More on Intelligence and Heritability

[Taraz]

Last week I had the pleasure of attending a talk given by James Flynn, a prominent intelligence researcher who has tried to explain what is known as the Flynn Effect. He raised some very interesting ideas and theories that I thought many of you would enjoy.

Basically, the Flynn Effect refers to the universal rise of IQ scores across the globe over time. Scores have risen continuously since the inception of the tests and this poses a problem for those who believe that genes are the dominant determinant of intelligence. If environment only plays a small part and intelligence is mostly about your genes, why would we see such huge IQ gains from generation to generation?

He did a remarkable job of explaining why the concept of general intelligence, or g, is flawed and actually blinds us to what might actually be occurring. He points to the fact that IQ tests with similar g-loadings (the degree to which a test reflects g) have had quite disparate gains over time.

The thrust of his argument is the proposal of what he termed the Dickens/Flynn model of intelligence. It was pretty stunningly brilliant in it's simplicity. Your genes will have a profound effect on your subsequent environment throughout life. He gave the analogy of identical twins separated at birth who happen to be a bit taller than average due to their genetic makeup. In elementary school, they will be picked first on the playground to play basketball because of their height. This might lead them to prefer basketball over other sports. In middle school, the coaches might see their height advantage and spend a bit more time instructing them. In high school they will receive even more special attention and so on. By the time they reach college, they have received a ton more attention and instruction in basketball than their peers, only it is their genes that are given the credit! Basically, a small genetic difference gets compounded many times by environmental factors and results in a large difference when it is all said and done.

If you have a small genetic advantage in intelligence, your teachers may pick up on it and treat you differently. Research has already shown that teacher perception can vastly increase performance in the classroom even if that perception is false. You will then be placed in the honors tracks and get even more attention, etc., etc. So while it may seem that the intelligence displayed by a bright adult is due to a genetic advantage, this individual has actually received an huge environmental advantage because of this genetic advantage.

I want to note that Flynn believes that genes do play into the equation, but that environmental factors are far, far more explanatory than genetics. If you are interested I found a short article he wrote about the subject, it's really cool stuff.

http://www.cato-unbound.org/2007/11/05/j...-interventions/

[yukoncpa]

[ QUOTE ]
Last week I had the pleasure of attending a talk given by James Flynn, a prominent intelligence researcher who has tried to explain what is known as the Flynn Effect. He raised some very interesting ideas and theories that I thought many of you would enjoy.

Basically, the Flynn Effect refers to the universal rise of IQ scores across the globe over time. Scores have risen continuously since the inception of the tests and this poses a problem for those who believe that genes are the dominant determinant of intelligence. If environment only plays a small part and intelligence is mostly about your genes, why would we see such huge IQ gains from generation to generation?

He did a remarkable job of explaining why the concept of general intelligence, or g, is flawed and actually blinds us to what might actually be occurring. He points to the fact that IQ tests with similar g-loadings (the degree to which a test reflects g) have had quite disparate gains over time.

The thrust of his argument is the proposal of what he termed the Dickens/Flynn model of intelligence. It was pretty stunningly brilliant in it's simplicity. Your genes will have a profound effect on your subsequent environment throughout life. He gave the analogy of identical twins separated at birth who happen to be a bit taller than average due to their genetic makeup. In elementary school, they will be picked first on the playground to play basketball because of their height. This might lead them to prefer basketball over other sports. In middle school, the coaches might see their height advantage and spend a bit more time instructing them. In high school they will receive even more special attention and so on. By the time they reach college, they have received a ton more attention and instruction in basketball than their peers, only it is their genes that are given the credit! Basically, a small genetic difference gets compounded many times by environmental factors and results in a large difference when it is all said and done.

If you have a small genetic advantage in intelligence, your teachers may pick up on it and treat you differently. Research has already shown that teacher perception can vastly increase performance in the classroom even if that perception is false. You will then be placed in the honors tracks and get even more attention, etc., etc. So while it may seem that the intelligence displayed by a bright adult is due to a genetic advantage, this individual has actually received an huge environmental advantage because of this genetic advantage.

I want to note that Flynn believes that genes do play into the equation, but that environmental factors are far, far more explanatory than genetics. If you are interested I found a short article he wrote about the subject, it's really cool stuff.

http://www.cato-unbound.org/2007/11/...interventions/

Post Extras



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The human genome has been cracked, what isn’t known is how exactly various genes and combinations of genes act on the body. Please explain now, which gene, or combination of genes contribute to intelligence. What brain gene or gene combination shows up in white people that doesn’t show up in black people? Prove that it is genetics. This should be a trivial thing for scientists in the near future.

edit - I'm only using white people v. black people as my own example, because these debates seem to alway diverge on race. My guess is there is a smart gene that is a complete random mutation that effects everyone, including all races alike. Prove me wrong.

