The Calhoun Experiments On Rats and Mice
Population Density And Its Effect On Behavior
John Bumpass Calhoun (1917–1995) was an American ethologist and behavioral researcher noted for his studies of population density and its effects on behavior.
Calhoun coined the term "behavioral sink" — the tipping point after which all civility broke down, and aberrant behaviors appeared as a result of overcrowding. He used the term "beautiful ones" to describe passive individuals who withdrew from all social interaction.
These concepts derive from a series of over-population experiments Calhoun conducted on rats as well as mice, between 1958 and 1962. In the experiments, Calhoun and his researchers created a series of "rodent utopias" — enclosed spaces in which the rodents were given unlimited access to food and water, enabling unfettered population growth.
Calhoun was studying the breakdown of social bonds that occurs under extreme overcrowding. He claimed that the bleak effects of overpopulation on rodents were a grim model for the future of the human race.
His work gained world recognition. He spoke at conferences around the world and his opinion was sought by groups as diverse as NASA and the District of Columbia's Panel on overcrowding in local jails.
Source: Wikipedia.
Escaping the Laboratory: The Rodent Experiments of John B. Calhoun & Their Cultural Influence
— Edmund Ramsden & Jon Adams. Department of Economic History London School of Economics. January 2008.
Abstract
“In John B. Calhoun’s early crowding experiments, rats were supplied with everything they needed — except space. The result was a population boom, followed by such severe psychological disruption that the animals died off to extinction. The take-home message was that crowding resulted in pathological behaviour — in rats and by extension in humans. For those pessimistic about Earth’s ‘carrying capacity,’ the macabre spectacle of this ‘behavioural sink’ was a compelling symbol of the problems awaiting overpopulation. Calhoun’s work enjoyed considerable popular success. But cultural influence can run both ways.”
Introduction
“In 1947, John B. Calhoun’s neighbour agreed to let him build a rat enclosure on disused woodland behind his house in Towson, Maryland. Calhoun would later reflect that his neighbour probably expected a few hutches, perhaps a small run. What Calhoun built was quarter acre pen, what he called a ‘rat city,’ and which he seeded with five pregnant females. Calhoun calculated that the habitat was sufficient to accommodate as many as 5000 rats. Instead, the population levelled off at 150, and throughout the two years Calhoun kept watch, never exceeded 200. That the predicated maximum was never reached ought to come as no surprise: 5000 rats would be tight indeed. A quarter acre is little over 1000 square meters, meaning each rat would have to itself an area of only about 2000 square centimetres, roughly the size of an individual laboratory cage. Be that as it may, a population of only 150 seemed surprisingly low. What had happened?
Employed in the Laboratory of Psychology of the National Institute of Mental Health from 1954, Calhoun repeated the experiment in specially constructed ‘rodent universes’ — room-sized pens which could be viewed from the attic above via windows cut through the ceiling. Using a variety of strains of rats and mice, he once more provided his populations with food, bedding, and shelter. With no predators and with exposure to disease kept at a minimum, Calhoun described his experimental universes as ‘rat utopia,’ ‘mouse paradise.’ With all their visible needs met, the animals bred rapidly. The only restriction Calhoun imposed on his population was of space — and as the population grew, this became increasingly problematic. As the pens heaved with animals, one of his assistants described rodent ‘utopia’ as having become ‘hell’ (Marsden 1972; See note in PDF).
Dominant males became aggressive, some moving in groups, attacking females and the young. Mating behaviors were disrupted. Some became exclusively homosexual. Others became pansexual and hypersexual, attempting to mount any rat they encountered. Mothers neglected their infants, first failing to construct proper nests, and then carelessly abandoning and even attacking their pups. In certain sections of the pens, infant mortality rose as high as 96%, the dead cannibalized by adults. Subordinate animals withdrew psychologically, surviving in a physical sense but at an immense psychological cost. They were the majority in the late phases of growth, existing as a vacant, huddled mass in the centre of the pens. Unable to breed, the population plummeted and did not recover. The crowded rodents had lost the ability to co-exist harmoniously, even after the population numbers once again fell to low levels. At a certain density, they had ceased to act like rats and mice, and the change was permanent.”
