Have you ever scrolled through social media at 2 AM, surrounded by every comfort imaginable, yet feeling completely empty inside? Your fridge is stocked, your Netflix queue is endless, and theoretically, you could connect with billions of people at the tap of a screen. Yet something feels fundamentally broken.
You are not alone in this feeling, and surprisingly, a bizarre experiment conducted over 50 years ago might explain exactly what is happening to us.
In 1968, a scientist named John B. Calhoun decided to build the perfect world. Not for humans, but for mice. He constructed a large multi-level metal enclosure, roughly 1.4 metres on each side, equipped with everything a mouse could possibly need. There were 256 “apartments”, unlimited food dispensers, perfect climate control, and absolutely no predators. He called it a “Mortality-Inhibiting Environment” because, in theory, nothing could go wrong. On July 9th of that year, he introduced 8 healthy white mice into this paradise and waited to see what would happen.
This was not Calhoun’s first attempt at creating a mouse utopia. Back in 1947, fresh out of graduate school, he had built a thousand-square-metre rat paradise in the woods of Maryland. He calculated that with abundant food and zero predators, the space could easily support 5000 rats. Strangely, the population never exceeded about 200. The rats became stressed, stopped reproducing normally, and descended into bizarre behaviors like rolling dirt into balls instead of building proper tunnels. This early failure haunted Calhoun, driving him to perfect his design until he finally launched Universe 25 two decades later.
The beginning seemed promising. The mouse population doubled every 55 days like clockwork. Parents raised their young successfully, and the community appeared to thrive in ways that validated Calhoun’s carefully constructed paradise. But around day 315, something shifted. Calhoun called this moment the Wendepunkt, a German term meaning “turning point.” The population had reached 620 mice, and while the numbers continued climbing on paper, the the social foundation was gradually collapsing.
What Calhoun discovered was deeply unsettling. Removing the traditional challenges of survival did not create happiness. The mice had everything they needed to survive, but nothing they needed to truly live. He called this phenomenon the “Death of the Spirit“, and it happened long before any mouse actually died.
As the population swelled toward its peak of 2200, Calhoun observed something he called the “Behavioral Sink“. This was not simply overcrowding in the traditional sense. The habitat still had plenty of physical space and resources. Rather, the mice had become psychologically dependent on constant social contact. They would crowd around a single food dispenser in a frantic, biting mass while dozens of other feeders sat completely empty just centimetres away. They had developed what Calhoun described as “pathological togetherness“, an addiction to the crowd that made them incapable of functioning independently.
The social structure that had maintained order in the early days completely collapsed. Dominant males, exhausted by the relentless frequency of unwanted interactions, simply gave up their territorial roles. In the lack of leadership that followed, violence became random and senseless. Their social system fell apart entirely
Perhaps the most haunting development was the emergence of a group Calhoun called “The Beautiful Ones“. These were young male mice who had grown up entirely within the chaos of the behavioral sink. Having never learned to fight, compete, or mate, they withdrew completely from mouse society. They spent their entire existence eating, sleeping, and obsessively grooming themselves. Their fur was perfect, yet they were psychologically hollow.
The females underwent equally disturbing transformations. In the overcrowded “apartments”, maternal instincts disintegrated. Mothers became hyper-aggressive, often attacking their own young or abandoning them entirely. Infant mortality rates, which had been normal in the early days, climbed past 80% and, in the final phase, exceeded 90%. Even when Calhoun later reduced the population density, the damage could not be undone. The mice had, as he put it, “lost the ability to be mice”. The last mouse in Universe 25 died in 1973.
Modern researchers caution, however, that Calhoun’s findings cannot be mapped directly onto human societies. The enclosure’s simplified architecture, lack of social complexity beyond physical proximity, and forced congregation at limited feeders created stressors unlike those faced by people. Later rodent colonies raised in more varied environments did not always collapse in the same way. For demographers, Universe 25 is therefore a provocative metaphor rather than empirical evidence about human population trends.
It would be easy to dismiss all of this as a rodent problem. But Calhoun himself never saw it that way. He spent the rest of his career arguing that Universe 25 was a mirror, not a cage. He was famously quoted saying: “I shall largely speak of mice, but my thoughts are on man.”
When survival is no longer the organizing principle of a society, something has to replace it. In the absence of meaningful struggle, people do not automatically flourish. They often retreat. The sociologist’s term for what Calhoun observed is anomie: a state of normlessness, where individuals lose their sense of purpose because the social structure no longer demands anything meaningful from them. We see versions of this today in the explosion of social withdrawal, in Japan’s hikikomori phenomenon where hundreds of thousands of young people have simply stopped participating in public life, in rising rates of loneliness across the wealthiest countries in the world, and in a generation that has more material comfort than any before it and, by many measures, less hope.
Calhoun did not end his career as a pessimist, which is worth remembering. He believed that humans possess something mice do not: the capacity to consciously redesign the environments we live in. He called this “extracortical prostheses“, meaning culture, art, technology, and the ability to create meaning beyond the purely physical. We can, in theory, build systems that keep purpose alive even when survival no longer demands it. We can design cities, institutions, and relationships that give people a role to play and a reason to show up.
The question is whether we are actually doing that. Universe 25 ended because its population lost the will to continue. Not from lack of resources. Not from disease or disaster. But because, somewhere along the way, they forgot why any of it was worth doing in the first place.
If we have already built our paradise, what exactly are we living it for?
This is a different kind of topic, less about humans and more about experiments. Originally thought it would have a stronger parallel, but it opens up some intriguing questions about human nature, like whether money really brings happiness, how boredom might be as harmful as stress (hence bore-out) or how a lack of challenges affects mental health.
Here are some sources and further reading and listening:
The ‘mad egghead’ who built a mouse utopia – The Guardian
Mouse Utopia Experiment – Sam Kean
Escaping The Laboratory: The Rodent Experiments Of John B. Calhoun & Their Cultural Influence – Edmund Ramsden & Jon Adams
Universe 25 – Everything Everywhere Daily: History, Science, Geography & More
Leave a Reply