Special Report
Highlights After rising for thousands of years, human intelligence has begun to decline in developed economies. This can be seen in falling IQ scores and a decline in math and science test scores. Environmental factors appear to account for the bulk of this decline, but no one knows what these factors are. If left unchecked, falling intelligence will severely undermine productivity growth. This could lead to lower equity multiples, larger budget deficits, and ultimately, much higher government bond yields. Technological advances, particularly in the genetic realm, promise to radically raise IQs. In a complete abandonment of its one-child policy, China will combine these controversial technologies with pro-natal measures in order to boost sagging birth rates. The coming Eugenic Wars will be one of the most important economic and geopolitical developments of the 21st century. Feature Part 1: What The Tame Fox Says In 1959, a Soviet scientist named Dmitry Belyaev embarked on an ambitious experiment: to domesticate the silver fox. A geneticist by training, Belyaev wanted to replicate the process by which animals such as cats and dogs came to live side-by-side with humans. It was a risky endeavor. The Soviets had essentially banned the study of Mendelian genetics in favor of the blank slate ideology that is popular in progressive circles today. Belyaev persevered. Working under the guise of studying vulpine physiology, he selected foxes based on only one trait – tamability. Less than 10% of foxes made it to the subsequent generation, with the other 90% being sent off to fur farms. By the fourth generation, the changes were undeniable. Rather than fleeing humans, the foxes sought out their attention with no prompting whatsoever. They even wagged their tails and whined and whimpered like dogs do. The tame foxes also displayed physical changes. Their ears flopped over. Their snouts became shorter and their tails stood upright. “By intense selective breeding, we have compressed into a few decades an ancient process that originally unfolded over thousands of years,” wrote Lyudmila Trut, who began as Belyaev’s assistant and took over the project when her boss died in 1985. Genetically Capitalist? Evolution can broadly proceed in two ways. The first way is through random mutations. This form of evolution, which scientists sometimes refer to as genetic drift, can take thousands of years to yield any discernable changes. The second way is through natural selection, a process that exploits existing variations in genetic traits. As the Russian fox experiment illustrates, evolution driven by selective pressures (either natural or artificial) can occur fairly quickly. Did selective pressures manifest themselves in human evolution in the lead up to the Industrial Revolution? Did humans, in some sense, domesticate themselves? In his book, A Farewell To Alms, economic historian Gregory Clark argued in the affirmative. Clark documented that members of skilled professions in Medieval England had twice as many surviving children as unskilled workers (Chart 1). Indeed, the fledgling middle class of the time had even more surviving children than the aristocracy, who were often out fighting wars. As a result, the wages of craftsmen declined by a third relative to laborers between 1200 and 1800, implying that the supply of skilled labor was growing more quickly than the demand for skilled workers over this period. In subsequent work, Clark and Cummins argued that the spread of bourgeois values across pre-industrial England was more consistent with a model of genetic transmission than a cultural one (see Box 1 for details). Similar developments occurred in other parts of the world. For example, in China, the gateway into the bureaucracy for a thousand years was the highly competitive imperial exam. Xi Song, Cameron Campbell, and James Lee showed that high-status men had more surviving children during the eighteenth- and nineteenth-centuries (Chart 2).1 The 10,000 Year Explosion Stephen Jay Gould famously said that “There’s been no biological change in humans in 40,000 or 50,000 years. Everything we call culture and civilization we’ve built with the same body and brain.” Gould was wrong. Data from the International HapMap Project show that human evolution accelerated by 100-fold starting around 10,000 years ago (Chart 3). In their book The 10,000 Year Explosion: How Civilization Accelerated Human Evolution, Gregory Cochran and the late Henry Harpending explained why evolution sped up so rapidly.2 The advent of agriculture led to a surge in population levels. This, in turn, increased the absolute number of potentially beneficial genetic mutations that could be subject to selection effects. Farming and the rise of city states also completely reshaped the environment in which people lived. Basic biology teaches us that environmental dislocations of this kind tend to generate selective pressures that cause evolution to accelerate. John