But isn't IQ supposed to be relatively knowledge-independent? I.E. the test should not rely on advanced language knowledge or knowledge of mathematics.
How can poor (or good) education then affect IQ scores?
1. Not everyone had a birth certificate, so you could not base it on age.
2. City kids tended to be ready for school earlier than rural kids because they were more familiar with processes like queuing up.
The entire concept and history of intelligence testing is rife with problems and remains controversial.
Jesus. No it’s not, and no it isn’t.
This doesn’t mean that people love that variation in intelligence is a thing, but to say it’s rife with problems is just patently false. For sure some people don’t like that intelligence is “a thing” and don’t want to accept the reality of the construct, but that’s a different matter from claiming the construct itself is somehow still up for debate or otherwise questionable as as you seem to be doing.
Psychology and assessment more generally are a long way from the first ability measures.
"Most authorities feel that current intelligence tests are more aptly described as 'scholastic aptitude' tests because they are so highly related to academic performance, although current use suggests that the term intelligence test is going to be with us for some time. This reservation is based not on the opinion that intelligence tests do not reflect intelligence but on the belief that there are other kinds of intelligence that are not reflected in current tests; the term intelligence is too inclusive."
https://news.ycombinator.com/item?id=4740784
Edit: And that's without getting into the long history of classism, racism, etc impacting such tests.
The Role of General Cognitive Ability and Job Performance: Why There Cannot Be a Debate
Given the overwhelming research evidence showing the strong link between general cognitive ability (GCA) and job performance, it is not logically possible for industrial -organizational (I/O) psychologists to have a serious debate over whether GCA is important for job performance. However, even if none of this evidence existed in I/O psychology, research findings in differential psychology on the nature and correlates of GCA provide a sufficient basis for the conclusion that GCA is strongly related to job performance. In I/O psychology, the theoretical basis for the empirical evidence linking GCA and job performance is rarely presented, but is critical to understanding and acceptance of these findings. The theory explains the why behind the empirical findings. From the viewpoint of the kind of world we would like to live in-and would like to believe we live in-the research findings on GCA are not what most people would hope for and are not welcome. However, if we want to remain a science-based field, we cannot reject what we know to be true in favor of what we would like to be true.
The pull quote says nothing about IQ testing. Testing is what's under discussion here, not whether or not some people are actually smarter than others.
YouTube recently offered up some throwbacks, and I remembered a great kids TV programme on the BBC from 1980.
https://youtu.be/rOuAzHjsiOg?t=9m56s
Between the Adventure Game and the Great Egg Race, there was mainstream (3 TV stations) fodder for developing minds with an interest.
There's a lot of modern stimulating educational material on YouTube, but it's in an ocean of filler.