12 of 12
12
The worst news ever
Posted: 15 October 2008 02:57 PM   [ Ignore ]   [ # 166 ]
Moderator
Avatar
RankRankRankRankRankRankRankRankRankRank
Total Posts:  4108
Joined  2006-11-28

Sorry to start up the genes and IQ discussion again for those who aren’t interested, but here we go so BE WARNED!

HERE is a recent article in Scientific American about genes and IQ. Short of detail, as always, but a few interesting points. One has to do with the argument I frequently make that environment can override at the extremes and determine how influential genes are.

genes do not act in isolation from the environment. In fact, the same gene can have different effects in different environments. Turk­heimer was led to this realization when he noticed that the large twin studies on intelligence contained few poor children…He was able to analyze the test scores of hundreds of twins, taking into consideration their socioeconomic status—a category based on factors that include a family’s income and the education level of the parents. He found that the strength of genes’ effect depended on the socioeconomic status of the children. In children from affluent families, about 60 percent of the variance in IQ scores could be accounted for by genes. For children from impoverished families, on the other hand, genes accounted for almost none…in May 2007 they replicated the pattern with another database. Instead of comparing IQ scores, the researchers looked at how 839 pairs of twins fared on the National Merit Scholarship Qualifying Test in 1962. Once more genes played little role in the variance of scores among poor children and played a far stronger one in more affluent children. Turkheimer posits that poverty brings with it powerful environmental forces that may shape intelligence from the womb through school and onward. But when children grow up in the relative stability of an affluent home, gene-based differences can begin to make themselves felt.

 Signature 

The SkeptVet Blog
You cannot reason a person out of a position he did not reason himself into in the first place. 
Johnathan Swift

Profile
 
 
Posted: 15 October 2008 04:30 PM   [ Ignore ]   [ # 167 ]
Sr. Member
Avatar
RankRankRankRankRankRankRankRankRankRank
Total Posts:  7684
Joined  2008-04-11

So what he is saying in effect is if you suffering from chronic starvation, it is hard to appreciate that you’re eating a gourmet meal-it’s just sustenance!

 Signature 

Church; where sheep congregate to worship a zombie on a stick that turns into a cracker on Sundays…

Profile
 
 
Posted: 15 October 2008 05:14 PM   [ Ignore ]   [ # 168 ]
Moderator
Avatar
RankRankRankRankRankRankRankRankRankRank
Total Posts:  4108
Joined  2006-11-28

That’s one way to read it. grin

I take it to mean just that while genes are important, theri improtance depends on the background circumstances. Genes for being a genius won’t make you one if you suffer brain damage from severe malnutrition as a child. Weh everyone has basically adequate environmental conditions, then genes become mroe improtant in determining differences between us.

 Signature 

The SkeptVet Blog
You cannot reason a person out of a position he did not reason himself into in the first place. 
Johnathan Swift

Profile
 
 
Posted: 15 October 2008 06:11 PM   [ Ignore ]   [ # 169 ]
Sr. Member
Avatar
RankRankRankRankRankRankRankRankRankRank
Total Posts:  7684
Joined  2008-04-11
mckenzievmd - 15 October 2008 05:14 PM

That’s one way to read it. grin

I meant it metaphorically!

 Signature 

Church; where sheep congregate to worship a zombie on a stick that turns into a cracker on Sundays…

Profile
 
 
Posted: 15 October 2008 10:02 PM   [ Ignore ]   [ # 170 ]
Moderator
RankRankRankRankRankRankRankRankRankRank
Total Posts:  5508
Joined  2006-10-22

I agree witt most of the article, but while I do feel that genes determine the potential, other factors besides malnutrition and brain damage can affect final apparent intelligence.  My oldest stepdaughter was speaking full sentences when she was nine months old, and tested as superior in elementary school.  She always got excellent nutrition.  However, she was gorgeous as a child and grew up to be model quality.  She was extremely popular with all the other kids, male and female, my wife and I are academically oriented and my daughter (from my first marriage) and some of the other step-kids did well in school and we have one lawyer, two engineers, and one teacher.  However, the one who demonstrated the highest early intelligence is a hairdresser.  mind boggling.

Occam

Profile
 
 
Posted: 15 October 2008 10:08 PM   [ Ignore ]   [ # 171 ]
Sr. Member
Avatar
RankRankRankRankRankRankRankRankRankRank
Total Posts:  7684
Joined  2008-04-11
Occam - 15 October 2008 10:02 PM

I agree witt most of the article, but while I do feel that genes determine the potential, other factors besides malnutrition and brain damage can affect final apparent intelligence.  My oldest stepdaughter was speaking full sentences when she was nine months old, and tested as superior in elementary school.  She always got excellent nutrition.  However, she was gorgeous as a child and grew up to be model quality.  She was extremely popular with all the other kids, male and female, my wife and I are academically oriented and my daughter (from my first marriage) and some of the other step-kids did well in school and we have one lawyer, two engineers, and one teacher.  However, the one who demonstrated the highest early intelligence is a hairdresser.  mind boggling.

