Twins study reveals influence of genes and environment on academic achievement

Sally Larsen: People jump straight to that when we talk about twin studies and genetics, they jump to this idea of genetic essentialism, that somehow you can't change your genes and so there's no point trying, and that's really not what twin studies are telling us. So twin studies are telling us about potentially the proportion of an outcome that could be attributed to genetics in this particular context at this time. So they tell us what is happening now, but not about potential and what could be. And so it's really important to have that message clearly, that even if something is partly heritable, the fact is that that doesn't mean it's not changeable.

Robyn Williams: Genes are not destiny. Sally Larsen from the University of New England on their huge twin study about schooling. Also in this Science Show on RN, how to plan for driverless transport, especially in a Estonia. I thought you'd never ask. And how to unscramble an egg, and why.

So as we contemplate the struggle public schools in Australia have in recruiting pupils and teachers, and as so many go private, despite the financial strain, it's worth thinking about that huge piece of research at Armidale. This is Dr Sally Larsen, who lectures at the School of Education there.

Now, 2,700 families provided twins. Were some identical twins and some unidentical?

Sally Larsen: Yes, so we have about 40% identical twins and about 60% non-identical twins. And of the non-identical, it's a mix of both girls, both boys and some boy-girl pairs.

Robyn Williams: And they stayed with you for ten years, did they?

Sally Larsen: So overall it's been ten years, but the families, around about seven years.

Robyn Williams: Now, many of us will think that life, going to school and studying and absorbing all these things is so complex; it depends on whether you mucked up, whether you concentrated, whether you were well behaved, whether you went to a posh school, spent lots of money on private education and all that sort of thing. So many variables. But what did you find overall?

Sally Larsen: I think the main finding overall is that school achievement is like a balance of genetic influences and environmental influences. We're looking over time, and what tends to happen is that shocks in the environment will tend to balance out. So, one of the things that's good about twin studies is that you can look at the similarities between twins or the differences between twins. And notwithstanding the environmental things that we think might make a difference, those things might make a short-term difference, but over time they tend to wash out.

Robyn Williams: But what about going to a very posh school for a lot money, or the local kind of bog-ordinary public school?

Sally Larsen: Yeah, and that's another one of those things that people really strongly believe will make a huge difference to the lives of their kids. One of the studies that we've done in this particular project, we looked at the differences between groups of kids going all the way through from year three to year nine in public schools, and all the way through from year three to year nine in private schools. And what we found was that there was really no difference in the amount of progress that students made, notwithstanding the marketing around private schools being better quality. So that's one instance of where something that's in the environment is potentially not having the effect that we think it is.

Robyn Williams: Do you mean all those listeners (and we've got lots of them) who are spending $30,000, $35,000 more per annum on either Bunty or Darren are wasting their money?

Sally Larsen: Well, I think that's just up to families to decide really. I think one thing about studies like this, it gives us information on average. So on average what happens when we look at big populations or big groups of students, and so those averages show that there's lots of variability between students. But if we look at on average the progress, there's no differences in progress over time. Having said that though, for individual students, different school environments might suit them better, they might feel that a particular school environment suits that student for their particular progress, and that's something that twin studies can't necessarily tell us about.

Robyn Williams: No, but if you had a collection, and I'm sure you did in your figures, of one twin who went to a private school and one who did the public course, in general what did you find? Who did better?

Sally Larsen: I think, in general, particularly for identical twins, there'd be very little difference at the end of their schooling career, that notwithstanding those different schools, that that wouldn't make a great deal of difference. And we did talk to some parents of identical twins, and these identical twins who had done really differently at school, so were persistently quite different in their reading or numeracy results, and different schools attended often came as a consequence of that difference rather than a cause. So parents could identify differences in personality between identical twins that they had observed since the twins were very small, or differences in interests, or on occasion one twin would have had some kind of medical problem that the other twin didn't, and those were the sorts of things that parents observed had caused the differences in academic achievement, and that in those cases sometimes twins did go to different schools. But for the large majority of the twins, even if they've attended different schools or been in different classrooms, particularly identical twins come out the end very similar.

Robyn Williams: Very similar indeed. Well, one wonders, if you've got identical twins and they seem to have different personalities as they're growing up, it just shows you how complex the influences might be, because they're all…wherever they are, even if they are on the other side of the room, the same room, they're having a different experience. So those sorts of things do impact.

Sally Larsen: Yes, absolutely. And as I've said, twin studies will give you information about averages, but for those individual perceptual experiences, we do know from twin studies that twins, even if they're in the same objective environment, say they're in the same family or in the same school classroom, they can experience that environment differently. And so we can only find that out by actually asking the twins themselves. So other twin studies have done this, we didn't get the opportunity to do that, but it is a phenomenon in twin studies that even though we say we've provided the same environment to these twins, why have they turned out differently, sometimes that's differences in perception that are really hard to pin down.

Robyn Williams: Now, you have no other comparison, as far as I can tell, for a study in Australia, but overseas they've done similar sorts of things. Have they reached the same conclusions as you have?

Sally Larsen: Largely yes, they do find similar conclusions to what we find. Particularly there's a big study in the UK called the Twins Early Development Study, and we do find similar results to them in terms of academic achievement. So what we find is that on average, say, for example, reading might be 60% heritable, and so people when they hear that figure and they see summaries of this research that shows that different locations come with the same sorts of results, they sort of jump immediately to, well, it's genes and I can't do anything about it. But the thing that I've discovered about twin studies along the way is that heritability statistic doesn't necessarily mean it's inherited.

Robyn Williams: Hang on! That was a conjuring trick.

Sally Larsen: Yes, I know, and it's a terminological problem. And that's a problem with a lot of scientific domains, they have this specific terminology that's in layperson language, and it doesn't mean the same thing.

Robyn Williams: What do you then decide…now, I've made you over the last few seconds Minister for Education, okay, you have total control now of the development of, let's say, secondary education in Australia for the next 20 years. What would you recommend?

Sally Larsen: I think one thing we have written about in terms of policy is the idea of how do we support students that struggle with academic domains? And so what we see often is that policy will say, all right, we'll provide funding to schools if they have a proportion of students with learning difficulties or learning disabilities. Often that funding doesn't go directly towards the student. So in terms of supporting students with learning difficulties, it's probably going to be more effective to direct the funding to the student rather than the school, because if you do a school-level intervention, say you go in and you say, okay, we're going to get lots of iPads and that's going to help students with learning difficulties, it probably won't. So what you need to do is think about how you can intervene for those specific students, depending on what their learning difficulty or disability is. Now, that's really complicated because it's quite expensive to do. But in terms of supporting students with learning difficulties, that's something we've written about in this study.

Robyn Williams: Does that make sense to you as an ex-teacher?

Sally Larsen: It certainly does, yes, because as a school teacher you're teaching a class of students, you might not have the personal resources or the time to then go and support those students who are struggling to the extent that you can. So additional support for students that require additional support would be super, super helpful.

Robyn Williams: Dr Sally Larsen with a glance of that huge twin study just published by the University of New England. So the message is fund your teachers and public schools to get results, and genes are not destiny. Much more in that report.