A larger family worsens kids' cognitive development, suggests 30-year study | Hacker News Reader

A larger family worsens kids' cognitive development, suggests 30-year study

bigthink.com

33 pointsBrajeshwar60 comments

The bias for negativity in headlines and SEO is at play again here. Later on ITA:

> While cognitive development took a hit, kids’ behaviors were assessed as better on average in larger families.

Note that overall life success can depend on both of these factors. And in today's isolating times, the cognitive skills may be more replaceable/recoverable than the social/behavioral ones.

Yes but I think few metrics are as loaded and culturally mediated as "well behaved" for children. For a lot of people this could simply mean quiet and capable of extended occupation alone. It could mean different things for boys and for girls, depending on the expectations of the assessor.

It seems like this is possibly self-assessment by a parent, which has what I hope are obvious issues. But even if you take say a teacher or other third party you run into a lot of the same problems with it.

Ehhh I social skills are overrated. As long as you're able to do effective collaboration and work within a team you dont need to be a social butterfly. The most successful engineers and researchers I know personally; are not particularly social people, obviously they're able to exist in polite company and collaborate etc but socialization is just another tool.

Sounds like a false equivalence. No one is saying you need to be a social butterfly.

> The most successful engineers and researchers I know personally; are not particularly social people

I've seen plenty of capable or at least promising engineers torpedo their development by not being to read the room or adjust their social behavior.

> obviously they're able to exist in polite company and collaborate etc

Ok, so having the skills is considered a baseline? Sounds like they're pretty important then.

Youre right basic social skills are absolutely a baseline but being charming/sociable/a social butterfly and being able to integrate into a team, collaborate, express technical ideas to others and vice versa arent necessarily the same thing. My most effective teachers/mentors/role models throughout my life were often by all accounts kind of awkward sometimes. I think we as a society put lots of emphasis on the former and conflate it with the latter.

>> The most successful engineers and researchers I know personally; are not particularly social people

Could you imagine how successful they'd be if they added those skills?

The happiest and most successful people I know are social butterflies.

The underlying survey is from ~12,000 children born 1957-1964, when America was much poorer. My own aunts and uncles, who were middle class, report competing for food with their 9 other siblings. Results may not hold for, say, a 4-child household living on $100,000 today.

https://www.nlsinfo.org/content/cohorts/nlsy79

"America" the country was poorer, but it has a lot more poor people now, a lot more people living in poverty and without food security now than in the post-war years.

No, poverty was different back then in a worse way. Poor Americans often lived in a state of caloric deficit fifty years a go, the poor in 2023 are much better fed. The standard for "food insecurity" is so low it would have captured a large part of the middle-class in the 1970s.

There are not more poor people now than there were in the 1960s. The only way to make this argument is to reference census data on incomes and hope that the reader doesn't realize that those data inexplicably exclude the overwhelming majority of wealth transfers, including Food Stamps, HUD, and even cash welfare programs (euphemistically referred to as "refundable tax credits").

The war on poverty has obliterated actual poverty, but the political incentives to pretend otherwise are too appealing to allow an honest accounting from either side.

There is a big difference between being food insecure and being malnourished to the extent that it impacts cognitive development. The rate of malnutrition now is significantly lower than when the study subjects were children.

If that is true it’s an important observation however I suspect it isn’t. In general, and everywhere, the past was much tougher than the present.

Yeah, I would much rather be 5th percentile income in the United States today than 5th pc income in it 50 years ago. I don't see how this is even slightly arguable.

It’s not except by those who have been indoctrinated by misleading socialist propaganda.

I disagree.

A family could be supported by a single income up until a few decades ago, not just in the US but in many countries.

Today, often two incomes aren't enough for a family, even with families getting smaller since people tend to have less children.

The key being "supported" - that definition has changed dramatically in the past 50 years, and what you're referencing in the US was the middle class, not those living in poverty (then or now).

What has also dramatically increased in the past 50 years is our productivity.

Strangely, there has been a negative correlation between increased worker productivity and the amount of work required to support a family.

I wonder where did all that surplus value go? Is it a coincidence that inequality has raised in the last decades?

> what you're referencing in the US was the middle class, not those living in poverty

There is no middle class, only proletariat and bourgeoisie. Either you own means of production or you don't.

The proletariat could afford a decent lifestyle without living paycheck to paycheck until a few years ago, but not anymore.