[Taraz]

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The human genome has been cracked, what isn’t known is how exactly various genes and combinations of genes act on the body. Please explain now, which gene, or combination of genes contribute to intelligence. What brain gene or gene combination shows up in white people that doesn’t show up in black people? Prove that it is genetics. This should be a trivial thing for scientists in the near future.

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I think you're asking the wrong person. I am one of the ones in this debate who thinks that "intelligence" is practically a meaningless term because it can't be defined. In fact, I think Flynn agrees with me to a large degree. I think all we're really doing right now is explaining differences in performance on certain tests and tasks.

[ QUOTE ]

edit - I'm only using white people v. black people as my own example, because these debates seem to alway diverge on race. My guess is there is a smart gene that is a complete random mutation that effects everyone, including all races alike. Prove me wrong.

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I think the burden of proof would fall on you. We have lots of evidence that environmental factors contribute to intelligence to a large degree. You should have to prove that there is a single gene that is actually the real determining factor.

[tame_deuces]

A very nice post. Really the mere fact that intelligence scores have risen continuously since the tests were made less than 100 years ago should alone be proof enough that culture is a very significant contributer to the intelligence measure.

But this is common in psychology also, as I'm sure you have seen in other areas too. We 'within' the field are aware of the methodological limitations of measures and models, but when they 'go public' these limitations are forgotten and the models used in a near Newtonian fashion. Which can have potentially extremely negative consequences.

[Taraz]

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But this is common in psychology also, as I'm sure you have seen in other areas too. We 'within' the field are aware of the methodological limitations of measures and models, but when they 'go public' these limitations are forgotten and the models used in a near Newtonian fashion. Which can have potentially extremely negative consequences.

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I think the problem stems from media reporting which sensationalizes the issue and from scientists who make more outlandish claims to get more recognition. It is quite annoying, but it is difficult to spread information to the masses in any other way.

[Phil153]

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A very nice post. Really the mere fact that intelligence scores have risen continuously since the tests were made less than 100 years ago should alone be proof enough that culture is a very significant contributer to the intelligence measure.

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I disagree. The case in the OP is quite overstated - they've risen in some areas and on some tests and not in others. Further, heights have also risen - can I conclude from that fact that:

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Really the mere fact that heights have risen continuously in the last hundred years should alone be proof enough that culture is a very significant contributer to height.

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This is what I mean about hard sciences vs soft.

There are a number of suggested reasons for these scores that don't involve environment being key. The effects of two massive world wars and a worldwide depression are a possible answer - most of these tests compare the period around the 50s and 60s with today. Such events may have depressed the scores of entire generations. We simply don't have much data from before then.

Furthermore, those using this to explain away the race gap are missing some important points. The first is that, from what I've read, the improvements in score are occurring almost entirely in the bottom half. This suggests that a number of people - the poorest whites - weren't fulfilling their intelligence potential. My claim has always been that intelligence potential is capped by genes and varies highly between individuals and between races, not that something like poor nutrition isn't important in depressing a score. Secondly, I'd need to know how widespread the data actually is. It's claimed to be global but I'd say the actual data available is far worse than that available to Intelligence and the Wealth of Nations, for example. Thirdly, other groups have benefited from many of the proposed reasons for the increase, yet the differential remains large and not that dissimilar to what it was prior to massive improvements in living and educational conditions for one particular group.

[Phil153]

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I think the problem stems from media reporting which sensationalizes the issue and from scientists who make more outlandish claims to get more recognition. It is quite annoying, but it is difficult to spread information to the masses in any other way.

[/ QUOTE ]
Are you serious? The default position in the media and academia today is that everyone is equal and that differences are 100% environmental.

[Taraz]

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I think the problem stems from media reporting which sensationalizes the issue and from scientists who make more outlandish claims to get more recognition. It is quite annoying, but it is difficult to spread information to the masses in any other way.

[/ QUOTE ]
Are you serious? The default position in the media and academia today is that everyone is equal and that differences are 100% environmental.

[/ QUOTE ]

I was referring to the problem that the public is not aware of the methodological limitations of certain studies. Basically that the actual conclusions of science are quite often overstated and sensationalized to sell to the masses.

[Taraz]

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[ QUOTE ]
A very nice post. Really the mere fact that intelligence scores have risen continuously since the tests were made less than 100 years ago should alone be proof enough that culture is a very significant contributer to the intelligence measure.