Hawks, professor of anthropology and genetics at the University of Wisconsin-Madison, put it best: “We are more different genetically from people living 5,000 years ago than they were different from Neanderthals.” Many of the changes to our genomes relate to diet and diseases. The various genetic resistances that people have built up to malaria are all less than 10,000 years old. Mutations to the LCT gene, which confers lactose tolerance into adulthood, occurred independently in three different geographical locations: one in East Asia, one in the Middle East, and one in Africa. The Middle Eastern variant was probably responsible for the rapid enlargement of the Indo-European language group, which now stretches from India to Ireland. The African variant likely facilitated the Bantu expansion, which started near the present-day border of Nigeria and Cameroon, and then spread out across almost all of sub-Saharan Africa. Evolution Of The Human Brain About half of the genes in the human genome regulate some aspect of brain function. Given the rapid acceleration in evolution, it would be rather surprising if our own brains had not been affected. And indeed, there is plenty of evidence that they were. The frontal lobe of the brain has increased in size over the past 10,000 years. This is the part of the brain that regulates such things as language, memory, and long-term planning. Testosterone levels have also declined. That may explain the steady reduction in violent crime rates (Chart 4). We know that certain genes that are associated with higher intelligence have been under recent selective pressure. For example, the gene that leads to torsion dystonia – a debilitating movement disorder – appears to have increased in frequency. Why would a gene that causes a known disease become more widespread? The answer is that individuals who have this particular mutation tend to have IQs that are around 10-to 20-points above the population average. Why IQ Matters IQ has a long and contentious history. Yet, despite numerous efforts to jettison the concept, it has endured for one simple reason: It has more predictive power than virtually anything else in the psychological realm. A simple 30-minute IQ test can help predict future educational attainment, job performance, income, health, criminality, and fertility choices (Table 1 and Chart 5). IQ even predicts trader performance!3 Table 1What IQ Predicts (Results From Meta-Analyses) Like most physiological traits, IQ is highly heritable.4 The genetic contribution to IQ increases from 20% in early childhood to as high as 80% by one’s late teens and remains at that level well into adulthood.5 This makes IQ almost as heritable as height (Chart 6). Although there is a great deal of variation among individuals, on average, more intelligent people earn higher incomes (Chart 7). If the same relationship existed in the pre-industrial era, as seems likely, then human intelligence probably increased in a way that facilitated the economic explosion that we associate with the Industrial Revolution. The stunning implication is that the emergence of the modern era was a question of “when, not if.” Part 2: The Flynn Effect By the late-19th century, it had become clear that the rich were no longer having as many children as the poor. This realization, together with the growing popularity of Darwin’s theories, helped galvanize the eugenics movement. Contrary to popular belief, this movement was not a product of the far-right. In fact, the most vocal proponents of eugenics were among the progressive left. John Maynard Keynes, for example, served as the Director of the British Eugenics Society between 1937 and 1944. Yet, a funny thing happened on the road to idiocracy: The concerns of eugenicists did not come to pass. Rather than becoming dimmer, people became smarter. This phenomenon is now known as the Flynn Effect, named after James Flynn, a psychologist who was among the first to document it. Chart 8 shows the evolution of IQ scores in a sample of countries between 1940 and 1990. The average country recorded IQ gains of three points per decade over this period, a remarkably large increase over such a relatively short period of time. Explaining The Flynn Effect The Flynn Effect must have been entirely driven by environmental factors since genetic factors – namely the tendency of less-educated people to have more children, and to have them at an earlier age – would have reduced average IQs over the past two hundred years. But how could environmental factors have played the dominant role in light of the strong role of genes discussed above? The answer was proposed by geneticist Richard Lewontin in the 1970s. Lewontin suggested imagining a genetically-diverse sack of seed corn randomly distributed between two large identical fields. One field had fertilizer added to it while the other did not. Genetic variation would explain all of the differences in the height of corn stalks within each field, while