I bet if we were to reiterate the definition of work, the math would show us we are actually less productive with a small handful doing the real work and carrying the country.

Fix the title? "In the old days, children in America in larger families tested poorer than those in smaller families."

Possibly, completely different today? Not much relevant conclusion to draw from folks raised in the 1950's and 60's.

The younger children have lower IQs because mom runs out of resources to make people as time goes on. This is a well-known and easily solvable phenomenon.

Edit:

I am the oldest of 11, and would not trade the experience for anything. It's wonderful, and made me more knowledgeable, since we were unschooled, and would study different topics and compare cliff notes. Still the only reason I know anything about quantum mechanics.

You have 10 siblings and didn't attend any schools? What is the range of careers/skills everyone has? Any pods, like 3 of the youngest all learned the same skill together and went with that, like 3 engineers?

I'm a software engineer, I have a couple brothers in permaculture design, one is a gunsmith, and the rest are too young to be sure yet.

Plenty of shared knowledge, like gunsmithing is a hobby of mine, but he took it seriously. Still no real "pods".

I'd classify us as classically educated. We had somewhere around 5000 nonfiction books in the house, and most of us had read a significant chunk of them. Nobody has a bachelor's, but I suspect that'll change with some of the younger ones who are more patient.

Edit:

Some of us did do real school. I paid my way through an Associate's degree at 13 because I was bored. Also online classes, apprenticeships, stuff like that.

I'm sorry but what? Do you have any references for this?

Sure. Omega-3, a critical ingredient for having smart kids, is depleted during pregnancy, and few women supplement enough to fully replenish.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3046737/

This article is about diet. Where is the source that says that women have stored reserves of omega 3 that are depleted with measurable impacts on later born children?

Omega-3 stays in your body for only about 6 months and must be continuously replenished. This can be an issue over the course of a single pregnancy. But it's not something that gets progressively depleted over multiple pregnancies.

I'm sorry, do I need to post a biology class in here too? I can post the study about how women with bigger butts have smarter children due to higher Omega-3 availability, and the study detailing the depletion during pregnancy, and the study I already posted on Omega 3 in the diet.

Or, the idea that building a human depletes resources could be relatively uncontroversial, because duh.

Please post those studies I want to seem something.

Aren't prenatal vitamins (which include omega-3) essentially prescribed by default nowadays?

Yes, which is why OP's study based on data from the 1950s is already problematic.

However, a fixed cocktail of supplements isn't ideal. Some people actually get their bloodwork done and concentrate on what they really need.

This study doesn’t at all say what you originally claimed about moms “running out of resources as time goes on” when it comes to birth order and IQs. Either you missed the point or you honest to god don’t care about spreading disgusting misinformation.

Actually, it does, but only if you have reasonable reading comprehension.

How is what I'm saying "disgusting misinformation"? I'm very interested in what precisely you're angry at.

This is obviously real, and timelines/effects differ. How could growth in utero not matter? And how could pregnancy not deplete resources? That depletion can be reduced and managed, but it happens. I would suspect that most women are anemic by third trimester, just to pick an easy one. Even keeping on weight while breastfeeding can be challenging, to look at an even coarser metric. All of this is pretty consistent with the general unlikelihood of getting pregnant within one year or , sometimes, up to 18 months postpartum, amd you'll often see 3 year spacing as an ideal target. Obviously, that spacing requires that you start having kids pretty early or continue pretty late if you want a large family.

Seeking published results about this is hard because, first, social science and therefore observational studies with results that can readily be disputed; and second, this is one of those "shaming mothers" things that gets tabled or not suggested as research in the first place.

The actual data indicates that while gestational anemia is a significant problem, it doesn't impact most US women. The majority of US residents get adequate dietary iron, and prenatal vitamin supplements also contain iron. The problem is more severe in developing countries.

https://doi.org/10.3945%2Fajcn.117.155986

Considering that OP's study is from the US in the 40s through 60s, gestational anemia probably factors in.

Also, anemia is a single deficiency. How many more opportunities for deficiency are there? Hundreds?

They say that they account for the log of the family income, but do not elaborate on that point beyond saying they do (at least after a quick skim). It seems to me that this would be extremely difficult - does anyone have insight on how they might have done this?

