Educators have struggled in vain to establish a simple, direct predictor of academic success: the IQ score, the standardized test result, and (most recently) “grit,” a measure of sustained effort and interest. Perhaps educators would do better to consider a composite score, one that takes into account as many as 20,000 factors. These factors are genetic. For example, it is possible to assess DNA variants called single nucleotide polymorphisms (SNPs). Such variants say little individually. Together, however, they can explain almost 10% of the differences in educational attainment among young students.
This finding, offered by scientists based at King’s College London, comes at an opportune time. Of late, there has been a lot of debate over the value of grit as a means of predicting educational attainments and, incidentally, defining educational interventions. Recent conference presentations and journal articles have suggested that the significance of grit has been greatly overstated.
“Nobody wants to hear that success in life is made up of many small factors that all add up,” said Marcus Credé, an associate professor of psychology at the University of Iowa and the author of a grit-skeptical study in the Journal of Personality and Social Psychology. “It’s your education, it’s how hard you work, it’s your conscientious and creativity—all these little pieces that add up. We want to be told here's one big thing that explains everything.”
Crede, however, did not mention the “little pieces” called SNPs. To find these, it is necessary to do genome-wide association studies (GWASs), which find specific genetic variants linked to particular traits. Most often, GWASs look at traits such as susceptibility to disease, as a means of defining personalized medical interventions. But GWASs can also look at academic achievement. They may also succeed as a means of defining personalized educational interventions.
To explore this possibility, the King’s scientists carried out a GWAS that examined almost 10 million SNPs and identified 74 genetic variants that were significantly associated with years of completed education. “Years of education” was used as a proxy measure for education achievement and related traits.
The King’s scientists presented their results July 19 in the journal Molecular Psychiatry, in an article entitled, “Predicting educational achievement from DNA.” The article explained how the scientists used a genome-wide polygenic score (GPS) to predict academic achievement from DNA alone.
“Here, we tested the association between this latest EduYears GPS and educational achievement scores at ages 7, 12, and 16 in an independent sample of 5,825 UK individuals,” wrote the article’s authors. “We found that EduYears GPS explained greater amounts of variance in educational achievement over time, up to 9% at age 16, accounting for 15% of the heritable variance. This is the strongest GPS prediction to date for quantitative behavioral traits.”
As human traits are so complex and influenced by thousands of gene variants of very small effect, it is useful to consider the joint effects of all of these trait-associated variants. It is this principle that underlies the polygenic score method. Some genetic variants are more strongly associated with a particular trait, and some are less strongly associated. In a polygenic score, the effects of these variants are weighed by the strength of association and then summed to a score, so that people with many variants related to academic achievement will have a higher polygenic score and higher academic achievement, whereas people with fewer associated variants will have a lower score and lower levels of academic achievement.
In the current study, on average, those with a higher polygenic score would obtain a grade between A and B, whereas those with a lower score obtained an entire grade below in terms of GCSE scores at age 16. As well as this, 65 % of people in the higher polygenic group went on to do A-levels, whereas only 35% from the lower group did so.
Saskia Selzam, first author from the MRC Social, Genetic & Developmental Psychiatry (SGDP) Centre at King's, said: 'We believe that, very soon, polygenic scores will be used to identify individuals who are at greater risk of having learning difficulties.
“Through polygenic scoring, we found that almost 10% of the differences between children's achievement is due to DNA alone. [It] is a lot better than we usually do in predicting behavior. For instance, when we think about differences between boys and girls in maths, gender explains around 1% of the variance. Another example is 'grit', which describes the perseverance of an individual, and only predicts around 5% of the variance in educational achievement.”
Professor Robert Plomin, senior author of the study, also from the MRC SGDP Centre at King's, added: “We are at a tipping point for predicting individuals’ educational strengths and weaknesses from their DNA.
“Polygenic scores could be used to give us information about whether a child may develop learning problems later on, and these details could guide additional support that is tailored to a child's individual needs. We believe personalized support of this nature could help to prevent later developmental difficulties.”