By Brian Byrne, Katrina Grasby and Richard Olson for The Conversation.
Some interpret this as meaning there is little that can be done to help those who struggle academically – and that spending extra money on these students to help them succeed is pointless.
But is this the case?
A major misconception is that genes are destiny. This is wrong because genes are never the full story.
This is because environmental factors (“nurture”) also play a role in levels of academic achievement. Well-designed and well-delivered remediation can also help struggling students even in cases where genetic factors (“nature”) may be the source of the difficulties.
What we know about genetic influence.
We know about strong genetic influences on academic skills primarily through the use of the twin method.
This is where the genetic makeup of identical twins is compared with non-identical twins. Evidence of genetic influence emerges if identical twins are more alike in terms of academic performance than non-identical (“fraternal”) twins.
Identical twins share all their genes, “fraternal” twins share half of their genes, but both types share homes and schools.
So researchers can estimate the degree to which genes affect academic achievement over and above the effects of homes and schools: that is, they can estimate how much ability is inherited. And because non-identical twins can be opposite-sex, researchers can also identify if nature and nurture play out differently with males and females.
For the most part the same genes appear to affect boys and girls, and in general gender effects are in danger of being exaggerated in public discourse.
Studies with twin children have been conducted worldwide, including in Australia, the US, the UK, continental Europe, Asia, and Africa, with an emphasis on the core areas of literacy and numeracy.
Estimates of genetic influence vary somewhat among subjects and locations, but range from near 50% to as high as 80%. The studies have used standardised tests as well as school-administered tests.
Less is known about creative and technical subjects, where particular talents clearly exist.
What about environmental influence?
Twin studies can also parse environmental influence into factors that twin children mostly share, such as home socio-economic status (SES) and school attended. There are also those that are unique to each child in a twin, such as illnesses and, often enough, separate teachers.
Contrary to many people’s expectations, some shared factors such as family SES and school attended are relatively minor influences on student differences once genetic endowment has been taken into consideration.
It is important to note, however, that some groups may show lower average levels of achievement due to adverse environmental circumstances such as poorer rates of school attendance and retention.
Other groups may be affected by unusual environments, such as heavy metal contamination from mining and metals processing, which can be associated with lower NAPLAN scores.
What works are well-designed, well-delivered and timely interventions that can help struggling children to reach or more closely approach normal-range levels.
These interventions are usually designed for individuals or small groups but have proven successful when implemented at school district level.
We do not claim that compensating for genetic disadvantage is easy, but with the right frame of mind and sustained help with an emphasis on how the alphabet represents the sounds of speech, plus supported reading practice, progress is real and rewarding.
This is why the conclusion that strong genetic influence makes additional spending pointless is too pessimistic.
It could be argued that if some children struggling with literacy or numeracy are doing so because of constraints on learning with biological origins, then extra funding delivered to these children is exactly what is needed.
This is especially so if we wish to counter increasing gaps between the best - and worst -performing students.
Implications for the teaching profession
Some teachers have been reluctant to acknowledge the role of genes in school performance, perhaps because of an aversion to biological explanations - so-called “biological determinism” - and perhaps because of the false impression that if genes matter, teachers don’t.
Among other consequences, this has meant an overemphasis on the role of teacher skill and dedication in determining why some students prosper and others struggle.
There is direct evidence from twins that teacher differences are not responsible for much in the way of student differences in literacy. So teachers do matter in that they are the reasons why children know more at the end of the year or even the day. But our teachers are more uniformly effective than many give them credit for.
The Colorado story
It is unfortunate that in some education systems, such as in Colorado in the US, teacher employment and remuneration are tied to evaluations that give undue weight to student progress.
This ignores the fact that some students struggle because of biological constraints on learning that can be overcome to an encouraging degree, but only with special and adequate resources.
In the US, teacher morale is at an all time low, and in other places, including Australia, teachers are blamed by many in the media and politics.
What is needed
We need a more nuanced understanding of the factors that influence academic achievement, including the role that genes play.
At the same time, we need to avoid the unwarranted pessimism that can accompany acknowledgement of genetic influence, a danger that applies not only to attitudes toward academic development but to mental and physical health as well.
We need to take comfort from the existence of scientifically-grounded interventions, which in the hands of teachers with sufficient resources, can make a difference to the prospects of students who initially find the going in particular subjects tough.
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