Back in the years before World War I, the I.Q. test was invented in Europe, first by Francis Galton in England, then by Alfred Binet in France. The idea of I.Q. testing was adapted in the United States for use in sorting millions of recruits for the Army, deciding which ones were officer material and which were the troops headed for the front lines.
After the war, American psychologists enthusiastically endorsed I.Q. testing. They were widely adapted and used in public schools to classify students. For many decades, psychologists believed that I.Q. was inherited and unchanging. Those who had high I.Q. were born that way, and those who had lower scores were born that way. But right after World War I, as some psychologists insisted that certain races and ethnic groups were superior to others, a few dissident psychologists (William Bagley comes to mind) discovered an inconvenient fact: Black students in the North had higher I.Q. scores than white students in the Appalachian South. Bagley and others made the case that environment was powerful in shaping intelligence and that education was key to changing the odds for poor kids. I wrote about this in chapter four of my 2000 book Left Back in a chapter called “I.Q. Testing: “That Brutal Pessimism.” It was Binet, the father of I.Q. testing who wrote in 1909, that we must reject those who “assert that an individual’s intelligence is a fixed quantity, a quantity which cannot be increased. We must protest and react against this brutal pessimism.” (p. 133).
In response to a reader who quoted I.Q. figures by race, I wrote:
You need not bring IQ into the discussion. It is impossible to make accurate generalizations, as impossible as it is to know what part of intelligence can be attributed to nature or nurture.
And in response to me, Robert Shepherd wrote that scientists are learning more and more now about the effects of environment on intelligence.
He writes:
We are currently experiencing a revolution in our understanding of environmental effects on gene expression, and this emerging field of epigenetics completely invalidates those studies with identical twins on which the notion of IQ being highly heritable is based. It turns out that the environmental conditions experienced by the mother affect the conditions within her eggs which in turn dramatically affect gene expression which in turn dramatically affects the resulting phenotype. And, of course, that makes complete sense evolutionarily. For complex traits involving multiple genes, one should think of the genotype not as immutable inheritance but, rather, as a set of switches set in response to environmental conditions experienced by the mother. And that explains why one can get dramatic evolutionary change in very short time frames; in other words, epigenetics is an explanation for punctuated equilibria. All this science is relatively new, and it is revolutionary–paradigm shifting–and popular notions about genetics (including the vast literature of pop and pseudo-scientific evolutionary psychology to which The Bell Curve belongs) haven’t caught up with it. See the following report on a recent epigenetics conference for more information:
Folks who talk the Bell Curve line about immutable genetic inheritances and high heritability and folks who spout those IQ by race figures are talking antiquated, now-discredited nonsense. But it’s understandable that they still believe this crap because the relevant disconfirming science, here, is very, very recent. Another good current account:
http://www.amazon.com/Evolution-Four-Dimensions-Epigenetic-Philosophical/dp/0262600692
Diane Ravitch's blog 
Wow.This is a lot to absorb. but a popularization of these concepts will be a real game changer for the social sciences.
As usual, Robert is ahead of the rest of us. Having spent years as an Early Childhood educator, specializing in Early Intervention for at-risk children, I have seen first hand the role that environment and parenting plays on later education success. For 9 years I spent time in the homes of mostly high poverty families in an effort to provide early intervention prior to entering school. I have seen early intervention succeed with some parents and fail with others. Why? Because nature and nurture are so intermingled that you can never separate one from the other. What I do know for sure is this… Parenting and Environment are the keys. In order to truly change the poverty paradigm, we must start with parents at the earliest stages of an infants development. Healthy brain development, creating healthy neuropathways, and early exposure to positive adult interactions will create healthy learners who will better succeed in school.
I am no neuroscientist, but I know this to be true from my own experiences and graduate level research. At the same time I worked in homes with families, I continued to work as an Early Childhood special education teacher in a public school setting. This gave me a unique perspective for a long term relationship with these families. I later became an administrator and now a district Special Education Supervisor. I have been with these families over the long haul. My first students are now parents. The vicious cycle continues. The relationships built in those early years help me to support these same at-risk students through Middle and High School. There are no magic bullets for success. Those of us in the trenches have known this for a long time. It takes hard work and building relationships. As has been said before, by someone far wiser than myself…. We can’t test our way out of this. The education process begins long before children enter school.
