Letter written to the New Statesman in response to ‘The IQ Trap’ by Philip Ball

After reading Philip Ball’s article The IQ Trap (13-19 April) I am more confused than ever about the argument over the role of genetics in intelligence. At one moment the point is made that ‘the information available from sequencing a person’s genome... can be used to make predictions about their potential to achieve academic success’ – then: ‘there’s rather little in your genetic make-up that fixes traits or behaviour with any clarity.’ And further: ‘When it comes to behavioural traits such as intelligence, prediction from genes is unclear.’

This point is clarified by recognising that the environment influences genes – so they can be ‘activated or suppressed’.

Then we have: ‘there are no genes “for” intelligence [etc]... although some genes affect those things.’ However: from twin studies and DNA analysis ‘intelligence is strongly heritable’, with ‘around 50% of variations in intelligence between individuals [that] can be ascribed to genes. ‘

Note: ‘strongly’ and 50% (though ‘of variations’ probably renders this pretty meaningless But Ball goes on: apparently we cannot easily identify which genes are involved because it means ‘spotting very small effects.’

Nevertheless ‘GPS can now be used to make [a fair prediction] about intelligence’ even though in Plomin’s study ‘the young person with the second highest GPS for intelligence achieved results only slightly above average... [because] ‘environmental factors still play a role.’

So, ‘the era of genetic forecasting of intelligence is... already upon us.’ Really? There are so many caveats that have been passed over on the way to this conclusion that I wondered if Philip Ball was really convinced of any of this. As for me, I’m confused!

I found much more clarity and consistency in two other articles:

(1) Ian Sample (Guardian May 22^nd 2017) comments on a study by Professor Danielle Posthuma, a statistical geneticist at the Free University of Amsterdam, who led the study published in Nature Genetics.: ‘It is thought that hundreds, if not thousands, of genes play a role in human intelligence, with most contributing only a minuscule amount to a person’s cognitive prowess. The vast majority have yet to be found, and those that have do not have a huge impact. Taken together, all of the genes identified in the latest study explain only about 5% of the variation in people’s IQs, the scientists found...

Eventually, the work may reach a point where the genomes of IVF embryos could be used to rank them according to their intellectual potential, even if the difference is so small as to be insignificant...’

(2) An Editorial in The Guardian (1^st April 2018) arguing that Plomin’s ‘latest paper claimed “differences in exam performance between pupils attending selective and non-selective schools mirror the genetic differences between them”. With such a billing the work was predictably greeted by a raft of absurd claims about “genetics determining academic success”. What the research revealed was the rather less surprising result: the educational benefits of selective schools largely disappear once pupils’ innate ability and socio-economic background were taken into account. It is a glimpse of the blindingly obvious – and there’s nothing to back strongly either a hereditary or environmental argument.’

This letter is getting much too long, but I must comment on Ball’s extraordinary comment: ‘why genes have acquired this deterministic, and therefore ominous, aura isn’t clear.’ To anyone aware of the uses to which genetics have been put in the heated argument over race and intelligence (Jensen), and the mis-use of twin studies in early (also heated) arguments about grammar schools,(Sir Cyril Burt) it comes as no surprise. Sadly, ‘science’ will only too often be distorted for ideological ends.

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