environmental factors (the addition of fertilizer) would explain all of the difference in the average height of corn stalks between the two fields. This logic explains why genes can account for the bulk of the variation in IQs within any demographic group, while environmental effects may explain most of the variation across groups, as well as why average scores have changed over time. And what environmental effects are these? The truth is that no one really knows. Plenty of theories have been advanced, but so far there is still little consensus on the matter. Bigger, Healthier Brains It has long been known that learning increases the amount of grey matter in the brain. For example, a recent study showed that the hippocampi of London taxi drivers tend to be larger due to the need for drivers to memorize and navigate complex routes.6 The emergence of modern societies likely kicked off a virtuous circle where the need to solve increasingly complex tasks forced people to hone their learning skills, leading to higher IQs and further technological progress. The introduction of universal primary education amplified this virtuous circle. Better health undoubtedly helped as well. Early childhood diseases reduce IQ by diverting the body’s resources away from mental development towards fighting off infections. There is a strong correlation between measured IQ and disease burden across countries (Chart 9). A number of studies have documented a strong relationship between the timing of malaria eradication in the U.S. and other parts of the world and subsequent observed gains in childhood IQs.7 Brain size and IQ are positively correlated. Forensic evidence from the U.S. suggests that the average volume of adult human skulls has increased by 7% since the late 1800s, or roughly the size of a tennis ball.8 Part 3: The End Of A 10,000 Year Trend The problem with environmental effects is that they eventually run into diminishing returns. This appears to have happened with the Flynn Effect. In fact, not only does the recent evidence suggest that the Flynn Effect has ended, but the data suggest that IQs are starting to decline. Chart 10 shows that average math and science test scores fell in the OECD’s Program For International Scholastic Achievement (PISA) between 2009 and 2015, the latest year of the examination. The drop in math and science test scores has been mirrored in falling IQ scores. Flynn observed a decade ago that IQs of British teenagers were slipping.9 Similar results have been documented in France, the Netherlands, Germany, Denmark, and most recently, Norway. The Norwegian results, published last year, are particularly noteworthy.10 Bernt Bratsberg and Ole Rogeberg examined three-decades worth of data on IQ tests of Norwegian military conscripts. Military duty has been mandatory for almost all men in Norway since 1814, which means that the study’s authors were able to collect comprehensive data on most Norwegian men and their fathers. Their paper clearly shows that IQ peaked with the generation born in the mid-1970s and declined by about five points, or one-third of a standard deviation, for the one born in 1990 (Chart 11). For the first time in recorded history, Norwegian kids today are not scoring as well as their parents. A Mystery What caused the sudden reversal of the Flynn Effect in Norway and most other developed economies? Nobody knows. We can, however, offer three possible theories: New Technologies For much of human history, rising intelligence and technological innovation were complementary processes, meaning that the smartest people were the ones who could best exploit the new technologies that were coming their way. Moreover, as noted above, even those who were less gifted benefited from the mental stimulation that a technologically advanced society provided. It remains to be seen how future technological advances such as generalized AI will affect human intelligence, but recent technological advances seem to have had a dumbing down effect.11 For example, the GPS has obviated the need for people to navigate unfamiliar locations, thus blunting the development of their visuospatial skills. Modern word processors have made spelling skills less important. Having all the information in the world just a click away is a wonderful thing, but it has reduced the need for our brains to retain and codify what we learn. Meanwhile, the constant bombardment of information to which we are subject has made it difficult to concentrate on anything for long. How many youth today can read a report of this length without checking their Facebook feed multiple times? My guess is not many. Diminishing Returns To Education The ability to take young bright minds, who would have otherwise spent their lives doing menial labor, and provide them with an education was probably the greatest tailwind to growth that the 20th century enjoyed. There is undoubtedly still scope to continue this process, but the low-hanging fruit have been picked. Educational