Can you pass a Grade 8 exam that was given to American children in 1912? Why the Flynn effect never really happened.
My last post elicited a tweet from Elon Bachman:
Argument by incredulity (w.r.t. retardation) bedevils discussions of intelligence data. What's striking about most retards is the *congenital* speech & motor impairment, not the level of g. Height also increased 1 SD last century. There used to be a lot of malnourished peasants. @ElonBachman
In a population with an average IQ of 100, an IQ below 70 is usually due to abnormal circumstances, either freak accidents during pregnancy or rare mutations that haven’t been eliminated by natural selection. In either case, the adverse effects are wide-ranging and affect many aspects of mind and behavior. If your IQ is below 70, you’re lacking in much more than cognitive ability. You probably suffer from various speech and motor impairments. In short, you look and act “funny.”
A century ago, if we use current norming of IQ tests, average IQ was below 70 in the Western world. Yet it was not associated with looking and acting “funny.” How come? For Elon Bachman, this is because an IQ of 70 was normal back then. It was not an outcome of freak accidents or rare mutations. The mental deficit was therefore confined to cognitive ability alone.
I understand that argument. Nonetheless, the increase in IQ between then and now is still 35 points—more than two standard deviations. Such a difference in cognitive ability should be visible in popular culture, particularly the books and newspapers that people read. It should also be visible in the academic requirements of elementary school, which was compulsory by that time in most North American jurisdictions.
The following are some questions from a Grade 8 exam that was given in 1912 to children in Bullitt County, Kentucky:
Find cost at 12½ cents per sq. yd. of kalsomining the walls of a room 20 ft. long, 16 ft. wide and 9 ft. high, deducting 1 door 8 ft. by 4 ft. 6 in. and 2 windows 5 ft. by 3 ft. 6 in. each.
A man sold a watch for $180 and lost 16 2/3%. What was the cost of the watch?
How many parts of speech are there? Define each.
What is a personal pronoun? Decline I.
Define longitude and latitude.
Tell what you know of the Gulf Stream.
Through what waters would a vessel pass in going from England through the Suez Canal to Manila?
Compare arteries and veins as to function. Where is the blood carried to be purified?
Define Cerebrum; Cerebellum.
Define the following forms of government: Democracy, Limited Monarchy, Absolute Monarchy, Republic. Give examples of each.
Name five county officers and the principal duties of each.
What is a copyright? Patent right?
Describe the Battle of Quebec.
Name the last battle of the Civil War; War of 1812; French and Indian War and the commanders in each battle.
Those are only a few of the questions. The full exam is here.
I understand why some want to believe that Western societies were much less intelligent a century ago. If we cannot use IQ to compare different populations over time, perhaps we cannot use it to compare different populations over space, i.e., in different parts of the world. And then what?
I’ve heard that sort of argument before. “If we accept genetic determinism for this, we may have to accept it for that. And then what?” If that’s your frame of mind, I have nothing more to say.
The increase in IQ and the increase in height during the 20th century
But what about the increase in height? That was real. If insufficient nutrition held back height during the 20th century, it should have also held back cognitive ability. The assumption here is that IQ and height are equally constrained by nutrition during development. Has that assumption been tested?
It has. The Dutch suffered a terrible famine during the winter of 1944-1945, as did much of continental Europe. Yet that famine had no discernable impact on the mental development of unborn children from that time:
A detailed retrospective study was made of 125,000 19-yr-old male Dutch military inductees of whom 20,000 were exposed to the Netherland's winter famine, 1944-1945, through maternal starvation. […] Findings show that (a) starvation during pregnancy had no detectable effects on adult mental performance of surviving male offspring. (b) Mental performance of surviving adult males from the entire population had no association with changing levels of mean birth weight in a hospital sample from the population. And (c) there was a strong association of social class with mental performance. (Stein et al. 1972)
It isn’t as if the Flynn effect didn’t occur in the Netherlands, As James Flynn points out:
As for nutrition, to my knowledge no one has actually shown that American or British or Western European children have a better diet today than they did in 1950, indeed, the critics of junk food argue that diets are worse. Yet, post-1950 IQ gains have been very large. Military samples tested in 1952, 1962, 1972, and 1982 show that Dutch males made a 20-point gain on a Raven’s-type test (Flynn, 1987, p. 172). Even the latest period shows a huge gain, that is, the Dutch 18-year olds tested in 1982 outscored the Dutch 18-year olds tested in 1972 by fully 8 IQ points. Did the quality of the Dutch diet really escalate that much in 10 years? The gains posted by the 1962 males over the 1952 males are interesting. (Flynn 2008)
Those 1962 males were born or still in the womb during the 1944-45 famine. Yet they “do not show up even as a blip in the pattern of Dutch IQ gains” (Flynn 2008). One could argue that the famine was too brief to affect cognitive ability. Perhaps malnutrition needs a longer time span to affect mental development. And again, what about the increase in height? What was driving that increase?
