Study: The Nature and Nurture of Kids’ Reading Development

Reading Time: 3 minutes
This is exactly what happens at my house. You know, when we're not playing video games or watching TV. Image: Flickr/ThomasLife
This is exactly what happens at my house. You know, when we’re not playing video games or watching TV. Image: Flickr/ThomasLife

Admit it: you’re ever so slightly jealous of those glowing parents you’ve seen in infomercials gushing over their 2yo who reads Proust. In the original, for gosh sakes! A new study in the journal Child Development lets you largely off the hook. For better and for worse, your child’s reading level is not your fault. Or at least not in the “I should have read more French literature to my toddler” sense of the word fault. Instead, by the time your child reaches middle elementary school, it’s genetics and perhaps the school that determine reading level. Those summer reading programs you incentivized by buying Skylanders characters? Not so much.

To come to this somewhat predeterministic conclusion, researchers from The Ohio State University tested the environments and reading abilities of 371 twin pairs, every year for six years, from about ages 6 to 12. Then the group used something poetically named “phenotypic and genetically sensitive latent growth modeling” to turn children into bar-coded, automaton-like shells of their former selves — you know, in a statistical modeling kind of way. The inclusion of fraternal and identical twins (in this case, raised in the same environment) allowed the researchers to discover how much variance in reading level is due to genetic variance and how much to environmental differences — i.e., if identical twins read identically while fraternal twins read differently, you could say with some statistical gusto that genetics are to blame. However, if the differences are between families with different home environments and not necessarily between fraternal compared to identical twins, you could confidently blame parenting practices.

So what is nature and what is nurture in kids’ reading development?

IMHO, the answer is nothing short of stunning: genetics matter greatly. But genetics seem to matter especially after the first assessment in kindergarten. Take a second to sit with that: genetics play a late rather than an early role in a child’s reading development. The authors write:

“This suggests that the genetic influences related to how quickly or slowly a student grows in their reading skill are not the same as the genetic influences on their skill at the first assessment. In other words, some new genetic component related to growth is coming online after that first assessment wave, and it is influencing development.”

Please note that this is surprisingly comprehensible academese for researchers who use things like “phenotypic and genetically sensitive latent growth modeling.” Second, this is cool: something in the genome is turning on around kindergarten age that affects how quickly kids pick up the skill of reading. After this gene kicks in, the learning trajectories of the best readers tend to flatten and the trajectories of the worst readers tend to climb, until kids are (generally) re-sorted along the reading spectrum with little regard for their initial scores. Okay, the best readers *tend* to remain the best and the worst *tend* to remain the worst, but once kids hit school age, the influence of environment takes a major backseat to the influence of genetics.

Or, the authors point out, maybe instead of good parenting practices eventually giving way genetics as everyone regresses to the mean of their genes, this great norming of reading ability is school’s fault. The authors write that “at school entry, much of the variance in reading scores represents what has been occurring in the home.” But then kids start school and for the most part, everyone receives the same instruction. At that point “these environmental factors increase mean reading performance across all children,” the authors write. In school, it’s not only the children whose parents read to Proust in the original at bedtime who learn to read — it’s everyone. Or at least everyone is given (very generally) the same instruction and at that point, kids learn to the degree their genes permit and not to the degree you hope would be the result of years of selfless parenting.

One moral of the story is this: choose a school wisely, for while a true school will give your child reading, a false one may take it away — or at least flatten the growth trajectory of your Proust-exposed toddler.

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