In my “former” life, I was a public defender in Baltimore City. I can tell you without equivocation that many of my clients were extremely intelligent. It was clear to me that had they been raised with the benefits I had as a child, they may very well have ascended to the top ranks of the corporate world, for example, rather than the high ranks of their local drug rings.
What you say about environment influencing IQ seems to go beyond diet, the home and the socioeconomic lifestyle.
It seems that Latitude also has something to do with average intelligence.
First, let’s not mistake a high IQ number as a ticket to success. Even with a high IQ there is no guarantee of a successful life without disciplined goals and motivation.
A child with a high IQ born into an abusive, dysfunctional wealthy family probably has less chance of success than a child with a lower IQ born into a supportive, loving family—a family that is poor but not dysfunctional. I taught a few kids who lived in poerty in a violent, street-gang infested community who went to Cal Tech or MIT or USC or UCLA or Berkeley or Stanford on full-ride scholarships. But that was the exception—not the average.
When compared, a person with a lower IQ who sets goals and is determined to never give up has a much better chance of achieving success than a person with a high IQ with no goals who is a depressed, disturbed couch potato watching several hours of TV daily or who plays endless violent video games.
In fact, serial killers usually have above average intelligence. They are also usually white and between age 25 to 45. For instance, Adolf Hitler’s IQ was 141, but Andy Warhol’s IQ was 86. However, it can’t be denied that IQ helps. See the following list of the IQ’s of famous people [in Hitler’s case infamous]:
http://aceviper.net/estimated_iq_of_famous_people.php
But—according to a University of Central Missouri study, states with cooler average temperatures are more likely to have populations with higher IQs—estimated from scores on a standardized test administered to students.
This finding corroborates a 2006 international study that surveyed 129 countries and found that those with lower temperatures trended toward higher IQs.
The international researchers speculated that evolution was to blame, arguing that ancestors of the frigid folks from high latitudes needed more wits to survive than their equatorial kin—a notion that, given our present malaise, seems at the very least arguable.
http://www.utne.com/science-and-technology/latitude-for-aptitude-temperature-iq-correlation.aspx
I think that IQ is not an indication of racial or cultural superiority. It has to do with adapting to ones environment and survival. Also keep in mind that every race no matter the Latitude has individuals who score at the top of that IQ Bell curve—a lower IQ average for a larger group doesn’t mean everyone has a lower IQ.
I agree that genetics and the environment interact to determine exactly how inherited genes are expressed or how they adapt over time from generation to generation. There are many studies that focus on nutrition—not intelligence/IQ—that provide ample evidence that what we eat as part of our lifestyle choices determines the lifestyle diseases we may get later in life that flips those genetic switches on or off from the nutrition we consume. In fact, a host of studies over several decades have determined that 84% of disease is determined by lifestyle choices.
“Even with a high IQ there is no guarantee of a successful life without disciplined goals and motivation.”
Thank you for making this very salient point, Lloyd. How one is able to utilize innate potential is dependent on many variables.
This posting brings up “inconvenient facts.”
In some circles there will be howls of protest. To be expected given the toxic confluence of innumeracy, lacking of understanding about what standardized tests of all kinds measure and don’t measure, and the charterite/privatizer zeal in massaging and torturing numbers and stats in the interests of labeling, sorting and ranking.
Not unexpectedly, the advantaged find themselves and their children—supposedly by laws natural and divine—at the top of the testing heap. For them, what’s not to like?
If it makes ₵ent¢—even if it doesn’t make sense—there a pot of $tudent $ucce$$ at the end of the High-Stakes Standardized Testing Rainbow for the winners in the EduMetric Sweepstakes.
But could it really be that easy to fool oneself for gain and ego?
Apparently so. It’s been going on for a very long time:
“A man is his own easiest dupe, for what he wishes to be true he generally believes to be true.” [Demosthenes]
So to take your students from the 13th percentile to the 90th, not that hard…
Rheeally!
😎
I would like to believe that most educators have left behind the fixed trait theories of intelligence. There can be no doubt that this concept circulates in the larger culture. There is also a faddish interest in the role of environment in shaping “intelligence” evident in the Baby Einstein pre-natal and infant products.
