The FLynn Effect has not acted uniformly across the various domains of intelligence.
To put it very roughly, in the past century, the developed world has seen a two S.D. improvement on Raven’s Progressive Matrices, hardly any improvement in verbal or Backward Digit Span tests, and a one S.D. improvement in various picture arrangement and completion tasks.
This has translated to an approximately one S.D. improvement in general intelligence.
Raven’s loads heavily on visuospatial ability, which in turn is highly dependent on brain size. OTOH, verbal ability to seems to have little, if any, correlation with brain size.
Brain size increased by well more than an S.D. since the late 19th century, in line with increased in body size as a whole [see the book The Changing Body by Floud et al. for a comprehensive treatment]. However, people familiar with classical literature, with contemporary journals, magazines, and letters, etc., could be understood for dismissing this on account of it just being too incredible.
At it happens, they would be right to do so. According to one study (Henrichsen et al., 1986), which was highlighted by IQ blogger Pumpkin Person, fourteen pairs of MZ twins who had weight differentials of more than 25% at birth had their bodies and minds measured at the age of 13. The heavier twins had a 0.5 S.D. higher head circumference, a 0.5 S.D. higher performance IQ, but there was no difference in verbal IQ.
Two other bits of evidence from HBD. First, larger-brained men have a 10 IQ point advantage in visuospatial ability over women, but verbal abilities are at best equal. The Inuit and Yakuts have some of the biggest brains on the planet, more so even than their other Mongoloid cousins, but while their visuospatial abilities are legendary – early Soviet psychometrists noted the ability of the Altai to notice one missing animal in a herd of hundreds – their verbal IQs are nothing to write home about. Meanwhile, Jews dominate verbal IQ, being almost one S.D. above Whites, while having normal sized brains and unremarkable visuospatial IQ.
Apart from auxological factors, which was emphasized by Richard Lynn, performance also increases with greater training, an observation that was stressed more by James Flynn. One study (Armstrong et al., 2014) discovered a correlation between the FLynn effect on various tests, and the extent to which said tests are rule-dependent. Rule-dependent tests, in turn, benefit from retesting effects and the progressively greater emphasis on abstract thinking skills in schooling during the course of the 20th century. Raven’s maxes out on both factors, and has consequently seen the greatest increase.
Verbal skills, in contrast, benefit little if at all from greater brain size, and children in the developed world were already getting very stringently trained on it even a century ago. Even brutally so (spare the rod and spoil the child; one beaten is worth two unbeaten; etc.). OTOH, there must have been a large improvement in average verbal proficiency between, say, 1600 and 1900.
Verbal skills are much more important for economic productivity than recognizing patterns in weird shapes, ergo GDP per capita and development levels showing the highest levels of correlation precisely with verbal IQ. Incidentally, this is why I find PISA tests – which are both strongly g loaded, as well as focusing on precisely the most economically useful skills – to really be the most useful psychometric tests from a real world perspective, as opposed to Lynn & Vanhanen’s and David Becker’s laudable efforts.
Note that neither of these two factors “disprove” genetic racial differences in IQ. Within countries, especially the modern developed world, both the auxological environment and the learning environment tend to be very similar across racial groups. American Negroes, if anything, benefit from being more urban than Caucasians, and contrary to leftist rhetoric, inner city schools are typically very well financed. However, in both the US and across all other countries where studies have been conducted, including African ones, Negroes consistently place at least half an S.D. to one S.D. lower than Caucasians across pretty much all types of IQ tests.
The immigrants who came to the US in the late 19th/early 20th centuries from places like Southern Italy or Ireland were nutritionally underdeveloped (so lower scores on culture neutral but auxology-dependent tests), usually less intensely educated and certainly not in the English language (so lower verbal IQ performance), and certainly had less practice with more abstract problems. This made for a large gap with indigenous Americans, and up until the 1960s/70s, with residents of the most developed nations in general. Since then, nutritional and educational convergence has almost entirely closed those gaps.
However, precisely because our world is now much more biorealistic than in the past, with best practices filtering through to all but the most benighted places, I am skeptical of existing gaps continuing to get closed to any significant extent (even if there is still considerable room for improvement in Africa and the Indian subcontinent). For instance, Jason Richwine has noted – and gotten into trouble for it – that Mexican-Americans stop converging to White Americans norms after the second generation.
East Asians (Chinese, Koreans, Japanese) tend to have larger brains and larger visuospatial IQs than Caucasians, but similar verbal IQs. However, they modestly lag in GDP per capita (relative to what it should be), significantly lag in elite science output (again, relative to what it should be), and grossly lag in historical accomplishment (how China was not first to the Industrial Revolution must be one of the biggest puzzles of Intelligence Theory).
