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[personal profile] haggholm

To change one’s mind when presented with sufficient evidence is a hallmark of a rational person. This is the ideal of the scientific method, and the failure to pursue it is the bane of human rationality. We are burdened with various cognitive biases and shortcomings that make all us humans naturally bad at it: We tend to seek out observations that confirm our beliefs and credit them when we find them; we tend to be more critical and skeptical of observations that contradict what we believe to be true. I often speak at length about this, criticising others when they insist in the face of evidence.

So what about me, then? When do I change my mind?

I must regretfully admit that I can’t think of a great many examples. Probably no small part of this is due to the fact that no one, however much they may appreciate the importance of evidence and perniciousness of cognitive biases, is actually immune to those biases. I do my very best to re-examine my beliefs when rationally challenged, but I suspect that every one of us carries a great many beliefs obtained for irrational reasons that, correct or incorrent, we just never come to critically re-examine. As a child you were taught a thousand thousand things, and as a child you had no choice but to absorb them, no framework for critical evaluation. Probably you will not re-examine all of those beliefs in your entire lifetime.

I’d like to think that another significant part of this is that I try not to form beliefs without a rational basis. I like to think that I rarely say anything that is flat-out wrong, because I try to avoid making claims that I’m not confident about. Maybe there’s something to this—I hope so—but no one is infallible; I am inevitably wrong about some things, ergo there must be beliefs I ought to change, but have so far failed to.

Maybe the most obvious example of an area where I have changed my mind is religion, but it seems kind of trivial. It was only as a child that I was capable of blind faith, the conviction of things not seen; I grew up and grew out of it when I realised that there just wasn’t anything supporting it, and I was firmly atheist long before my voice changed. For a long time I held the curious faitheist position that although it’s mistaken, it’s still somehow noble and worthy of respect to have committed faith; I have changed my position here too, recognising that holding irrational beliefs is inherently bad (and in fact intellectually a much worse crime than happening to reach erroneous conclusions). But all that is rather trivial; the total dearth of supporting observations makes it childishly easy to discard.

A much more recent, complicated, and difficult belief was upset some time last year or the year before, when I first started reading and learning how little parents matter to the personalities of their children. Steven Pinker summarises it in this video; the gist of it is that for most behavioural metrics,

  • up to 50% of the variation in the trait is genetic;
  • 0%–10% of the variation is due to parenting/upbringing;
  • the rest is due to culture, peer groups, &c.

This is illustrated by facts such as

  • adoptive siblings are hardly more similar than people picked at random;
  • monozygous twins reared apart by different parents tend to have very similar personalities, even if they are raised in very different environments and never meet.

I found this surprising. Indeed, if a fact could be offensive, this would be pretty close to it. Parenting doesn’t matter? Intuitively this makes roughly no sense at all to me. My parents matter intensely to me. Surely they shaped me? I can identify many, many traits, beliefs, and tendencies that correlate incredibly well with my parents. For better or worse, I think of myself as very much my father’s son, and I share many of his strengths and weaknesses. I have the same intellectual bent that he had, and many of the same interests.

And I value my parents. My father was a very flawed man, but he was always good to me, I got along well with him, and I loved him in spite of all his many flaws. My mother is wonderful, and I often consider myself very lucky in that she is so accepting, so ready to have a grown-up parent/child relationship with me, even when we deeply disagree on things. The notion that their influence on me was much less than I had thought seems…disparaging.

But the fact of the matter is that surprising and counterintuitive though it may be to me, that doesn’t alter the truth one whit, and I know damn well that intuition does not trump evidence. There are various studies on the subject, and I gather many are summarised in The Nurture Assumption by Judith Rich Harris, which I really ought to read at some point… If the evidence contradicts my intuition, then I should discard my intuition, not the evidence.

There are also perfectly good explanations for the observed correlations under the working theory above. Of course I resemble my parents in many respects: I share 50% of my genetic material with each of them, and just as I look quite like my father did when he was young, demonstrating that he contributed to my visible phenotype, so he surely contributed to my behavioural phenotype, as well. And while I wasn’t brought up in quite the same environment as my parents were, still there were surely similarities.

Additionally, I can think of hardly anything more conducive to confirmation bias than an informal analysis of a child’s resemblance to its parents. Of course I can think of commonalities: After all I spent eighteen years living in the same house as my parents, and had extremely ample time to learn just what traits and behaviours I shared with them.

Finally, I think that the deep personality traits that psychologists measure—agreeability, neuroticism, and so on—are probably less tangible, less open to obvious observations, than more superficial behaviours. It’s surely true that I read Biggles books as a child because my father had done so when he was a boy, had saved the books, read them aloud to me for a while. But this is a very superficial behaviour compared with whatever personality traits make me someone who enjoys shutting himself in with a book.

Of course, all of this is just reinterpreting old data in a new framework: Take the observations I made under the paradigm of “I am this way because parenting so made me”, and reinterpret them under the paradigm of “Parenting doesn’t matter nearly so much; genes and social environment are more important”. This is a fine thing to do, but were I unable to account for these data, still I should have to bow to the evidence: My personal, anecdotal observations do not trump the data.

I should add that I am not convinced that no kind of parenting can have fundamental, important effects. I vaguely seem to recall reading, and at any rate I have seen nothing to contradict this belief: That a truly poor environment, such as abusive parents, can have deep and terrible effects on a child. I do not base this on any real data, so I will not vouch for its truth at all, but until I read otherwise this is my working hypothesis: Terrible parents can psychologically damage their children and have disproportionate influence, for the worse. Parents who aren’t terrible, though, have surprisingly small effects on personality, and while a good parent is a very different creature from a terrible one, the differences in outcome vary surprisingly (disappointingly!) little between mediocre, good, and great parents.

Here, though, more data are needed.

(You may protest that people who are particularly good and responsible tend to have children who grow up to be particularly good and responsible. To this I say: Recall that these are people who may be genetically predisposed to be particularly good and responsible, and with up to 50% heritability in most personality traits, it’s no wonder if that is passed down.)

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Petter Häggholm

April 2016

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