Reluctance to address the importance of intelligence has led to urban theories that lack a solid theoretical foundation. Simply asserting that cities attract intelligent people who then interact with one another reduces the explanation to density alone, as if proximity itself were the primary driver. In reality, all the systems that make cities function—economics, infrastructure, and governance—depend on human intelligence. Intelligence is therefore foundational to understanding why cities become centers of innovation and power.¹
Many have written of the importance of IQ to innovation and how cities foster innovation.² IQ being a zero-sum game also explains why cities always outperform rural areas.
The problem is using statistics to demonstrate the magnitude IQ plays in any organization is that as with everything using statistics, the conclusions are subject to challenges from egalitarians and communists who see all differences between peoples and groups as based on class and exploitation. What is much harder to challenge is a real world field experiment lasting several years and involving over a quarter of a million subjects. In 1966 the Secretary of Defense of the United States Robert McNamara began Project 100,000 which became known as McNamara’s Morons. Over 320,000 low IQ men were drafted and recruited into the Army and sent to fight in America’s War in Vietnam. Of that number 290,000 had scored in Category IV and 30,000 scored Category V of the Armed Forces Qualification Test, which placed them in the 10th-30th percentile and 1st-9th percentile range respectively.³˒⁴
The normal distribution IQ curve has approximately 40% of any population group mentally deficient. No one in this group will ever serve on a nuclear submarine, design a skyscraper, build a rocket, command a ship or understand why a sewer system is necessary. Yet, they are an influence on society’s values and norms.
There are several factors affecting IQ in a population. Intermarriage is one. Rural communities tended throughout history to have a higher rate of consanguineous marriages than in cities, which leads to lower intelligence, mental health problems. This would tend to result in a higher ratio of low IQ and sickly people in rural areas than in cities. Lower average cognitive ability (IQ) correlates with higher rates of impulsive/reactive violence, crime, and antisocial behavior at individual and population levels which would not be conducive to social order. Cousin marriages being less common in cities skewed the IQ curve to favor cities with brighter people. Cities not being as inflicted with as many low IQ individuals would tend to more complex social organization requiring internal stability.
High infant mortality and the influx of population distorted the normal IQ distribution in cities. The in-migration would have been people who were risk takers and sought out the complexity and opportunities city living offered. Studies show most in this group were brighter than average. The continual influx of bright, risk taking individuals would have pushed the IQ distribution curve to the right. The ratio of city citizens would have been higher than in rural communities.
Before 1800, cities across much of the world generally depended on a constant inflow of people from the surrounding countryside to maintain their populations because urban death rates often matched or exceeded birth rates.
At the same time, cities relied on their rural hinterlands for food, raw materials, labor, military recruits, and trade. This continual interaction with people from the countryside helped anchor urban values tied to the practical realities of the wider society around them. This steady movement of people and goods helped keep urban morals, values, religion, and habits of life anchored in realities outside the city itself, preserving continuity between urban and rural populations even as cities developed distinct institutions. Once sanitation, public health, and modern medicine lowered mortality, however, cities no longer depended to the same extent on constant replacement from the countryside simply to survive. As cities became more capable of sustaining themselves internally, one of the long-standing forces that had helped keep urban life grounded was weakened, and cities gained more room to develop beliefs, norms, and ways of life at a greater distance from the outside world.
After cities became population buckets, the distribution of IQ would have been less skewed to the right of the normal distribution curve. Unfortunately, the increasing protective environment cities offered would lead to higher survival rates of lower IQ individuals not capable of surviving outside of the city, pushing the curve more to a normal curve or possibly to the left.⁵ ⁶ ⁷ ⁸ ⁹
Footnotes:
¹ Edward L. Glaeser, Triumph of the City: How Our Greatest Invention Makes Us Richer, Smarter, Greener, Healthier, and Happier (New York: Penguin Press, 2011).
² Richard Lynn and Tatu Vanhanen, IQ and the Wealth of Nations (Westport, CT: Praeger, 2002).
³ Thomas G. Sticht, “Project 100,000 in the Vietnam War and Afterward,” in Scraping the Barrel: The Military Use of Sub-Standard Manpower, 1860–1960, ed. Sanders Marble (New York: Fordham University Press, 2012).
⁴ Marvin E. Grunzke et al., Comparative Performance of Low-Ability Airmen (Lackland Air Force Base, TX: Air Force Human Resources Laboratory, 1970).
⁵ Richard Lynn, Dysgenics: Genetic Deterioration in Modern Populations (1996).
⁶ Francis Galton. Civilization diminishes the rigor of natural selection by preserving weakly lives (including low intelligence) that would perish in harsher conditions.
⁷ Charles Darwin (1871). Civilized societies check elimination by saving the weak, allowing them to propagate.
⁸ E.O. Wilson (Sociobiology: The New Synthesis, 1975; On Human Nature, 1978). Genetic basis of intelligence variation exists; sociobiology concepts support selection pressures on cognitive traits, with modern environments implying relaxed selection.
⁹ James Watson. Genetic factors influence intelligence differences; modern societal structures affect IQ-related outcomes consistent with hereditary views.