Good teachers help students to realise their genetic potential at reading

By Ed Yong | April 23, 2010 5:11 am

Teacher_writing_on_a_BlackboardGenetic studies suggest that genes have a big influence on a child’s reading ability. Twins, for example, tend to share similar reading skills regardless of whether they share the same teacher. On the other hand, other studies have found that the quality of teaching that a child receives also has a big impact on their fluency with the written word. How can we make sense of these apparently conflicting results? Which is more important for a child’s ability to read: the genes they inherit from their parents, or the quality of the teaching they receive?

According to a new study, the answer, perhaps unsurprisingly, is both. Genes do have a strong effect on a child’s reading ability, but good teaching is vital for helping them to realise that potential. In classes with poor teachers, all the kids suffer regardless of the innate abilities bestowed by their genes. In classes with excellent teachers, the true variation between the children becomes clearer and their genetic differences come to the fore. Only with good teaching do children with the greatest natural abilities reach their true potential.

This study demonstrates yet again how tired the “nature versus nurture” debate is. As I wrote about recently in New Scientist, nature and nurture are not conflicting forces, but partners that work together to influence our behaviour.

This latest choreography of genes and environment was decoded by Jeanette Taylor from Florida State University. She studied over 800 pairs of Florida twins in the first and second grades. Of the pairs, 280 are identical twins who share 100% of their DNA, and 526 are non-identical twins who share just 50% of their DNA. These twin studies are commonly used to understand the genetic influences of behaviour. If a trait is strongly affected by genes, then the variation in that trait should be less pronounced in the identical twins than the non-identical ones.

Florida just happens to collects data on the reading skills of its young children, using a test called the Oral Reading Fluency (ORF) test. The twins’ scores told Taylor how good they were at reading, and the improvement in the scores of their classmates told her how good their teachers were. Crunching the numbers, Taylor found that genes influenced around half of the variation in reading scores (47%), while shared environments (like a common household) accounts for 37% and non-shared environments accounted for 16%.

Teaching_genetic_readingGenes are clearly important, but teaching mattered too. At the highest echelons of teaching quality, genes explained around 70% of the variance in reading scores. At the lowest troughs, they only accounted for around 30%.

Taylor confirmed the effect of teaching quality in a couple of different ways. She took a sample of 42 pairs of identical twins and found that those whose reading skills were below average did indeed have poorer teachers than those with above-average skills. She also looked at 216 pairs of identical twins, where each twin had a different teacher. Among these children, the difference in quality between their teachers strongly predicted the difference in their reading abilities.

These results are somewhat different to previous genetic studies, which found that around 65% of the variation in children’s reading skills can be explained by genetic factors. These same studies have suggested that outside influences, like family and school, are far less important – the genes are at the wheel, and the environment is in the backseat shouting instructions.

But Taylor says that the twins in these earlier studies often came from similar and wealthy backgrounds. If they all get similar educations, that would mask the effect of teaching. So she deliberately set out to recruit twins from a wide variety of ethnic groups and social backgrounds. A third were Hispanic, a third were white, and around a quarter were black. Half of the children came from families that qualified for free lunches on the grounds of low income.

There are many caveats to the study, which Taylor herself lists. The reading improvements of a classroom may reflect the school, students or resources, as well as the quality of teaching. You might see different results if you used different measures of teaching quality (like class observations), or of reading skill. The effect of teaching quality might also be different in higher education, or in richer schools.

Nonetheless, Taylor’s work does demonstrate that poor teaching constricts genetic variation in reading ability so that it never germinates. Only in the light of quality teaching does that variation bloom. Teachers should be pleased with the result, for, as Taylor says, “Reading will not develop optimally in the absence of effective instruction.” Likewise, putting really good teachers into a classroom won’t magically make all the students into literary Jedis, and (contrary to what some parents expect) it won’t benefit all students equally.

I wrote about something similar in my New Scientist piece – a variant of the MAOA gene can lead to aggressive behaviour, but only in people who were raised in abusive environments. Again, the environment sets the stage in which genetic actors can express themselves.

Reference: Science 10.1126/science.1186149

Image: by Tostie14

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Comments (11)

  1. sounds interesting. the only thing i can think of is if there is some correlation between perceptions of students, and which teachers they get sent to. for example, not to put a too fine a point on it, but in elementary school we had two tracks, one for smart kids and one for dumb. the dumb kids track classes were always staffed by the dumber teacher (1 half day out of the week we’d switch teachers, and it was invariably obvious that the kids tracked into the less academic trough had the duller teacher). i doubt this can explain these findings though since i doubt florida’s program would be so systematic.