I work in arts education where the very definition of “intelligence” and intelligent behavior has been expanded by the work of cultural and behavioral anthropologists and many psychologists (before they renamed themselves cognitive scientists).
In the 1950s for example, J.P. Guilford and E. Paul Torrance were among others who developed concepts about and tests bearing on creative thinking–especially ideational fluency and flexibility, elaboration, resistance to closure, humor, fantasy, and originality (uncommon visualization such as thinking outside of the box). Scores on these tests, then relatively new, and the scores were unrelated to other measures of intelligence of that era.
These conceptual distinctions, and some of the non-verbal test items that empirically support them, have been buried in the sea of the Common Core standardized assessments, and discredited by specific actions taken by the Council of Chief School Officers (CCSSO) and other policy makers who are fixated on strictly academic tests that have only one best answer.
Of course, Howard Gardner drew on Guilford’s work, and his medical understanding of brain/behavior functioning in an effort to refresh and expand a conception of intelligence as multifaceted. Unfortunately the popularized version led to a hardening of categories for his theory of “multiple intelligences.”
We are also quick to jump the gun to test kids for special education which in some places continue to rely on the discrepancy rule (IQ & academic achievement). From what I heard is that a disability means it is biological not environmentally caused to qualify for special education and yet many are.
Even within our teaching profession, we inadvertently want to qualify kids for special ed., when much of kids’ prior knowledge and “developmental readiness” (cognitive & social) are simply different learning styles and cultural differences. NOTE: CCS will ramp up the waiting line for special education, if we all agree that CCS & high stakes testing are environmentally influential.
So we have our work cut out for us, if home and school environment (created by ed. reformers) are indicative of our intelligence. Those who come to school traumatized and/or lack of readiness will be unsuccessful trying to keep up with CCS rigor & testing.
Well, IQ is just an estimate quantitative measure of cognitive abilities. Which is just an aspect of overall intelligence.
There are other types of intelligence as well. Such as; Emotional intelligence, social intelligence, environmental intelligence and more.
It is just a mass misconception that if a person has high IQ score then he must be really intelligent. Yeah, he might be a quick learner compared to others but he also might be an emotional fool. An emotional fool is the one who is incompetent of interpreting people’s emotions correctly.
And yes, unarguably, the physical environment does play a very vital role in development of a persons intelligence.
The idea that southern children are not as smart as northern ones goes back to around WW1 and the years following. She was born in 1926 so you know the era My mother’s parents were with the carnival and she would stay with her grandmother in Iowa when they were on the road and start the school year up there. Then, when her parents went into winter quarters in New Orleans she would come down on the train , stay with them, and go to school there. She noticed that the kids in New Orleans were way behind what she was learning up north and when she went back she was behind the northern kids. So I think there must have been an assumption at the time that northern kids were smarter than southern ones. Maybe this followed since the South was largely rural and there were still people around who were slaves and whose families had owned slaves, which was considered ignorant.
Nature and nurture, a persistent debate. And yet you see kids who break the mold. Homeless children, foster children, children of alcoholic and drug addicted parents achieve and go to college. Middle class and upper class kids drop out of school and go to prison. This is where teachers come in. It is why we need to put the best educated and most experienced teachers with the least advantaged children in the most difficult schools and pay them extra both with money and perks for choosing the hardest job. (Not that a spoiled brat who is upper middle class is not much more difficult than most inner city kids. But a lot of people don’t realize that.)
The mantra All Children Can Learn is common in Special Education. I like to add: All children will learn if they have a teacher who believes in them and knows what she is doing.
“Folks who talk the Bell Curve line about immutable genetic inheritances and high heritability and folks who spout those IQ by race figures are talking antiquated, now-discredited nonsense.” Wow! Now discredited by whom? Certainly not by the geneticists. Nothing in the link to your conference paper discredits this.
Environment plays a role – how could it not. By to discredit the role of heritability suggests little to no understanding of evolution. There are literally thousands of studies showing the role of heritability in learning, here is one from last year on literacy:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3834736/
Even if all switches are “turned on” via a good environment, this doesn’t equalize outcomes. The whole point of natural selection is heritability of beneficial traits!
Diane, why was this reader’s comment highlighted in a post? This reader seems to possess no real understanding of evolutionary theory and certainly should not be portrayed as an expert on such.
