#robert plomin

“We saw in the previous chapter that shared environmental influence hardly affects personality, mental health or cognitive abilities after adolescence.

This even includes personality traits that seem especially susceptible to parental influence such as altruism, kindness and conscientiousness.

The only exception from hundreds of traits that shows some evidence of shared environmental influence is religious and political beliefs.

As a parent, you can make a difference to your child’s beliefs, but even here shared environmental influence accounts for only 20 per cent of the variance. (…)

As a parent, you feel deep down that you can make a difference in how your children develop.

You can help children with their reading and arithmetic. You can help a shy child overcome shyness.

Also it seems as if you must be able to make a difference because you are bombarded with childrearing books and the media telling you how to do it right and making you anxious about doing it wrong.

(These books are, however, useful in providing parenting tips, for example, about how to get children to go to sleep, how to feed fussy children and how to handle issues of discipline.)

But when these bestselling parenting books promise to deliver developmental outcomes, they are peddling snake oil. (…)

If we are happy and confident, we might credit this to our parents’ love and support.

Or if we are psychologically damaged, we might blame this on inadequate parenting.

However, the implications of genetic research are just as applicable here. 

These differences in parenting are not correlated with differences in children’s outcomes once you control for genetics. 

A major study of the use of growth mindset in schools in England has found that it made no difference to pupils’ English or maths results.

Growth mindset, a concept developed by Stanford professor Carol Dweck, is the idea that an individual’s learning can be improved if they believe that their intelligence can grow through hard work.

The theory has become popular in schools in England but is also controversial, with geneticist Robert Plomin claiming it is a “gimmick”.

Now, a study of 5,018 10- and 11-year-old pupils funded by the Education Endowment Foundation (EEF) has found that pupils who were taught after their teachers had been on the Changing Mindsets project, delivered by the University of Portsmouth, made no additional progress to those in a control group.

"The independent evaluators found that pupils who received the intervention didn’t make any more progress than those who did not," said Sir Kevan Collins, chief executive of the EEF.

…

The new evaluation, which was carried out by the National Institute of Economic and Social Research, found that pupils who had been part of the project did no better in the Sats tests in reading, spelling, punctuation and grammar (Spag) and maths at the end of Year 6 than those who were not part of the project.

Sam Harris:

“What you’re saying is that, for virtually everything in psychology and human difference one could care about,

from intelligence to Big Five personality traits, to susceptibility to things like depression and schizophrenia,

the punchline here is that something like 50% of human difference is accounted for by genes.

And the other half is environment, but it is not the environment that parents or anyone else can systematically control.

And for the environmental component of things, very often half of what’s ascribed to the environment is actually genes in disguise.

Because people, based on their own genetic proclivities, wind up shaping their environment.”

Robert Plomin:

“(…) When we find correlation, like between parents reading to kids, and kids’ reading ability at school, you can’t assume that’s environmental.

They’re often genetic effects in disguise.

I find that what helps people put these two things together is if I tell you that one of your daughters had been switched at birth in the maternity ward, and raised in a different family,

she would have grown up to be very similar to who she is, even though she was raised in a different family.

That’s not hypothetical. We have studies of [genetically] identical twins reared apart.

This wonderful documentary that won an award last year, called Three Identical Strangers, is about three identical twins and just how similar they are despite being raised in quite different family environments.”

Abstract

“This is an example of the larger dilemma of what to do if we find out that we have a hefty genetic risk for a disorder that we can’t do much about.

For some problems, it is useful to know if you are at high risk because there are things you can do to lessen your risk.

A good example is learning that I am at high genetic risk for being overweight. Obviously, there are things I can do about that.

However, there are some psychological problems that you can’t do much about at present, such as finding out that you have a high genetic risk for schizophrenia.

Worse, what if your child has a high genetic risk for schizophrenia?

As yet, there is little we can do to prevent these problems, other than common-sense things like avoiding mind-altering drugs. (…)

Although parental curiosity about their children’s future might seem frivolous or even dangerous, good can come from parents getting a genetic glimpse of their children’s individuality – their strengths and weaknesses, their personalities and their interests.

This information might help parents to try to maximize their children’s strengths and minimize their weaknesses.

There are many examples of how polygenic score information could be useful to intervene to prevent problems, or at least to be forewarned about them.

For example, polygenic scores will be able to predict reading disability.

“Most people accept that DNA matters for psychological traits, even though they underestimate its influence.

I hope my reading of the zeitgeist is correct because, otherwise, there would be a huge amount of research to review, many tens of thousands of studies, with more than 20,000 papers published during the past five years alone.

It would be boring to condense this research here because the bottom line message is similar for all areas of psychology. 

As you can see in Table 2, psychological traits are all substantially heritable, about 50 per cent on average. 

Heritability is so ubiquitous that this has been called the first law of behavioural genetics: All psychological traits show significant and substantial genetic influence. (…)

Subsequent research has shown that certain personality traits account for a third of the genetic influence on divorce.

Surprisingly, people are more likely to get divorced if they are joyful and engaged with life, emotional and impulsive.

These are not bad aspects of personality – indeed, they might be the same good traits that make people desirable as marriage partners in the first place. 

It has long been known that the offspring of divorced parents are more likely to get divorced themselves. 

Possible environmental explanations leap to mind, for example, living through their parents’ divorce causes children to have relationship problems, or because they do not have good models for a stable relationship. 

However, a recent adoption study in Sweden showed that the link between divorce in parents and divorce in their children is forged genetically, not environmentally.