Book Density & IQ

Found this convenient summary table of the amount of books people had in their adolescence based on the PIAAC surveys.

Sikora, Joanna, M. D. R. Evans, and Jonathan Kelley. 2019. “Scholarly Culture: How Books in Adolescence Enhance Adult Literacy, Numeracy and Technology Skills in 31 Societies.” Social Science Research 77 (January): 1–15.

The Scandinavians are highest at around ~200 books; Anglos, Germanics, and Slavs tend to have ~150; strangely, Japanese and Koreans – only ~100 (Singapore especially is an outlier at just 52); the Meds around 80. Lowest is Turkey at just 27, joint second is Chile at 52; also the lowest IQ countries in this sample.

Heiner Rindermann in Cognitive Capitalism:

The number of books is the third best parental indicator of children’s intelligence (rBo = .25; Section 3.4.5) and at the international level the correlation is very high with cognitive ability (rBo = .70; Table 10.5) – much higher than any attribute of instruction or schools. The average number of books at home can be used as a proxy of national cognitive ability. Looking at the numbers taken from student assessment studies (see Appendix and Table A.3) the average for Latin America at home is 28 books, in Brazil 34 books, approximately a quarter to a third compared to Britain with 102 or Scandinavia with 111 books.

See also Steve Sailer’s commentary on (the paucity of) books in Mexico.

That said, I expect these correlations to start collapsing soon, if they haven’t already, as the most developed/higher IQ countries start shifting to e-books amongst the younger generations.

Anatoly Karlin is a transhumanist interested in psychometrics, life extension, UBI, crypto/network states, X risks, and ushering in the Biosingularity.


Inventor of Idiot’s Limbo, the Katechon Hypothesis, and Elite Human Capital.


Apart from writing booksreviewstravel writing, and sundry blogging, I Tweet at @powerfultakes and run a Substack newsletter.


  1. advancedatheist says

    I’ve noticed from visiting the Food City supermarkets in the Phoenix area, which serve mainly Hispanics, that they don’t carry magazines, not even in Spanish. (Makes you wonder why they don’t name these stores Ciudad de la Comida or something.)

    By contrast, Walmart, Fry’s (Arizona’s division of Kroger) and Safeway supermarkets all have magazines for sale in plain sight.

  2. The stats line up with real-world experience in my country anyway. Reading seems to have totally died out among young people. Hard to imagine a future where people don’t have fond memories of particular books or series they read as children/teens.

  3. advancedatheist says

    On the other hand in the U.S. I see stacks of newly published “young adult” novels for sale at Costco and Barnes & Noble stores. A market must exist for that kind of literature in the early-teens demographic.

  4. Philip Owen says

    Under 30, actual paper? Even I am making serious efforts at dematerialisation.

  5. A market must exist for that kind of literature in the early-teens demographic.

    Some women keep reading this nonsense into their twenties

  6. I have problem trusting the methodology how the home library size was measured. Only people who are dedicated book readers and book collectors know how many books there are in their home and usually they tend to overestimate.

  7. simple_pseudonymic_handle says

    They could go to the homes and count the books.

    In Merriman’s History Modern France you tube he tells a story about a friend of his and their PhD project. He read like 20 000 wills from the 18th century and plotted which libraries were properly Catholic and which libraries lent towards the heretical and made a map of which regions in the country the clusters of proper Catholics lived in. There was so little property back then that every book title was often listed. Or often enough that this guy could manufacture a PhD out of them.

    He claimed (I have no idea how rigorous, authentic, or dependable the research is) that the guy’s findings held continuously in French politics right down to today.

  8. “They could go to the homes and count the books.” – They could but I doubt that they did. It was self reporting, I think.

  9. The Japanese number, like many things about Japan, makes sense if you remember that the average Japanese home is by Western standards very small. Space is therefore at a premium and possessions must be limited.

    A bit of practical advice that follows from this: in the unlikely event that you are invited to a Japanese person’s home, remember that while a gift is expected, it ought to be disposable. A bottle of wine or sake fits the bill nicely.

  10. Whats their methodology? I honestly cant remember how many books there were in my childhood, only that there were “a lot”, and I probably didn`t finish something like a third of them.

    Sure loved Jules Verne though…

  11. women

    Hah. Methinks there is a big demand for positivist fiction, and YA whatever fits it nicely, explaining its broad reach. Just look at what assorted leftoid lunatics did to sci-fi! Even hard variety is not impenetrable anymore.

  12. anonymous coward says

    Under 12, actual paper is still a healthy market. My kids have hundreds and hundreds of books.
    (Most of them are under 50 pages, though, so not a really useful metric.)

  13. I’m impressed that anyone can remember how many books were around the house in childhood.

    (Also, will the latter correlate negatively with how conveniently the nearest public library is located?)

  14. (Also, will the latter correlate negatively with how conveniently the nearest public library is located?)

    Probably. It did for me, anyway. I know some rural people who own more books than me though they read less, only because they buy all of theirs while I read many of mine through the very convenient library system in my city (I did this when I was young, too).
    Countries like Japan and Singapore are densely packed (many highrises) and have good library infrastructure. That’s probably what’s going on. Scandinavia has more spread out housing development.
    Don’t even have to bring ebooks into the analysis (for that matter, libraries are lending ebooks out too).

  15. I thought this post was about actual dense books.

  16. Hence, Marie Kondo recommends being strict even about what books to keep in your home (despite having written more than one), which pissed off some people (for whom books are more about signalling than real utility).

  17. Note Czechia (alone beside Nordics) has a fully Nordic reading profile. (A playwright was president.)

    On Singapore:
    a) it may suffer even more “small house effect” than Japan and South Korea;
    b) it’s often accused of the crassest materialism/lack of high culture, which may be showing;
    c) the Indians and especially Malays may have about 0 books (or: 1 Quran/Malay home, end).

    The people working on this definitely need to develop good e-reading metrics. And what about if someone reads a lot these days, but most is articles?

    (And make sure your reading includes non-fiction.)

  18. First-rate texts are much better read in their material format.

    There’s book and book, reading and reading.

  19. anonymous says

    Good data indicator for curiosity. Lithuania is half of Estonia. Guess the stereotypes about Lithuanians are true. Estonian figure is higher than Finland. Finns as we know suffer from lack of curiosity compared to other Western Europeans and are the Asian Europeans. Despite affinity of languages, Estonians based on books and number of startups don’t appear to be laggards in curiosity. Any hypothesis?

  20. Anonymous says

    The lowest IQ in the world must be the IQ in USA. The population and government still dont know that the wall will not stop illegal imigration. It will be a big waste of money, 20 billions for nothing. The illegals can cross easily look and read this:

       The only way  to stop illegal imigration to USA is to make laws for  death  sentence for  people  that is illegally  within USA land, and  cancel all welfare  for aliens.