Matt,
On hereditary vs. environment. No one questions that both are important but I know of zero studies that demonstrate what % of intelligence I’d due to heredity or environment. Even in the same family, with the same parents, and the same environment, children have widely different intelligence. Can you explain that?
Yes, I can. The latest numbers show that 22- 46% of childhood intelligence is inheritable:
http://www.nature.com/mp/journal/v19/n2/full/mp2012184a.html
The rest is due to genetic variation, shared environment, non-shared environment, etc. Therefore, it is not an exact transmission from parent to child.
Next, the correlation of IQ across identical twins is around 0.80. The correlation of IQ across biological siblings is about 0.46 or so. So as the genetic differences increase (from twins to siblings), the similarities in IQ decrease.
But my main point was not how children end up genetically different, but that there are genetic differences that are separate from environmental influences. In other words, even if all children came from good, stimulating environments, you would still end up with differences in academic ability due to genetics.
Academic ability in subjects is a polygenic trait, and you would expect to see a bell curve distribution across the population in terms of abilities. You see this exact outcome for reading ability:
http://www.ncbi.nlm.nih.gov/pubmed/1727544
And for math ability:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2855870/
The hogwash that Robert Shepherd is stating about “punctuated equilibria” does not match up with the volumes of research showing heritable differences in academic ability.
Matt. It seems that you did not follow what I was saying and that you did not read the links that I posted.
Researchers who carry out those twin studies assume that by rearing identical twins in different environments, they are holding an immutable genetic endowment constant while varying the environmental influences, but that’s not so.The environmental conditions experienced by the mother affect the chemical environment within her eggs and this environment in turn affects the expression of genes in the twins. In other words, those twin studies have not and do not rule out third factors–environmental factors–that directly affect what genes will be expressed in the twins and how! These unaccounted for, uncontrolled for environmental influences on gene expression invalidate those twin studies and the heritability figures derived from them, and we are just now learning that that is so and why. Again, all this is cutting edge science. It’s very, very new, and it’s a game changer. Here’s another link for you:
http://en.wikipedia.org/wiki/Behavioral_epigenetics
There’s going to be a lot of rewriting of intro psych books, and those heritability figures for IQ are going to go the way of phlogiston and the ether.
Also mind blowing is the fact that we are seeing clear examples of Lamarckian inheritance–acquired characteristics that are inherited.
Diane,
Siblings are not genetically identical unless they are identical twins; therefore siblings average about one standard deviation difference in their IQs (two people selected at random from the general population differ more). There are numerous studies addressing the relative contributions of genetics and environment in IQ and academic ability (both are facets of general cognitive ability AKA “intelligence”). Please read some books and papers by major modern scholars of human intelligence such as Robert Plomin, Ian Deary, Dorret Boomsma, Arthur Jensen, Thomas Bouchard, David Lykken, Matthew McGue, Nancy Segal, Nicholas Martin, Stephen Petrill, John DeFries, and Earl Hunt. The gist of most studies is that gene differences become increasingly important as children age into adulthood so that by early adulthood about 60 to 80% of variation in cognitive ability is due to genetic differences. Remember that studies show that the IQs of adopted children are correlated with the IQs of their biological parents, and NOT THEIR ADOPTIVE PARENTS!!! This is a big problem for your theory that wishes to discount the effects of gene differences.
Even if you have problems with classical twin studies and adoption studies, there is now a new method of measuring genetic effects that directly uses measurements of DNA sequence similarity (the GCTA method developed by Professor Peter Visscher), this new method also provides strong proof that genetic differences are very important in determining IQ and academic ability (see recent studies led by Professor Robert Plomin).
The assertions by Robert Sheperd which I paraphrase as “now you can forget about classical genetics and heredity because epigenetics changes everything” is a big bunch of malarkey. I know this field quite well and have done research in molecular genetics and have studied genes that control epigenetics. Gene differences in the form of DNA sequence differences still account for the vast vast vast majority of heritable differences, whereas epigenetic effects are more like little tweaks around the edges associated with very particular circumstances. The search for the gene alleles (the specific DNA sequence differences) that determine differences in IQ are now the subject of two massive genome sequencing efforts, one is led by Bowen Zhao, Steve Hsu and Robert Plomin (the BGI study) and the other is led by Jonathan Rothberg (the inventor of the modern Ion Torrent gene sequencing machine). I strongly suspect that within the next few years we will have a compelling molecular genetic understanding of the nature of human intelligence differences, and I predict it will be almost entirely about genetic DNA differences and NOT epigenetic effects.
