Behavioral Genetics
"Why Progressives Should Embrace the Genetics of Education"
-Paige Harden
"Now new research has found that college graduation, with all its advantages, is partly the outcome of a genetic lottery... On Monday, scientists published a study in Nature Genetics that analyzed the genes of 1.1 million people of European ancestry, including over 300,000 23andMe customers. Over 99 percent of our DNA is identical in all humans, but researchers focused on the remaining 1 percent and found thousands of DNA variants that are correlated with educational attainment.
This information can be combined into a single number, called a polygenic score.
In Americans with European ancestry, just over 10 percent of people with a
low polygenic score completed college, compared with 55 percent of people
with a high polygenic score. This genetic disparity in college completion is as
big as the disparity between rich and poor students in America.
Because researchers focused on differences within an ancestrally
homogeneous group of people, their results have no implications for
understanding racial disparities in education…
But research like this makes many people nervous. Linking social inequality
to DNA — isnʼt this eugenics? …In the United States, the idea that inferior genes were to blame for poverty led to state-sponsored atrocities, including forced sterilization and institutionalization…
This has led people who value social justice to argue that, when it comes to
issues like education, genetic research should simply not be conducted…
Lenin himself wrote that “the transfer of biological concepts into the field of
the social sciences is a meaningless phrase.”
But this is a mistake. Those of us who value social justice should instead be
asking: How can the power of the genomic revolution be harnessed to create
a more equal society?
Discovering specific DNA variants that are correlated with education can
help us in two ways.
First, these genetic results reveal the injustice of our so-called meritocracy. As a nation, we justify stark inequalities with the idea that people who stayed in school deserve more than people who didnʼt finish high school or college — more money, more security, more health, more life.
But success in our educational system is partially a result of genetic luck. No
one earned his or her DNA sequence, yet some of us are benefiting enormously from it. By showing us the links between genes and educational success, this new study reminds us that everyone should share in our national prosperity, regardless of which genetic variants he or she happens to inherit.
Second, knowing which genes are associated with educational success will help scientists understand how different environments also affect that success. The eventual development of a polygenic score that statistically predicts educational outcomes will allow researchers to control for genetic differences between people, so that the causal effects of the environment are thrown into sharper focus.
Understanding which environments cause improvements in childrenʼs ability to think and learn is necessary if we want to invest wisely in interventions that can truly make a difference.
Talking about including genetics as a variable in statistical models doesnʼt have the same dark allure as eugenic proposals to screen embryos or assign children to schools based on their genotypes. But the widespread use of polygenic scoring in research aiming to understand how environments shape childrenʼs lives will yield big payoffs for knowing how to maximize a childʼs potential. We canʼt change someoneʼs genes, but we can try to change how she grows up.
Our genes shape nearly every aspect of our lives — our weight, fertility, health, life span and, yes, our intelligence and success in school. Scientists have known this for years, based on results from twin and adoption studies, but itʼs only recently that we have been able to measure DNA directly and use it to predict outcomes with any degree of certainty.
Genetic differences in human life are a scientific fact, like climate change. Many progressives resist acknowledging this… fearing that it will compromise their egalitarian beliefs. But just like acknowledging the reality of climate change is necessary to ensure a sustainably habitable planet, acknowledging the reality of genetic differences between people is a necessary step for us to ensure a more just society."
-Paige Harden
"Now new research has found that college graduation, with all its advantages, is partly the outcome of a genetic lottery... On Monday, scientists published a study in Nature Genetics that analyzed the genes of 1.1 million people of European ancestry, including over 300,000 23andMe customers. Over 99 percent of our DNA is identical in all humans, but researchers focused on the remaining 1 percent and found thousands of DNA variants that are correlated with educational attainment.
This information can be combined into a single number, called a polygenic score.
In Americans with European ancestry, just over 10 percent of people with a
low polygenic score completed college, compared with 55 percent of people
with a high polygenic score. This genetic disparity in college completion is as
big as the disparity between rich and poor students in America.
