I don't think that controlling for variables can produce a conclusion of causation. (I'm posting half because I think this is correct, and half because I'd love to hear someone more knowledgeable about statistics confirm or deny this :) )
I think that controlling for variables means that you've tried to reduce the impact of other variables on the two that you're interested in. From Wikipedia: "In statistics, controlling for a variable is the attempt to reduce the effect of confounding variables on an observational study. It means that when looking at the effect of one variable, all other variable predictors are held constant." [1]
If you could control for all other variables then you'd know how much of a connection between the two variables that you're looking at.
I think this doesn't guarantee causation, though - you'd need to do experiments where you adjust the independent variable and then verify that the dependent variable changes the way you're proposing it should.
At least, I think that's how it works. Anyone else want to chime in?
Yes, you're right. To guarantee causation, you need to either directly manipulate the variable, or control for every other variable in the universe (impossible). The more extraneous variables you control for, though, the more evidence you have for causation.
Not true, you do not have to control for everything. You have to control for everything that may have an effect on both the treatment and the outcome. That implies you have to assume that everything you don't control for does not affect both the treatment and outcome, (though something can affect one). This assumption is not testable but sometimes reasonable.
You also have to assume that it's possible for every person/unit of study to have a non-zero probability of receiving either treatment for all levels of the variables you are controlling for in order for the effect you're estimating to be defined. That is more likely to be violated the more things you have to control for.
> I don't think that controlling for variables can produce a conclusion of causation.
Controlling for variables can rule out alternative causal relationships (shared causes between A and B rather than A causes B) as explanation for correlation, but can't rule out coincidence. They strengthen the case for these plausibility of a causal explanation.
In my view, controlling for a variable X doesn't directly strenghten a causal claim, but allows to "rule out" another plausible explanation. In a way it shows that the observed effect is not accounted for, even if we take X into account, which means that it could be that the father's age influences filial geekiness. It could still be the case that another variable (that was not controlled for) accounts for the effect.
Curious what the correlation is between geekiness, length in career, and career success of women, and also how career success correlates with the age of parenthood.
My completely unscientific impression is that scientific & mathematic acumen generates less of a financial return for women, and that when it does, it tends to generate a return earlier, with technical skills providing a foot in the door but subsequent success due to professional relationships. If, as I think the grandparent is suggesting, you posit that the reason for the observed correlation is that geekier males tend to be the ones that have children late in life (as opposed to earlier or not at all), then if geekiness in females leads to either no delay or not having children at all, you wouldn't observe the effect in females.
Or that it's a product of a Y-linked genetic trait.
Or that it's a product of the socio-environmental factors discussed, but other socio-environmental factors like cultural gender roles mitigate it to undetectable levels in the mother » child and parent » daughter cases.
Or the he previous comment about lifestyle is applicable but only manifests itself for fathers as a result of society only recently starting to transition to women being able to be breadwinners.
Plenty of men with single mothers* learn to play sports just fine (see many NBA and NFL players).
*This is not to say that women don't play sports with their sons, but to say that it's silly to assume that all young fathers play sports with their sons.
> Plenty of men with single mothers* learn to play sports just fine (see many NBA and NFL players).
True but I'd bet that many of these men came from urban areas where the community had services in place for younger people to find older mentors, and generally stay out of trouble.
I'm from eastern Kentucky originally and was lucky to have a fantastic stepfather, but I watched a lot of kids grow up with not much support past their single parent of either gender, and only a few of those I knew made it to 18 going anywhere near the correct trajectory. Outside of churches, there wasn't a lot of taxpayer-funded support for kids with single parents as it was probably a "moral" issue to the local politicians who still find the idea of a single parent family abhorrent and prefer to ignore it.
that might be comparing two different things. In a single parent household (which I'm sure is heavily swayed towards single mothers) kids may be out playing with other kids.
In families with older fathers, [assuming] there is a higher percentage of dual parenting ... which could mean more attention at home = less time playing sports with the neighborhood kids
I would not limit it to athleticism: men generally tend to lose "broism" and gain "wisdom" as they age. The relative levels of bravado and bookish authority that young boys could admire will therefore vary a lot with the age of the father. In addition to that, children calibrate their perception of normality to however their parents are. Many people believe that they don't want to be like their parents, but this normality calibration influences them nonetheless.
I remember a Stanford professor dived into this advanced age gamete suboptimality and stressed to everyone the compromises folks take in delaying past prime biological stages. He showed some time profiles of the diminishing chances for implantation, genetic disorders, etc. It was really palpable because you could sense he was a bit off balance having to present this sort of news to a bunch of young folks with the fountain of youth in their back pockets. The classmates were pretty much silent throughout the delivery. It got me to start thinking about biological optimum and I easily realized it was in the 20s as one would expect. All nighters were a piece of cake, probably to serve the care of an infant waking every 2 hours into the early hours of the night. Another piece of easily perceived evidence was the sheer force of the libido at that age and just how attractive women are in their peak. Lots of conspiring biology to contemplate teleologically.