We don’t know for sure. We do know that height increased independently of the increase in IQ.
Norway was cited above as a nation in which the nutrition hypothesis is viable thanks to greater gains in the lower half of the IQ distribution. Actually, it counts against the posited connection between height gains and IQ gains. Height gains have been larger in the upper half of the height distribution than in the lower half (Sundet et al., 2004). This combination, greater height gains in the upper half of the distribution, greater IQ gains in the lower, poses a serious problem. Are there two kinds of enhanced nutrition, one of which raises height more than it does IQ, the other of which raises IQ more than it does height? (Flynn 2008)
There is no common cause behind the increase in IQ and the increase in height. The latter seems to be due to people eating a more varied diet after the Second World War. In particular, fewer and fewer people were subsisting largely on bread. That food item is problematic not only because it lacks many nutrients but also because it has a high content of phytic acid, which binds to calcium and other essential minerals in the food we eat (Harrison and Mellanby 1939; McCance and Widdowson 1942a; McCance and Widdowson 1942b; Sandstead 1992). With the postwar boom, and with efforts to educate people about the benefits of a balanced diet, bread made up a smaller and smaller proportion of total food intake. Bones could now fully develop.
Excessive consumption of bread, and the resulting lack of essential minerals, constrained skeletal development during the early 20th century. But it did not constrain cognitive ability.
References
Flynn, J.R. (2008). Requiem for nutrition as the cause of IQ gains: Raven's gains in Britain 1938-2008. Economics and Human Biology 7(1):18-27. https://doi.org/10.1016/j.ehb.2009.01.009
Harrison, D.C., and E. Mellanby. (1939). Phytic acid and the rickets-producing action of cereals. Biochemical Journal 33: 1660-1680. https://doi.org/10.1042%2Fbj0331660
McCance, R.A., and E.M. Widdowson. (1942a). Mineral metabolism of healthy adults on white and brown bread dietaries. The Journal of Physiology 101: 44-85. https://doi.org/10.1113%2Fjphysiol.1942.sp003967
McCance, R.A., and E.M. Widdowson. (1942b). Mineral metabolism on dephytinized bread. The Journal of Physiology 101: 304-313. https://doi.org/10.1113%2Fjphysiol.1942.sp003984
Sandstead, H.H. (1992). Fiber, phytates, and mineral nutrition. Nutrition Reviews 50: 30-31. https://doi.org/10.1111/j.1753-4887.1992.tb02464.x
Sieczkowksi, C. (2013). 1912 Eighth-Grade Exam Stumps 21st-Century Test Takers. Could You Pass This Eighth-Grade Exam from 1912? Huffpost, August 12. https://www.huffpost.com/entry/1912-eighth-grade-exam_n_3744163
Stein, Z., M. Susser, G. Saenger, and F. Marolla. (1972). Nutrition and mental performance. Science 178(4062): 708–713. https://doi.org/10.1126/science.178.4062.708
Sundet, J.M., D.G. Barlaug, and T.M. Torjussen. (2004). The end of the Flynn effect? A study of secular trends in mean intelligence test scores of Norwegian conscripts during half a century. Intelligence32: 349– 362. https://doi.org/10.1016/j.intell.2004.06.004