Behavioral sink

In 1958, ethologist John B. Calhoun conducted over-population experiments on rats on a farmland in Rockfille, Maryland which resulted in the publication of an article titled Crowding into the Behavioral Sink ("Scientific American, 206: 139-148") a study of behavior under conditions of overcrowding. This study has become a touchstone of urban sociology and psychology in general; the term has passed into common use.

Calhoun provided a cage of rats with food and water replenished to support any increase in population, but the cage was fixed at a size considered sufficient for only 50 rats. Population peaked at 80 rats and thereafter exhibited a variety of abnormal, often destructive behaviors; his conclusion was that space itself is a necessity. Subsequent studies involving humans have shown it is not mere lack of space that causes the behavioral sink; it is the necessity for community members to interact with one another. When forced interactions exceed some threshold, social norms break down. Thus "social density" is considered more critical than geometric spatial density.

Notable conditions in the behavioral sink include hyperaggression, failure to breed and nurture young normally, infant cannibalism, increased mortality at all ages, and abnormal sexual patterns. Often, population peaks, then crashes. Actual physical disease, mental illness, and psychosomatic disorders increase. There are eating disorders; in human populations, drug and alcohol use rises.

The only known counter to the effect of the behavioral sink is to reduce the frequency and intensity of social interaction.

References

*cite book | last = Hall | first = Edward, T. | title = The Hidden Dimension | publisher = Anchor Books | year = 1966 | id = ASIN B0006BNQW2
* "Forty Studies that Changed Psychology : Explorations into the History of Psychological Research (5th Edition)" (includes Calhoun) Prentice Hall (2004) ISBN 0-13-114729-3