Being poor can suppress children's genetic potentials

Growing up poor can suppress a child's genetic potential to excel cognitively even before the age of 2, according to research from psychologists at The University of Texas at Austin.

Half of the gains that wealthier show on tests of between 10 months and 2 years of age can be attributed to their genes, the study finds. But children from poorer families, who already lag behind their peers by that age, show almost no improvements that are driven by their .

The study of 750 sets of twins by Assistant Professor Elliot Tucker-Drob does not suggest that children from wealthier families are genetically superior or smarter. They simply have more opportunities to reach their potential.

These findings go to the heart of the age-old debate about whether "nature" or "nurture" is more important to a child's development. They suggest the two work together and that the right environment can help children begin to reach their genetic potentials at a much earlier age than previously thought.

"You can't have environmental contributions to a child's development without genetics. And you can't have genetic contributions without environment," says Tucker-Drob, who is also a research associate in the university's Population Research Center. "Socioeconomic disadvantages suppress children's genetic potentials."

The study, published in the journal , was co-authored by K. Paige Harden of The University of Texas at Austin, Mijke Rhemtulla of The University of Texas at Austin and the University of British Columbia, and Eric Turkheimer and David Fask of the University of Virginia.

The researchers looked at test results from twins who had taken a version of the Bayley Scales of Infant Development at about 10 months and again at about 2 years of age. The test, which is widely used to measure early cognitive ability, asks children to perform such tasks as pulling a string to ring a bell, putting three cubes in a cup and matching pictures.

At 10 months, there was no difference in how the children from different socioeconomic backgrounds performed. By 2 years, children from high socioeconomic background scored significantly higher than those from low socioeconomic backgrounds.

In general, the 2-year-olds from poorer families performed very similarly to one another. That was true among both fraternal and identical twins, suggesting that genetic similarity was unrelated to similarities in cognitive ability. Instead, their environments determine their cognitive success.

Among 2-year-olds from wealthier families, identical twins (who share identical genetic makeups) performed very similarly to one another. But fraternal twins were not as similar — suggesting their different genetic makeups and potentials were already driving their .

"Our findings suggest that socioeconomic disparities in cognitive development start early," says Tucker-Drob. "For children from poorer homes, genetic influences on changes in cognitive ability were close to zero. For children from wealthier homes, genes accounted for about half of the variation in cognitive changes."

The study notes that wealthier parents are often able to provide better educational resources and spend more time with their children but does not examine what factors, in particular, help their children reach their genetic potentials. Tucker-Drob is planning follow-up studies to examine that question.

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More information: The study can be found at … 392926.full.pdf+html
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Jan 10, 2011
Commence speculation.....

Jan 10, 2011
My girlfriend and I teach in a poor, rural area. Both of us did a "duh!" face-palm when reading the conclusion of this article. I like the data, but this is obvious to any Pre-K or Elementary teacher.

I am excited to see more applied research on the best strategies that could be readily implemented to help mitigate this gap -- be it social or educational.

Jan 10, 2011
I am excited to see more applied research on the best strategies that could be readily implemented to help mitigate this gap -- be it social or educational.

I know I just bad mouthed speculation, but that was mostly a joke. What do you think the causes / solutions are? My completely uneducated guess would be nutrition, free time w/ parents, and possibly stress levels.

Jan 10, 2011
Its as much of a social/cultural issue as it is an educational one -- they are usually one in the same. The barriers preventing children from reaching genetic potential, or even just having access quality education, are so numerous and variable depending on socioeconomic status, culture, or geographic region. Thus, there are many possible approaches.

I like the directions that some early childhood programs are taking (something like the head-start program) but they need to be adequately staffed and funded.

The cradle-to-college approach by Harlem Children's zone is also inspirational, and I hope it can be scaled.

Jan 11, 2011
The effects of bad nutrition on gene expression aren't really that new. Might explain why there is no difference for the 10 months old group because breastfeeding is pretty identical between the socioeconomic groups.

As Skultch puts it: Commence speculation. It's very hard to have truly controlled experiments when you can't have your test subjects in controlled environments.

Jan 11, 2011
What's important is not the wealth or income of the parents but that they love and care for their children and that they try to be a good example of how one should live.

I know some poor Asian families whose children reach excellent results at school. There are many other similar examples but what is important is not the origin but a tradition which emphasizes the importance of education.

Jan 11, 2011
Are we to believe you speak from experience michael. It doesn't sound like you do.

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