You may remember a previous post on whether being at school boosts intelligence.
Re-reading it now I recollect that there are strong papers suggesting a boosting effect on intelligence, yet I had remained dubious about the strength of the effects, and I would still like to see a long data set to confirm the imputed effects. If staying longer at school really boosts intelligence then there should be a discernable and sustained jump in ability from previous levels. My scepticism may be simply because I had followed the previous orthodoxy that schools boost knowledge and skills, but not children’s underlying intellectual horse-power. Intelligence is the engine, education the gears.
You may also recall another one of my quips, cast as a tweet: Academic debates should be punctuated by long moments of silence, broken only by pages turning as the combatants do the necessary reading.
As testimony to the inherent wisdom of this pronouncement, it was a delight to receive a further comment on “School” a mere 162 days later. We do not rush things here. Elijah Armstrong has a “Psychological Comments” VIP card and Executive Lounge entrance key, so it is a pleasure to post up his comments immediately.
Sorry for the very late reply, but as the issue is quite important I think a response is warranted.
Ritchie et al. find, in their regression analysis, that school exerts a strong effect on crystallized intelligence but not on fluid intelligence or chronometric g –– as one would expect. If their findings were really the result of measurement error, why don't they find spurious effects across the entire intelligence domain?
Further, this analysis dovetails with other studies using similar designs––studies of uneducated, isolated communities; of regression discontinuity designs; of the effect of closed schools, during desegregation, on the IQs of communities; etc.
Yes, these studies have flaws. Maybe the measurement error that contaminates the Ritchie et al. study was actually confined to the verbal/crystallized domain, or maybe it's a product of the fact that they only used verbal tests to assess childhood IQs. Maybe isolated communities really have low IQs because they're inbred or malnourished, not because they're uneducated. Maybe the schooling effects found using regression discontinuity designs don't persist into adulthood. But these are ad hoc explanations: in essence, degenerative science. The total evidence that schooling influences IQ is quite strong.
JayMan: you implicitly admit that schooling influences IQ, above, but claim that its effects are likely g-hollow. This is an interesting question. However, it should be pointed out that even non-g increases in IQ may be valid. We know this because TBI, foetal alcohol syndrome, prenatal cocaine exposure, and malnutrition all lower IQ –– and are often causes of genuinely low "intelligence" –- but the method of correlated vectors suggests that none of them are on g. Thomas Coyle has also shown that SAT and ACT residuals (controlled for g) are good predictors of performance in allied college majors.
Furthermore, there are specific abilities or sources of variance for every cognitive task that has thus far been studied, including "real-world" ones like job performance: there are no really pure measures of g; so it is at least theoretically possible to increase or decrease a huge variety of specific abilities but leave biological g untouched, and thereby increase "real intelligence". I think this is what the Flynn effect has done, and very likely it's what educational effects do as well.
But this is an open question.
Three good studies on the issue would be:
a) a study of the effects of schooling on a massive array of cognitive abilities, including every Stratum II in Carroll's taxonomy, plus on a large set of information domains (including non-academic ones like sport, fashion, agriculture, etc.), plus on psychophysical variables like brain size and neural conduction velocity;
b) a regression-based mediation study to see if educational IQ gains affect occupational status, mortality, crime, financial distress, income and net worth, all that good stuff (this one suggested to me by Stuart Ritchie);
c) thorough interviews and impressionistic assessments of uneducated people. (I was in Dominica early this year, where most people are quite unlettered and the average Raven's IQ is ~70, and they didn't seem that dumb at all. But I only rarely saw them doing complex or abstract tasks.)