Perhaps the BEST B1G Forum anywhere, here at College Football Fan Site, CFB51!!!

I'll try to look around for the data but I completely disagree with you here and what limited data I've been able to find supports that IQ is MUCH more important than environment.

Here is from NPR:
https://www.npr.org/2007/10/25/15629096/identical-strangers-explore-nature-vs-nurture

They literally have the perfect set-up, identical twins separated at birth but the actual results are locked away due to ethical objections to, ya know, separating identical twins at birth. However, there is this quote"
"Twins really do force us to question what is it that makes each of us who we are. Since meeting Elyse, it is undeniable that genetics play a huge role — probably more than 50 percent," Bernstein says.

The source for this article looks pretty shady so who knows, but:
https://michigantoday.umich.edu/2022/12/16/nature-vs-nurture-its-both/

The key here is a reference to a UMinnesota study that:
"Research from the Minnesota Center for Twin and Adoption Research (The Minnesota Study of Twins Reared Apart) includes more than 137 pairs of separated identical and fraternal twins and triplets who participated in a battery of medical and psychological tests. Over the years, identical twins reared apart developed personalities and interests that showed about the same degree of resemblance as identical twins raised together."

Emphasis added, ie nature is decisive and nurture is more-or-less irrelevant.

The bottom line is that nature is FAR more impactful than nurture. If you have a kid with an IQ of 115 you really can't mess that up and if you have a kid with an IQ of 85 there isn't really anything you can do to help much.

True story. My wife’s aunt and uncle travel the country as retirees. Anyways they were in Vegas or somewhere and met this young lady, 20 or 30 years old. Anyways they noticed that she looked really similar to a friend of theirs from back home. Even had the same facial expressions and very similar personality traits. They said they were just really taken aback by how similar she was to their friend. They casually asked her where she was from and she named the exact small town in Texas where their friend was from. They were taken aback at this, and asked her who her daddy was. The person she named was not their friend. They asked if she knew their friend, Mr So and so. She said she didn’t know this person. Anyways, kinda got off track but it was obvious to them who the real daddy was and how strong genetics drive much of our personality and traits. 

75% of Germans starved to death?

Medina,

I think we're talking about two different things, but thanks for providing the info you did. 

I'm talking about the infant/toddler years and saying that proper care and engagement is critical, and that if a kid lacks it, no amount of genetics is going to salvage that.  You could breed two super-geniuses with sci-fi technology to make sure the kid gets all the best traits, and an uncared-for child is still going to be permanently stunted, and in worst cases, feral (there are unfortunately recorded instances of that--not the super-genius-alien breeding part).  I have anecdotal evidence to add there, but it is anecdotal.  You have a crucial stage of development in the first few years, and if you stunt that environmentally, no amount of genetics is going to make you really smart, or even of normal intelligence.  That is my assertion, anyway.

If I'm understanding you correctly, you're talking about once a kid gets through that stage with no problems, their genetics will either catapult them to a level of corresponding greatness, or curtail their ability to exceed a certain threshold, regardless of their home life, socioeconomic circumstance, and other environmental factors.  I think that makes sense and I don't dispute it.  

I'm not going to go looking for it now, but I think I've seen data in the past showing a positive correlation between activities like reading to your child, talking to them regularly, doing little games and puzzles with them, and their intelligence outcome.  But again, if I understand you correctly, that doesn't contradict anything you're saying.  

The problem, as you noted, is how to operationalize any good experiment to test the hypothesis.  Proving the counterfactual in either case is a really tough ask, and if it can be done at all, I don't think it could be done ethically.  

Medina,

I think we're talking about two different things, but thanks for providing the info you did. 

I'm talking about the infant/toddler years and saying that proper care and engagement is critical, and that if a kid lacks it, no amount of genetics is going to salvage that.  You could breed two super-geniuses with sci-fi technology to make sure the kid gets all the best traits, and an uncared-for child is still going to be permanently stunted, and in worst cases, feral (there are unfortunately recorded instances of that--not the super-genius-alien breeding part).  I have anecdotal evidence to add there, but it is anecdotal.  You have a crucial stage of development in the first few years, and if you stunt that environmentally, no amount of genetics is going to make you really smart, or even of normal intelligence.  That is my assertion, anyway.

If I'm understanding you correctly, you're talking about once a kid gets through that stage with no problems, their genetics will either catapult them to a level of corresponding greatness, or curtail their ability to exceed a certain threshold, regardless of their home life, socioeconomic circumstance, and other environmental factors.  I think that makes sense and I don't dispute it. 

I'm not going to go looking for it now, but I think I've seen data in the past showing a positive correlation between activities like reading to your child, talking to them regularly, doing little games and puzzles with them, and their intelligence outcome.  But again, if I understand you correctly, that doesn't contradict anything you're saying. 

The problem, as you noted, is how to operationalize any good experiment to test the hypothesis.  Proving the counterfactual in either case is a really tough ask, and if it can be done at all, I don't think it could be done ethically. 

This is the Nature vs Nurture debate.  It is a long-running debate and there really isn't a 100% consensus but there are some general parameters.  

It seems pretty clear that I am more on the nature side than you but I am not at all stating that nurture is 100% irrelevant.  The Head Start example, however, is telling.  Head Start REALLY helps kindergarten performance but the impact dissipates as the child ages.  

