Population Problems and Mice and John B. Calhoun

Another subject on the laundry list of things I’m fascinated with is the effects of population (amount, density, growth rate, etc) on human life (happiness, loneliness, romance). For example, people in large cities have more difficulty in finding a spouse than people in smaller or less dense places. Why? Increased choice also means increased comparisons (and presumably, competition), making it more difficult to make the final “this is the best person in the world for me” decision as in a city one is, for example, looking for the best (fit) out of a million instead of the best out of one thousand.

Another interesting phenomenon is Dunbar’s number, the idea that the maximum amount of people that we are able to maintain regular stable relationships with at any given time is between 100 and 230 people (the wikipedia says 150 is the generally accepted approximation). This number/theory is important to consider, especially in the Facebook era. Dunbar himself has said that preliminary research is showing that the 150 number seen in non-digital life is the same number seen in digital life.

Moving onward!

The Daily Dish brought up an article about mice and population today. It is very cool. It’s an old study (from the late 70s) by John B. Calhoun: CABINET // The Behavioral Sink

Here’s the premise: instead of looking at population growth in terms of strain on resources, let’s look at what happens when all “strains” are controlled except for one: space

The Universe took the form of a tank, 101 inches square… Each wall had sixteen vertical mesh tunnels—call them stairwells—soldered to it. Four horizontal corridors opened off each stairwell, each leading to four nesting boxes. That means 256 boxes in total, each capable of housing fifteen mice. There was abundant clean food, water, and nesting material. The Universe was cleaned every four to eight weeks. There were no predators, the temperature was kept at a steady 68°F, and the mice were a disease-free elite selected from the National Institutes of Health’s breeding colony. Heaven.

Four breeding pairs of mice were moved in on day one. After 104 days of upheaval as they familiarized themselves with their new world, they started to reproduce.

Such a cool idea.

In their fully catered paradise, the population increased exponentially, doubling every fifty-five days. Those were the good times, as the mice feasted on the fruited plain. To its members, the mouse civilization of Universe 25 must have seemed prosperous indeed. But its downfall was already certain—not just stagnation, but total and inevitable destruction.

Anarchy! Except with unlimited food and cleaning and no natural disasters or weather problems. So how did the downfall begin?

Past day 315, population growth slowed. More than six hundred mice now lived in Universe 25, constantly rubbing shoulders on their way up and down the stairwells to eat, drink, and sleep. Mice found themselves born into a world that was more crowded every day, and there were far more mice than meaningful social roles.

Plenty of ways to extrapolate that to modern living. It’s a stretch, but not a huge one, as we’ll soon see…

Normal social discourse within the mouse community broke down, and with it the ability of mice to form social bonds. The failures and dropouts congregated in large groups in the middle of the enclosure, their listless withdrawal occasionally interrupted by spasms and waves of pointless violence. The victims of these random attacks became attackers.

Ok, starting to get a bit creepy.

Procreation slumped, infant abandonment and mortality soared. Lone females retreated to isolated nesting boxes on penthouse levels. Other males, a group Calhoun termed “the beautiful ones,” never sought sex and never fought—they just ate, slept, and groomed, wrapped in narcissistic introspection. Elsewhere, cannibalism, pansexualism, and violence became endemic. Mouse society had collapsed.


 There would be no recovery, not even after numbers had dwindled back to those of the heady early days of the Universe. The mice had lost the capacity to rebuild their numbers—many of the mice that could still conceive, such as the “beautiful ones” and their secluded singleton female counterparts, had lost the social ability to do so. In a way, the creatures had ceased to be mice long before their death—a “first death,” as Calhoun put it, ruining their spirit and their society as thoroughly as the later “second death” of the physical body.

Well now I’m just plain scared.

This formula might apply to rats and mice—but could the same happen to humankind? For Calhoun, there was little question about it.

Oh, great.

And that lesson found a ready audience. “Population Density and Social Pathology” was, for an academic paper, a smash hit, being cited up to 150 times a year. Particularly effective was Calhoun’s name for the point past which the slide into breakdown becomes irretrievable: the “behavioral sink.” “The unhealthy connotations of the term are not accidental,” Calhoun noted drily. The “sink,” a para-pathology of shared hopelessness, drew in pathological behavior and exacerbated its effects. Once the event horizon of the behavioral sink was passed, the end was certain. Pathological behavior would escalate beyond any possibility of control.

More good news!

It’s entirely possible that without several social programs in the US we would be much closer to Calhoun’s predicted doom and gloom. For example, “The 1930 census…found 58 percent of men over 65 still in the workforce; in contrast, by 2002, the figure was 18 percent.” (NYT article from 2005) Imagine combining today’s employment woes with a US in which 3 times as many seniors hold jobs and in which, according to the same article, 30% to 50% of seniors were also being primarily supported by their children, friends or relatives.

Put plainly: more unemployed youth and more people living in close quarters, both factors that Calhoun showed to catalyze social decline. Social Security without a doubt helped slow or divert movement in that direction.

Moving back away from politics and over to science:

The misery of the rodent universes was not uniform—it had contours, and some did better than others. Calhoun consistently found that those animals better able to handle high numbers of social interactions fared comparatively well. “High social velocity” mice were the winners in hell. As for the losers, Calhoun found they sometimes became more creative, exhibiting an un-mouse-like drive to innovate. They were forced to, in order to survive.

More wonderful real-life correlations!

But Calhoun was optimistic about the problem.

Man, he argued, was a positive animal, and creativity and design could solve our problems. He advocated overcoming the limitations of the planet, and as part of a multidisciplinary group called the Space Cadets promoted the colonization of space.

Ok, I was hoping for something better than that.

Three cheers for the inevitable fall of mankind!

Closing words:

The point was that crowding itself could destroy a society before famine even got a chance. In Calhoun’s heaven, hell was other mice.



Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s