Because researchers focused on differences within an ancestrally
homogeneous group of people, their results have no implications for
understanding racial disparities in education…
But research like this makes many people nervous. Linking social inequality
to DNA — isnʼt this eugenics? …In the United States, the idea that inferior genes were to blame for poverty led to state-sponsored atrocities, including forced sterilization and institutionalization…
This has led people who value social justice to argue that, when it comes to
issues like education, genetic research should simply not be conducted…
Lenin himself wrote that “the transfer of biological concepts into the field of
the social sciences is a meaningless phrase.”
But this is a mistake. Those of us who value social justice should instead be
asking: How can the power of the genomic revolution be harnessed to create
a more equal society?
Discovering specific DNA variants that are correlated with education can
help us in two ways.
First, these genetic results reveal the injustice of our so-called meritocracy. As a nation, we justify stark inequalities with the idea that people who stayed in school deserve more than people who didnʼt finish high school or college — more money, more security, more health, more life.
But success in our educational system is partially a result of genetic luck. No
one earned his or her DNA sequence, yet some of us are benefiting enormously from it. By showing us the links between genes and educational success, this new study reminds us that everyone should share in our national prosperity, regardless of which genetic variants he or she happens to inherit.
Second, knowing which genes are associated with educational success will help scientists understand how different environments also affect that success. The eventual development of a polygenic score that statistically predicts educational outcomes will allow researchers to control for genetic differences between people, so that the causal effects of the environment are thrown into sharper focus.
Understanding which environments cause improvements in childrenʼs ability to think and learn is necessary if we want to invest wisely in interventions that can truly make a difference.
Talking about including genetics as a variable in statistical models doesnʼt have the same dark allure as eugenic proposals to screen embryos or assign children to schools based on their genotypes. But the widespread use of polygenic scoring in research aiming to understand how environments shape childrenʼs lives will yield big payoffs for knowing how to maximize a childʼs potential. We canʼt change someoneʼs genes, but we can try to change how she grows up.
Our genes shape nearly every aspect of our lives — our weight, fertility, health, life span and, yes, our intelligence and success in school. Scientists have known this for years, based on results from twin and adoption studies, but itʼs only recently that we have been able to measure DNA directly and use it to predict outcomes with any degree of certainty.
Genetic differences in human life are a scientific fact, like climate change. Many progressives resist acknowledging this… fearing that it will compromise their egalitarian beliefs. But just like acknowledging the reality of climate change is necessary to ensure a sustainably habitable planet, acknowledging the reality of genetic differences between people is a necessary step for us to ensure a more just society."
"Top 10 Replicated Findings of Behavioral Genetics" Robert Plomin, et al.
"In the context of current concerns about replication in psychological science, we describe 10 findings from behavioral genetic research that have replicated robustly. These are “big” findings, both in terms of effect size and potential impact on psychological science, such as linearly increasing heritability of intelligence from infancy (20%) through adulthood (60%). Four of our top 10 findings involve the environment, discoveries that could have been found only with genetically sensitive research designs. We also consider reasons specific to behavioral genetics that might explain why these findings replicate..."
Top 10 Replicated Findings
Finding 1. All psychological traits show significant and substantial genetic influence...
Finding 2. No traits are 100% heritable...
Finding 3. Heritability is caused by many genes of small effect...
Finding 4. Phenotypic correlations between psychological traits show significant and substantial genetic mediation...
Finding 5. The heritability of intelligence increases throughout development...
Finding 6. Age-to-age stability is mainly due to genetics...
Finding 7. Most measures of the “environment” show significant genetic influence...
Finding 8. Most associations between environmental measures and psychological traits are significantly mediated genetically...
Finding 9. Most environmental effects are not shared by children growing up in the same family...
Finding 10. Abnormal is normal...
Reasons for Replication Specific to Behavioral Genetics
Controversy...
The new statistics are not new to behavioral genetics...
Incentives for replication and meta-analysis...
Genetic effect sizes are large...
Conclusions
The discovery of such big and often counterintuitive findings is a cause for celebration in psychology, especially coming from behavioral genetics, which has been so controversial during the past century. These findings have begun to change the received psychological perspective about the origins of individual differences in behavior. During the past century, the pendulum of opinion has swung from nature to nurture and is now swinging back toward nature. We hope that this research has stopped the pendulum at a point between nature and nurture because the most basic message (Findings 1 and 2) is that both genetics and environment contribute substantially to individual differences in psychological traits. It is worth noting again that four of these findings are primarily about the environment rather than genetics, which emphasizes the value of studying environmental influences in genetically sensitive designs.
