Genetics accounts for more than half of variation in exam results

[AngryAmish]

Environment, including home and school life, is a less important factor in pupils' GCSE results than genes, study suggests

http://www.theguardian.com/science/2013/dec/11/genetics-variation-exam-results1

"Differences in children's exam results at secondary school owe more to genetics than teachers, schools or the family environment, according to a study published yesterday.

The research drew on the exam scores of more than 11,000 16-year-olds who sat GCSEs at the end of their secondary school education. In the compulsory core subjects of English, maths and science, genetics accounted for on average 58% of the differences in scores that children achieved.

Grades in the sciences, such as physics, biology and chemistry, were more heritable than those in humanities subjects, such as art and music, at 58% and 42% respectively.

The findings do not mean that children's performance at school is determined by their genes, or that schools and the child's environment have no influence. The overall effect of a child's environment – including their home and school life – accounted for 36% of the variation seen in students' exam scores across all subjects, the study found."

Can we finally stop blaming teachers for poor results?

[Jackpine Radical]

1. Of course genetics is important; however, the issue is far more complicated than

these twin studies would make it appear.

First, people tend to treat identical twins differently than they do fraternal twins, dressing them alike, giving them similar-sounding names, providing them with nearly-identical experiences in life, confusing them with each other, etc. Thus the "identical twin experience" is conflated with genetics.

Second, the fraternal twins are generally reared in the same households, which provide very similar environments, thus reducing the amount of variance available to be accounted for by environmental factors.

Some attempts have been made to compare identical versus fraternal twins reared in different environments, e.g. through adoption at early ages. In these studies, the impact of the environment appeared to be somewhat greater; however, because of adoption procedures just about everywhere in the First World, kids tend to get adopted into similar (generally middle-class) families, thereby still reducing the available environmental variance.

Only a study in which fraternal and identical twins are randomly assigned individually to families across the socioeconomic and cultural spectrum could you have a true test of the heredity/environment question. Nobody in their right mind is contemplating such a study, for reasons that should be obvious.

[sendero]

10. I read an EXHAUSTIVE study..

.. of 18 identical twins separated at birth and raised in mostly polar opposite environments (in the late 80s). The study concluded WITHOUT EQUIVOCATION that genetics had more to do with mood, disposition, mental health and performance than any environmental factor. In almost every case of the 18 sets of twins studied, those who were depressed or had other issues BOTH HAD THE SAME ISSUE even though their life circumstances were practically opposite. Not only that, but these issues tended to manifest AT THE SAME AGE.

This is not to say that one's potential is strictly determined by their genetics but IMHO the day you are born that is your lottery winnings and you will have to make the best of them.

Of course there are numerous studies that show how environment affects outcomes. No doubt that if you are put into a rough enough situation it is going to drag you down.

I think many "science facts" come with viewpoints of the scientist built in and that is one reason even largely undisputed science like climate change is easily seen as dubious in the minds of many. Too many times things that are accepted as "science fact" turn out not to be fact at all, especially with medical, social, psychological and mental health issues.

FWIW I found the study compelling and persuasive, and I believe in its conclusions (that your genetics has more to do with who you are than any other factor by a large margin).

[Egalitarian Thug]

18. You're right and we are learning just how prevalent it is almost every day.

So many of the sciences are mired in erroneous preconceptions, many coming out of the completely perverse era known as the "Victorian".

The absurd weeding process to get in and the stupidly dangerous internship and residency requirements we put doctors through, are a good example. 19th century idiocy and the Victorian mindset that insists on limiting the supply of doctors for no reason beyond profiting at the expense of society.

[El_Johns]

2. "heritable" is a misleading concept. Height is 100% heritable, yet pre-war Japanese were

significantly (something like 5 inches) shorter than post-war generations, and the current generation is comparable with Americans.

[Jackpine Radical]

5. Heritability is a statistical concept, i.e. the portion of variance in a given study

that is attributed to the genetic factor. It will vary depending of the circumstances of the study. For example, if the environment is held constant for all the cases, then the genetic component is the only thing left free to vary. If, on the other hand, there is wide variation in the environmental histories of the study subjects, then the environmental variables are likely to account for a larger portion of the variance. Analysis of variance (and sometimes multiple regression, which is mathematically equivalent to analysis of variance) has of course been for many years the standard statistical model employed in these investigations.

[El_Johns]

7. I don't think I'm saying anything different from you. I'm saying that "heritability" is often

mistaken to mean "inherited fraction" v. "environmental fraction", but it doesn't mean that.

Think about the relative heights of men in a poor village in an underdeveloped country 100 years ago. The average height for these malnourished men might be 5 feet 2 inches. The heritability in observed heights within this particular society can be quite high; men of tall fathers are on the average considerably taller than men of short fathers. However, this does not mean that a program of improved sanitation and nutrition could not significantly raise the average height of this group in a few generations.

This reflects one of the many significant errors of Herrnstein and Murray's controversial 1994 book, The Bell Curve.

The error is to assume that genetic variation that can account for variation within a group is also the reason for the variation between groups. The converse is also true. Even if the heritability of a trait is 0, it can still be tremendously affected by genetic factors.

http://apcentral.collegeboard.com/apc/members/homepage/45829.html


Personally I have no idea how anyone could make the claim that "genetics" is responsible for more than half the variation in test scores.