attainment has slowed dramatically in most of the world (Chart 12). Economist James Heckman estimates that U.S. high-school graduation rates, properly measured, peaked over 40 years ago.12 Despite billions of dollars spent, efforts to improve school performance have generally fallen flat. A recent high-level report by the U.S. Department of Education concluded that “The panel did not find any empirical studies that reached the rigor necessary to determine that specific turnaround practices produce significantly better academic outcomes.”13 This gets to a point that most parents already know, which is that when people talk about “bad schools,” they are really talking about “bad students.” Deteriorating Health Better health probably contributed to the Flynn Effect. But is it possible to have too much of a good thing? More calories are welcome when people are starving, but today’s calorie-rich, nutrient-poor diets have led to a surge in obesity rates. A clean environment reduces the spread of germs, but it also makes children hypersensitive to foreign substances. Following German reunification, researchers observed that allergies were much more common among West German children than their Eastern peers, presumably because of the West’s more salubrious environment.14 All sorts of weird and concerning physiological changes are occurring. Sperm counts have fallen by nearly 60% since the early 1970s.15 Testosterone levels in young men are dropping. Among girls, the age of first menarche has declined by two years over the past century.16 Are chemical agents in the environment responsible? If they are, what impact are they having on cognitive development? Nobody knows. Reported mental illness is also on the rise. The share of U.S. teenagers with a reported major depressive episode over the prior year surged by over 60% between 2010 and 2017 (Chart 13). The fraction of young adults that made suicide plans nearly doubled.17 More than 20% of U.S. women over the age of 40 are on antidepressants.18 Five percent of U.S. children are receiving ADHD medication.19 Implications For Economic Growth And Asset Markets So far, the reversal of the Flynn Effect has been largely confined to the developed economies. Test scores are still rising in the developing world, albeit from fairly low levels. For example, two recent studies have documented significant IQ gains in Kenya and Brazil.20 In the poorest countries, opportunities for improving health abound. Even small steps such as fortifying salt with iodine (which costs about five cents per person per year) have been shown to boost IQ by nearly one standard deviation.21 Measures to reduce inbreeding are also likely to boost IQ scores.22 Yet, we should not underestimate the importance of falling cognitive skills in developed economies. Chart 14 shows that there is a clear positive correlation between student score on math and science and per capita incomes. Most technological innovation still takes place in developed economies. There is an extremely tight relationship between visuospatial IQ and the likelihood of becoming an inventor (Chart 15). Since IQ is distributed along a bell curve, a 0.1 standard deviation drop in IQs across the entire distribution will result in an 8% decline in the share of people with IQs over 100, a 14% decline in those with IQs over 115, and a 21% decline in those with an IQ over 130 (by convention, each standard deviation on an IQ test is worth 15 points). Falling IQs could result in slower productivity growth, which could further strain fiscal balances. Lower IQs are also associated with decreased future orientation.23 People who live for the moment tend to save less. A decline in savings would push up real rates, leading to less capital accumulation. History suggests that a deceleration in productivity growth and higher real rates will put downward pressure on equity multiples (Chart 16). Chart 16Equity Multiples Tend To Fall When Real Rates Rise And Productivity Growth Declines Part 4: Generation E For 200 years, the environmentally-driven Flynn Effect disguised the underlying genetically-driven decline in IQs that began not long after the dawn of the Industrial Revolution. Flynn has acknowledged this himself, noting at the 2017 International Society For Intelligence Research Conference that “I have no doubt that there has been some deterioration of genetic quality for intelligence since the late Victorian times.”24 Now that the Flynn Effect has reversed, both genes and the environment are working together to reduce cognitive abilities in developed economies. This means that the most important trend in the world – a trend that allowed the human population to increase during the Malthusian era and later allowed output-per-worker to soar following the Industrial Revolution – has broken down. Yet, there may be another twist in the story – one that began just a few months ago: the first members of Generation E were born. E Is For Edited ... Or Eugenics