• Renee Koh

Contemplating Overpopulation while in Isolation

Given that many of us have been under quarantine circumstances for almost three months, it seems almost counterintuitive to explore the heady not-so-distant future of overpopulation that has plagued the human consciousness since we hit the 7 billion population mark in October of 2011. It has been the inspiration for movies such as What Happened to Monday, Downsizing, and most notably, Avengers: Infinity War and Endgame.

Sure. Food supply will dwindle. Natural resources will struggle to keep up with demand. Prime land will only belong to the richest people. But what does this mean for us, as one human race, socially? What are the dire consequences that overpopulation will have on the human psyche, when humans are forced into living in slums and without proper privacy, just to live near jobs and to be connected to the grid?

In 1962, John B. Calhoun published a study on the effects of living in a small, crowded space in mice, in which he tracked the collapse of social and societal organization when faced with overpopulation. He coined this the behavioural sink.

Although experiments with rodents will never fully predict human behaviour under the same circumstance, we may draw some conclusions based on the behavioural changes that arose throughout the experiments that Calhoun subjected his mice to, so as to understand what it is that humans might face in the likely dystopian event of severe overpopulation.

Observation 1: Stress

Anxiety, a drastic increase in cortisol, the thing that causes your hair to turn grey—no matter what it's called, having a large amount of it every day, everywhere, will never be a good thing. Without proper methods of understanding and processing stress, human behaviour tends to aggression, or apathy, and even depression. Biological processes begin to disfunction, and less-than-ideal interactions with others may lead to injury or even death. This is what Calhoun observed in the sections of the room that had a large density of mice and an unbalanced sex ratio (20:10 male to female; whereas the "safe zones" in the room only had about 2:7. This is in mice; humans tend to appreciate a 1:1 ratio)

The stress of fighting off unwanted suitors and having to bring up pups in an area where other mice are struggling to bring up theirs caused the female mice to abandon making adequate nests when expecting, not feeding their young properly, and even dropping them on the floor (to later be eaten by other mice) when moving their litter from one place to another. The infant mortality rate was as high as 96% in the first experiment and 80% in the second.

While a human mother may not experience the particular stressor of bringing up the same amount of young, the observation of apathy and mistreatment after generations spent in non-ideal environments are a real threat to those living in housing conditions where privacy and social niceties are only vague constructs.

Observation 2: Pressure

In the mice, peer and social pressure present themselves as a desire to use the feeders and water fountains where other mice and feeding and drinking from. This is a social pathology that takes root in strength in numbers, and it translates into our human world as the glittering allure of major cities and forests of skyscrapers.

What draws us to them? Is it the need for a secure job? The beckoning of nightly fun? Or do we crave the illusion of intimacy that a city and all its inhabitants provide? It may be none of those things, but what is obvious is the innate human desire to be physically close to others in our increasingly globalised communities. And although noble, it is an instinct that may eventually lead us down the road to...

Observation 3: Psychological Anarchy

Anarchy has never been a new idea in human history.

(Anarchy is...) a state of disorder due to absence or non-recognition of authority or other controlling systems.

In the Book of Genesis, Eve disobeys God by eating an apple. Cain kills his brother Abel in contempt of the social hierarchy he has been subjected to as the second son.

However, that's not the anarchy we are looking at. I mean psychological anarchy, where our morality and sense of ethics dissolves into nothing more than a pile of ash. When our constructs of right and wrong descend into violent fantasies and base instinct.

In the experiment, mice displayed violent tendencies, even more so than usual, when fighting for the top spot in the dominance hierarchy. Female mice whose privacy was usually respected during estrus were harassed constantly. Male mice who established a harem early on protected their females against any invaders and allowed them to breed and raise their young safely, but many of the other mice developed abnormal behaviours (for mice) such as apathetic social ignorance, hypersexuality, pansexuality, and homicide.

We can say now that humans are intelligent beings, and although stressors may come and go, we believe that the inherent desire to preserve human lives will always be at the forefront of the humanity's goals.

However, despite the numerous works of fiction that depict dark, dystopian futures, we have never properly experienced dystopia on a global scale. We will never know how we will react to an event until it happens, but we can be ready for it.

So what does this mean for humanity?

We need to educate ourselves, not just on the social issues and injustices of today's system, but on the possible outcomes of these issues and the psychological destruction that they may bring. Today, we may be fighting a deadly virus, but tomorrow can easily bring the next environmental crisis. We have to be ready, always, do our part in preserving the best of the human condition and to reject the deformity of behavioural sinks.

And to never be mindless, ignorant mice.


Population Density and Social Pathology. (1962). Scientific American, Inc. Retrieved from https://www.gwern.net/docs/sociology/1962-calhoun.pdf

The Effects of Overcrowding and Behavioural Sink Theory. (2018). Borgen Project. Retrieved from https://borgenproject.org/theory-behavioral-sink/


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