Embryo Selection and Our Stone-Age Psychology

Our minds evolved for a world that no longer exists. Embryo selection offers a way forward.

Note: I wrote this piece in 2023 for a now-defunct Substack specializing in embryo selection. It appears below unedited.

When I talk about embryo selection¹, people seem far more uneasy about general traits than clinical traits. What I mean by “general” is a trait we all share, such as height, intelligence, or charisma. “Clinical” traits are those that are labeled a disorder or illness such as tay sachs, ADHD, or schizophrenia. I think what’s happening is that there is an aversion to playing god, offset by compassion for those that are caused significant pain due to genetics. If we can avert clear cases, so be it, but don’t give us Gattaca. I’m sure many readers of this blog are fully Gattaca-pilled, and I am preaching to the choir. However, I’d like to push back on the intuition that clinical traits are inherently different, which may influence those on the fence. To do so, I will discuss dimensional models of personality disorders and the evolutionary mismatch we find ourselves in now.

Dimensional Models

Clinical diagnoses are widely perceived as the more acceptable traits for embryo selection. After all, reducing the potential of an individual developing debilitating conditions like Alzheimer's, schizophrenia, or congenital deafness is viewed as a compassionate act. Consider ADHD, with a heritability estimated at around 80%, similar to the genetic component of height. Given that ADHD is defined by disrupting function (i.e., causing pain) and is mostly a result of the genetic lottery, this also seems like a just target of embryo selection. 

The dimensional model of personality disorders is a relatively new perspective. It views mental disorders, including ADHD, as extremes on a continuum of human behavior. In this light, disorders are seen as the tail ends of a normally distributed trait, like attentional capacity, across a population.

This is the basis of the HiTOP model, which aims to replace the DSM with a nested hierarchy of continuous traits. Described by Psychiatry at the Margins :

The Hierarchical Taxonomy of Psychopathology (HiTOP) is an empirically based, quantitative nosology of mental disorders. HiTOP was developed as an alternative to prevailing classification and diagnostic systems like the DSM.  Instead of categorical diagnoses, the HiTOP system consists of hierarchically organized dimensions of psychopathology from specific signs and symptoms to increasingly broad constructs (e.g., internalizing/externalizing) encompassing features that cut across traditional disorders. This hierarchical, dimensional model is based on consensus from findings on the empirical psychometric structure of psychopathology.

At the top of this hierarchy rests the General Factor of Psychopathology, the p-factor.

HiTOP

So at least personality-related clinical traits can be thought of as a spectrum. This is fairly obvious and does not necessarily justify the trait being selected. Take, for example, ADHD. A couple with a family history of ADHD is likely to have a child in the clinical zone of attention. A skeptic may be okay with embryo selection in this case, but not for a family whose offspring will likely be in the normal range.

Further, there may be a happy medium for traits where both extremes cause problems, as is true of Openness to Experience. In fact, we should expect most traits to be like this, or nature would have already selected them in a certain direction until they obtain equilibrium. However, there are some traits where all or most people are deficient. There just hasn’t been time for evolution to catch up.

Emotional Intelligence

In personality research, a single factor explains much of the variance of any questionnaire. This goes by many names: Alpha, the General Factor of Personality (GFP), Emotional Intelligence, Social Intelligence, and social self-regulation. My favorite characterization is the tendency to live the Golden Rule. This is subtle; it’s not about being a doormat, for I would not want to be a tyrant toward others². It also goes beyond social effectiveness, as it requires caring about others. On top of that, it requires Theory of Mind—the ability to put yourself in others’ shoes and look inward at your own desires. Like all personality traits, it is substantially heritable (~50%).

This happens to be highly correlated with the p-factor from HiTOP, as well as the general factor obtained from measures of personality disorders (g-PD). One study gave a single population surveys to calculate all three factors³. It found the GFP correlates 0.9 with g-PD, which in turn correlates 0.92 with the p-factor. These factors concern the same latent trait, even when the instruments differ. (Personality tests include questions asking whether you talk to many people at a party, whereas psychopathology surveys ask if it feels like your leg belongs to you.) If I had to guess, this concordance is related to Theory of Mind and the ability to integrate your self-conception into society.