Lulu and Nana will be like most other children, but with one key difference: They will be the first humans ever to have their genomes edited through a procedure know as CRISPR-Cas9. Rogue Chinese scientist He Jiankui deactivated their CCR5 gene, which the HIV virus uses as a gateway into the body. His actions were rightfully condemned around the world for endangering the twins’ health by using a procedure that has not yet been fully vetted in animal studies, let alone in human trials (Lulu and Nana’s father is HIV+ but it is debatable whether the children were at an elevated risk of infection). He Jiankui remains under house arrest at the university where he worked. But whatever his fate, the dam has been broken. For better or for worse, the era of personal eugenics has arrived. The Return Of The Silver Fox It is easier to delete a gene than to add one. It is even more difficult to swap out a large number of genes in a way that achieves a predictable outcome. Thus, the successful manipulation of highly polygenic traits such as intelligence – traits that are linked to hundreds of different genes – may still be decades away.25 Predicting a trait is much simpler than modifying it, however. The cost of sequencing a human genome has fallen by more than 99% since 2001 (Chart 17). Start-up company Genomic Prediction has already developed a test for fertilized embryos for IVF users that predicts height within a few centimetres and IQ with a correlation of 0.3-to-0.4, roughly as accurate as standardized tests such as the SAT or ACT.26 Other companies are following suit.27 Some will recoil in horror at the prospect of selecting prospective children in this manner. They will argue that such technologies, beyond being simply immoral, will widen social inequality between those who can afford them and those who cannot. Others will counter that screening embryos for certain traits is not that dissimilar to what people already do with prospective romantic partners. They will also point out that mass usage of these technologies will drive down prices to the point that even poor people will be able to access them, thus giving low IQ parents the chance to have high IQ kids. They might also note that such technologies may be the only way to reverse the ongoing accumulation of deleterious mutations within the human germline that has been the unintended by-product of the proliferation of life-saving medicines.28 We will not wade into this thorny debate, other than to note that there will be huge incentives for people to avail themselves of these technologies. The Coming Eugenic Wars And not just individuals either – governments too. While the initial impact of eugenic technologies will be small, the effects will compound over time. Carl Shulman and Nick Bostrom estimate that genetic screening could boost average IQs by up to 65 points in five generations (Table 2). Table 2A Poisoned Chalice? Genetic Screening Can Raise IQ China has been investing heavily in genetic technologies. As Geoffrey Miller has argued, China’s infatuation with eugenics spans into the modern day.29 Like most other countries, fertility in China is negatively correlated with IQ. Mingrui Wang, John Fuerst, and Jianjun Ren estimate that China is currently losing nearly one-third of a point in generalized intelligence per decade, with the loss having accelerated rapidly between the 1960s and mid-1980s.30 The decline in the genetic component of Chinese IQs is coming at a time when the population itself is about to shrink. According to the UN’s baseline forecast, China will lose 450 million working-age people by the end of the century (Chart 18). Meanwhile, the country is saddled with debt, the result of an economic model that has, for decades, recycled copious household savings into debt-financed fixed-investment spending in an effort to shore up domestic demand. The authorities may be tempted to tackle all three problems simultaneously by adopting generous pro-natal measures – call it the “at least one-child policy”– which increasingly harnesses emerging eugenic technologies. The resulting baby boom would strengthen domestic demand, thus making the economy less dependent on exports, while ensuring China’s long-term geopolitical viability. The Eugenic Wars are coming, and they will be unlike anything the world has seen before. Peter Berezin, Chief Global Strategist Global Investment Strategy peterb@bcaresearch.com Box 1 The Diffusion Of Bourgeois Values: Culture Or Genes? Higher-income people had more surviving children in the centuries leading up to the Industrial Revolution. Real per capita income was broadly stable during this period. This implies that there must have been downward social mobility, with sons, on average, being less wealthy than their fathers. This downward mobility, in turn, spread the characteristics of higher-income people across the broad swathe of society. What were these characteristics? Cultural values that emphasized thrift, diligence, and literacy