Stress and the city: Urban decay - Scientists are testing the idea that the stress of modern city...

Scientists are testing the idea that the stress of modern city life is a breeding ground for psychosis.

In 1965, health authorities in Camberwell, a bustling quarter of London's southward sprawl, began an unusual tally. They started to keep case records for every person in the area who was diagnosed with schizophrenia, depression, bipolar disorder or any other psychiatric condition. Decades later, when psychiatrists looked...

Yet the results of his study, published last year in Nature (F. Lederbogen et al. Nature 474, 498–501; 2011), clearly showed that people who grow up in cities process negative emotions such as stress differently from those who move to the city as adults. His team scanned the brains of 55 healthy volunteers as they carried out arithmetic tasks under a constant bombardment of negative social feedback. “We'd always let them know through headphones that we thought they were failing, or at least not doing as well as other subjects we'd had in the scanner,” says Meyer-Lindenberg. “In one set of experiments we let them see our impatient faces on computer screens.”

This social stress activated two brain areas — but the pattern depended on the volunteers' histories of urban living. The amygdala, which processes emotion, showed much greater activity in people who were currently living in a city. And the cingulate cortex, which helps to regulate the amygdala and processes negative emotion, responded more strongly in those brought up in large cities than in those brought up in the countryside, irrespective of where they lived now. Meyer-Lindenberg thinks that this over-responsiveness to stress could make city-dwellers more prone to psychiatric conditions such as schizophrenia — and his results chime with the idea that stress in childhood or adolescence can have a lasting effect on the brain's development and increase susceptibility to psychiatric disease...

More info:

Universe 25

Sep 1, 1998

Imagine a group of humans, indeterminate in number, confined in a place of fixed dimensions, wanting for nothing. They have plenty to eat, plenty of water, plenty of places to live, and only the dimmest sort of apprehension of a larger world. They might even think of “the outside” as a kind of malicious fiction perpetrated by malcontents. It’s a circumstance not unlike the one “sustainable development” is supposed to create for us. Also, not unlike the universes of John Calhoun’s rats.

Laboratory animals often substitute for humans in tests of hazardous environmental factors. Their use in the study of cancer-causing and toxic chemicals is almost universally accepted. Their responses can, and do, give insight into human behavioral psychology. They are useful as models for humans precisely because their repertoire of behaviors is simpler than that of men and women, and so it is easier for scientists to control the variables. This also gives us the latitude to say, when we don’t like the results of such tests, that humans and rats are different.

And that is why, when ecologist John B. Calhoun passed from the scene in September of 1995, The New York Times noted in his obituary that his work had often met with “studied disregard.” He had spent his life studying the behavior of enclosed rodents.

The term “enclosure” has a specific meaning different from crowding. (See an earlier article, First Principles, for a more complete explanation.) Calhoun’s animals were not just thrown together in a cage. They grew up in confinement, generation after generation, without the ability to imagine an escape.

The research began at Johns Hopkins in 1946 and continued through the ‘60s, when Calhoun, then a research psychologist at the National Institute of Mental Health, published a report of the work in Scientific American. What fascinated students and readers of this research, then and now, is that the rats in Calhoun’s experiments developed social pathologies similar to the behavior of humans trapped in cities. Among the males, behavioral disturbances included sexual deviation and cannibalism. Even the most normal males in the group occasionally went berserk, attacking less dominant males, juveniles and females. Failures of reproductive function in the females - the rat equivalence of neglect, abuse and endangerment - were so severe that the colonies would have died out eventually, had they been permitted to continue.

Before going on, it is especially important to be clear on this point: None of Calhoun’s experiments began with throngs. All of his populations started out small, with superabundant resources, and grew after many generations into a state of crowding that approximated 80% of carrying capacity. That is to say, 80% of the nesting boxes in the enclosures were occupied at the peak population.

Appropriately, Calhoun called his confinements “universes,” since the animals inside them knew nothing of an outside. The rats of the early days required complete rooms as universes. This, and the fact that crazy rats are notoriously difficult to care for, is what must have shifted Calhoun’s affections to mice in later experiments. Full details of Universe 25 appear in a 1970 paper titled The Explosive Growth and Demise of a Mouse Population.

A few salient points from the paper:

* The mice in Universe 25 developed a social system with a fixed number of places. In nature, the excess population emigrates to what, in human terms, would be a frontier. But in Calhoun’s rodent Shangri-La, the possibility of emigration is excluded because ecologists define emigration as a “mortality factor.” It is therefore not utopian. Rejected males gathered in “pools” on the floor of the universe, where they fought frequently. Females not accepted in the social structure withdrew to less-preferred nesting boxes in the higher reaches of the universe.

* Dealing with large numbers of maturing competitors overtaxed the territorial males. In response to the invasion of nesting sites by interlopers, females became aggressive, taking over some of the defensive duties of the males. This aggression generalized to their young. A pronounced rise in preweaning mortality marked the end of social structure in Universe 25.

* With the end of successful reproductive activity, the population plunged exponentially and the age distribution shifted into senescence. The remaining individuals of reproductive age had, by this time, lost interest in courting. Calhoun dubbed the males “beautiful ones” for their obsessive grooming. It had been expected that the population would rebound after declining to a few remnant groups. It did not. What’s more, healthy young individuals from Universe 25, transplanted to an empty universe of their own, failed to develop a social structure or engage in reproductive activity.

It seems clear that, for rodents at least, the absence of frontiers leads to what Calhoun calls “death of the spirit.” This first death leads to species extinction, the “second death.” A study of the headlines over the last thirty years or so yields some interesting parallels with the human condition, but there’s no room for that here.

A final observation: Calhoun’s work remains unfinished. His experiments could be extended to include a frontier, or an unlimited succession of frontiers, by linking a populated universe with a string of empty ones. The path to each new universe would have to be made arduous, say by a maze, or by an electrical grid designed to deliver painful but non-fatal shocks. Even more interesting, for computational types, would be the creation of digital life forms complex enough to check out frontier theory analytically.

Those of you readers interested in such things, do try. One might say your life depends on it.

_________________________________________________________

I should note Calhouns original work was entitled “Population Density and Social Pathology” Scientific American, March, 1962, pps 139-148

He passed, and an Obituary was posted about Sept, 1995

Not sure if his work continues.

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.