Behavioral sink

Calhoun coined the term "behavioral sink"[3] in a February 1, 1962, Scientific American article titled "Population Density and Social Pathology" on the rat experiment.

[9] In the 1962 study, Calhoun described the behavior as follows: Many [female rats] were unable to carry the pregnancy to full term or to survive delivery of their litters if they did.

Among the males the behavior disturbances ranged from sexual deviation to cannibalism and from frenetic overactivity to a pathological withdrawal from which individuals would emerge to eat, drink and move about only when other members of the community were asleep.

The common source of these disturbances became most dramatically apparent in the populations of our first series of three experiments, in which we observed the development of what we called a behavioral sink.

Having reached a level of high population density, the mice began exhibiting a variety of abnormal, often destructive, behaviors including refusal to engage in courtship, and females abandoning their young.

Calhoun eventually found a way to prevent this by changing some of the settings and thereby decreased mortality somewhat, but the overall pathological consequences of overcrowding remained.

[13] Further, researchers argued that "Calhoun's work was not simply about density in a physical sense, as number of individuals-per-square-unit-area, but was about degrees of social interaction.

Calhoun's worries primarily concerned a human population surge and a potentially independent increase in urbanization as an early stage of rendering much of a given society functionally sterile.

[21] As of today, this primarily concerns elite population decline,[22] but can be due to positive feedback in social diffusion, and Calhoun's empirical predictions can be applied to a much wider segment of society as well.