Behavioral sink
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 the Scientific American weekly newspaper 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.