Menus Subscribe Search

Follow us


Genes Are Us

book-math

(Photo: Syda Productions/Shutterstock)

How and Why Does the Social Become Biological?

• August 01, 2014 • 4:00 AM

(Photo: Syda Productions/Shutterstock)

To get closer to an answer, it’s helpful to look at two things we’ve taught ourselves over time: reading and math.

Every Friday this month we’ll be taking a look at the relationship between the social and the biological—specifically, how and why the former becomes the latter. Check back each week for a new installment.

It’s one of the most irresistible and controversial questions in science: “How and why does the social become biological?” The classic mind-body split is something we feel intuitively, a distinction between our “biology”—our anatomy or our physical health—and our social, decision-making minds. So it can be jarring to hear claims like this: “People differ in their intelligence, personality, and behavior, and a century of research in behavioral genetics leaves little doubt that some of this variation is caused by differences in their genomes.” No matter where we look, we always find the influence of genetics—the social is never entirely free of the biological. But what does it really mean to say that social or mental traits are influenced by genes?

Consider two traits that didn’t evolve “naturally,” but rather were completely invented by humans: the ability to read and do mathematics. Last month, a consortium of scientists sponsored by the Wellcome Trust published a study showing that “the correlation between reading and mathematics ability at age twelve has a substantial genetic component.” In other words, reading and math abilities aren’t merely the result of a decision to work hard at them, or an opportunity to learn; they also depend on DNA.

Genetic distinctions affect every chemical process in our cells, and because absolutely nothing we do happens without some cell chemistry, everything about us is potentially influenced by genetic variation.

In one sense, this is trivially obvious. The reason that children learn to read and chimpanzees don’t has nothing to do with the chimps’ lack of educational opportunities; it’s entirely genetic. The physical nature of our brains allows us to develop mental skills that are hopelessly out of reach for other animals.

But when we say a mental trait is influenced by genetics, we clearly mean more than that; we’re also making a statement about the role of genetic differences among people. Learning to read and do math involves some very complex brain biology. New links are made between different specialized areas of the brain, and old parts are re-purposed to engage in something that human brains didn’t do until relatively recently. All of this brain rewiring depends intimately on the chemistry of our neural cells, chemistry that is subtly altered by thousands of genetic differences that change the properties of the molecules involved. Unlike the precision engineering that goes into the latest Intel chip, the human brain’s process tolerances are rather wide—nearly all of our molecular parts show some variation among the human population.

Genetic variation is an unavoidable and central fact of biology, and it is at the heart of the relationship between the social and the biological. There never was a master copy of the human genome; species nearly always exist as populations of genetically varied individuals. These genetic distinctions affect every chemical process in our cells, and because absolutely nothing we do happens without some cell chemistry, everything about us is potentially influenced by genetic variation.

The Wellcome Trust researchers studied the influence of genetic variation on math and reading skills, and the correlation between them. Using data collected from nearly 3,000 sets of twins who had taken standard reading and math tests, they used two methods to examine the role of genetics.

In the first method, they searched directly for an association between a specific DNA difference and scores on tests for math or reading. The idea behind this is fairly simple: Consider a place in the human genome where people differ—some people may have the chemical letter “A,” while others have “G.” Do people with an “A” have, on average, higher test scores than those with a “G?” You repeat this test for thousands or millions of different places in the genome and find the DNA differences with the strongest association. In practice, scientists don’t merely compare the averages of “A” versus “G”; they use a more powerful statistical procedure, but the point is the same: to find specific genetic variants that correlate with differences in test scores.

The second approach, using the resemblance between twins, is more indirect—it doesn’t involve knowing any of the actual DNA differences involved. Since twins share a common family environment, but identical twins are closer genetically than fraternal twins, it’s possible to quantify the genetic and environmental influences on a trait without saying specifically what those influences are.

From these analyses, the researchers came away with three big results that nicely illustrate what it means to say that a behavioral or mental trait has a genetic component. First, the twin analysis showed that genetics explains many of the differences in reading and math test scores in the studied population. But the researchers were unable to find any reproducible association between any specific DNA difference and reading and math ability, suggesting that the total genetic effect is the cumulative result of small changes in many different genes. And finally, they found that not only were reading and math scores influenced by genetics, but also that the correlation between reading and math scores showed a strong genetic influence, suggesting that these skills are influenced by “generalist genes.”

What is a “generalist gene”? The idea, proposed years ago by Robert Plomin, one of the study authors, and Yulia Kovas, is that many of the genes involved in cognitive processes don’t have highly specialized roles limited to one part of the brain. Instead, each generalist gene influences many different brain processes, and conversely, each brain process is the combined result of many different genes. Hence, common genetic variation in any one gene will have only a small effect, but on many different traits at the same time.

Importantly, genetic studies like this one also say something about the importance of the environment. The authors argue that “our results highlight the potential role of the learning environment in contributing to differences in a child’s cognitive abilities at age twelve.” They’re suggesting that when a child’s reading and math abilities—which should be correlated—diverge from each other, there is an opportunity to make a productive change in the learning environment.

Genetic variation influences every cellular process, and everything we do depends in some way on the processes in our cells; ultimately, the social and the biological are inseparable.

Michael White
Michael White is a systems biologist at the Department of Genetics and the Center for Genome Sciences and Systems Biology at the Washington University School of Medicine in St. Louis, where he studies how DNA encodes information for gene regulation. He co-founded the online science pub The Finch and Pea. Follow him on Twitter @genologos.

