Last summer I went to the prize-giving at a school in the country. Very few of the absurdly tall and elegant teenagers receiving heavy books and shiny plaques were being cited for just one quality. Some had, it seemed, run for their counties, played the oboe to concert level, achieved field marshal rank in the school cadets and saved several African villages from drought. And they were so polite.

That their ascent up the ladder of achievement had started early was obvious from watching their happy parents, as they sipped wine on the lawn afterwards. The parents had, many of them, done most of the things that they could and been all the things that they had to be, in order to reach this point on this warm day, their children poised balletically for flight into the adult world.

But what were these things? Yesterday the University of London’s Centre for Longitudinal Studies (based at the Institute of Education) published its outline findings into the attainment of a cohort of 15,500 children born between 2000 and 2002. The study found that by the time that the kids were three years old the offspring of graduate parents were ten months ahead of children from relatively unqualified parents in vocabulary, and a year ahead in their comprehension of sizes, shapes, colours, letters and numbers. And while this may be an expected advantage, it is still a hell of a gap to have opened up at such a young age.

Gender made a difference, the girls being on average three months ahead of the boys (which doesn’t matter, because by the time you grow up and become, say, a newspaper columnist, the gap has all but closed, apparently). But for the rest, there could only be speculation as to exactly why such a gulf had opened up. The Guardian credited wealth and class as being behind the figures. Heather Joshi, of the institute, cautiously suggested that there was a connection with poverty or family income. In the days of Dr Eysenck we would doubtless have had the link made between IQ and genetics.

There were some intriguing possible clues in the way in which different groups measured up.

Children from Bangladeshi families were a year behind white children in tests measuring “school readiness”; West Indian and African children were six times more likely than whites to be behind. But Scottish children were two months ahead of the UK average in “school readiness”. Professor Joshi provisionally accounted for some of this by suggesting that some immigrant households had mothers who couldn’t go to work, and the children therefore missed out on the benefits of childminders and nurseries.

But why would money buy a two-year-old an understanding of shapes and colours? Why would a nursery give the same child an expanded word-hoard? If we were to take £10,000 a year from the wealthy and simply give it to the families of the most “backward” of these children, would we expect a dramatic change in their vocabularies at 3?

Also yesterday we discovered that, notwithstanding the superior school readiness of the Scots kids, their country was bottom of the Federation of Small Businesses’ annual index of wealth, comparing ten similar-sized countries in terms of economic performance and lifestyle. This position, it turned out, was almost entirely due to the poor health suffered by the average Scot.

Again: why? Why do Scots die when Sassenachs live? On the Today programme the writer and musician Pat Kane suggested that this was partly due to the “legacy of early industrialisation”and partly Scottish depression caused by not running their own separate country. Give the people independence, he seemed to be suggesting, and watch the heart patients throw away their stents and power-walk.

This was a fun idea. But also yesterday, the Institute of Education published a childhood obesity study using the same cohort. This showed that one quarter of three-year-olds were overweight, but that there were dramatic variations between ethnic groups. Nine per cent of Indian children were overweight, compared with a quarter of whites and a third of African and Caribbean children. The Scots did better than the Welsh.

Why would Indians be less depressed about having a say in society than whites? Or does Scottish nationalism somehow unconsciously ape the cultural conditions of Hinduism?

The reason why some children do far better than others is obvious from the walk home from school. It was clear to me the moment one parent in my daughter’s class complained that her six-year-old son, to whom she gave Coca-Cola just before he arrived in school, was in no condition to do the boring reading that the school expected them to accomplish together in the evenings. Boys play football, she announced.

Babies need to be talked to, toddlers need to be read to, children need to be considered. Kids need to be fed decent food. Except in instances of dire poverty, money itself is rarely the explanation as to why these things don’t happen. Perhaps one reason for the growing advantage of the middle classes is not that they are richer, but that they assimilate better all the dire warnings about face-time, junk food and smoking. None of it is a mystery, Pat – watch the Scottish mortality statistics improve as a consequence of the year-old smoking ban.

So it’s about culture. Last weekend I was forced by my ten-year-old to see a witless Hollywood comedy about a black journalist who moves his step-family to the countryside. Had the film been about a white middle-class family then I think it unlikely that the 12-year-old son would have been depicted eating Pop-Tarts for breakfast, or that the father’s useless and macho attempts at parenting would have been so sympathetically portrayed. “This,” the film seemed to be suggesting, “is how we do it.” And a bad, bad way it was.

There are too many families who don’t have books in the house, who don’t limit TV watching, who don’t set boundaries, who don't set their children an example. There are too many families who don’t or can’t care that much about their very young children. Maybe they don’t care because they weren’t cared about. Perhaps such cultural poverty is as much a cause of actual poverty as a consequence.

This illustrates the need for early intervention, which is quite another column. But, crudely, the message of these studies is that we should now pay the Scots to bring up our children, but let the Indians feed them.

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