Probably a fixed multiplier. There's a tremendous amount missing from this study, and I wouldn't take any of its conclusions at face value.

Usually, you do a multivariate statistical analysis, and "accounting for" means, it was one of the variables thrown in.

Yeah, this is just turning the long-standing observation about family size and cognitive ability on its head in such a way that (if it became a popular notion) would just make the problem worse. Smart parents would dutifully have just one or two kids.

This cannot be separated from the fact that in America and most of the developed world, poor, less educated people are more likely to have large families.

Do you read this as distinct from the global trend that female lifetime fertility drops with increases in years of schooling (not stabilizing until safely below 'large family')? At least in every US state, it seems that larger households have higher household income, though my stat only goes to household size of 4 (https://www.justice.gov/ust/eo/bapcpa/20201101/bci_data/medi...).

It seems to be true that wealthy and highly educated women are less likely to have many or any children.And at the other end, I think it's reasonable to suspect that having children has a causal relationship with unwed mothers not subsequently marrying.

My first reaction was "uh oh, hypermeritocracy" i.e. children drilled for test-taking success from the earliest age - so of course more children would dilute the tiger parent effect. But that was based on just a quick skim.

Not an issue when I was a kid; parents drilling kids academically didn't even go as far as mine checking whether we did our homework. All four of us turned out OK by the standards of "finish university and have an appropriate (to the level of education) career".

It’s probably just women having children too late. After 30, the quality of child is going to gradually get worse.

You are correct, but as women get older, the chance of genetic defects becomes higher. The intelligence of a genetically nominal child wouldn't be affected.

People generally dont want to say this outloud, and most men are not aware the degree to which this is true.

Men having children later in life is associated with a litany of developmental problems too.

_The rate of Down syndrome for both maternal and paternal age greater than 40 years is approximately 60 per 10,000 births, which is a six-fold increase compared with maternal and paternal ages less than 35 years of age._

Eh.... I come from a family of 8 kids. All of us have at least bachelors degrees, many have multiple graduate degrees, including doctorates.

> Additional siblings have lower cognitive scores than their older siblings.

One of my youngest siblings was valedictorian of a high school class of 4,000 students, got perfect scores on the ACT and SAT, was accepted into MIT and many ivy league schools and recently was incentivized to move to a new company with a $1 million bonus. He is straight up a genius.

I mean, obviously there are outliers to everything, but this study strikes me as maybe having a correlation and causation issue.

Weak correlations or weak effects shouldn't drive your personal behavior.

If you're worried about it, make sure your 5th/6th/nth children are way out the end of the distribution of daily minutes reading; that should do plenty to combat this effect.

I mean, do you account for that fact that your family has a correlation issue? You all are in the same geographic area, social class and economic bracket, go to the same kind of schools, have the same parents. To the extent any of these things can influence degree-having (which is not, quite, intelligence) they influence it for all of you yeah?

Your brother would probably understand that anecdotes aren't an argument against statistical phenomena. Or maybe you would, if you had half as many siblings.

Tech workers are the only people that I know in my age range (almost 40) who have a handful of children instead of the usual 1-2. Like 3-5. I will never understand why someone actually intends to have 3-5 children in modern times when we're not working on a farm or in the mines. We're at 4, ok when can we have 5? ... Why, what does having a 5th child change for you? Are you bored? Is your hobby at that point literally just raising children?

Well I have 4 and we would seriously consider another if it wasn't for my wife's health.

But these 4 little children are the greatest joy in my life, and it has multiplied with each one of them not decreased. There is no greater feeling in the world than when my little girl runs up the stairs to me and screams "DADDY! LOOK WHAT I MADE!" when she gets home from school. Many times my wife and I will just sneak into the toy room and watch them play together and have fun and it is so rewarding. Not to mention how much fun it is to see my son get super excited about D&D and wanting to play it all the time with me.

Sure it's hard there are long nights, and poopy diapers and dealing with tantrums, but most of that gets forgotten when you walk into the baby's room after she wakes up from a nap and gives you the biggest smile in the world and claps and laughs just to see you.

As my mother recently observed, parenting is one of the hardest and most rewarding things in the world, and I tend to agree.

>why someone actually intends to have 3-5 children in modern times when we're not working on a farm or in the mines.

Mine write great boilerplate code - better than GPT by a good margin, anyway. Also, they're a more reliable retirement option than the state, if you have enough of them.

