En 1965, cuando propuso la Ley de Educación Primaria y Secundaria al Congreso, el presidente Lyndon B. Johnson escribió : “Se debe alentar a cada niño a recibir tanta educación como su capacidad pueda tomar”.

Hoy en día, ese lenguaje podría parecer un poco anticuado (y sexista); en cambio, podríamos decir que nuestro objetivo es que “todos los niños alcancen su máximo potencial académico”. Pero la misma idea se esconde en estas declaraciones aparentemente anodinas, y es a la vez sentido común y algo que quienes trabajamos en políticas educativas no nos gusta decir en voz alta.

La capacidad importa y varía de persona a persona. Por lo tanto, no todos tenemos la misma capacidad para recibir la misma educación.

Aunque esto pueda parecer obvio, sobre todo para cualquiera que haya criado a más de un hijo, ¿es científicamente cierto? ¿Es la capacidad innata, inscrita en nuestros genes, algo real? De ser así, ¿podemos medirla?

Respondiendo afirmativamente está Dalton Conley, profesor de Princeton, cuyo fascinante nuevo libro, The Social Genome (El Genoma Social ), explora la interacción de nuestro código genético con el entorno social. Conley desmiente lo que él llama “pizarra rasa”: la afirmación de que la variación en los rasgos, comportamientos y resultados humanos individuales se debe enteramente a nuestras circunstancias de vida, incluida la clase social. Pero también desmiente a los “hereditaristas”, quienes argumentan que todo está predeterminado por nuestros genes. No se trata de crianza versus naturaleza, argumenta, sino de naturaleza y crianza, unidas por una intrincada danza mediante la cual nuestros genes buscan entornos para expresarse plenamente.

En el ámbito educativo, nadie necesita que le convenzan de que factores de la crianza, como el entorno familiar en el que crecen los niños, el tipo de barrio en el que viven y las amistades que mantienen, influyan en los resultados escolares. De hecho, durante décadas, investigadores que han evaluado los efectos de nuevas intervenciones han intentado controlar estos factores, tan correlacionados están con el éxito o el fracaso escolar. Pero lo que quizás sea más difícil de aceptar es que nuestro ADN también influye considerablemente en nuestros resultados educativos.

We don’t tend to resist this line of thinking when it comes to physical attributes. Tall parents beget tall children. Kids who are athletically prodigious often have moms and dads who were superstars on the field, too. When it comes to cognition and other school-related skills, however, we grow sheepish about the role of our genes—and for good reason. We’ve all studied the horrors that resulted from the eugenics movement of a century ago, culminating in the gas chambers at Auschwitz and beyond. And we’ve all read or seen science fiction novels and movies, from Brave New World to Minority Report to Gattaca, that warn us of a future when genetic predispositions are taken to be determinative, or when tinkering with our genes to create tailor-made superhumans becomes the dystopian norm. (This is indeed already happening at fertility clinics worldwide to some extent, as parents select for preferred traits.)

Conley worries about all this, too, but can’t deny what science is teaching us: Our genetic code has a big impact on many human traits, behaviors, and outcomes, and we’re getting better at measuring the relationship.

Introducing the Education PGI

As Conley patiently explains in his book—and patiently explained to me in an interview—ever since the completion of the Human Genome Project in 2003, researchers have been racing to nail down the connection between individual genes and diseases, conditions, and attributes. What quickly became clear was that, in almost every case, variations in human attributes aren’t caused by variations in single genes, but in small variations across thousands of genes.

There’s no one gene for height, for example. But remarkably, researchers have been able to use advanced computational methods to identify the thousands of genes that together predict someone’s height and can calculate a “polygenetic index” (or PGI) for that attribute. This number measures an individual’s likelihood of exhibiting a specific trait—or, in Conley’s words, is “a single number for a single trait that sums the effects of thousands of different variations in our DNA across our genome observed in the population.”

So, when it comes to height, today anyone can have their “height PGI” calculated based on a genetic analysis of a cheek swab. Their genetic data will be fed into a complex algorithm and the score will predict their height within about one inch. (The difference comes down to the environment and depends on someone getting adequate nutrition—in the womb and beyond—and avoiding serious childhood accidents and illnesses.) We can talk, then, about whether someone has achieved their full genetic potential in terms of height.

Might we also someday be able to determine whether someone has achieved their full genetic potential in terms of education attainment? Harkening back to President Johnson, could we find out how many children “take” as much education as their ability allows? That is the tantalizing possibility presented by the “education PGI,” a similar calculation designed to predict someone’s eventual level of education based on their genetic code.

The first education PGI calculations were released in 2013 and were very imprecise, estimating only 3 percent of the variation in education attainment from person to person. A substantially updated version released in 2022 can explain 16 percent. To put that in context, consider this: Studies of twins indicate that education attainment is about 40 percent heritable, so we could describe education PGI as explaining about 40 percent of that 40 percent.

That’s still very noisy data, much too imprecise to predict individual outcomes—especially those in the middle of the education PGI distribution. However, a PGI’s predictive power is far stronger for individuals in the top or bottom 10 percent, and there we find insights from education PGI. As Conley writes, someone in the bottom 10 percent of the ranking has about a 7 percent likelihood of completing a four-year degree, while an individual in the top tenth has about a 71 percent chance of graduating from college.

Avoiding Dystopian Uses

Like virtually all polygenetic indices, education PGI can only be used for non-Hispanic whites—a major limitation to its utility. Currently, most of the DNA samples used in the research come from this one population and studies indicate they don’t work for people of other races. But it’s not hard to imagine researchers building similar indices for all major racial groups, as well as these polygenic computations growing more accurate over time.

Researchers are also examining the degree to which education PGI—again, which focuses on education attainment—overlaps with the PGI for particular traits. We already know there’s significant overlap with cognition, which is not surprising. But it might also overlap with certain personality traits as well as what we call “noncognitive” skills, like self-regulation, organization, and persistence. This may help settle some debates in education about what really matters when it comes to school success—brains, knowledge acquisition, perseverance, and so forth. Granted, some of those things that matter may be more malleable than others.