Nurture Assumption

This was a good read.

“Do parents have any important long-term effects on the development of their child’s personality? This article examines the evidence and concludes that the answer is no.”

Thus begins Judith Rich Harris’s ground-breaking 1995 Psychological Review article “Where is the child’s environment? A group socialization theory of development.”

Judith Rich Harris is one of the most unconventional heroes of behavior genetics. In 1960, she was a graduate student in psychology at Harvard University. After receiving her Master’s degree, she was dismissed from the program by the then acting department chair, George A. Miller, who thought Harris was not smart enough to earn a Ph.D.

Thirty-five years later, while supporting herself by writing psychology textbooks, Harris worked on her group socialization theory of development and published it in the prestigious academic journal Psychological Review. In 1997, her article won an award from the American Psychological Association, the George A. Miller Award for an Outstanding Recent Article in General Psychology. Yes, as Harris herself puts it, God has a sense of humor.

In her 1995 article, and then in her 1998 book The Nurture Assumption: Why Children Turn Out the Way They Do, Harris methodically demolishes the universally held assumption that how parents raise their children is a major determining factor in how they turn out.

Harris instead argues that parental socialization has very little effect on children because they are mostly socialized and influenced by their peers. While Harris’s conclusion was enormously controversial and widely condemned by politicians and the media alike, it is in fact corroborated by behavior genetic research.

Behavior geneticists decompose total variance in personality and behavior into three components: heritability (genes), shared environment (everything that happens within the family that makes siblings from one family similar to each other but different from those from another family), and unshared environment (everything that happens within and outside the family that makes siblings from one family different from each other).

Behavior geneticists contend that the rough rule of thumb when it comes to the determinants of child development is 50-0-50, that is, roughly 50% of the variance in personality, behavior, and other traits is heritable (influenced by genes), roughly 0% by the shared environment (what happens within the family and is experienced by all siblings), and roughly 50% by the nonshared environment (what happens inside and outside of the family, not shared by siblings).

I found an interesting exchange of 6 letters between Judith Harris and Jerome Kagan, back in 1998.

And this from Nancy McDermott, in 2019.

In one of my first email exchanges with Judith Rich Harris – the American psychology researcher and author, who sadly died just before New Year – I told her that I had managed to work her book, The Nurture Assumption, into every conversation for weeks. So much so that my husband pulled me up when I neglected to mention it over dinner: ‘What? Judith Rich Harris has nothing to say about meatloaf?’ I replied: ‘I bet she would if she were here!’

‘You’ve got me pegged’, Harris told me. ‘I’ve got more opinions than I know what to do with.’

When I interviewed her for spiked back in 2009, she was putting the finishing touches to the second edition of The Nurture Assumption: Why Children Turn Out The Way They Do, and, lucky for me, she was keen to take every opportunity to correct some of the misconceptions about the book that had proliferated since its publication 10 years earlier.

…’I hoped that parents would feel less guilty about every little thing they do, and that they would be more spontaneous and natural’, she said. But she was also fiercely motivated to follow the evidence in pursuit of the truth – wherever it might lead and no matter whom it might offend. It was this dedication that led Harris – who had been kicked out of Harvard’s department of psychology because, in her own words, ‘they didn’t think I’d amount to much’ – to the conclusion that the prevailing wisdom about child psychology was wrong.

…Reading her story, I often picture Harris, a diminutive woman with short cropped silver hair, as a sort of Joan of Arc figure. Not only did she eviscerate her critics in The Nurture Assumption, the book that grew out of her original article, but she also went on in her next book, No Two Alike, to advance her own theory of group socialisation and human individuality. Together they formed the basis of a new way of thinking about child development that takes human nature into account.

…Harris addressed some of the misunderstandings in my interview with her. It particularly irked her that the media condensed her message into the idea that ‘parents don’t matter’. ‘What I actually said’, she told me, ‘was that parents have no long-term effects on their children’s personalities or on the way that they behave when they’re outside the home. That doesn’t mean that parents don’t matter – they have other roles to play in their children’s’ lives. If I convince you that you can’t modify your husband’s personality, would you conclude that Wives Don’t Matter?’

Twenty years on from The Nurture Assumption, few parents today really believe it is possible to mould children to be musicians, dancers or athletes if they have no natural talent or inclination, or to turn introverts into extroverts. Most parents are fairly attuned to their children’s talents and temperament. But they still believe they can mould them indirectly by curating their experiences.