  2. Jan

    oral reading fluency only measures the number words read (WCPM) correctly per minute on a one minute timed test. It’s not a very thorough assessment…

  3. Simfish InquilineKea

    Quite interesting. It seems that in most schools/subjects, the gap widens even with poor teachers – since the smart students can self-study or their parents pursue additional resources for them. But this is 1st/2nd grade reading.

  4. Interesting. I’m troubled by some of the way this is expressed, although I know what you’re trying to say. If all of the environmental factors are balanced by good teaching, then the variation that’s left is much better explained by genetic variation. The genetic variation is always there (it doesn’t have to germinate…), but its effects may be compounded with other factors.

    Oral fluency sounds like a good measure, actually, because it’s open-ended; lots of measures are subject to floor and ceiling effects.

    Only with good teaching do children with the greatest natural abilities reach their true potential.

    Well, I’d read that slightly differently: good teaching benefits everyone, and helps everyone reach their reading potential. The difference made by good teaching to a poor reader may make a huge difference to their performance.

    (disclaimer: am reading as mother of dyslexic daughter – deeply depressed by the focus on high achievement, even if that’s exactly how I used to think)

  5. jdmimic

    This study is good for helping explain to people that teachers can not be blamed for every student that fails, but good teachers do make a difference.
    However, I would have thought it patently obvious by now that genetics can only set parameters of performance, genes determine potential. The environment determines how much of that potential is reached. The smartest person in the world will not prosper intellectually if beaten, deprived of decent food, and denied access to informative material. Surely everyone knows this by now? Are people really still debating this?

  6. Springs Alive Children’s Centre(SPACC) has some international schools we are having collaboration with but havenot really figured out a project to do with them,we even have signed Memorandum of Understanding with them.
    If we can have projects that SPACC can have with each of these schools for the benefit of either the children,teachers or our communities then please pass on those ideas we see how to set the ball-rolling.
    Our schools’ cooperations need to be kept alive
    Thanks alot

  7. Briana

    jdmimic: my thoughts exactly. In a psychology textbook I had for a psych 101 class, it had a chapter devoted to this, saying it was both but there was some debate still going just because the idea of genes dictating life is so strong (this was in 2003). But if the official word was “both” in a textbook, I thought the debate was pretty much over. Maybe now that the whole epi-genetics idea is starting up, that genes can be altered during the course of ones lifetime by the environment, we’ll get some more balance. Or at least the realization that things are always more complicated than we give credit for (which I thought THAT debate was over too haha).

  8. Preston

    It would be truly wonderful if research like this focused on dyslexia and dyscalculia. A treatment would be ideal, but just knowing that the child had a higher-than-normal risk would help the family and teachers choose teaching strategies.

    Children have enough to go through without being surrounded by baffled adults unintentionally making things worse.

    There is a potential downside that worries me. I would not want a perceived “biological ceiling” to achievement. I would not want an excuse for the educational abandonment of a child.

  9. gillt

    Young: “If they all get similar educations, that would mask the effect of teaching. So she deliberately set out to recruit twins from a wide variety of ethnic groups and social backgrounds.”

    That doesn’t make any sense to me. The author it seems is adding more unaccounted for variables, which could explain the different results.

  10. gcochran

    “Reading will not develop optimally in the absence of effective instruction.”

    I doubt if this is the case at the highest levels of proficiency. My daughter taught herself to read at age 3: should she have waited ?

  11. This is truly an informative article. Genes are in one way or another play a big part on how children can read. I just wonder how a good teacher copes up with those students who have ADHD and reading disabilities. I agree that those who usually handle them are those who are trained to do so but sometimes teaching kids goes beyond what is in text books. A teacher who has the heart to teach others the joy of reading will benefit from the knowledge that they are making a large contribution to molding young minds in the right direction.

    Having the knowledge that genes as its way of influencing the pace of how a person can easily or have a hard time reading one can only wonders if what will works best.

    Having a highly skilled teacher can make all the difference in the world even in just helping those who have a hard time learning move even an inch better in improving themselves. Some people who have the affluence may have the edge because they have better resources to give themselves the right care and nourishment while the baby is still in the womb. The right vitamins and minerals given to a growing baby inside the womb and outside can help create a better brain.

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