Behavioral sink

行為淪喪(Behavioral sink)由學者Calhoun所提出，實驗主要觀察在一空間無限提供老鼠食物飲水及無天敵狀態下會產生什麼狀況，在老鼠族群超過正常水準後，雌鼠不再照顧幼崽，任其被遺棄或吃下，雄鼠攻擊水準上升，性向產生偏差。於實驗第六百天，整個族群瀕臨滅絕狀態。{12}

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 February 1, 1962 report in an article titled Population Density and Social Pathology in Scientific American 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.{12}