More From Michael White

A weekly roundup of the best of Pacific Standard and PSmag.com, delivered straight to your inbox.

Recent Posts

December 20 • 10:28 AM

Flare-Ups

Are my emotions making me ill?


December 19 • 4:00 PM

How a Drug Policy Reform Organization Thinks of the Children

This valuable, newly updated resource for parents is based in the real world.


December 19 • 2:00 PM

Where Did the Ouija Board Come From?

It wasn’t just a toy.


December 19 • 12:00 PM

Social Scientists Can Do More to Eradicate Racial Oppression

Using our knowledge of social systems, all social scientists—black or white, race scholar or not—have an opportunity to challenge white privilege.


December 19 • 10:17 AM

How Scientists Contribute to Bad Science Reporting

By not taking university press officers and research press releases seriously, scientists are often complicit in the media falsehoods they so often deride.


December 19 • 10:00 AM

Pentecostalism in West Africa: A Boon or Barrier to Disease?

How has Ghana stayed Ebola-free despite being at high risk for infection? A look at their American-style Pentecostalism, a religion that threatens to do more harm than good.


December 19 • 8:00 AM

Don’t Text and Drive—Especially If You’re Old

A new study shows that texting while driving becomes even more dangerous with age.


December 19 • 6:12 AM

All That ‘Call of Duty’ With Your Friends Has Not Made You a More Violent Person

But all that solo Call of Duty has.


December 19 • 4:00 AM

Food for Thought: WIC Works

New research finds participation in the federal WIC program, which subsidizes healthy foods for young children, is linked with stronger cognitive development and higher test scores.


December 18 • 4:00 PM

How I Navigated Life as a Newly Sober Mom

Saying “no” to my kids was harder than saying “no” to alcohol. But for their sake and mine, I had to learn to put myself first sometimes.


December 18 • 2:00 PM

Women in Apocalyptic Fiction Shaving Their Armpits

Because our interest in realism apparently only goes so far.


December 18 • 12:00 PM

The Paradox of Choice, 10 Years Later

Paul Hiebert talks to psychologist Barry Schwartz about how modern trends—social media, FOMO, customer review sites—fit in with arguments he made a decade ago in his highly influential book, The Paradox of Choice: Why More Is Less.


December 18 • 10:00 AM

What It’s Like to Spend a Few Hours in the Church of Scientology

Wrestling with thetans, attempting to unlock a memory bank, and a personality test seemingly aimed at people with depression. This is Scientology’s “dissemination drill” for potential new members.


December 18 • 8:00 AM

Gendering #BlackLivesMatter: A Feminist Perspective

Black men are stereotyped as violent, while black women are rendered invisible. Here’s why the gendering of black lives matters.


December 18 • 7:06 AM

Apparently You Can Bring Your Religion to Work

New research says offices that encourage talk of religion actually make for happier workplaces.


December 18 • 6:00 AM

The Very Weak and Complicated Links Between Mental Illness and Gun Violence

Vanderbilt University’s Jonathan Metzl and Kenneth MacLeish address our anxieties and correct our assumptions.


December 18 • 4:00 AM

Should Movies Be Rated RD for Reckless Driving?

A new study finds a link between watching films featuring reckless driving and engaging in similar behavior years later.


December 17 • 4:00 PM

How to Run a Drug Dealing Network in Prison

People tend not to hear about the prison drug dealing operations that succeed. Substance.com asks a veteran of the game to explain his system.


December 17 • 2:00 PM

Gender Segregation of Toys Is on the Rise

Charting the use of “toys for boys” and “toys for girls” in American English.


December 17 • 12:41 PM

Why the College Football Playoff Is Terrible But Better Than Before

The sample size is still embarrassingly small, but at least there’s less room for the availability cascade.


December 17 • 11:06 AM

Canadian Kids Have a Serious Smoking Problem

Bootleg cigarette sales could be leading Canadian teens to more serious drugs, a recent study finds.


December 17 • 10:37 AM

A Public Lynching in Sproul Plaza

When photographs of lynching victims showed up on a hallowed site of democracy in action, a provocation was issued—but to whom, by whom, and why?


December 17 • 8:00 AM

What Was the Job?

This was the year the job broke, the year we accepted a re-interpretation of its fundamental bargain and bought in to the push to get us to all work for ourselves rather than each other.


December 17 • 6:00 AM

White Kids Will Be Kids

Even the “good” kids—bound for college, upwardly mobile—sometimes break the law. The difference? They don’t have much to fear. A professor of race and social movements reflects on her teenage years and faces some uncomfortable realities.



Follow us


Don’t Text and Drive—Especially If You’re Old

A new study shows that texting while driving becomes even more dangerous with age.

Apparently You Can Bring Your Religion to Work

New research says offices that encourage talk of religion actually make for happier workplaces.

Canadian Kids Have a Serious Smoking Problem

Bootleg cigarette sales could be leading Canadian teens to more serious drugs, a recent study finds.

The Hidden Psychology of the Home Ref

That old myth of home field bias isn’t a myth at all; it’s a statistical fact.

The Big One

One in two United States senators and two in five House members who left office between 1998 and 2004 became lobbyists. November/December 2014

Copyright © 2014 by Pacific Standard and The Miller-McCune Center for Research, Media, and Public Policy. All Rights Reserved.