Roy Frye, do you subscribe to the original assertion that there are racial and ethnic differences in IQ? I don’t.
Diane,
“IQ” is sort of a slang term for general cognitive ability (what many intelligence experts call the “g-factor”). Measures reflective of general cognitive ability include formal IQ tests as well as other g-loaded test such as academic achievement tests and the SAT and ACT. As Professor Douglas Detterman has shown, the SAT and ACT tests are essentially the same as IQ tests in that all of these various g-loaded cognitive tests produce similar measurements of general cognitive ability.
There are hundreds of data sets showing racial and ethnic group differences in IQ test performance, furthermore there are many thousands of data sets showing similar racial and ethnic group differences on other g-loaded tests such as academic achievement tests and the SAT and ACT. There are virtually no data sets showing an absence of racial/ethnic group differences in performance on IQ tests or other g-loaded tests.
So “the original assertion that there are racial and ethnic differences in IQ” is obviously true according to the vast preponderance of evidence from testing that has occurred in the USA and countries all over the globe. How can you possibly dispute the truth of this assertion?
I believe that what you really meant to ask was “Do you subscribe to the assertion that the well known existing racial and ethnic differences in IQ are in large part caused by heritable genetic differences?”.
Here the answer is still not completely proven, although if the gene alleles that determine differences in general cognitive ability are discovered by the massive genomic sequencing studies that are now underway (the ongoing research by BGI and the newer research project started by Jonathan Rothberg) then these results will probably be dispositive in answering this question. So brace yourself for these scientific findings which will likely be forthcoming within the next couple of years.
I have a question for you. First consider the existing empirical facts in our world regarding racial and ethnic group differences in cognitive test performance; now in what particular ways would you expect these existing facts to be different if hypothetically the race-IQ Hereditarians (such as Hans Eysenck, Arthur Jensen, Richard Lynn, and Linda Gottfredson) were actually correct?
The IQ comparisons are all based on averages. That means there are those who have lower IQ’s and those who have higher IQ’s in each cultural, country, ethnic or racial group.
When the average is low for a group that means fewer are at the top but there are some at the top. When the average is high, that mean fewer are at the bottom but there are some at the bottom.
There are always exceptions. Other studies show that higher IQ may be caused by environmental challenges. Studies show that average IQ’s are higher in colder climates compared to equatorial climates. Other studies also indicate that some groups have higher average IQ’s because of survival challenges. For instance the Jews who have had to struggle to survive for almost two thousand years. It could be argued that European Jews have a higher average IQ because of Hitler and the Nazis. It could be argued taht the Chinese, who have the highest average IQ
Don’t forget, tentmakers only test what is quantifiable. Who designs these tests? Mostly people of European ancestry. What is important to know? What the test makers or their bosses say is important. Being a caring, wise, courageous human being is not on the test.
I hit the wrong key before I finished with the Chinese. About 10% of China is arable where crops may be grown. China is also known as the land of famines. Until the early 1960s, China had droughts and famines annually—Imperial records track this back more than 2,000 years. In addition, starting in the early 19th century with the Opium Wars, China stayed in turmoil until Mao died in 1976. Hundreds of millions died. It could be argued that the reason for the higher average IQ is because people with more constitutive ability as measured by IQ tests stand a better change to survive.
I don’t think IQ averages have anything to do with racial, cultural or ethnic superiority. China also focuses on merit in their schools weeding out those who can’t compete until about 10% of the 199 million who started school between age 6 and 7 are left to compete for a seat in college.
To survive, China spent centuries building the Grand Canal to help irrigate more crop land. China built the Great Wall. All signs of a culture struggling to survive against the odds.
This is where it is arguable that evolution steps in and lends a hand by throwing genetic switches to increase IQ—on average.
Roy, I never said that you can forget about classical genetics. I believe that what I said is that those twin studies (Jensen et al) didn’t control for epigenetic factors.
I must says that I find it really fascinating to think about why some people are so passionate about IQ being highly heritable. One doesn’t find such zealotry, often, this side of the Westboro Baptist Church.
It’s almost impossible to get the true believers, here, to read any of the epigenetics material.