Just kidding, but seriously, having kids opens up a form and depth of love that is otherwise difficult to access. It's sort of like romance - why do people care so much about sex and romantic intimacy?

I believe we live in a time of love poverty. Compared to people in the past, who grew up surrounded by many siblings, and two parents, and extended family, and friends, and then lovers, and a lifelong spouse, and many children, and grandchildren, and so on - think of how wealthy in love is such a person. The love of God that fills all suchness with a certain hefty presence, like a thick blanket atop reality. Like a baby knowing his parent is there while he plays. Not to romanticize the past - but I believe a modernity with such love was possible. It's still within grasp.

On the other hand, DINK life does seem really awesome in its own way. I guess for me, both paths lead to a very cool kind of wealth, and I understand the merits of both ways.

I'm lucky I have a beautiful lovely kind wife and sweet, playful children who fall asleep easily lol.

My experience is the exact opposite - people in tech have either 0 or 1 kid(and swear they won't have any more - after all, how can you fit any more in your life). People outside of tech(teachers, academics, accountants, musicians) all have 2-3 kids.

>>Why, what does having a 5th child change for you? Are you bored?

I mean, I only have 1 personally, but I get it - kids are fun. And the process of being a parent is fun(outside of the parts that absolutely suck) and extremely rewarding, it's been more rewarding than everything I have ever done in my professional career, and I have some things under my belt that I'm very proud of - seeing my son develop is still more rewarding than any of these. I assume that with every new child you just get to repeat the process and get that reward again and again and again. So I suppose the answer is ultimately - for somewhat selfish reasons. Kids are not just mine workers or care for the elderly.

I have no kids, and due to my medical circumstances will probably never have them.

As I get older there seems to be more and more Death around. Grandparents, Aunts and Uncles are getting older and Dying. Having more people expanding the family, becoming alive and growing is just better for the psyche. So I can see the appeal of having a lot of kids.

That's interesting considering one big obvious reason my coworkers/friends have 3+ kids is because they easily clear $300k+ single income and can live in 6 bedroom homes, etc. Drive those massive suburbans..

I have a very difficult time believing that the 3rd, 4th, etc children have a dad like you who still has the time to have fun with them and treat them properly and love their achievements each, etc. But it's possible. My mom has 6 siblings and they were raised like wolves, but they're boomers.

I have one (older) sibling and we absolutely vied for our parents attention and do not get along whatsoever.

I think there's probably a few things at play here.

Here in UK tech workers don't earn anywhere near what their US counterparts do. A senior programmer might be paid 50-100k depending on the company, but it's very rare to cross that level(and once you do, you start losing state benefits related to child care and paying higher and higher levels of tax). "Tech workers" definitely don't have 6-bed houses and drive massive SUVs here, at best they enjoy relaxed "upper middle class" lifestyle - newish 4 bed house on a modern estate, 2 leased cars, swimming in mortgage payments and other debt. They aren't struggling but they aren't so comfortable to have 6 kids and pay for all of their childcare costs - because everyone knows that doing so would just erase those great salaries and would most likely mean a step down in the quality of life. They will earn more than teachers, but like 2-3x as much, not 10x as much.

Then most tech workers I know have had to move for their jobs - so they don't have immediate support of family, grandparents etc - so having more kids means more daily responsibilities and more daily costs for childcare. In contrast the other people I mentioned all live close to their families - so having 3 kids is not a big deal because half the time grandma is over and helps out. Like, for us we pay more in childcare(just for one child!) than what our mortgage is per month, partially because we don't have any family around us to help.

These are my observations anyway, anecdotes - take them as just that.

Caveat: having a large family is a goal that I haven't achieved yet to this degree

>Why, what does having a 5th child change for you?

The nth child can change a lot. exponential increase in dynamics amongst siblings, stronger family culture, and on and on.

>Are you bored?

Never even remotely, but I think we can handle more.

> Is your hobby at that point literally just raising children?

That's not a terrible understanding. Every day is full of getting to show someone something cool for the first time ("oh, wait until you see/try/hear/taste/experience this! "), boosting their pursuits, being impressed with their accomplishments, laughing until tears at their idiosyncrasies, and trying to break your own bad habits enough that they don't carry to the next generation. Parents lose their hobbies because they have way better stuff to do than those old hobbies.

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