Reading ability: nature or nurture?
For whosoever hath, to him shall be given, and he shall have more abundance: but whosoever hath not, from him shall be taken away even that he hath.
The Matthew Effect has become something of a truism. Those with find it easy to acquire more, whereas those without are trapped into a vicious cycle of poverty and disadvantage. Clearly this is a matter of social injustice: if only we could ensure that all were treated equally then we could do away with such asymmetry. This is something I’ve been particularly interested in ever since hearing Geoff Barton refer to Daniel Rigney’s book, The Matthew Effect: How Advantage Begets Further Advantage. In it Rigney summarises the work of Keith Stanovich and discusses how reading ability depends on social advantage.
This seemed to make perfect sense and I accepted it uncritically. (My post on this is the second result suggested by Google when you search for the Matthew Effect.) But as ever, comforting, convenient answers aren’t always as correct as we’d wish them to be.
Following a recommendation from Andrew Sabisky I’ve been reading Kathryn Asbury and Robert Plomin’s G is for Genes: The Impact of Genetics on Education and Achievement, and it has presented some new and troubling (to me) information. Asbury estimates that heritability accounts for between 60-80% of reading ability. (p. 24) This leaves as little as 20% down to the nurturing effects of our environments. While it’s not really possible to point out such percentages in individuals, twin studies across three continents have allowed researchers to estimate the genetic and environmental influences on reading for population groups.
Admittedly, this is horribly oversimplified, and Asbury says:
Genetic variation exists from the moment we are born, but is multiplied and magnified as our genes interact with each other and our environment. It is likely that some environmental effects are hidden within our heritably estimates because they are effective indirectly, via their interplay with genes. (P. 27)
The example offered to illustrate this interplay comes from this study. Researchers compared children’s reading ability in Colorado, New South Wales and Scandinavia. In each of these territories there are different environmental factors at play. In both America and Australia children are required to attend school from the age of 5. In New South Wales, children attend school from 9-3 every day and the state mandates that 35% of this time be devoted to centrally directed literacy instruction, but in Colorado, children only attend kindergarten for 3-4 hours a day and the curriculum is left entirely in the hands of individual schools. In Scandinavian countries children do not begin reading instruction until the age of 7. Unsurprisingly, researchers found enormous differences between the interplay of genetic and environmental factors:
But, after each of the different population groups had received 1 year of reading instruction, differences largely disappeared:
When environmental factors are broadly similar, genes account for the vast majority of the difference in reading ability. And very interestingly, shared environment (growing up in the same household with the same parental influences) practically vanishes as a source of influence.
This is deeply counterintuitive. As Asbury puts it, “More school – that is, more environmental input – leads to greater genetic influence rather than greater environmental influence.” (p. 28) As children’s environmental influences become more similar, genetic differences become more noticeable.
Reading is unnatural and, genetically speaking, a very recent development in human communication. We all pick up speech without formal instruction, but nobody just learns to read, no matter how genetically predisposed they might be having a high reading ability. So if we look at samples of children before they have begun to receive formal reading instruction at school it seems reasonable to infer that the greater part of their reading ability comes from their environments. Parents who value reading and read to their children are more likely to have children who can read. The ad hoc reading instruction in Colorado results in some non-shared environmental reading influence whereas the lack of any formal instruction in Scandinavia before the age of 7 suggests that reading ability is most likely attributable to shared environmental influences.
But, education is the great leveler. When all children have received similar reading instruction, the differences between them are explained by genetic influences, resulting in a bell curve with a normal distribution of reading ability:
This goes to show the huge importance of non-shared environmental influence (schooling) has. While the differences between children are mainly accounted for by genetic influences, education accounts for the fact that children learning to read is not left to chance. Although schools cannot eliminate these genetic differences, they can attempt to move the entire bell curve further to the right. “Genes, and therefore human potential, cannot grow in a vacuum.” (P. 30)
This is, I think, cause for some optimism. All children are different. We each have our own gifts, talents and potential, and no two people are exactly alike. But school provides – or should provide – the opportunity for all children to excel to the best of their ability. We cannot all be geniuses, we cannot all be wonderful readers, but we can all be better (and often significantly better) than we currently are. This then is the power and the possibility of the growth mindset. Blaming or rewarding children for their genetic inheritance is clearly ludicrous, but demonstrating that hard work, effort, practice and a willingness to learn from making mistakes allow us to achieve our genetic potential is a much fairer approach to take.
I’m only half way through G is for Gene and am finding it a challenging read; there are some aspects and conclusions of which I’m sceptical, but books which challenge our assumption are the only ones really worth reading.
Also, Assessment, Standards and the Bell Curve from Tom Sherrington