I have never postulated genetic isolation of the groups. Even with social mobility, more intelligent people have lower fertility rates and would end up reducing in numbers. Your point of less intelligent people having smart children randomly could be valid though. I was trying to model it mathematically, and if the proportion of ‘intelligent children born to less-intelligent parents’ is high enough to offset lower fertility rates in intelligent people and the proportion of ‘less-intelligent children born to intelligent parents’ then indeed we would not see a decline in average intelligence. These proportions are impossible to estimate accurately given current knowledge though, but I’ll keep it in mind. Thanks.
I’m afraid I don’t see how you’ve arrived at the confounding factor here, but it turns out I don’t need to correlate intelligence with fertility rates, it has been done for me by research studies. See post 28, and quote below.
Again, the intelligence-wealth/education-fertility connection would appear to not be needed anymore. I could still establish it, but it doesn’t seem useful anymore.
I am in fact saying that human sexual selection on average did favor intelligence in the past, but it doesn’t anymore. Also, I’m struggling to see how genetically isolated sub-populations make a difference here, could you please try and explain it to me again? I’ll do my best to understand and respond.
Hmm. You’re saying that genetics may have no difference at all on height/intelligence? While within the realms of possibility, it hardly seems likely don’t you think? I may be taller than my g-gps because of my better diet, but on average people with taller grandparents and my better diet would be taller than me.
Done. In this post and in post 28.
Ahem. I am actually not trying to imply any such thing. I have implied that intelligence was important in the past. I have no way of knowing whether it will be important in the future, and I don’t much care actually. I’m just curious. To attribute something to me that is the opposite of something I have explicitly stated just implies a great deal of disrespect for my intellectual honesty in my view. But considering you don’t know me at all I’ll assume you probably wouldn’t make such a statement if we weren’t on the ‘internets’
That is relevant…how? Who said or implied anything needs to be done IF average intelligence is indeed reducing?
It’s not a question of “if”. It’s an empirical reality in many western countries. Researchers like Seymour Itzkoff have written about this. Also, see William Hamilton’s review of 'Dysgenics’.
A review of Dysgenics: Genetic Deterioration in Modern Populations, Annals of Human Genetics Volume 64, Issue 4, pages 363–374, July 2000.
Regardless of whether there is a correlation between intelligence and fertility, the fact is that, in so far as it can be measured, intelligence has been increasing for most of the past century:
You could argue that I.Q. tests don’t really measure intelligence, but if they don’t, what does? The fact remains that there is no reason to think that the average intelligence of the human race is going down, and there is reason to think that it is going up.
This is what I came here to say. When you actually look at the evidence there appears very little reason to worry about society “devolving” into a lot of idiots. Idiocracy was not a documentary.
The problem with “Look at all those people in Africa- they have low IQs and lots of babies” is that malnutrition, malaria, and infectious disease all have an effect on IQ.
In many areas of Sub-Saharan Africa, small children can expect to have malaria several times before they hit school-age. The strain that is prevalent- malaria falciparum- is quite likely to escalate to cerebral malaria, which causes neurological damage. We are talking areas where malaria death rates can hit 20% of all kids. Everyone gets severe malaria. Everyone spends large chunks of their period of rapid brain development wracked by massive anemia, seizures and periods of extremely high fever that can last for days.
Also look at a map of childhood malnutrition. Both pre-natal and childhood malnutrition can affect brain development.
Not surprisingly, areas with huge disease burdens tend to have high child mortality. This naturally leads to high fertility. A family presumably wants at least some children who live in to adulthood- especially in areas with poor social services where children the only insurance you have that you’ll be taken care of in old age. High disease burdens also affect rural populations, which tend to have high fertility because of the way that agricultural economics incentivizes.
Of course, having a lot of children (and being mired in poverty) affects a parent’s ability to provide a stimulating learning environment for children aged 0-5, which has a dramatic effect on IQ. There just isn’t a lot in a desert somewhere to stimulate brain development during these critical years.
So what you are seeing is that people with huge disease burdens have lots of kids. That’s it.
Thanks for that link. Did you read the last part of it though? There does seem to be reason to think intelligence is going/can go down, although it is admittedly not conclusive. From that link -
This would imply the gains have halted, especially if the reasons for the gains were nutrition and more stimulating environment. The article even explicitly mentions that the recent IQ gains were not genetic in nature and suggests that the limits for gains are being reached.
