In the scientific community of the 1960s, behavioral ecologist John B. Calhoun conducted a series of radical experiments that explored the effects of overcrowding on animal behavior, leading to A profound reflection on the future of human society. The term "behavioral sink" he proposed vividly describes the collapse process of biological behavior in an overcrowded environment.
Calhoun conducted preliminary experiments on farmland in Maryland beginning in 1947. His earliest research subjects were Norway rats, and between 1958 and 1962, he designed a series of enclosed spaces for rats to breed and live in. These environments were called "rat utopias." In these experiments, mice were provided with unlimited food and water, making for an ideal habitat.
Calhoun stated in his 1962 study that many female rats were unable to carry pregnancy to birth and were unable to fulfill their maternal duties even after successful delivery.
Over time, the mice's social behavior began to become abnormal. Some male rats showed sexual deviations, and some even engaged in cannibalism. When sharing food, rats' aggregation behavior caused overcrowding in certain areas, leading to the collapse of the social structure of these spaces, which in turn resulted in behavioral decline. In this case, the mortality rate of young mice is as high as 96%.
In crowded environments, the behavior of rats becomes increasingly abnormal, ranging from refusal to mate to abandono behavior of female rats, and the social structure is severely disrupted.
Calhoun later conducted more advanced experiments on mice, creating Universe 25, a large environment measuring 101 x 101 inches. In this environment, despite being able to house up to 4,000 mice, the actual population began to exhibit abnormal behavior after reaching 2,200. The mice eventually no longer possess the social skills needed to mate, pushing themselves to the brink of extinction.
Calhoun's experiment made many people begin to reflect on the future of human society. He saw a possible future for humanity in the behavioral collapse of rats, describing the collapse of society as "spiritual death." This view has triggered debate among different scholars, including many critical voices. Early experiments conducted by psychologist Jonathan Freedman found no significant negative effects, making Calhoun's findings controversial.
Calhoun worried that humanity would encounter a similar social collapse as we rapidly urbanized. He speculated that such crowding would lead to a rapid deterioration in social functioning. In fact, many urban areas are currently facing the challenge of declining fertility rates, a phenomenon that has a lot to do with the animal behavior Calhoun described.
Calhoun's research not only profoundly influenced biology and sociology, but also caused deep thinking about the future. His experiments explore the subtle relationship between social interactions and environmental crowding, and how they affect individual and group behavior. As the world's population continues to grow, can we find a balance to avoid the mistakes of rats and usher in a harmonious society?