At least in Russia, I observed an opposite with women. All women of my generation I knew who were into thing like engineering did settle down in early twenties.
Russia is a tought life country. A decision to start a family when you are still in your prime may make more sense there.
This could be down to older fathers having more basements, garages and tools. There are fewer degrees of freedom when you live in a drywall and carpet apartment.
Take caution. Extraordinary claims require extraordinary evidence.
> The mother's age had no impact, and daughters seemed to be immune.
When a significant effect is seen in only one of four comparisons (maternal vs paternal, sons vs daughter), then you have to suspect that the effect might be spurious.
That's interesting, I thought there was a correlation between older mothers and autism, and autism has a correlation to geekiness.
My wife had our youngest daughter at 40 (I was 43), and my daughter was diagnosed as autistic at 3 and a half. After lots of therapy she was able to mainstream at age 8, and made the honor roll this year.
This morning she noticed a year in a book her older sister was reading. She exclaimed "That's the year Isaac Newton was born!". I said "okay" not sure if she could be right, and she then whispered to me, "and it's the year Galileo died". I looked it up, and she was right. So I kind of consider her geeky.
That could be true, but older fathers also have more defective genes, are less able to play with their children, etc. The children are just genetically "weaker", have more physical issues and participate in far less physical activity because their father is so old.
This is anecdotal evidence but one of my friends had a very old dad. He had issues which forced him to wear bifocals and hence he didn't participate in sports. And his father was 60 when he was conceived so his dad didn't play catch with him or get him to try out for little league or play basketball with him.
So instead, he stayed home mostly and used the computer and got into "geeky" stuff.
The father's other children he had when he was younger are all very active, athletic, etc and none of them have to wear bifocals, etc.
I got into sports because my dad played catch with me and encouraged me to play sports because my dad wasn't old when he had me.
On the one hand, older fathers will be more established, but on the other hand, they will have more defective genes and less active/physical.
Those are the rates for something like Down's syndrome. Gross chromosomal abnormalities are mostly determined by maternal age.
Everyone has a few mutations in protein coding regions, and the number rises with paternal age. Most mutations are neutral or harmful.
More rolls of the dice to accumulate more (likely small) damage is probably going to hurt you.
The way it almost certainly works is people who have better genes (for socioeconomic success in our current society) have kids later and these kids inherit these traits....
However it would probably be better if the dad had the kids younger.
It's also easier for denovo mutations to cause mental rather than physical problems as the brain is very complex so there's more genes used and more to go wrong.
PS I'm a 37 year old bioinformatician expecting a little geek in a few months :)
Genetic mutations. As you get older, you accumulate more genetic damage, which can be passed on to children. It's fairly well-studied that children of older parents are more susceptible to genetic disorders.
To start, I'm going to assume that, by defective, you mean unintentional, correct me if I'm wrong. This is equivalent to the assertion that there is no feasible mechanism to preventing your germ cells from accumulating damage due to age, because otherwise, if it was maladapative, AND evolution could design a mechanism for preventing it, it would have. It's been long enough since mammals started reproducing sexually.
This doesn't even make a little bit of sense though. It's clearly possible to keep the error rate constant. What's the difference between the germ cells in my body and the germ cells in my offspring's body. Why do those last longer?
As you grow older, your offspring have more genetic diversity. It seems like the accumulation of mutations is intentional for older parents. The more similar your children are, the more likely they are to compete with each other, and the older you are, the more children you are already likely to have. So I propose that this is not a defect, but rather by design.
Second, why on earth does this explain the hypothesis? Nerds are smarter on average, yes? Does it not make at least twice as much sense that smarter individuals are sexually attractive at older ages than athletic ones than reasoning that genetic defects are the thing that makes a person smart.
Naturally aborting a foetus due to genetic errors found in growth stagrs after combining with foreign DNA in your balls then shutting down the process and re-extract the germline cells is easy?
Why bother going to all that trouble when you can move the DNA to a new body and let the old one fall apart?
For it to have been worth it, a longer reproductive career has to pay off more than the opportunity cost of spending effort on other strategies eg aquiring more mates or investing more in your kids.
The most optimal balance is of course the DNA running around today.
I don't need to engineer the solution precisely, but the idea that it's impossible, or even difficult, to maintain the information degradation rate of mitosis, is clearly flawed. If your argument is that 'life has simply not found a way to do this yet', you should probably reconsider your argument.
My argument is that there are tradeoffs. There may be a way to do it but it has been thoroughly out competed by the make children and die strategy that dominates the planet.
But even at fairly old ages, the levels are very low. Yes, they are several multiples of the rates at younger ages, but the base rates are also very, very low.
So, it's a real issue, but it's also very was to percieved it as much bigger than it is.
Older fathers are more likely to have established careers, establishing higher socioeconomic status, affording a lifestyle that engenders "geekiness".