DNA Tests for Intelligence Ignore the Real Reasons Why Kids Succeed or Fail
[Editor's Note: This essay is in response to our current Big Question, which we posed to experts with different perspectives: "How should DNA tests for intelligence be used, if at all, by parents and educators?"]
It's 2019. Prenatal genetic tests are being used to help parents select from healthy and diseased eggs. Genetic risk profiles are being created for a range of common diseases. And embryonic gene editing has moved into the clinic. The science community is nearly unanimous on the question of whether we should be consulting our genomes as early as possible to create healthy offspring. If you can predict it, let's prevent it, and the sooner, the better.
There are big issues with IQ genetics that should be considered before parents and educators adopt DNA IQ predictions.
When it comes to care of our babies, kids, and future generations, we are doing things today that we never even dreamed would be possible. But one area that remains murky is the long fraught question of IQ, and whether to use DNA science to tell us something about it. There are big issues with IQ genetics that should be considered before parents and educators adopt DNA IQ predictions.
IQ tests have been around for over a century. They've been used by doctors, teachers, government officials, and a whole host of institutions as a proxy for intelligence, especially in youth. At times in history, test results have been used to determine whether to allow a person to procreate, remain a part of society, or merely stay alive. These abuses seem to be a distant part of our past, and IQ tests have since garnered their fair share of controversy for exhibiting racial and cultural biases. But they continue to be used across society. Indeed, much of the literature aimed at expecting parents justifies its recommendations (more omegas, less formula, etc.) based on promises of raising a baby's IQ.
This is the power of IQ testing sans DNA science. Until recently, the two were separate entities, with IQ tests indicating a coefficient created from individual responses to written questions and genetic tests indicating some disease susceptibility based on a sequence of one's DNA. Yet in recent years, scientists have begun to unlock the secrets of inherited aspects of intelligence with genetic analyses that scan millions of points of variation in DNA. Both bench scientists and direct-to-consumer companies have used these new technologies to find variants associated with exceptional IQ scores. There are a number of tests on the open market that parents and educators can use at will. These tests purport to reveal whether a child is inherently predisposed to be intelligent, and some suggest ways to track them for success.
I started looking into these tests when I was doing research for my book, "Social by Nature: The Promise and Peril of Sociogenomics." This book investigated the new genetic science of social phenomena, like educational attainment and political persuasion, investment strategies, and health habits. I learned that, while many of the scientists doing much of the basic research into these things cautioned that the effects of genetic factors were quite small, most saw testing as one data point among many that could help to somehow level the playing field for young people. The rationale went that in certain circumstances, some needed help more than others. Why not put our collective resources together to help them?
Good nutrition, support at home, and access to healthcare and education make a huge difference in how people do.
Some experts believed so strongly in the power of DNA behavioral prediction that they argued it would be unfair not to use predictors to determine a kid's future, prevent negative outcomes, and promote the possibility for positive ones. The educators out in the wider world that I spoke with agreed. With careful attention, they thought sociogenomic tests could help young people get the push they needed when they possessed DNA sequences that weren't working in their favor. Officials working with troubled youth told me they hoped DNA data could be marshaled early enough that kids would thrive at home and in school, thereby avoiding ending up in their care. While my conversations with folks centered around sociogenomic data in general, genetic IQ prediction was completely entangled in it all.
I present these prevailing views to demonstrate both the widespread appeal of genetic predictors as well as the well-meaning intentions of those in favor of using them. It's a truly progressive notion to help those who need help the most. But we must question whether genetic predictors are data points worth looking at.
When we examine the way DNA IQ predictors are generated, we see scientists grouping people with similar IQ test results and academic achievements, and then searching for the DNA those people have in common. But there's a lot more to scores and achievements than meets the eye. Good nutrition, support at home, and access to healthcare and education make a huge difference in how people do. Therefore, the first problem with using DNA IQ predictors is that the data points themselves may be compromised by numerous inaccuracies.
We must then ask ourselves where the deep, enduring inequities in our society are really coming from. A deluge of research has shown that poor life outcomes are a product of social inequalities, like toxic living conditions, underfunded schools, and unhealthy jobs. A wealth of research has also shown that race, gender, sexuality, and class heavily influence life outcomes in numerous ways. Parents and caregivers feed, talk, and play differently with babies of different genders. Teachers treat girls and boys, as well as members of different racial and ethnic backgrounds, differently to the point where they do better and worse in different subject areas.
