John Calhoun and the study of rat overcrowding

When all available space is taken and all social roles filled, competition and the stresses experienced by the individuals will result in a total breakdown in complex social behaviors, ultimately resulting in the demise of the population.

Calhoun saw the fate of the population of mice as a metaphor for the potential fate of man. He characterized the social breakdown as a “second death,” with reference to the “second death” mentioned in the Biblical book of Revelation 2:11. His study has been cited by writers such as Bill Perkins as a warning of the dangers of the living in an "increasingly crowded and impersonal world.

Calhoun believed that his research provided clues to the future of mankind as well as ways to avoid a looming disaster. During the 1960s, he and Dr. Leaonard Duhl formed an informal group, the Space Cadets, which met to discuss the social uses of space. The members of this group came from as diverse professions as architecture, city planning, physics, and psychiatry. In Calhoun’s own words “Our success in being human has so far derived from our honoring deviance more than tradition. Template changing always has gained a slight, though often tenuous, lead over template obeying. Now we must search diligently for those creative deviants from which, alone, will come the conceptualization of an evolutionary designing process. This can assure us an open-ended future toward whose realization we can participate.”