were undoubtedly part of what was passed on to future generations. But surprisingly, it also appears that genetic transmission played an important, and perhaps pivotal, role. Models of genetic transmission make very concrete predictions about the correlations in economic status that one would expect to see among relatives. Biological brothers share 50% of their genes, as do fathers and sons. Likewise, first cousins share 25% of their genes, the same as grandfathers and sons. These facts yield two testable predictions: The first is that the correlation coefficient on status measures such as wealth, occupation, and education should be the same for relatives that share the same fraction of genes such as sibling pairs and father-son pairs. Box Chart 1 shows that this is borne out by the data. The second prediction is that the correlation between status and genetic distance should follow a linear trend so that, for example, the correlation in wealth among brothers is twice that of first cousins and four times that of second cousins. Box Chart 2 shows that this is also borne out by the data. Other evidence supports the importance of genes in the transmission of status across generations. The correlation in measures such as wealth, education, and occupation is much higher among identical twins than fraternal twins. Adopted children turn out to be more similar to their biological parents on these measures when they reach adulthood than their adopted parents, even when the children have never met their biological parents. The parent-child correlation also remains the same regardless of family size, suggesting that spreading the same resources over more children may not harm life outcomes to any discernible degree, at least on the measures listed above. Source: Gregory Clark and Neil Cummins, "Nature Versus Nurture in Social Outcomes. A Lineage Study of 263,000 English Individuals, 1750-2017," Luxembourg Institute of Socio-Economic Research. Footnotes 1 Xi Song, Cameron Campbell, and James Lee, "Descent Line Growth and Extinction From A Multigenerational Perspective, Extended Abstract," American Sociological Review 80:3, (April 21, 2015): 574-602. 2 Gregory Cochran and Henry Harpending, "The 10,000 Year Explosion: How Civilization Accelerated Human Evolution," Basic Books, (2009). 3 Mark Grinblatt, Matti Keloharju, and Juhani T. Linnainmaa, “IQ, Trading Behavior, and Performance,” Journal of Financial Economics, 104:2, (May 2012): 339-362. 4 Thomas Bouchard, “Genetic Influence On Human Psychological Traits - A Survey,” Current Directions in Psychological Science 13:4, (August 2004): 148-151. 5 The tendency for the genetic contribution to IQ to increase until early adulthood and then to remain at high levels until old age is known as the Wilson Effect. There is no consensus on what causes it, but it probably reflects a number of factors: 1) It may take some children longer than normal to reach full intellectual maturity. Testing their IQs at a young age will result in scores that are lower than those expected based on their parents’ IQs. The opposite is true for children whose IQs increase relatively quickly in young age, but possibly top out earlier; 2) Environmental effects are probably more important in young age when a child’s brain is still quite malleable; 3) Self-reinforcing gene-environment interactions tend to increase with age. Children do not have much control over their environment, but as they get older, they will seek out activities that are more in keeping with their genetic predispositions. For example, a studious child may pursue a career that reinforces their love of learning. 6 "Cache Cab: Taxi Drivers' Brains Grow to Navigate London's Streets," Scientific American, (December 2011). 7 Atheendar Venkataramani, “Early Life Exposure to Malaria and Cognition in Adulthood: Evidence from Mexico,” Journal of Health Economics 31:5, (July 2012): 767-780; Hoyt Bleakley, “Health, Human Capital and Development,” Annual Review of Economics 2, (March 2010): 283-310; Hoyt Bleakley, “Malaria Eradication in the Americas: A Retrospective Analysis of Childhood Exposure,” American Economic Journal: Applied Economics 2, (April 2010): 1-45. 8 “Anthropologists Find American Heads Are Getting Larger,” ScienceDaily, (May 2012). 9 “British Teenagers Have Lower IQs Than Their Counterparts Did 30 Years Ago,” The Telegraph, (February 2009). 10 Bernt Bratsberg and Ole Rogeberg, “Flynn Effect And Its Reversal Are Both Environmentally Caused,” Proceedings of the National Academy of Sciences 115:26, (June 2018): 6674-6678. 