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The ethologist John B. Calhoun coined the term "behavioral sink" to describe the collapse in behavior which resulted from overcrowding. Over a number of years, Calhoun conducted over-population experiments on Norway rats (in 1958–1962) and mice (in 1968–1972). Calhoun coined the term "behavioral sink" in his 1962 report on the rat experiment. Calhoun's work became used as an animal model of societal collapse, and his study has become a touchstone of urban sociology and psychology in general. In the 1962 study, Calhoun described the behavior as follows: Calhoun would continue his experiments for many years, but the publication of the 1962 article put the concept in the public domain, where it took root in popular culture as an analogy for human behavior. Calhoun retired from NIMH in 1984, but continued to work on his research results until his death on September 7, 1995.〔(NLM Announces the Public Release of the Papers of John B. Calhoun ), U.S. National Library of Medicine, 2013-10-13.〕 == The experiments == Calhoun's early experiments with rats were carried out on farmland at Rockville, Maryland, starting in 1947. While Calhoun was working at NIMH in 1954, he began numerous experiments with rats and mice. During his first tests, he placed around 32 to 56 rodents in a 10 x 14-foot case in a barn in Montgomery County. He separated the space into four rooms. Every room was specifically created to support a dozen matured brown Norwegian rats. Rats could maneuver between the rooms by using the ramps. Since Calhoun provided unlimited resources, such as water, food, and also protection from predators as well as disease and weather, the rats were said to be in “rat utopia” or “mouse paradise,” another psychologist explained.〔(Medical Historian Examines NIMH Experiments in Crowding ), nih record, 2013-10-13.〕 Following his earlier experiments with rats, in 1972 Calhoun would later create his "Mortality-Inhibiting Environment for Mice": a 101-inch square cage for mice with food and water replenished to support any increase in population,〔 which took his experimental approach to its limits. In his most famous experiment in the series, "Universe 25", population peaked at 2,200 mice and thereafter exhibited a variety of abnormal, often destructive behaviors. By the 600th day, the population was on its way to extinction.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「behavioral sink」の詳細全文を読む スポンサード リンク
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