In 1968, biologist John Calhoun began an experiment at the National Institute of Mental Health in Maryland. Calhoun was interested in discovering the factors that drove and limited rodent population growth; he had joined the Rodent Ecology Project in Baltimore in 1946, and he and other members of the project had become interested in understanding how to reduce rodent pests in America’s cities without the use of poison.

Calhoun had already undertaken similar experiments. In fact, this would be his 25th attempt at creating a self-sustaining rodent colony. This experiment was known as the Mortality-Inhibiting Environment for Mice, but informally, it was known as mouse heaven or, more commonly, mouse utopia.

The experiment was carefully crafted, and Calhoun’s previous experience was used to design a “perfect” environment for mice. Free from predators, disease, and stress, with unlimited access to water and plentiful food supplies, the mice involved could, in theory, live much longer lives than mice in the wild. Calhoun built the “mouse universe,” added mice, and provided food and water. Then, for almost five years, he simply watched what happened in mouse utopia.

While it may be fair to wonder how a fairly obscure zoological experiment that took place over 50 years ago has any relevance to modern society, since the experiment ended, people have been using the findings of what became known as the Calhoun Mouse Utopia Experiment to make predictions about human behavior and human societies.

In the decades since Calhoun finished his work, this experiment has been used to “prove,” among other things, that modern urban society is doomed, that contemporary society will inevitably lead to lethal levels of overpopulation, and even that political creeds such as communism and socialism are unsustainable.