11 On the face of it, artificial intelligence would appear to be a substitute for human intelligence. Many applications of AI would undoubtedly have this feature, especially those that allow computers to perform complex mental tasks that humans now must do. However, there are several ways that AI may eventually come to complement human intelligence. First, and most obviously, AI could be used to augment human capabilities either directly by hardwiring it into our brains, or indirectly through the development of drugs or genetic techniques which improve cognition. Second, looking further out, the benefits of highly intelligent AI systems would be limited if humans did not possess the requisite intelligence to understand certain concepts that are currently beyond our mental reach. No matter how well intentioned, trying to explain string theory to a mouse is not going to succeed. There are probably a multitude of ideas that AI could reveal that we simply cannot comprehend at current levels of human intelligence. 12 James Heckman and Paul La Fontaine, “The American High School Graduation Rate: Trends and Levels,” The Review of Economics and Statistics 92:2, (May 2010): 244–262. 13 “Turning Around Chronically Low-Performing Schools,” The Institute of Education Sciences (IES), (May 2008). 14 E. von Mutius, F.D. Martinez, C. Fritzsch, T. Nicolai, G. Roell, and H. H. Thiemann, "Prevalence Of Asthma And Atopy In Two Areas Of West Germany And East Germany," American Journal of Respiratory and Critical Care Medicine 149:2, (February 1994): 358-64. 15 "Sperm Counts In The West Plunge By 60% In 40 Years As ‘Modern Life’ Damages Men’s Health," Independent, (July 2017). 16 Kaspar Sørensen, Annette Mouritsen, Lise Aksglaede, Casper P. Hagen, Signe Sloth Mogensen, and Anders Juul, "Recent Secular Trends in Pubertal Timing: Implications for Evaluation and Diagnosis of Precocious Puberty," Hormone Research in Paediatrics 77:3, (May 2012): 137-145. 17 “Results from the 2017 National Survey On Drug Use And Health: Detailed Tables,” Substance Abuse and Mental Health Services Administration, Center for Behavioral Health Statistics and Quality, Rockville (Maryland), (September, 2018). 18 Laura A. Pratt, Debra J. Brody, and Qiuping Gu, “Antidepressant Use Among Persons Aged 12 and Over: United States, 2011–2014,” NCHS Data Brief No. 283, Centers for Disease Control and Prevention, (August 2017). 19 Some, but not all, of the increase in reported rates of mental illness may be due to more aggressive diagnosis by health practitioners. For example, a recent study revealed that children born in August were 30% more likely to receive an ADHD diagnosis than those born in September, simply because they were less mature compared to other kids in the first few years of elementary school. See: Timothy J. Layton, Michael L. Barnett, Tanner R. Hicks, and Anupam B. Jena, “Attention Deficit-Hyperactivity Disorder and Month of School Enrollment,” New England Journal of Medicine 379:22, (November 2018): 2122-2130. 20 Tamara C. Daley, Shannon E. Whaley, Marian D. Sigman, Michael P. Espinosa, and Charlotte Neumann, “IQ On The Rise: The Flynn Effect In Rural Kenyan Children,” Psychological Science 14:3, (June 2003): 215-9; Jakob Pietschnig and Martin Voracek, “One Century of Global IQ Gains: A Formal Meta-Analysis of the Flynn Effect (1909-2013),” Perspectives on Psychological Science 10:3, (May 2015): 282-306. 21 N. Bleichrodt and M. P. Born, “Meta-Analysis of Research on Iodine and Its Relationship to Cognitive Development,” In: ed. J. B. Stanbury, “The Damaged Brain of Iodine Deficiency,” Cognizant Communication Corporation, New York, (1994): 195-200; “Iodine status worldwide: WHO Global Database on Iodine Deficiency,” World Health Organization, Geneva, (2004). 22 Mohd Fareed and Mohammad Afzal, “Estimating the Inbreeding Depression on Cognitive Behavior: A Population Based Study of Child Cohort,” PLOS ONE 9:12, (October 2015): e109585. 23 H. de Wit, J. D. Flory, A. Acheson, M. McCloskey, and S. B. Manuck, “IQ And Nonplanning Impulsivity Are Independently Associated With Delay Discounting In Middle-Aged Adults,” Personality and Individual Differences 42:1, (January 2007): 111-121; W. Mischel and R. Metzner, “Preference For Delayed Reward As A Function Of Age, Intelligence, And Length Of Delay Interval,” Journal of Abnormal and Social Psychology 64:6, (July 1962): 425-31. 24 James Flynn, “IQ decline and Piaget: Does the rot start at the top?” Lifetime Achievement Award Address, 18th Annual meeting of ISIR, (July 2017). 25 For a good discussion of these issues, please see Richard J. Haier, “The Neuroscience of Intelligence,” Cambridge Fundamentals of Neuroscience in Psychology, (December 2016). 26 “The Future of In-Vitro Fertilization and Gene Editing,” Psychology Today, (December 2018). 27 “DNA Tests For IQ Are Coming, But It Might Not Be Smart To Take One,” MIT Technology Review, (April 2018). 28 Michael Lynch, “Rate, Molecular Spectrum, And Consequences Of Human Mutation,” Proceedings of the National Academy of Sciences 107:3, (January 2010): 961-968. 29 Geoffrey Miller, “What *Should* We Be Worried About?” Edge, (2013). 30 Mingrui Wang, John Fuerst, and Jianjun Ren, “Evidence Of Dysgenic Fertility In China,” Intelligence 57, (April 2016): 15-24. Strategy & Market Trends MacroQuant Model And Current Subjective Scores Tactical Trades Strategic Recommendations Closed Trades
