As mentioned by others - it appears genetics creates the “platform” for intelligence, and how that mind is exercised in the formative years determines ho high the person lives up to the potential. So it’s likely, an isolated group of very intelligent people would produce very intelligent offspring, and even without serious care and nurturing, the population would average higher than the random population.
However, intelligence (as in abstract problem-solving) does not equate with common sense, willingnesss to recognize and change your beliefs when faced with contradictions, nor the motivation to do smart wok. It especially does not equate with social skills or empathy. Smart may even translate into intolerance for the less bright. Not everyone is like Obama, brilliant, raised by a brilliant mother, achieveing highly in academic life yet also having the charisma and drive to achieve something many did not think possible.
If you add olympic athletes into the mix - same as pro sports, the genes that select for fast swimming or running or hitting a fastball do not necessarily translate into smart. If you added 50% physical achievers into your colony - you would get some seriously smart, some seriously athletic, and likely a vast majority above current average but not too remarkable.
Since the basis for forming the group wasn’t heritable intelligence, there may be no effect at all. Also, I’m not aware that heritable intelligence is caused by some specific gene or combination, so people inheriting their intelligence from two different genetic lines may not be any more intelligent than his ancestors, and the genetic mix might result in lower intelligence. If this was a breeding experiment, you would perform this experiment many times, selecting children of the original groups who demonstrated great intelligence across generations and weeding out those who didn’t to create new groups. Otherwise you might be working with too much genetic diversity to be concentrating the occurence of any particular gene or combination.
You misunderstand the facts of the case. Intelligence is around 75% heritable. Given that, it’s unlikely that any mix of IQ-enhancing genes would cancel each other out in any way.
The brain isn’t ultimately mysterious and unknowable. Genes aren’t either. Intelligence is *highly * correlated with speed of thinking and also with making a very large number of distant connections in the brain. Those are very specific tendencies, and I seriously doubt there is much cancelling-out effect between genes that encourage either of those traits. I’m not saying you’re wrong, but the preponderance of the evidence is elsewhere.
Depends on how one defines “branches”. For large mammals, like us, it takes about 1M years to produce a new species, absent some huge environmental change (which is just as likely to wipe out the whole populations, especially if it’s as small as 500). After a few thousand years, you probably wouldn’t see much change due to mutations.
Also, just because we have a large population doesn’t mean that advantageous mutations get lost. They might not spread to the entire population, but there is no reason they should get lost if they truly give the possessor some reproductive advantage.
You’d have to cite something more to prove that point. Seeing intelligence run in a family doesn’t mean that combining genes from two different families results in increased intelligence. I didn’t mean by cancelling out that you end up with an idiot, only that you may not at all increase the average intelligence in offspring. If there’s evidence of a cumulative nature to this heritability I’d certainly say that was a major factor in evaluating this question.
But the very start of my post pointed out that intelligence isn’t always readily identifiable as heritable. A family with some average level intelligence may have members across the whole scale. Selecting the smartest members of a family may not be picking out people who have strongly heritable intelligence related genes, and their children may not be as intelligent as their parents.
Just think of more readily defineable characteristics in people. Tall people will tend to have taller children, but not always. The tall people you pick to breed taller children may be outliers within their families and carry genes that would result in children shorter than the average of their parents. To breed animals for a trait you have to repeatedly keep the offspring that display the trait, and weed out those that don’t.
That’s unlikely. We already know that intelligence is around 75% heritable. That indicates a STRONG genetic component. Given that, it’s unlikely that there would be no increase in average intelligence at all.
Doubtful. This is like saying that the 1000 smartest humans might have the same preponderance of intelligence genes as the average person. Very unlikely.
Absolutely. This is what allows for the partial regression to the mean in the hypothetical example. I agree this regression will happen to a certain degree.
The Flynn effect suggests otherwise – that IQ scores across the population ratchet upward over time. I don’t think we really know why the Flynn effect occurs, though, so it would be hard to predict whether it would apply to the sub-population contemplated in the OP.
I just don’t understand what you’re saying here. Intelligence isn’t 100% heritable, and I don’t know of any evidence that there’s a specific gene or combination resulting in greater intelligence, or that the same gene or combination results in greater intelligence between two different families. Also I believe your 75% number comes from IQ studies.
ETA: I’m not at all arguing that there is no genetic component to intelligence.
That’s not at all what I’m saying. I’m saying that any individual person may be very intelligent but not have highly heritable intelligence genes, or may have other heritable genes that do not produce high intelligence. Since you agree with the next part, I don’t see how you fail to realize this.
