It’s amazing that people don’t realise this. I always think back to the study that showed the amount of books in a household was a strong predictor for IQ. Background matters a whole lot, but high performance people don’t want to hear it, because they want to feel like it’s all their own credit.

Nope. Just like money, there’s also an intellectual family bank that gets inherited. And it’s not genes, it’s access to knowledge which is purchased by capital.

It can be even more basic. Just having your own quiet space makes a huge difference to study outcomes. Someone living in a tiny apartment with a shared bedroom, the TV next door, and constant street noise is going to have a much harder time concentrating than someone with a private bedroom at the top of a detached house.

Of course genes play a part, but eugenics is mostly economic and political discrimination, not objective assessment of absolute potential.

>the amount of books in a household was a strong predictor for IQ. Background matters a whole lot...

That doesn't follow at all. IQ is correlated with parental IQ, due to genetics. Equally plausible, if not more so, than "books cause high IQ" is "high IQ causes books". Smart people a) like to read, and b) have smart children. I don't think it's likely that kids are boosting their IQ scores by cracking open their parent's book collection.

Then you’re ignoring the whole study for Intellectual convenience.

Well, you didn't provide a link to the study, and people mistaking correlation for causation is a frequent thing even in science (replication crisis).

The hypothesis "smart people are likely to buy more books, and smart people are likely to have smart children" sounds quite plausible to me. Does it seem implausible to you?

The best way to convince me that books directly increase IQ is to donate a ton of books to kids who need it, and measure the gains. (As a side effect, you would probably win a Nobel price if that worked.) My experience with charity says that actually many people are willing to donate books to charities; charities refuse them, because they already have enough books and the kids are not reading them anyway.

There are many ways how poverty can hurt intellectual development. This is not one of them.

There are many people who want to get rid of old books for kids, because the kids grew up and don't need them anymore; if you asked them to donate the books to you, you would be doing them a favor -- saving them from a dilemma between the bad feeling of throwing the book away, and the wasted space at home. If any NGO would bring a truck and say "please give us the books for kids you no longer need", the truck would be full in an afternoon. Then... according to your theory, the truck could go a few blocks further and turn hundred poor kids into Einsteins. I would be so happy if that worked! Unfortunately, it does not.

Was that study done before everyone had an internet connection?

All studies ever have been done before everyone had an internet connection.

So is household book count even a valid metric any more, since quite a lot of the world has more information at their fingertips than ever before?

Book count being a predictor isn't the same thing as book count being the cause. It is likely that instead, book count is an easy to measure attribute of a household which has many other correlative factors that contribute to success.