Healthcare providers consistently racially profile, using diagnostics and prescribing therapies differently for the same health conditions. Access to good schools and healthcare are strongly mitigated by one's race and socioeconomic status. But even youth from privileged backgrounds suffer worse health and life outcomes when they identify or are identified as queer. These are but a few examples of the ways in which social inequities affect our chances in life. Therefore, the second problem with using DNA IQ predictors is that it obscures these very real, and frankly lethal, determinants. Instead of attending to the social environment, parents and educators take inborn genetics as the reason for a child's successes or failures.
It is time that we shift our priorities from seeking genetic causes to fixing the social causes we know to be real.
The other problem with using DNA IQ predictors is that research into the weightiness of DNA evidence has shown time and again that people take DNA evidence more seriously than they do other kinds of evidence. So it's not realistic to say that we can just consider IQ genetics as merely one tiny data point. People will always give more weight to DNA evidence than it deserves. And given its proven negligible effect, it would be irresponsible to do so.
It is time that we shift our priorities from seeking genetic causes to fixing the social causes we know to be real. Parents and educators need to be wary of solutions aimed at them and their individual children.
[Editor's Note: Read another perspective in the series here.]
This man spent over 70 years in an iron lung. What he was able to accomplish is amazing.
It’s a sight we don’t normally see these days: A man lying prone in a big, metal tube with his head sticking out of one end. But it wasn’t so long ago that this sight was unfortunately much more common.
In the first half of the 20th century, tens of thousands of people each year were infected by polio—a highly contagious virus that attacks nerves in the spinal cord and brainstem. Many people survived polio, but a small percentage of people who did were left permanently paralyzed from the virus, requiring support to help them breathe. This support, known as an “iron lung,” manually pulled oxygen in and out of a person’s lungs by changing the pressure inside the machine.
Paul Alexander was one of several thousand who were infected and paralyzed by polio in 1952. That year, a polio epidemic swept the United States, forcing businesses to close and polio wards in hospitals all over the country to fill up with sick children. When Paul caught polio in the summer of 1952, doctors urged his parents to let him rest and recover at home, since the hospital in his home suburb of Dallas, Texas was already overrun with polio patients.
Paul rested in bed for a few days with aching limbs and a fever. But his condition quickly got worse. Within a week, Paul could no longer speak or swallow, and his parents rushed him to the local hospital where the doctors performed an emergency procedure to help him breathe. Paul woke from the surgery three days later, and found himself unable to move and lying inside an iron lung in the polio ward, surrounded by rows of other paralyzed children.
Hospitals were commonly filled with polio patients who had been paralyzed by the virus before a vaccine became widely available in 1955. Associated Press
Paul struggled inside the polio ward for the next 18 months, bored and restless and needing to hold his breath when the nurses opened the iron lung to help him bathe. The doctors on the ward frequently told his parents that Paul was going to die.But against all odds, Paul lived. And with help from a physical therapist, Paul was able to thrive—sometimes for small periods outside the iron lung.
The way Paul did this was to practice glossopharyngeal breathing (or as Paul called it, “frog breathing”), where he would trap air in his mouth and force it down his throat and into his lungs by flattening his tongue. This breathing technique, taught to him by his physical therapist, would allow Paul to leave the iron lung for increasing periods of time.
With help from his iron lung (and for small periods of time without it), Paul managed to live a full, happy, and sometimes record-breaking life. At 21, Paul became the first person in Dallas, Texas to graduate high school without attending class in person, owing his success to memorization rather than taking notes. After high school, Paul received a scholarship to Southern Methodist University and pursued his dream of becoming a trial lawyer and successfully represented clients in court.
Paul Alexander, pictured here in his early 20s, mastered a type of breathing technique that allowed him to spend short amounts of time outside his iron lung. Paul Alexander
Paul practiced law in North Texas for more than 30 years, using a modified wheelchair that held his body upright. During his career, Paul even represented members of the biker gang Hells Angels—and became so close with them he was named an honorary member.Throughout his long life, Paul was also able to fly on a plane, visit the beach, adopt a dog, fall in love, and write a memoir using a plastic stick to tap out a draft on a keyboard. In recent years, Paul joined TikTok and became a viral sensation with more than 330,000 followers. In one of his first videos, Paul advocated for vaccination and warned against another polio epidemic.
Paul was reportedly hospitalized with COVID-19 at the end of February and died on March 11th, 2024. He currently holds the Guiness World Record for longest survival inside an iron lung—71 years.