[/ QUOTE ]
I disagree. The case in the OP is quite overstated - they've risen in some areas and on some tests and not in others. Further, heights have also risen - can I conclude from that fact that:

[ QUOTE ]
Really the mere fact that heights have risen continuously in the last hundred years should alone be proof enough that culture is a very significant contributer to height.

[/ QUOTE ]

[/ QUOTE ]

I agree with you that the simple increase in test scores doesn't prove that culture is a determining factor, but it does raise an interesting question that needs to bee looked at. If you look at it another way, many people from the 50s and 60s would be classified as mentally retarded today even though that is clearly not the case. Flynn gave an interesting account of what could be going on. If they ask what dogs and rabbits have in common, you get full points if you say they are both mammals but no points if you say that you use dogs to hunt rabbits. The "correct" answer depends on your environment/culture/society. In many areas (and more often than not in the past in general) utility is more important than classification. Knowing that dogs and rabbits are in the same family doesn't help you much, but knowing how to use dogs to hunt helps you get food. Our society is getting more and more scientific and classification is becoming a more important tool. He suggests that the makers of these tests were looking for the scientific answers before they were the normal way of approaching life in the general population.

I think I also mentioned that the disparate increases in scores across different tests in problematic for those that are big believers in g. The increase in scores should be roughly equivalent if the tests both have high g-loadings. If scores increase on one measure by 15 points and only 4 points on another, the tests probably aren't measuring a biological shift in intellectual capacity. It is much more likely that they are testing methods of solving particular classes of problems.

[ QUOTE ]

This is what I mean about hard sciences vs soft.

There are a number of suggested reasons for these scores that don't involve environment being key. The effects of two massive world wars and a worldwide depression are a possible answer - most of these tests compare the period around the 50s and 60s with today. Such events may have depressed the scores of entire generations. We simply don't have much data from before then.

[/ QUOTE ]

I don't think I understand your point here. Why are the scores depressed? If they are measuring genetically based aptitude why would they fluctuate so much? It's also untrue that the tests only measure back 40 or 50 years. The Raven's test is supposed to be the least culturally sensitive test, we have scores dating back 100 years, and this measure has the highest increase in scores from generation to generation! Someone scoring in the highest 10% a century ago would be in the bottom 5th percentile today.

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Furthermore, those using this to explain away the race gap are missing some important points. The first is that, from what I've read, the improvements in score are occurring almost entirely in the bottom half. This suggests that a number of people - the poorest whites - weren't fulfilling their intelligence potential. My claim has always been that intelligence potential is capped by genes and varies highly between individuals and between races, not that something like poor nutrition isn't important in depressing a score.

[/ QUOTE ]

You are correct that the increase in scores is primarily in the lower half of the distribution. Clearly this group was not "fulfilling their potential". But what does this mean? One could easily make the case that those in the bottom half were not immersed in an environment which valued the type of judgments that are necessary in an IQ test. I also don't see how you are interpreting this so that this refers to the poorest whites.

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Secondly, I'd need to know how widespread the data actually is. It's claimed to be global but I'd say the actual data available is far worse than that available to Intelligence and the Wealth of Nations, for example.

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Flynn claims to have data from over 30 countries presently. All I know is that his 1994 paper has data from the following countries: Australia, Austria, Belgium, Brazil, Britain, Canada, China, Denmark, East Germany, France, Israel, Japan, Netherlands, New Zealand, Northern Ireland, Norway, Sweden, Switzerland, United States of America, and West Germany.

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Thirdly, other groups have benefited from many of the proposed reasons for the increase, yet the differential remains large and not that dissimilar to what it was prior to massive improvements in living and educational conditions for one particular group.

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I'm not sure I understand what you mean by this point. Are you saying that the gap between groups hasn't lessened even though the lagging group has received disproportionate improvements in environment? Could you be a bit more specific?

[thesnowman22]

I'm no scientist, but this makes sense to me:

Your genes set a limit as to how smart you will be. The better the genes, the greater potential for intelligence.

Your environment can determine how far up or down you go in your genetic potential. If you are raised in a good home, eat right, are sent to good schools, etc, you come closer to realizing your potential.

Because our world has improved over the years in quality of life, etc. then it follows that IQ scores would have to rise as well.

I would think this would hold true in anything genetic. For example, your genes give you potential to jump a certain height off the floor, but your environment, lifting weightd, exercise, etc. determine how high you can jump.

The two are interelated, but I think the genes limit somewhat your outcomes.