Occam

One of the things one of my highly intelligent sons had to work through was a fear of failure. If you don’t do anything too mentally strenuous, you will never fail. He knew he was intelligent, his teachers knew he was intelligent, but he was afraid that if he tried something difficult and did not do well, people would think less of his intelligence. Warped thinking, took me years to turn it around. Perhaps your daughter has a bit of that going on.

 Signature 

Church; where sheep congregate to worship a zombie on a stick that turns into a cracker on Sundays…

Profile
 
 
Posted: 16 October 2008 06:58 AM   [ Ignore ]   [ # 172 ]
Sr. Member
Avatar
RankRankRankRankRankRankRankRankRankRank
Total Posts:  9301
Joined  2006-08-29

Deleted by a mistake. Sorry.

[ Edited: 17 October 2008 01:44 PM by George ]
Profile
 
 
Posted: 16 October 2008 01:46 PM   [ Ignore ]   [ # 173 ]
Moderator
Avatar
RankRankRankRankRankRankRankRankRankRank
Total Posts:  4108
Joined  2006-11-28

George,

Essentially yes. HERE is the original paper.

He looked at twins from a database commonly used for such research (basically a pool of twins with varying histories, including raised together or apart) and looked to see if there were statistical interaction effects between socioeconomic environment and genes and IQ. What he found is similar to the point I have made in our previous discussions: IQ is heritable, the percent of variance in IQ explained by genes is relatively high (the 50-70% Pinker uses) IF the kids studied are all in fundamentally adequate developmental environments.And the difference between and adequate environemtn and one with every toy and parenting gimmick to increase IQ available is about zero. But in impoverished environments, circumstances do not allow the normal expression of underlying genetic patterns, and the difference between these conditions and the other two are huge, so IQ in these cases is primarily determined by environment.

[ Edited: 17 October 2008 07:03 AM by mckenzievmd ]
 Signature 

The SkeptVet Blog
You cannot reason a person out of a position he did not reason himself into in the first place. 
Johnathan Swift

Profile
 
 
Posted: 17 October 2008 06:06 AM   [ Ignore ]   [ # 174 ]
Sr. Member
Avatar
RankRankRankRankRankRankRankRankRankRank
Total Posts:  9301
Joined  2006-08-29

This is all very interesting, Brennen. It raises many questions and clearly shows how little we now about epigenetics. I wonder, if a child who doesn’t develop his intelligence due to the environmental circumstances will pass his now low IQ to his children. I guess the answer would be no, since his parents are also poor and the child has the potential to succeed in life if given proper care. On the other hand, I read somewhere that famine, for example, can affect generations to come. In other words, epigenetic traits can probably be inheritable—or at least some of them.

This should clearly be of a great concern to any government. If epigenetic traits can be passed onto future generations, then by not dealing with issues like poverty can result in very undesirable outcomes for the whole country.

BTW, the link you provided doesn’t work. I assume you found it on Turkheimer’s home page, right? There are many interesting papers on his website. I will go through them as I find this absolutely fascinating.

[ Edited: 17 October 2008 06:08 AM by George ]
Profile
 
 
Posted: 17 October 2008 07:04 AM   [ Ignore ]   [ # 175 ]
Moderator
Avatar
RankRankRankRankRankRankRankRankRankRank
Total Posts:  4108
Joined  2006-11-28

Thanks for pointing out the borekn link, George. No idea why it doesn’t work, but I just linked to his CV list instead and that seems to work. Yes, fascinating stuff, and lots to learn yet.

 Signature 

The SkeptVet Blog
You cannot reason a person out of a position he did not reason himself into in the first place. 
Johnathan Swift

Profile
 
 
Posted: 17 October 2008 01:44 PM   [ Ignore ]   [ # 176 ]
Sr. Member
Avatar
RankRankRankRankRankRankRankRankRankRank
Total Posts:  9301
Joined  2006-08-29

I have now read the paper; I probably understood about 10% of it. I can’t stop thinking about one thing though: what if the reason why Turkheimer cannot find any IQ heritability in the poor compared to the middle class and the rich is simply because there isn’t enough IQ variance in the poor population? When I read in a Washington Post article that:

Plomin said his own unpublished work involving 4,000 pairs of twins has not produced the same results as Turkheimer’s. “We’ve looked at this for families unemployed, on state support and living in subsidized housing, and we still don’t find it, even at that low level” of socioeconomic status, he said.

it only seemed to confirm my suspicion that Turkheimer’s 623 twin pairs (“320 of whom were successfully located by the original researchers and tested for IQ at age 7 in the 1970s”) were probably not enough to find any significant difference that would help him to find any IQ heritability. Again, the reason for that being is that IQ of the poor population probably doesn’t vary that much.

Maybe it’s like asking a tone deaf person if he thinks that Bach is better than Mozart.

Profile
 
 
   
12 of 12
12