In a conversation with Mick Dodge (the barefoot sensei) the other day, it came up that the three biggest problems humanity faces are:
2. population, and
An astute, and very simple, observation.
It reminded me of something. Ever heard of John B. Calhoun? (if you’ve been reading my blog, the answer is yes).
Calhoun was an animal behavior researcher at NIH. Some of his work was popularized in a cartoon-movie in the early ’80′s (or late ’70′s?) called The Secret of NIMH.
Anywho, Calhoun created a “Rat Universe,” with unlimited food, safety, etc. And introduced a starter-population into it.
What happened next…well…here’s what happened next:
Initially the population grew rapidly, doubling every 55 days. The population reached 620 by day 315, after which the population growth dropped markedly. The last surviving birth was on day 600. This period between day 315 and day 600 saw a breakdown in social structure and in normal social behavior. Among the aberrations in behavior were the following: expulsion of young before weaning was complete, wounding of young, inability of dominant males to maintain the defense of their territory and females, aggressive behavior of females, passivity of non-dominant males with increased attacks on each other which were not defended against. After day 600, the social breakdown continued and the population declined toward extinction. During this period females ceased to reproduce. Their male counterparts withdrew completely, never engaging in courtship or fighting. They ate, drank, slept, and groomed themselves – all solitary pursuits. Sleek, healthy coats and an absence of scars characterized these males. They were dubbed “the beautiful ones”.
The conclusions drawn from this experiment were that when all available space is taken and all social roles filled, competition and the stresses experienced by the individuals will result in a total breakdown in complex social behaviors, ultimately resulting in the demise of the population.
Calhoun concluded that this would happen in human populations as well.
Obviously the causes are multifactorial.
But I feel like there’s something akin to what happens to certain species of grasshopper when populations grow to a certain density – they morph (physically change shape) and swarm…they become “locusts.”
In a similar way, the behavior Calhoun described in his experiment seems less “sociological” than “physiological.”
And, in a similar way, the behavioral patterns we witness through various chunks of the evolution of overcrowding/overpopulation in human societies seem much more physiological in nature than anything else.
As if there is a switch (or series of them) in our physiology that triggers certain behavioral patterns once certain levels of population are reached.
Which would make sense to me. We’ve evolved over a long period of time to sustain certain population dynamics, which tend to equalize our impact on our local habitat.
It’s true of all mammals (as far as I know) – and of Calhoun’s rats as well. It’s called The Dunbar Number. Populations tend to stabilize at 150.
Dunbar’s number is presented as a sociological phenomenon – “the number of social relationships one can maintain…”
But I think it’s physiological. Beyond a certain physiological limit, the capacity of the organism to process “information” breaks down. It’s just like muscle or organ physiology.
And it’s the same as other limits and checks-and-balances systems that we’ve evolved over time – circadian clocks, etc.
Approaching it this way, overpopulation becomes a physiology issue, rather than a sociology issue.
And we work with it physically, rather than theoretically.