities they are undoubtedly only part of the equation; environment plays a huge role too – not just during childhood but throughout life as well – thus suggesting that ‘intelligence’ is much more complex than simply being inherited through genes alone.

Scientific journal articles for intelligence hereditary

  • Sternberg RJ. Intelligence. Dialogues Clin Neurosci. 2012 Mar;14(1):19-27. Review. PubMed: 22577301. Free full-text available from PubMed Central: PMC3341646
  • Plomin R, von Stumm S. The new genetics of intelligence. Nat Rev Genet. 2018 Mar;19(3):148-159. doi: 10.1038/nrg.2017.104. Epub 2018 Jan 8. PubMed: 29335645. Free full-text available from PubMed Central: PMC5985927.
  • Sniekers S, Stringer S, Watanabe K, Jansen PR, Coleman JRI, Krapohl E, Taskesen E, Hammerschlag AR, Okbay A, Zabaneh D, Amin N, Breen G, Cesarini D, Chabris CF, Iacono WG, Ikram MA, Johannesson M, Koellinger P, Lee JJ, Magnusson PKE, McGue M, Miller MB, Ollier WER, Payton A, Pendleton N, Plomin R, Rietveld CA, Tiemeier H, van Duijn CM, Posthuma D. Genome-wide association meta-analysis of 78,308 individuals identifies new loci and genes influencing human intelligence. Nat Genet. 2017 Jul;49(7):1107-1112. doi: 10.1038/ng.3869. Epub 2017 May 22. Erratum in: Nat Genet. 2017 Sep 27;49(10 ):1558. PubMed: 28530673. Free full-text available from PubMed Central: PMC5665562
  • Plomin R, Deary IJ. Genetics and intelligence differences: five special findings. Mol Psychiatry. 2015 Feb;20(1):98-108. doi: 10.1038/mp.2014.105. Epub 2014 Sep 16. Review. PubMed: 25224258. Free full-text available from PubMed Central: PMC4270739.

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