[Jackpine Radical]

8. As to that last sentence, it is generally a mis-statement of the observation

that half the variance in a given trait within a given population is attributable to a measure of some kind that is taken as an operational definition of "genetics." It is not merely an oversimplification, it is incorrect.

[Thirties Child]

3. Genetics and environment work together

It seems to me that genetics is the switch, the environment the trigger - environment can't trigger a switch that isn't there, and the switch can remain in the off position if there are no triggers. This isn't true 100%, at least in health, e.g., if you inherit two genes for cystic fibrosis you're going to have cystic fibrosis.

Nature vs. nurture is another way of saying it. I inherited my father's nervous system - would much prefer my mother's - but we had different experiences playing off that nervous system.

[AngryAmish]

4. A lot of people are very invested in the idea that we are all a "blank slate".

That if every child was given an excellent education we all could get a degree in astrophysics. That is not true. Some people have the wherewithal to understand calculus, some like me do not. Education should be tailored to the interests and abilities of each child. THis bs of NCLB sees to think that if we just push everyone then everyone can be above average. It is a waste of teachers and students time.

In other words, do not forget about the kids with below 100 IQ. They count. They shouldn't go to college most likely but they need to learn things that will help them later in life. How to read well, how to do everyday maths, get a skill or apprenticeships. Heck, some basic home ec, on what foods are good or bad, how to cook some things, how to make lists and pay bills. This would help so many people but it is looked down upon by most in the education field.

[Yo_Mama]

6. Except that no such thing is proved

by studying identical twins, who almost always share a home/socio-economic environment that is much more similar than even fraternal twins or other siblings.

I don't mean to be mean, but this is witless reporting.

I do agree that teachers get blamed for a lot of things that they cannot affect, but I can't stand this type of misrepresentation. If the title said "other factors" I could agree with it.

[Jackpine Radical]

9. Yes, these are some of the points I was trying to make in posts 1 & 5 above.

[bemildred]

11. Seems like a dumb study. Both genetics and environment are necessary to the result.

And likely unfalsifiable twaddle too boot. It all hinges on what "accounts for" means in practice, how does one compute that number as "more than half"? Based on what?

But environment is the only one we can do much about, anyway.

[Donald Ian Rankin]

12. Studies of identical and fraternal twins. So at least the principle isn't twaddle.

I haven't checked the details of the methodology, so I can't vouch for it, but my guess is that your dismissal has more to do with the fact that the result is uncomfortable than with analysis of the method?

[bemildred]

17. Right, I must be being emotional about it, is that your argument?

I'm not uncomfortable with it, I think it's a dumb argument, you can't really separate the two "causal" factors, neither has any effect or meaning without the other.

Good nurture will never make a dog as smart as a human, but you can take a really smart human and make him little better than a dog with sufficiently bad nurture, so I think you have to look at genetics ("nature&quot as the context in which nurture acts, and then talk about the minimal level of nurture all of us are entitled to as a matter of having a fair chance to develop our inherited capabilities. When you talk about them as separate, you stop making sense too, neither makes any sense without the other as context.

[AngryAmish]

21. They compare monozygotic (identical) twins to dizygotic (fraternal) twins (and siblings and control)

Identical twins share the same DNA (mostly). Compared to fraternal twins the identical twins had much more similar scores, so the conclusion is that having same DNA means your scores are more similar and thus the DNA of a person determines a trait (test scores) rather than the enviroment.

[bemildred]

22. Right, I question all that. Consider this study here:

It pays to be pretty, starting in high school, research says

http://www.democraticunderground.com/1014674275

If I take your logic and apply it there I conclude that good looks determines intelligence because good lookers get better grades. Causation is not that simple.

[AngryAmish]

23. I think that you are missing the point.

Nobody is saying identical twins are smarter or duller than fraternal twins. They are saying that their scores are more similar (high, medium or low) than fraternal twins. So if one identical twin scores an 85 on a test, then the other twin is half again as likely to score near the 85 than a fraternal twin.

Thus, since identical twins has the same DNA, the DNA and how it is expressed makes up around 50% of the reasons for test varience...because the identical twins and fraternal twins have almost the same home enviroment.

[bemildred]

24. Right. nt

[bhikkhu]

13. If you add 58% and 42% to account for the various exam areas, you get exactly half

so it would be more accurate (though perhaps slightly less click-worthy) to say "about half".

"About half" is the conclusion of plenty of studies in the decades long nature vs nurture debate, for how much of our behavior and "who we are" is inherited through genetics and how much depends on our upbringing and environment. The best book I've read on the subject is Steven Pinker's "Blank Slate".

[FarCenter]

14. There have also been studies of virtual twins - unrelated babies adopted and raised together

They are no more similar than unrelated children and less similar than either fraternal or identical twins raised together.

[LittleBlue]

15. Ruh roh

Acknowledging academic performance might be tied to genetics? Can't have this, so blame it on the teachers.

[lumberjack_jeff]

16. You read this article and your first reaction is "Whew! I'm off the hook!"?

I find that an odd reaction to an article with such objectionable implications.

[AngryAmish]

20. I'm not a teacher

I do have an interest in education since I have kids.

What are the objectionable implications?

[Tierra_y_Libertad]

19. Now I understand why math bored the shit out of me.