It’s very interesting, well worth exploring, why that might be.
And, of course, what epigenetics is doing is redefining what “heritable” means. It can also, in cases that we are just beginning to discover, mean Lamarckian inheritance due to epigenetic factors!
And that’s an abject lesson in the nature of science. Science does not deal in first ideas, in a priori notions. Its an inductive and abductive undertaking. It evolves. And sometimes it is punctuated by major shifts.
How well I remember the legions of American scientists who shouted bloody murder any time one mentioned anything having to do with mind. And then came Chomsky’s review of Skinner’s Verbal Behavior and Lashley on serial processes, and the cognitive revolution was born.
cxs: say, not says; it’s, not its, of courses
sorry about the typos
Just amazing that you are accusing people of zealotry, when your original statements were:
“antiquated, now-discredited nonsense. But it’s understandable that they still believe this crap”
The bottom line – you have no idea what you are talking about. Yes, I read your link and I understand what you are saying, but you do not seem to possess even a basic understanding of evolutionary theory. Regardless of the potential for epigenetics, the evidence shows IQ is heritable. Roy pointed to a number of authors you should read – Plomin, etc. And as he also mentioned, you have the newer DNA sequence evidence: http://www.ncbi.nlm.nih.gov/pubmed/23358156
Your “true believer” angle seems desperate. So if people don’t agree with your wacky ideas then they are “true believers”? I’ve linked to 3 papers already, I could link to a thousand more. Roy gave a thorough response to your nonsense as well. You’ve linked to a group conference paper that does not substantiate anything you are saying.
Again, I think it would be apparent to any outside observer that you have no idea what you are talking about.
I stand by my original assertion that taking seriously the heritability estimates based on the identical twin studies has been dealt a decisive blow by our understanding that those studies were not properly controlled for environmental influences on the sex cell that effect changes in gene expression. The conference proceedings that I referenced describe several such. It will be very interesting, indeed, to see the results of the BGI (formerly the Beijing Genomics Institute) and similar studies. (For those not familiar with this–BGI has over a billion dollars to do research into the genetic basis for intelligence. I think that the funding comes mostly from the Chinese government.)
There is, of course, a genetic component to general cognitive ability, but I think it likely that puzzling out the determinants of g will prove to be quite complex, and I suspect that the circumstances in which the mother lives–her general level of nutrition, her exposure to stress, etc., will prove to be significant and that that explains why, since IQ tests and other general aptitude tests started to be given, we have seen, again and again, dramatic shifts of results for particular populations over short time frames.
At a recent talk, Stephen Hsu of BGI, in the Q&A afterward, mentioned his belief that IQ could be improved by 30 standard deviations (yes, you read that correctly–30 standard deviations!) by genetic engineering. Although specific genes for intelligence have not yet been discovered, he fully expects that his team will do so. He also dismisses, in the same discussion, rather blithely, unintended consequences of manipulation of genes–the problem of specific genes influencing multiple phenotypical traits. Another important consideration: Sudden, dramatic cultural change can cause sudden, dramatic changes in selection pressures. So, ground-dwelling rats, transported by ship to a place where there are pine trees and pine nuts, do some cultural learning (that they can eat the nuts in those trees), and this leads their progeny to spend more time in trees and to be selected for ability in that new environment.
I suspect that there are many, many mechanisms, some of which we understand now, many of which we have no clue about, that invalidate genetic determinism–that evolution benefits, enormously, from various mechanisms that make it flexible, plastic, able to respond over short time frames to changed conditions.
Robert, thanks for this science fiction. Let’s take a look at this “decisive blow”. Here’s one recent paper: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2892514/pdf/pone.0011329.pdf
From the conclusion: “The association between genetic variation in DNMT3L and childhood intelligence reported here must be considered an initial and as yet un-replicated finding, with the priority being to replicate the association in other populations.” An association, that’s all, and as of 2010 had not been replicated anywhere else.
From this you get: “Folks who talk the Bell Curve line about immutable genetic inheritances and high heritability and folks who spout those IQ by race figures are talking antiquated, now-discredited nonsense. But it’s understandable that they still believe this crap…” So you simply discredited decades of work and the scientists associated with that work.
Again, you are not citing any evidence for your claims. You are talking in general terms and telling stories about rats that have no meaning.