Note: These PDF files are the same but the 2008 file includes the References and the 2009 file has the Endnotes.
The Norway Rat Experiments
Calhoun first pursued experiments in rat behavior at his lab on the second floor of a huge barn on the Casey farm in the country outside Rockville, MD. The research area was divided into three parts: In the center section a box-like room, divided into 4 rooms, or habitats, 10 x 14 x 9 ft. Each room had a door for a researcher or caretaker to enter by, and in the ceiling of each room was a glass window. The activity in each room could be observed through these windows.
Each room was divided into quarters by 2-foot-high partitions. Ramps connected pens I and II, II and III, and III and IV. Pens I and IV were not connected. Mounted on the wall in the corner of each quarter was an artificial burrow, which could be accessed via a spiral staircase. In two of the quarters the burrows were 3 feet from the floor, and in the other two the burrows were 6 feet from the floor. Each quarter also contained a drinking station and a feeding station.
Source: Wikipedia.
The Falls of 1972: John B Calhoun and Urban Pessimism
— Jon Adams and Edmund Ramsden, PhD. Medicine on Screen, Films and Essays From The National Library of Medicine.
“Universe 25 is a nine-by-nine-foot square arena with five-foot high metal walls built within the National Institute of Mental Health (NIMH) in Bethesda, MD. Its floor is a spindle of sixteen segments split by low dividers — just tall enough to keep mice from making contact, but not so high they can’t easily climb over. Good fences make good neighbors. Its designer, NIMH scientist John B. Calhoun, climbs down into the pen, watched by the camera that McGraw-Hill educational films have brought to record the interview. The interviewer stays outside. Calhoun’s daughter would later recall the smell, above all the stench of two thousand mice.
But only a few now survived — about 120 specimens. They’re clustered together around a single feeder, dumbly nuzzling and preening. Calhoun’s rodents had been through the Mad Max period: they had experienced their orgy of ultraviolence, sexual predation, incest, and cannibalism. Trapped inside Universe 25 with all their material needs met, the mice had bred until the stresses of over-population led them into a permanent state of fight-or-flight. Calhoun had termed this ‘the Behavioural Sink’ — the tipping point after which all civility broke down, and the animals were drawn into an irreversible vortex of self-destruction, a frenzied mass panic from which only these huddled, withdrawn specimens now survive. […]
Calhoun displays one of the mice on his palm, he notes its smooth pelage. It’s a balb-C albino, a common lab mouse, bred by the NIH Animal Center and more or less guaranteed disease-free and behaviourally normal. But these survivors are third- or fourth-generation descendants of those original specimens. In autopsy, their parents and grandparents had all been laced with scar tissue, tails chewed to stumps, ragged ears. Hypertrophy of the adrenal glands. These mice show none of that trauma. Calhoun and his researchers came to call them ‘the Beautiful Ones.’
The Beautiful Ones of Universe 25, the Behavioural-Sink survivors, are no less selfish than the rampaging actors of McCarthy or Miller’s post-apocalyptic universes. But their particular brand of non-cooperation doesn’t involve destructive interference. Rather, they avoid the problems of unwanted contact by never developing the complex adult behaviours that lead to conflict in the first place. The Beautiful Ones broker a form of mutual peace predicated on a form of extended infantilism.”
Film 7.1 by John B. Calhoun
Description: This film is a trimmed version of a longer set of stitched-together reels that contain remarks by and interviews with National Institute of Mental Health scientist John B. Calhoun, as well as extensive footage of the thousands of mice Calhoun studied over many years. In Mouse City, Calhoun provided his research subjects food, water, bedding, protection from predators — all that they needed except adequate space. The results were destructive and dramatic. Based on these experiments, Calhoun drew conclusions about human behavior in overcrowded conditions, such as high-density public housing.