Nohe last years the question “Is intelligence genetic?” has sparked many debates between neuroscientists, psychologists and social science enthusiasts. A curious episode made the debate even better known: Seven years ago, political scientist Charles Murray and psychologist Eric Turkheimer made a bet. Murray was convinced that by 2025 it would be possible to identify how DNA determines intelligence. Turkheimer, however, believed that the complexity of genetic and neural mechanisms made it impossible to arrive at this knowledge so quickly. Today, Turkheimer published an article in the Atlantic explaining why he believes having won the bet.
What do we really know about intelligence?
THE’intelligence it is a difficult concept to define univocally. THE IQ test they remain the most widespread tool for measuring it, especially in the United States, but they are not perfect and do not capture all cognitive nuances. Science has made a few things clear: intelligence is partly hereditaryand those who obtain high results in one test tend to confirm them in other types of tests, a phenomenon known as “general intelligence”. But here the simplification ends: no single gene determines how intelligent we are. The human genome sequence has shown that cognitive abilities arise from hundreds of genetic variantseach with minimal effect. Even adding all these effects together explains only a small part of the differences in IQ scores among people.
Genes and environment: an inseparable connection
Turkheimer underlines a fundamental point: genetic inheritance is not a written destiny. Even when a trait is largely hereditary, environment, education, experiences and even chance they profoundly influence how it manifests itself.
A person can be born with a high potentialbut without stimuli, opportunities or adequate support, that potential risks remaining unexplored. In other words, genes and environment interact in a complex and dynamic way. Genes, particularly maternal ones, can influence the development of brain areas related to thinking, language and planning. Intelligence is not a “closed package” transmitted by parents, but a set of skills that develop throughout life, modulated by factors social, cultural and even casual.
The truth about the bet: is intelligence genetic or not?
According to Turkheimer, the bet has it won in any case because, despite the progress in genetics and neurosciencewe are not yet able to explain how genes produce intelligence differences among people. Science can identify correlations and variationsbut the complex mechanisms that lead some people to excel remain largely a mystery. The lesson is clear: intelligence is not just in DNAand those who study it today underline the need to also look at education, opportunities, stimuli and environment. If it is true that we are influenced by genes, it is equally true that the environment can amplify, modulate and even transform innate potential.
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