Why don’t you try to dispute the DNA sequence study I linked to? Why don’t you try to focus on the actual scientific evidence at hand built over decades, rather than pinning your hopes on a conference paper and some stories?
Or better yet, why don’t you just admit you have no idea what you are talking about and move on?
Matt, from the paper to which you linked:
The potential involvement of epigenetics, and imprinting in
particular, raises the intriguing possibility that even the heritable
component of intelligence could be modifiable by factors such as
diet during early development.
Thanks for making my point with this.
It’s pretty sad when you are using a paper that I mentioned to you to make your case. Again, you don’t seem to really be understanding anything in this. No one ever said it wasn’t modifiable. You were stating that epigenetics would wipe out the genetic inheritance. This has been the issue.
From the beginning again – if you would have just said, “hey, research is showing epigenetics has more of an effect than previously realized” – then fine, that would have been a normal statement.
You were the one who called the decades of genetic research “crap”. Then called the people who believe it “true believers”.
By the way, I am still waiting for you to address the DNA sequence study: http://www.ncbi.nlm.nih.gov/pubmed/21826061
“Our results unequivocally confirm that a substantial proportion of individual differences in human intelligence is due to genetic variation…”
Or do I have to educate you about that as well now?
You were stating that epigenetics would wipe out the genetic inheritance.
Matt, I said no such thing.
You are going to educate me, Matt.
Do tell.
Yes, you did say this. Your quote:
“Folks who talk the Bell Curve line about immutable genetic inheritances and high heritability and folks who spout those IQ by race figures are talking antiquated, now-discredited nonsense.”
Traits that can be passed from parents to children will generally result in a bell curve distribution. In other words, for a polygenic trait you would expect to see a normal statistical distribution across the population.
You you were saying this wouldn’t be the case due to epigenetics. Do you not even know what your own statements mean?
Also, for the third time, are you going to address the DNA study?
http://www.technologyreview.com/news/411880/a-comeback-for-lamarckian-evolution/
We’ve already addressed this point, remember? It can have an effect. Please tell me how the article you linked to makes decades of genetic research into “crap”.
Also, for the fourth time, are you going to address the DNA study? I’m assuming you either have no response to it or you cannot understand the article itself.
http://www.ncbi.nlm.nih.gov/pubmed/9242404
Sorry, I meant to say “cognitive” not “constitutive”
I agree with Diane. I don’t’ think heredity has that much to do with IQ. But I do think environment and evolutionary factors influence the growth of IQ—higher cognitive abilities to deal with the challenges—when survival of the species is at stake. And there is no way to predict who the individuals will be who have those genetic switches flipped that leads to a higher IQ. Higher IQ may run in families but I argue that once threats to survival are gone—little or no more competition—and there’s no need for higher cognitive abilities, the average IQ’s in those families, races, cultures, ethnic groups will start to drop.
In fact, recent studies show that IQ—on average—is on a gradual decline around the world.
What studies, Lloyd? I am familiar with the Flynn Effect, which indicates the opposite:
http://en.wikipedia.org/wiki/Flynn_effect
Click to access KidsIQ__IQ_Wealth_of_Nations_Paper50109%5B1%5D.pdf
You might be able to speed your search up of this 26 page report by just searching for the 26x Latitude appears.
There is also this study: Intelligence and Latitude in the US:
http://anepigone.blogspot.com/2007/04/intelligence-and-latitude-in-us.html
Or: Temperature and evolutionary novelty as forces behind the evolution
of general intelligence
Click to access Temperature-and-evolutionary-novelty-as-forces-behind-the-evolution-of-general-intelligence.pdf
The last one is also interesting but it runs more than 200 pages:
“In other words, even within the same broad racial
categories, those living at higher latitudes have higher IQs than
those living in the tropics. … Interestingly, latitude is related to brain size as well as IQ. … The map shows that cranial capacity correlates more with
latitude than with race. For example, Koreans and Malays are
both classified as Mongoloid, but the Koreans have big brains
(and an IQ of 106) while the Malays have small brains (and an
IQ of 92).” (pg: 195)
“Populations that, for whatever reason, have more than their
fair share of high-IQ genes are more likely than others to
develop an advanced civilization with a rational mode of
thinking and a contraceptive culture.” (pg. 199)
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