What we like best about some of these findings is that they are counterintuitive. For example, who would have thought that the heritability of intelligence increases throughout development (Finding 5) or that environmental measures show genetic influence (Finding 7) or that the abnormal is normal (Finding 10)? Another feature of these findings is that each is falsifiable. For example, if major gene effects on complex traits and common disorders are found, they would falsify the hypothesis that heritability is caused by many genes of small effect (Finding 3).
We also speculated on the reasons that behavioral genetic results replicate, suggesting possible reasons that are specific to behavioral genetics. For example, the controversies that permeated the field during the past century raised the bar for the quality and quantity of research needed to convince people of the importance of genetics throughout psychology. In addition, behavioral genetic research is conducive to replication for practical reasons rather than for lofty ideals of a progressive science.
However, as researchers in the field for several decades, we have found that the field is imbued with an ethos of building a progressive science based on replicable findings. It is crucial to build from this firm foundation of replicable findings, and the most difficult tasks lie ahead, understanding the actual processes that mediate these replicable findings. What we have learned about the genetic and environmental architecture hints at just how difficult this will be because heritability is caused by many genes of small effect (Finding 3) and most environmental effects are not shared by children growing up in the same family (Finding 9)."
Top 10 Replicated Findings
Finding 1. All psychological traits show significant and substantial genetic influence...
Finding 2. No traits are 100% heritable...
Finding 3. Heritability is caused by many genes of small effect...
Finding 4. Phenotypic correlations between psychological traits show significant and substantial genetic mediation...
Finding 5. The heritability of intelligence increases throughout development...
Finding 6. Age-to-age stability is mainly due to genetics...
Finding 7. Most measures of the “environment” show significant genetic influence...
Finding 8. Most associations between environmental measures and psychological traits are significantly mediated genetically...
Finding 9. Most environmental effects are not shared by children growing up in the same family...
Finding 10. Abnormal is normal...
Reasons for Replication Specific to Behavioral Genetics
Controversy...
The new statistics are not new to behavioral genetics...
Incentives for replication and meta-analysis...
Genetic effect sizes are large...
Conclusions
The discovery of such big and often counterintuitive findings is a cause for celebration in psychology, especially coming from behavioral genetics, which has been so controversial during the past century. These findings have begun to change the received psychological perspective about the origins of individual differences in behavior. During the past century, the pendulum of opinion has swung from nature to nurture and is now swinging back toward nature. We hope that this research has stopped the pendulum at a point between nature and nurture because the most basic message (Findings 1 and 2) is that both genetics and environment contribute substantially to individual differences in psychological traits. It is worth noting again that four of these findings are primarily about the environment rather than genetics, which emphasizes the value of studying environmental influences in genetically sensitive designs.
What we like best about some of these findings is that they are counterintuitive. For example, who would have thought that the heritability of intelligence increases throughout development (Finding 5) or that environmental measures show genetic influence (Finding 7) or that the abnormal is normal (Finding 10)? Another feature of these findings is that each is falsifiable. For example, if major gene effects on complex traits and common disorders are found, they would falsify the hypothesis that heritability is caused by many genes of small effect (Finding 3).
We also speculated on the reasons that behavioral genetic results replicate, suggesting possible reasons that are specific to behavioral genetics. For example, the controversies that permeated the field during the past century raised the bar for the quality and quantity of research needed to convince people of the importance of genetics throughout psychology. In addition, behavioral genetic research is conducive to replication for practical reasons rather than for lofty ideals of a progressive science.
However, as researchers in the field for several decades, we have found that the field is imbued with an ethos of building a progressive science based on replicable findings. It is crucial to build from this firm foundation of replicable findings, and the most difficult tasks lie ahead, understanding the actual processes that mediate these replicable findings. What we have learned about the genetic and environmental architecture hints at just how difficult this will be because heritability is caused by many genes of small effect (Finding 3) and most environmental effects are not shared by children growing up in the same family (Finding 9)."