Intelligence is VERY highly correlated with having a larger number of distant connections in the brain. It’s ALSO highly correlated with speed of thought.
Those are VERY specific tendencies, and I would venture to say that it’s very likely they are highly heritable, ESPECIALLY since intelligence is so heritable.
And if you’re going to dispute the 75% number, we might as well stop discussing this altogether. I just don’t have the energy to argue such a basic premise with you. That would be several pages of discussion, at minimum.
But it IS what you are saying. You are saying that the smarter members of one family may not have a higher preponderance of intelligence genes that the dumber members.
But what defines family? One set of kids from one set of parents? How about all the descendants of a particular set of great-grandparents? How about all the descendants of a particular set of great-great-great-great-great (etc) grandparents?
There’s no clear line. At some point, you have to include the whole human race in the hypothetical “family”. At that point, you ARE saying that the 1000 smartest humans do not have any higher-than-average preponderance of intelligence genes.
I still don’t know what you are arguing here. I didn’t deny this correlation at all. And I’m asking for a source for your 75% figure. Not unreasonable.
You seem to want to argue about points I’m not making.
I am saying that any one highly intelligent person may not have highly intelligent children. Do you deny this?
If you were to select the tallest people in the world for an experiment like this you might end up with a lot of people with non-heritable pituitary characteristics and they may produce children of average height. Again, this is why selective breeding requires multiple stages of selection and elimination. This is how to establish the traits you want to create a greater prepoderance of are heritable.
I googled. So can you. There are a lot of studies on this. It’s not my job to spend 15 or 20 minutes finding 10 or 12 good links, perusing them, and posting them, when you can accomplish the same in half the time. You can do it faster because you don’t have to post them. It’s all on the first couple of pages of search results, not hard to find at all.
You sound like you are simultaneously backpedaling, and/or also still claiming that, in the OP’s hypothetical example, that there would be a 100% regression to the mean.
I don’t know what your problem is on this point. Intelligence is not 100% heritable by your own admission. And nobody can identify the specific mechanism, so what is your point? There’s no doubt about the evidence of heritability of intelligence.
You are still making up arguments. I never said anything about 100% regression. I have stated repeatedly the obvious point that the OP didn’t propose selecting these people for hertable intelligence. And your argument is to deny things that I didn’t say.
This has become off topic, but the first thing that occurred to me when reading the OP is that if you start a colony of over-achievers, you will probably face the problem of not having enough of other needed qualities such as the ability to create harmonious outcomes in groups, accept other people’s ideas, or tolerate their shortcomings. Strange unpleasant things might happen. But it would be interesting.
Which reminds me of the question of why intelligent people are often less socially successful. Is it because people of average intelligence are not their peers, intellectually, or is there something about very high intelligence that makes it harder to relate to others, even if they are your intellectual peers?
Or they’d just die out; 500 people is a dangerously small population to start with. They’d also suffer from low genetic diversity; that’s an effect of such population bottlenecks.
Actually, it is your job to back up any specific claims you make. Looks like you’ve been here for over a year, so I’m surprised if you haven’t learned yet that “go google it yourself” is not part of our culture.
No, that’s not what heritability means. A highly heritable trait
simply means that there is a high correlation between a specific phenotype and an underlying genotype. However, it is just that: a correlation, not a causation.
Because heritability is based, in part, on the phenotype, and because phenotypic expression is highly dependent on an organism’s environment, heritability is, pretty much by definition, also affected by environment. One can only reasonably state that a trait is highly heritable for a specific population in a specific environment; a highly heritable trait in one environment does not guarantee such in a different environment. Consequently, heritability values in general are poor predictors of phenotypic expression across multiple environments. Knowing that intelligence
may be 75%+ heritable in general for humans says nothing about how heritable it might be in a small subpopulation of isolated geniuses.
If you can find 5 or 6 relevant, peer-reviewed studies on the first page of google results, then yes, it IS reasonable to ask people to do their own googling.
It’s not like this is an obscure topic. High heritability of intelligence is a foregone conclusion to people who’ve done the relevant research/reading, and I am not willing to devote hours and hours of my time to “teaching” perfectly intelligent and educated but RESISTANT adults about this fact.
Only I feared (and still fear) that it wouldn’t really be teaching. It’d be more like a Great Debates thread, or even a Pit thread.
The previous threads on race and intelligence are, I’m guessing, a good example of where such a discussion could go. People are often very highly emotional on these issues.