The dispute about the "genes of intelligence"

School performance is not in the genes

Dmitry Tselikov, Compulenta

Can we assume that intelligence is genetically determined? The other day, the education adviser to the UK government, Dominic Cummings, presented a report to the Minister of Education, Michael Gove, as a parting gift, in which it was said that the ability to learn is largely inherent in the genes (Some Thoughts on Education and Political Priorities). Many thought that the debate on this topic was over, but the 240-page essay ignited them with renewed vigor.

Honorary Professor of Biology at the Open University (UK) Stephen Rose recalls that such claims are based on two assumptions: 1) we can define and measure intelligence and 2) we can separate the role of genes and environment.

Children can't stand school. Is it in the genes too?

Attempts to measure intelligence date back to the beginning of the last century, when French psychologist Alfred Binet developed a series of tests for schoolchildren of different ages in order to help teachers identify those who may need additional classes. Having determined the average score for each age as 100, he compared the children's performance with the average for the age group and thus obtained a mental coefficient – Intelligence Quotient (IQ).

In the 1920s, tests for adults appeared, and their purpose changed. IQ has come to be considered a fixed measure of a person's abilities compared to other people. The purpose of testing was not to help, but to describe the individual, placing him on a surrogate linear scale, as if something like growth is being measured. From the point of view of IQ theorists, intelligence was a kind of permanent unitarity, amenable to a firm assessment.

In fact, Mr. Rose notes, unlike growth, which can be measured with a simple ruler, the IQ scale resembles rather an elastic band that stretches to fit public expectations. Despite attempts to develop tests that would fit all cultures, they invariably reflect assumptions about which answers are "correct" and how people should behave.

When boys and girls scored the same number of points on average, when middle-class children performed better on tests than those from working-class backgrounds, when whites outperformed African-Americans, it did not surprise anyone: "this is how it should be." It was believed that the results reflected the real situation.

IQ tests correlated with school performance (and with the socio-economic status of parents) only because that's what they were created for, emphasizes Mr. Rose. But they predicted the individual's future career success very poorly. As critics soon found out, IQ tests are not able to capture such ephemeral characteristics of a person as a practical mind, creativity, emotional and social intelligence, musical and artistic talent... The list goes on.

More flexible psychometrists started talking about the multiplicity of intelligences. Moreover, neuroscientists, who are well aware that the mind depends on processes such as perception, attention, memory and reaction speed, have always been skeptical about the reduction of intelligence to a single unit of measurement.

So does intelligence, defined in this way, depend on genes? The answer is quite obvious: yes, of course – like everything else that the body possesses. But, like everything else, it is also determined by the environment in which the child grows up. Is it possible to understand to what extent the mind depends on genes and to what extent on the environment?

Even before the advent of modern genetics, to answer this question, scientists developed an equation of heritability (the degree of genotypic conditionality of trait variability for a population): V = G + E + (GXE), where V is trait variability, G is a genetic factor, E is an environmental factor. To put it simply, genes and the environment complement each other, and their interaction is expressed by the GXE member.

Based on this formula, as well as from comparing the IQ scores of identical and fraternal twins, psychometrists agreed to believe that heredity determines intelligence by about 50%. Robert Plomin, Mr. Gove's adviser on psychogenetics, who actively promotes this science, raises the bar to 70%. It is this figure that Mr. Cummings' report cites.

However, according to Mr. Rose, these calculations are meaningless. They are good only if there is a homogeneous environment, that is, when you study grain yields or milk yields. That's what they were created for. But the environment in which people grow up varies greatly, so it is useless to apply this formula to a person.

For example, research suggests that for middle–class families, heritability is estimated at about 70%, and for poor families, where the environment is less stable, at 10%. That is why (the environment is changing) over the past century, children of developing countries have begun to receive an average of 15 points more according to the results of IQ tests - to the surprise of determinists.

More importantly, calculations only make sense when the interaction between genes and the environment is relatively small. Forty years ago, IQ could be considered a reasonable assumption. Today, in the light of new genetic studies that have grown out of the sequencing of the human genome, it is obvious not only that behavioral traits are conditioned by many hundreds of genes, but also the interaction of the latter with the environment during the development of the organism (studied by actively developing epigenetics). Attempts to rigidly link one or another gene with a certain type of behavior have failed.

For example, one of the recent studies, in which 127 thousand people took part, was devoted to the connection of genes with school performance. It was possible to find only genes that are responsible for only 0.02% of the difference between schoolchildren on this indicator.

Mr. Plomin claims to have found something, and now the genomes of his wards are being decoded by the Beijing Institute of Genetics (PRC), the world's largest specialized institution. But Mr. Rose is sure that nothing will come out of this – just as nothing came out of numerous previous studies. In genetics, the concept of a "black hole" has even appeared, which refers precisely to the research of heredity.

Whatever intelligence ultimately turns out to be, such failures suggest that the search for genes responsible for the mind is primarily due to ideological considerations, not biological or sociological. Mr. Rose considers Mr. Cummings' proposal to find such genes and develop individual school courses for children with a particular heredity to be fantastical. This is a return to the practice that went out of use back in the 1970s, when, after finishing primary school, English children took exams that determined which course would suit them best in secondary school. Mr. Rose is convinced that genes do not determine the ability to learn and do not limit it.

Based on the materials of NewScientist: School achievement isn't just in your genes.

Portal "Eternal youth" http://vechnayamolodost.ru 22.10.2013