The "rat utopia" experiment, also known as the?behavioral sink, was a series of studies by?John B. Calhoun?in the 1950s and 1960s that created ideal environments for rats to study the effects of overpopulation. In these enclosed "utopias," rats had unlimited food, water, and shelter but a limited amount of space, which led to a collapse of social structures and behaviors. The experiment resulted in high stress, violence, cannibalism, and ultimately, population decline and extinction, a phenomenon Calhoun termed "behavioral sink".?
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Experiment details
The setup: Calhoun created large, enclosed pens with everything the rats needed to thrive, but with a finite amount of space.
Population growth: Initially, the populations grew rapidly, with new generations never having experienced a world with predators or disease.
Social breakdown: As the population density increased, social hierarchies collapsed, and a variety of pathological behaviors emerged.
Pathological behaviors: These included increased aggression, cannibalism, infanticide, and disruptions in mating, with some males becoming hypersexual or homosexual and mothers abandoning or attacking their young.
The "behavioral sink": Calhoun coined this term to describe the resulting collapse in social behavior due to overpopulation, where the animals became unable to maintain social roles.
The outcome: The populations eventually entered a terminal decline, and those survivors that did exist were completely withdrawn and "socially autistic," clustering together in a vacant state.?
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Legacy and interpretation
The experiment is influential in discussions about overpopulation and its potential social consequences.
However, it is also critiqued for oversimplifying complex human societies and for using anthropomorphic language, which makes drawing direct parallels to human behavior questionable.
Critics argue that human intelligence and adaptability allow for different coping mechanisms in crowded conditions than are available to rats.?