I haven’t considered ‘All those people in Africa’ at all. Studies solely in the United States have found a negative correlation between intelligence and fertility. Africa will no doubt experience what the poster before linked to - the ‘Flynn effect’ as fewer people suffer the burden of disease and malnutrition, IQ will increase. I think it is highly likely that as that IQ increases, fertility rates will decline, which brings us back to my original question.
> There does seem to be reason to think intelligence is going/can go down,
> although it is admittedly not conclusive.
Actually what it implies is that in countries with the highest median incomes and a lot of equality in those incomes, the improvement in I.Q. scores may have topped out in the last decade. Perhaps this means that whatever causes the Flynn effect can’t produce any further increase in those societies. Given that this is only true in a few countries and in the last decade, there’s no reason to think that intelligence will decrease anywhere, just that the Flynn effect can only increase average intelligence to a limited extent (although that extent is more than 20 points over the past century, which is a large increase). There’s some evidence that the Flynn effect works mostly by bringing up the I.Q. of the poorest sectors of any society. In other words, the richest people in every society may have always gotten the nutritional, medical, or intellectual environments that they needed (or whatever is causing the Flynn effect), while the improvements of the past century (in some societies, at least) have been toward giving the poorer people of those societies some of the same environments.
I’m not saying there’s no effect for height, but for intelligence? There are so many types of intelligence and development is so crucial to intelligence that I don’t think genetics are as important as upbringing. As an extreme example, your “raised by wolves” feral child will NEVER learn to speak or count normally. A feral child Einstein might be smarter than other feral children, but even he will never learn multiplication, let alone calculus. Those kids missed out on necessary learning during a developmental stage; genetics can’t fill that gap.
In a more everyday example, researchers found that wealthier parents talk to their young kids nearly twice as much as poorer parents. (Cite) Poorer kids showed a lower vocabulary and a lower rate of communication themselves - the kind of thing that can hinder learning in all areas of intelligence.
This is exactly what I meant when I said there is reason to think it can go down. The Flynn effect is entirely non-genetic, while the question I have posed is based on genetic selection. If the Flynn effect is limited and has reached that limit, as it seems it has, upbringing/nutrition/reduced disease burdens can no longer boost IQ, at least in rich countries. Read with the post above, it is only logical that genetics will play a more important role in the time to come in determining intelligence, since genetics is the sole arbiter of the ‘Intelligence potential’ of an individual. My original question still remains valid I think.
True, the discussion is irrelevant for Africa or any traditional societies where social status and inherited wealth are the primary deteminants of current wealth and scial class is very stratified.
We might argue that the whole middle ages was a breeding program to remove the smartest men from the breeding pool, as the smarter ones tended t be given the education and become (allegedly) celibate clergy… or at least the men did. As a result, we have a European race where women mst be on average obviously much smarter than men.
Similarly our agrarian societies have bred for docile inhabitants, where those unable to contain their temper quickly were hung for crimes of violence, or joined the army and killed each other off (except, ths just means they also spread their berserker genes across the countryside before their demise.) Except of course, Scandinavia which seems to have bred for berserkers during their Viking phase.
Freakonomics goes into a bit more detail about the correlation between parental success and child sucess. The single biggest indicator of the success of a child is the education level of their parents.
Indeed, with spread-out suburbs of similar-sized houses, there is a lot less mixing between classes apparently happening now in North America than in past history, where different socio-economic levels lived closer together.
I am aware of that, but if you had read the previous posts, then you would be aware that was discussing a scenario where only the wealthy could afford to use genetic selection. In that scenario, then those IQ numbers were accurate. If such technology was applied generally then you would be correct. It would be more accurate to refer to a new normal distribution that was a couple of standard deviations to the right to the old normal.
The tendency of less intelligent people to have more children is fairly recent. I doubt it will last long. It is becoming increasingly necessary to be of superior intelligence to earn a decent income.
The Personal Responsibility and Work Opportunity Reconciliation Act of 1996 ended Aid to Families With Dependent Children as a life time entitlement. For decades this made possible the reproduction of the unemployable. As time goes on I think that those who are able to support themselves will become increasingly unwilling to support the predominately illegitimate children of those who are not.