My guess is that this underperformance can be ascribed to greater East Asian conformism, relative to the other major races of man (Kura et al., 2015).
Let’s take an extreme case. Women do not significantly lag men in intelligence, or at least on the sort of intelligence that is useful for making discoveries. And if anything they are better – more conscientious, more diligent – at office work. And yet the achievement gap is awesome. According to Charles Murray’s calculations, women only account for about 2% of human accomplishment across most scientific or cultural domains, and this figure hasn’t budged upwards despite the appearance of feminism and affirmative action. Women are, of course, far more conformist than men, less willing to challenge the dominant paradigms, and there is good reason to think East Asians are “tilted” in a similar direction. Just look at their inventions: As Steve Sailer is wont to say, while the Indians invented the zero, the Chinese invented paper and the compass. Even in the Early Modern Age, East Asian mathematics was most developed relative to Europe in the highly non-abstract field of numerical techniques, while lagging cardinally in more theoretical fields such as calculus and number theory.
As I argued in Apollo’s Ascent, the Sinosphere was also very much hampered on account of their logographic writing systems. As anyone who has studied Mandarin can confirm, literacy is MUCH simpler to acquire with alphabetic systems, while even retaining literacy in logographic systems such as Hanzi is not trivial without constant practice. In contrast, the civilizations of the Med shifted to alphabets, beginning with the Phoenicians, as soon as literacy rates began expanding beyond the priestly castes. Possibly it was precisely East Asian conformism that preempted similar developments there (note that Korea’s Sejong the Great did introduce an alphabetic system from above in the 15th century, and for the express purpose of increasing literacy amongst the commonfolk, but the system was apparently so resistant to change that it took until the 20th century to truly catch on).
Moreover, even in the modern day US, as I pointed out, East Asians (though not South Asians!) take much less of an interest, especially relative to their IQ levels, in “out of left field” topics and communities such as rationalism and transhumanism. The usual boors will rejoinder “good for them,” but I am sure that they will not come up with anything or original either. But just to address their autistic screeching: (The Japanese researcher) Kenya Kura notes: “Among undergrads, 40% or more are Asians, but graduate students are something like 20% (depending on departments). Faculty members are well less than 10%.” Getting an undergraduate degree is the normal, handshakeworthy thing to do in modern society. Slaving away for a PhD? Not so much.
More conformism, literacy retarding writing system, no advantage in verbal IQ. And so China didn’t launch a Scientific Revolution, or an Industrial one, despite consistently having high human capital, an unusually unified and free market of 100 million+ people, vast numbers of schools, etc.
There isn’t near as much to explain about the Middle East and India. They are simply less intelligent – significantly so – than the Europeans or East Asians. They got to intensive agriculture, urbanization, and some degree of literacy – these all very much went together before the Industrial Revolution – faster than China or Europe. They made vast progress when that happened, but they ran into cognitive barriers, which were pushed back as soon as each new wave of more cold-adapted, higher IQ peoples got into the innovation game. This is the argument that Richard Hart makes in Understanding History.
I also don’t consider it at all necessary to invoke Christianity to explain European intellectual success, as Charles Murray insists on doing in Human Accomplishment. I am certainly not one of those militant atheist types, but it’s hard to deny that Christianity’s influence in late Antiquity was highly negative, helping push the Roman sphere further into obscurantism. It did play a role in conserving knowledge during the Dark Ages, and in advancing knowledge after 1100, but it’s not clear how it did that, or promoted literacy, beyond what it would have been the case under a different religion (e.g. William Harris in Ancient Literacy estimates Roman Italy’s literacy rate to have been at 10%-15% at its peak, and that was without the benefit of cheap paper). Protestantism did raise literacy way above what it would have been, due to the emphasis it placed on a personal reading of the Bible. But by the time Protestantism rolled around, Europe was already way scientifically ahead of China, not to mention all other civilization.
Finally, I don’t think Jaychick’s ideas about clannishness played a major role either. They are correct and original in their observations that countries within the Hajnal Line are indeed less corrupt and more civic-minded than those outside it, and East Asian evolved an alternate prosociality based on shame instead of guilt. These have important consequences with respect to everyday life, institutions, etc. But economic development, or innovation? Not so much. The reality is that there were plenty of very bright and creative Middle Easterners and Mediterraneans – especially Greeks and Italians – who pushed the scientific frontier forwards. Almost everything can be explained by IQ, and differential rates in the appearance of intensive agriculture, urbanization, and literacy. The two biggest factors that can’t be are the relative underperformance (relative to IQ!) of East Asians vs. everyone else, and women vs. men. Common factor there seems to be higher conformism.
Rant over. Did I miss anything?