mildly relevant: fΙynn on the "fΙynn effect"

here's an excerpt from "Are We Really Getting Smarter?" @wsj:

Modern people do so well on these tests because we are new and peculiar. We are the first of our species to live in a world dominated by categories, hypotheticals, nonverbal symbols and visual images that paint alternative realities. We have evolved to deal with a world that would have been alien to previous generations.
..
The prescientific person is fixated on differences between things that give them different uses. My father was born in 1885. If you asked him what dogs and rabbits had in common, he would have said, "You use dogs to hunt rabbits." Today a schoolboy would say, "They are both mammals." The latter is the right answer on an IQ test. Today we find it quite natural to classify the world as a prerequisite to understanding it.

what bothers me about this is that ..

1. the use of the word "prescientific" here is imprecise. abstraction is important and essential in science, sure, but i wouldn't say that would be its defining characteristic. i suppose that in general, i'm against using the word "science" for "knowledge," even though common parlance is suggesting otherwise. (as i've insisted before, a discipline is a science if its epistemology involves the scientific method.)
   
   
2. the question above has no canonical, well-defined answer. it's fine to insist that "in common" means what qualities dogs and rabbits have that are the same .. as long as the test-taker also knows what it means [1]. from my experience (with large-scale university education), students need to be informed that some words do have precise meanings, especially in mathematics. definitions are crucial.
   
   "mammals" would be a right answer. there are others, though, like "both have fur" and "both appear on television a lot" and "humans have been known to eat both of them." even if one wants to stick to animal classifications, one should still say "placental mammals" for the most precise answer.

at any rate, these are just nitpicky details of mine. the phenomenon of this "fΙynn effect" [0] is pretty interesting.

Our ancestors weren't dumb compared with us, of course. They had the same practical intelligence and ability to deal with the everyday world that we do. Where we differ from them is more fundamental: Rising IQ scores show how the modern world, particularly education, has changed the human mind itself and set us apart from our ancestors. They lived in a much simpler world, and most had no formal schooling beyond the sixth grade.

i wonder how quantitative that trend is: i.e. if it is true that IQ increases with the the number of years of formal schooling, then is it a linear relationship? exponential? logistical, in the sense of solutions to $\frac{dx}{dt} = k x (x_{\rm max} - x)$?

assuming that kind of (suggestive) causality, it makes me wonder if today's growing prevalence of college education amongst adults will cause even higher IQs. (in fact, it would be even more interesting if it didn't ..!)


[0] interestingly enough, the article is written by james r. fΙynn.

[1]it could easily happen, in such a setting, that the test-taker uses the wrong definition and looks for how dogs and rabbits are related. the father's answer would be perfectly correct.