Whenever an international report, such as the recent IELS study, is published, reactions quickly follow that basically amount to: “See? My solution was right all along.” I’m probably guilty of that myself from time to time. So today I wanted to try something different by putting two very different sources next to each other to broaden my perspective. Yesterday, for instance, I read an interview in the Belgian newspaper De Tijd with Nobel Prize winner James Heckman, alongside a new blog and paper from UCL researchers on genetic predisposition and social inequality.
At first sight, these seem like completely different worlds. Heckman (and IELS) talk about early childhood and development, while the other focuses on polygenic scores and genetics. But in reality, they raise the same uncomfortable question: why do we see differences between children so early? And why do these differences prove so persistent?
For years, Heckman has stressed the importance of the early years of life. You probably know his central idea: investing in young children yields strong returns, especially for vulnerable groups. Not only cognitive skills such as language and numeracy develop early, but also self-regulation, attention, motivation and perseverance. That part of his work has become highly influential, even if he himself has increasingly emphasised the importance of sustaining environments in later work.
In the interview, he goes further still. According to Heckman, the family remains the most important environment for development. He refers to research suggesting that even strong welfare states such as Denmark can only partially compensate for the influence of social background. That may sound provocative, but at the same time, there is little genuinely new about it. Since Coleman, we have known that social background is strongly associated with school success.
Yet such findings are sometimes interpreted too simplistically. Saying that families matter enormously does not automatically mean that schools matter little. It mainly means that inequality operates through many mechanisms simultaneously: language exposure, stress, expectations, health, social networks, neighbourhoods, stability, interactions… Schools never receive children as blank slates. But neither do they receive them as fully written pages.
And that is precisely where the new genetics paper becomes interesting.
The researchers examined children from both low- and high-income families with high polygenic indices for educational attainment. In short, children who, according to current genetic measures, appear to have a relatively strong predisposition towards school success. One might expect such children to follow broadly similar trajectories regardless of background.
But that is not what happened.
Even within this group, the differences remained striking. By the age of three, children from poorer and richer families already showed clear gaps in language development. By five, those gaps had grown even larger, especially in vocabulary and verbal skills. And by sixteen, the pattern resurfaced once again in high-stakes examination results.
What makes the paper particularly interesting, however, is the authors’ own caution. They repeatedly emphasise that polygenic scores are not simple measures of “innate talent”. Social processes such as assortative mating, social stratification, and the intergenerational transmission of opportunity also shape these scores. In other words, genetic predispositions do not operate separately from the environment. They are deeply entangled with it.
Yet discussions about education and development still too often fall back into old oppositions:
- nature versus nurture;
- ability versus environment;
- parents versus schools.
But modern developmental science increasingly makes it difficult to sustain such distinctions. Reality seems much more like a continuous interaction. Children do not develop independently of their context. But context also does not affect every child in exactly the same way. Differences emerge from interactions among predispositions, experiences, opportunities, expectations, and environments.
That also makes the IELS story more interesting. Perhaps the most striking thing is that differences between children become visible so early. But it is also why I remain cautious about grand statements such as “schools make little difference” or “home determines everything”. Even when they come from a Nobel Prize winner.
At the same time, it is important to recognise that education alone will never completely eliminate social inequality. The mechanisms involved are simply too broad and too deeply intertwined. But that does not mean schools are powerless either. It may simply mean we need to be more realistic about what education alone can carry.
One thing should be clear: children are not fixed by the age of five. Quite the opposite. But development from the very beginning is a complex interplay among predispositions, interactions, environments, and opportunities. That is precisely why those early years remain so important.