Three identical strangers, and the genetics of personality

Inheritability of traits is one of the greatest of insights; it’s so significant and apparent, that one who does not accept it may safely be called a dullard. Personal variation exists, but most everyone accepts that if your parents are tall, you are likely to be tall; If they are dark, you too will likely be dark, etc., but when it comes to intelligence, or proclivities, or psychological leanings, it is more than a little impolite to acknowledge that genetics holds sway. This unwillingness is glaringly apparent in the voice-over narration of a popular movie about three identical triplets who were raised separately without knowing of one another. The movie is “Three identical strangers”, and it recounts their meeting, and their life afterwards.

Triplets, raised separately, came out near identical.

As one might expect, given my introduction, though raised separately, the three showed near identical intelligence, and near identical proclivities: two of them picked the same out-of-the way college. All of them liked the same sort of clothes and had the same taste in women. There were differences as well: one was a more outgoing, one was depressed, but in many ways, they were identical. Meanwhile, the voice-over kept saying things like, “isn’t it a shame that we never saw any results on nature/nurture from this study.” Let me clear this us: genetics applies to psychology too. It’s not all genetics, but it is at least as influential as upbringing/ nurture.

This movie also included pairs of identical twins, raised separately, they also showed strong personality similarities. It’s a finding that is well replicated in broader studies involving siblings raised separately, and unrelated adoptees raised together. Blood, it seems, is stronger than nurture. See for example the research survey paper, “Genetic Influence on Human Psychological Traits” Journal of the American Psychological Society 13-4, pp 148-151 (2004). A table from that paper appears below. Genetics plays a fairly strong role in all personal traits including intelligence, personality, self-control, mental illness, criminality, political views (even mobile phone use). The role is age-dependent, though so that intelligence (test determined) is strongly environment-dependent in 5 year olds, almost entirely genetic in 25-50 year olds. One area that is not strongly genetic, it seems, is religion.

In a sense, the only thing surprising about this result is that anyone is surprised. Genetics is accepted as crucial for all things physical, so why not mental and social. As an example of the genetic influence on sports, consider Jewish chess genius, Lazlo Polgar: he decided to prove that anyone could be great at chess, and decided to train his three daughters: he got two grand masters and an international master. By comparison, there are only 2 chess grand masters in all of Finland. Then consider that there are five all-star, baseball players named Alou, all from the same household, including the three brothers below. The household has seven pro baseball players in all.

Most people are uncomfortable with such evidence of genetic proclivity. The movie has been called “deeply disturbing” as any evidence of proclivity contradicts the promise of education: that all men are equal, blank slates at birth that can be fashioned into whatever you want through education. What we claim we want is leaders — lots of them, and we expect that education will produce equal ratios of woman and men, black and white and Hispanic, etc. and we expect to be able to get there without testing for skills, — especially without blind testing. I notice that the great universities have moved to have testing optional, instead relying on interviews and related measures of leadership. I think this is nonsense, but then I don’t run Harvard. As a professor, I’ve found that some kids have an aptitude and a burning interest, and others do not. You can tell a lot by testing, but the folks who run the universities disagree.

The All star Alou brothers share an outfield.

University heads claim that blind testing is racist. They find that some races score poorly on spacial sense, for example, or vocabulary suggesting that the tests are to blame. There is some truth to these concerns, but I find that the lack of blind testing is more racist. Once the test is eliminated, academia finds a way to elevate their friends, and the progeny of the powerful.

The variety of proclivities plays into an observation that you can be super intelligent in one area, and super stupid in others. That was the humor of some TV shows: “Big Bang Theory” and “Fraser”. That was also the tragedy of Bobby Fischer. He was brilliant in chess (and the child of brilliant parents), but was a blithering idiot in all other areas of life. Finland should not feel bad about their lack of great chess players. The country has produced two phone companies, two strong operating systems, and the all time top sniper.

Robert Buxbaum, May 15, 2022

One thought on “Three identical strangers, and the genetics of personality

  1. Peter Shenkin

    “Everybody” knows that intelligence (as conventionally measured) has been shown by identical-twin studies to be about 50% genetic. So it is in no way politically incorrect to acknowledge that. The question, though, is how to factor in low performance on, say, the SATs, into, say, college admission, for individuals who have grown up in unpromising environments.

    One approach would be to say it doesn’t matter; if they are not doing better than they are by now, they never will.

    Another would be to offer cutouts in the general admission process for those individuals if they show evidence of promise otherwise (for example, SAT scores below that which a top-ranking school might consider the minimum for acceptance for someone from a promising environment). It’s worth recalling that colleges do offer cutouts for outstanding athletes (who themselves don’t often to well academically) and for “legacy” students (students who come from families who have long associated themselves with pride to the institution, and perhaps have donated lots of money).

    Another is to eliminate standardized tests. But I agree with you that eliminating “blind testing” is more racist than requiring it.

    Reply

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