I guess my position (leaning more nature than yours) is something like this:
At the very high and very low ends of the IQ spectrum, I tend to think that nature predominates and nurture is more-or-less irrelevant.  IE:
Mean IQ is approximately 100 with a Standard Deviation of approximately 15.  Contra your theory, I think that a super-genius (whether naturally occurring or sci-fi created) is going to be fine no matter how awful their upbringing.  Basically I would say that anyone above about 115 (one SD above mean) is just plain smart enough to overcome poor upbringing so it doesn't much matter.  Similarly, at the other end of the scale, I would say that anyone under about 85 (one SD below mean) is just not smart enough to accomplish much no matter how great their upbringing.  

Note that when I say that, I mean IN THE LONG run.  Ie, an 85 IQ kid with REALLY good parenting is probably going to be a better student in Kindergarten and early Elementary than a 15 IQ kid with REALLY bad parenting.  However, the difference caused by nurture is temporary unlike the "nature" difference which is permanent so over time the high-IQ poorly-parented kid will overtake the low-IQ well-parented kid and eventually, certainly long before HS Graduation the 115 IQ kid will have completely overcome the initial advantage enjoyed by the well-parented 85-IQ kid.  

That being said, only approximately 16% of people have IQ of 115 and above and another 16% have IQ of 85 and below.  The other roughly 2/3 of the population is within +/- 1 SD of average IQ.  I think that the closer you get to average, the more impact parenting can have.  For the ~50% of the population with IQ's of 90-110 parenting matters a lot because they are:

• Not so smart that long-term success is more-or-less inevitable like the 115+ kids, and 
• Not so dull that long-term success is more-or-less impossible like the 85- kids.  

For this half of the population, things can go different ways.  


It might help to think of it with an analogy.  If you think of racing cars, I think IQ is like the car and parenting is like the driver.  At the very low end, if you are driving a 1982 Pinto (sub 85 IQ kid), you aren't going to get good lap times no matter how great of a driver you are.  At the very high end, if you are driving a McClaren F1 (115 IQ kid), you are going to get very good lap times even if you don't really know how to drive.  

Where I think nurture matters the most is if you are closer to average so, in this analogy, if you are racing a Toyota Corrolla against a Honda Accord (I have no idea of the relative performance of those two, I'm just assuming they are both average and about the same) the better driver is going to win every time.  

Just to clarify, I'm not asserting that 85 and 115 are the EXACT points where nurture becomes more-or-less irrelevant and nature predominates.  What I am saying is that I think there ARE points where that happens.  It is probably more of a gradual shift.  I am saying that I think that as you move away from average (in either direction) the impact of nature becomes stronger relative to nurture and eventually you will reach a point (again, in either direction) at which nurture is basically irrelevant.  

So should we write a book titled Nature AND Nuture and get rich?

The other roughly 2/3 of the population is within +/- 1 SD of average IQ.  I think that the closer you get to average, the more impact parenting can have. 

That's an interesting angle I hadn't considered.  It makes sense, the causal mechanism is certainly there, and, I would guess, current data likely backs it up.  (I don't know, I'm still operating from a rationalism perspective, and anecdotal evidence.)

Where I do think there is hard evidence is in the early childhood stages.  A kid who in most situations with any decent raising would've wound up a genius could instead suffer neglect and abuse in the toddler years, and will never overcome it to reach even the mean, let alone the +1/+2 st. dev.  As I understand it, child psychology is fairly firm in that you only have a certain amount of time to develop linguistic skill, and if you don't, or it's not to a certain level, it's not going to happen.  And without language or language of a certain sophistication, a person won't reach certain levels of higher intelligence. 

This unfortunately happened to my four adopted cousins I recently referenced elsewhere.  All the same biological mom and dad, all suffering roughly the same abuse, but the impact on them increased with birth order.  It's possible that the youngest was abused the worst and the oldest was abused the least--I don't have a way to know that--but they all had it pretty bad from what I understand.  I believe the reason the oldest is "mostly normal" followed by increasing problems on down to the youngest who is fully mentally retarded is little more than the youngest was so young, whereas his older brother and sisters had gotten further and further past that crucial stage before things got bad, allowing them to reach or exceed the point where environment is critical. 

All that said, I'm as subject to domain expertise as could be.  I have no accredited knowledge in that area and everything I've said is either anecdotal or based on stuff I've read from others who are supposed to know what they're talking about. 

I'm just curious what the current understanding is about IQ being hereditary.  It seems I've known so many highly intelligent people who stood out from the rest of their family (siblings and parents alike), as well as highly intelligent couples who produced what seemed to be very normal children, that I guess it's never really crossed my mind that much. 

That said, I don't know what any of their IQs are.  I'm basing intelligence solely off of the obvious horsepower under the skull I perceived from them, or lack thereof. 

I don't know what to make of IQ tests in the first place.  Some say they're the most telling psychological test we have, others think they're bunk.  I've done a couple different tests in my life and they put my IQ in about the same spot, so I guess if nothing else, at least there's consistency.  What it means, I have no idea.  It's a high percentile, but not exactly a high number compared to the geniuses you read about.  I have a hard time believing I have a higher IQ than that much of the population.  I've never thought of myself as unintelligent, but it must be said I often meet, and always have, people who seem every bit as intelligent as me, and quite a few over the years who I'd bet money flat-out have superior CPU's.  

Hell, after posting here for 19 years, I'm convinced that most here are at least as intelligent as I am, if not more so in many cases.  Doesn't really jive with my supposed score.  

To your point, my dad, my sister and I are all very similar.  They are highly intelligent, if I had to guess, smarter than me, though probably not by much.  To my point, I was read to a lot, and talked to, and played with, and had encouragement and help through my learning years.  

Beats the hell out of me.  Guess I'm not so smart after all.