John B. Calhoun spent his career studying the effects of overpopulation on the health and behavior of rats. Why, are rats having serious overpopulation issues? No, he used rats as a model organism. As he explained in the opening lines of his paper “Death Squared: The Explosive Growth and Demise of a Mouse Population”:
“I shall largely speak of mice, but my thoughts are on man, on healing, on life and its evolution. Threatening life and evolution are the two deaths, death of the spirit and death of the body. Evolution, in terms of ancient wisdom, is the acquisition of access to the tree of life. This takes us back to the white first horse of the Apocalypse which with its rider set out to conquer the forces that threaten the spirit with death. Further in Revelation (ii.7) we note: 'To him who conquers I will grant to eat the tree' of life, which is in the paradise of God' and further on (Rev. xxii.2): 'The leaves of the tree were for the healing of nations.'”
His research was influenced by the work of Thomas Malthus. Most of us know Malthus as the guy who “got it wrong” about overpopulation leading to disease and starvation which would stabilize and limit further population growth. This is our sophomoric reading of Malthus. What Malthus was talking about was a bit more subtle. And Calhoun put that point more cryptically in his opening statement above.
Malthus argued that population size is limited by forces external AND internal to the population. Those external forces already mentioned, disease and starvation, fall under the force of misery. The internal force, called vice, comprises those self-destructive behaviors that limit the growth of a population. Calhoun’s research focused on eliminating the first variable – misery – from his population to find out whether vice does play a role in limiting population growth.
He wrote about these ideas in an earlier paper, “Population Density and Social Pathology”, saying:
“In the celebrated thesis of Thomas Malthus, vice and misery impose the ultimate natural limit on the growth of populations. Students of the subject have given most of their attention to misery, that is, to predation, disease and food supply as forces that operate to adjust the size of a population to its environment. But what of vice? Setting aside the moral burden of this word, what are the effects of the social behavior of a species on population growth – and of population density on social behavior?"
Calhoun’s first experiment attempted to study overpopulation in an enclosed quarter acre piece of land. He estimated that the five pregnant females he placed in the enclosure would generate a population of 2000, from which he could learn about the dynamics of overcrowding. Unfortunately, after two years his rat population only reached 10% of that number. The rats would break off into bands of about a dozen members, and they would cluster in designated living areas, leaving most of the enclosure uninhabited.
Why did the rats not overproduce? As the population reached about 150, mothers would stop caring for their litters and only 1 or 2 would survive into the next generation. These terrible parents created a zero-growth community in which the population would never exhaust their resources and the community itself would live on indefinitely. He would have to do more experiments, controlling for many variables to understand the dynamics of this behavioral change.
In his next set of experiments, he created an artificial habitat where resources would be inexhaustible. See a diagram of one of these habitats below. Moving clockwise from the northeast quadrant, each boxed off area was accessible to the next by a single bridge, creating one long space that wrapped in on itself. It was as “urban” of a space as you can get for rats. With an inexhaustible food supply, the space was able to indefinitely support a super dense population of rats.
Initially, the population would sleep together evenly dispersed throughout the quadrants. Each morning, the less dominant males would wake up earlier than the rest of the population and explore the enclosure. Overtime, the dominant males took advantage of this and guarded the bridges between each quadrant, causing the males toward the bottom of the hierarchy to cluster in the southern quadrats while the dominant males achieved exclusive access to females in the northern quadrants.
The growing division between two classes of males lead to the less dominant males in the southern quadrants developing distinct personality types. The first group, called the pansexuals, would often be allowed back into the northern quadrants because they would not compete for status with the dominant males, and they attempted to mate with the males and females equally. Another class of males called the “somnambulists” would keep to themselves and seldom interact with the other rats. These rats would lumber around as if they were sleepwalking. Another set of pansexual rats also emerged, called “probers”, and were hyper-social and hyperactive. They would viciously pursue mates of both sexes, and when in the female burrows would cannibalize the young who were being uncared for.
After Calhoun ended this phase of experiments, he attempted to reproduce new rats with the healthiest from the experiments, but they were so behaviorally altered they would never raise a litter of surviving pups. He called the whole phenomenon a “behavioral sink”, or pathologically self-destructive personalities unique to the dense populations that could not sustain the reproduction of the species.
While it certainly appears to many that these personality types can be found in genuine human cities, the categories of pansexuals, somnambulists, and probers are describing phenomena that came out of controlled experimental conditions. The real world still has the variable of scarce resources, so these personalities will only very rarely come out of both naturally occurring rat populations and “naturally occurring” human populations. These categories are called “ideal types” – or useful fictions. The are just as real as frictionless planes are in physics, and patriarchies are in sociology.
That being said, modern life is pretty well divorced from the struggle for existence to the point that we might see imperfect variations of these personality types might become more frequent in “the real world”. See one of my previous posts about narratives, theories and models here. In the next few posts, I am going to keep peeling back the layers of the shallot here and get into the chatter that has been going on for a while about utopian and anti-utopian arguments, the distinction between science and politics, and so on. Hope you stick around.
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