Over at Vectors of Mind , I have been making the case that the GFP is real and important. For some technical statistical reasons, this is a fierce debate within psychometrics. I also have a quixotic theory that connects this trait to the emergence of the human condition. In developing this idea, I have been struck by how radically different our lives are now from our evolutionary condition. Let’s start with an easy one, the Industrial Revolution.

Evolutionary Mismatch

In the last couple hundred years, we have become exponentially better at extracting calories from the environment. For the first time in human history—or indeed animal history—you are not a few bad decisions from starvation or predation. Our psychology has, obviously, not caught up to this fact. How many attachment disorders are built from cognitive mechanics that assume relationships are literally life and death? As a species, we can finally calm down. Then there is language itself. In the words of Darwin in The Descent of Man:

After the power of language had been acquired, and the wishes of the community could be expressed, the common opinion of how each member ought to act for the public good, would naturally become in a paramount degree the guide to action.

Language would have produced strong selection pressure for social/emotional intelligence—the GFP. It’s not clear when this happened, but the typical response is somewhere around 100,000 years ago. (I review the evolution of the related ability recursion here. Chomsky, for example, said it emerged 50,000 years ago.) That is not very long in evolutionary terms, and we may not have evolved to “optimal” levels of self-regulation since the advent of language, much less the invention of lawyers, police, and atomic bombs.

Relatedly, Dunbar said that humans can maintain relationships with about 150 people. This would not have been a constraint for much of our evolutionary history as our tribes did not exceed that size. We now live in cities with millions of people but are still constrained to 150 relationships by our Pleistocene heritage. This isn’t to say we need to embryo select to increase Dunbar’s number, just that many people accept that Pleistocene adaptations still shape our basic psychology⁴. If Dunbar’s number has not been updated, then likewise, the differing moral and introspective climate wrought by language may not be fully integrated. 

Writing is another stark example. It was invented 5,000 years ago by the Sumerians, was not a common skill until the last 100 years, and is now table stakes for modern life. The human brain is incredibly plastic; however, about 20% of people have dyslexia. And that is only those that pass the clinical threshold!

Our modern evolutionary mismatch causes much pain. Many external sources of suffering have been eradicated or greatly reduced in the last few hundred years, including disease and violence. There is still much work to be done, but more than ever, when we do suffer, we make our own Hell. This is a great achievement! It’s good that life is less nasty, brutish, and short by default. But our psyches were not designed for the choices which now decide our destiny. They are always on alert for predation, starvation, and especially social rejection.

Never before have humans been tasked with finding their center while swimming in a society of millions. We aren’t about to eliminate cities, the internet, or writing, but we can take the edge off well-understood human foibles. If clinical conditions are justified for embryo selection, then emotional intelligence (or GFP, Theory of Mind, etc...) ought to be as well, at basically any level. We are all deficient for the demands of the Holocene.

1. This involves genetic screening of embryos before they are implanted in IVF. If you have several embryos, their DNA gives a rough idea of their disease risks and other attributes like eye color or intelligence. Most people think it’s all right to know if an embryo has Down Syndrome or Tay Sachs, but naturally, eye color, intelligence, and personality are highly debated.

2. Maybe I’m just an angel 😇. But there is room to say we were not built to be tyrants, as a rule. At the very least, a society of tyrants is not game-theoretically stable (though perhaps a society of would-be tyrants is?). To those that view evolution through Machiavellian Neo-Darwinist terms, I encourage you to read Darwin, who wrote extensively about morality. And empirically, there is a debate on the evolution of warfare, which may not have existed before 15 kya. Another data point is that “gullible” does not load on the GFP; it requires being street-smart. Another way to think of it is, “Would I like this person on my team”? If they are a doormat, then no.

3. General Factors of Psychopathology, Personality, and Personality Disorder: Across Domain Comparisons

4. In fact, Neuroscientist Eric Hoel uses Dunbar’s number to explain the Sapient Paradox in his award-winning essay The Gossip Trap. In brief, he argues that when our social circles surpassed Dunbar’s number, this produced a phase transition in our society (as well as psychology?), which allowed humans to be creative, make art, and invent new technologies about 10,000 years ago.