Polio thankfully no longer circulates in the United States, or in most of the world, thanks to vaccines. But Paul continues to serve as a reminder of the importance of vaccination—and the power of the human spirit.
““I’ve got some big dreams. I’m not going to accept from anybody their limitations,” he said in a 2022 interview with CNN. “My life is incredible.”
When doctors couldn’t stop her daughter’s seizures, this mom earned a PhD and found a treatment herself.
Twenty-eight years ago, Tracy Dixon-Salazaar woke to the sound of her daughter, two-year-old Savannah, in the midst of a medical emergency.
“I entered [Savannah’s room] to see her tiny little body jerking about violently in her bed,” Tracy said in an interview. “I thought she was choking.” When she and her husband frantically called 911, the paramedic told them it was likely that Savannah had had a seizure—a term neither Tracy nor her husband had ever heard before.
Over the next several years, Savannah’s seizures continued and worsened. By age five Savannah was having seizures dozens of times each day, and her parents noticed significant developmental delays. Savannah was unable to use the restroom and functioned more like a toddler than a five-year-old.
Doctors were mystified: Tracy and her husband had no family history of seizures, and there was no event—such as an injury or infection—that could have caused them. Doctors were also confused as to why Savannah’s seizures were happening so frequently despite trying different seizure medications.
Doctors eventually diagnosed Savannah with Lennox-Gaustaut Syndrome, or LGS, an epilepsy disorder with no cure and a poor prognosis. People with LGS are often resistant to several kinds of anti-seizure medications, and often suffer from developmental delays and behavioral problems. People with LGS also have a higher chance of injury as well as a higher chance of sudden unexpected death (SUDEP) due to the frequent seizures. In about 70 percent of cases, LGS has an identifiable cause such as a brain injury or genetic syndrome. In about 30 percent of cases, however, the cause is unknown.
Watching her daughter struggle through repeated seizures was devastating to Tracy and the rest of the family.
“This disease, it comes into your life. It’s uninvited. It’s unannounced and it takes over every aspect of your daily life,” said Tracy in an interview with Today.com. “Plus it’s attacking the thing that is most precious to you—your kid.”
Desperate to find some answers, Tracy began combing the medical literature for information about epilepsy and LGS. She enrolled in college courses to better understand the papers she was reading.
“Ironically, I thought I needed to go to college to take English classes to understand these papers—but soon learned it wasn’t English classes I needed, It was science,” Tracy said. When she took her first college science course, Tracy says, she “fell in love with the subject.”
Tracy was now a caregiver to Savannah, who continued to have hundreds of seizures a month, as well as a full-time student, studying late into the night and while her kids were at school, using classwork as “an outlet for the pain.”
“I couldn’t help my daughter,” Tracy said. “Studying was something I could do.”
Twelve years later, Tracy had earned a PhD in neurobiology.
After her post-doctoral training, Tracy started working at a lab that explored the genetics of epilepsy. Savannah’s doctors hadn’t found a genetic cause for her seizures, so Tracy decided to sequence her genome again to check for other abnormalities—and what she found was life-changing.
Tracy discovered that Savannah had a calcium channel mutation, meaning that too much calcium was passing through Savannah’s neural pathways, leading to seizures. The information made sense to Tracy: Anti-seizure medications often leech calcium from a person’s bones. When doctors had prescribed Savannah calcium supplements in the past to counteract these effects, her seizures had gotten worse every time she took the medication. Tracy took her discovery to Savannah’s doctor, who agreed to prescribe her a calcium blocker.
The change in Savannah was almost immediate.
Within two weeks, Savannah’s seizures had decreased by 95 percent. Once on a daily seven-drug regimen, she was soon weaned to just four, and then three. Amazingly, Tracy started to notice changes in Savannah’s personality and development, too.
“She just exploded in her personality and her talking and her walking and her potty training and oh my gosh she is just so sassy,” Tracy said in an interview.
Since starting the calcium blocker eleven years ago, Savannah has continued to make enormous strides. Though still unable to read or write, Savannah enjoys puzzles and social media. She’s “obsessed” with boys, says Tracy. And while Tracy suspects she’ll never be able to live independently, she and her daughter can now share more “normal” moments—something she never anticipated at the start of Savannah’s journey with LGS. While preparing for an event, Savannah helped Tracy get ready.
“We picked out a dress and it was the first time in our lives that we did something normal as a mother and a daughter,” she said. “It was pretty cool.”