The Universe 25 Experiment: A Look at Overpopulation and Social Collapse

John B. Calhoun's ‘Universe 25’ experiment shows the frightening effects of overpopulation and social disintegration – even under conditions of abundance. But what happens when the causes of the collapse are not excessive density, but systemic social inequality and neoliberal policies? The parallels to current developments in Western societies are unmistakable.

At the same time, the experiment is often interpreted in a neo-Malthusian and social-Darwinian framework. This view, which regards overpopulation as an unavoidable cause of social decay, distracts from the actual structural causes and often serves to justify unequal power relations and unjust resource distribution. Such a framework also ignores the fact that human societies are far more complex than populations of mice: they have discourses, dispositives of discourse and symbolic capital that define and influence normality and normativity in social interaction.

What was the Universe 25 experiment?

In 1972, John B. Calhoun created a so-called ‘mouse utopia’ – a self-contained environment of 2.7 square metres with unlimited access to food, water and nesting material. The aim was to study the behavioural effects of overpopulation. Starting with eight mice, the population initially grew exponentially. But what began promisingly ended in total social collapse and ultimately in the extinction of the entire colony.

The key finding: it was not a lack of resources but the dissolution of social structures that was the driving force behind the collapse.

The phases of the experiment: from rise to decline

Phase 1: Growth and Harmony

During the first 104 days, a seemingly ideal community developed. The mice shared resources, formed social structures and raised their young. However, this stage lasted only a short time.

Phase 2: The Turning Point

From day 315, the population reached 620 mice. Lack of space and stress destabilised the social order.

Phase 3: Social Collapse

As the population density increased, disturbing behaviours emerged:

• Aggression: violence became the norm. Male mice attacked others for no reason.

• Neglect: females no longer protected their young or killed them.

• Isolation: some mice, the ‘beautiful’ ones, withdrew and refused all social interaction.

Phase 4: The ‘behavioural quagmire’

From day 560, the population reached 2,200 mice. Birth rates plummeted, cannibalism increased, and social roles completely disintegrated. Despite unlimited resources, the society was finished.

Phase 5: Extinction

By day 920, the last remnants of this society had disappeared. The population became extinct.

Parallels to neoliberal society

The mechanisms that destroyed Universe 25 cannot simply be transferred to the current neoliberal transformation of Western societies. Despite enormous material resources, homelessness, hunger and social isolation are growing. These conditions are not laws of nature, but direct consequences of political decisions. Contrary to the experiment, the supposed abundance of resources is not equally available to everyone in society.

Social inequality

The Gini index is a measure of inequality within a society. It quantifies the distribution of income or wealth and indicates how equally or unequally it is distributed. The value lies between 0 and 1 (or in some representations between 0 and 100, where 0 and 100 per cent are used).

Gini index = 0: This indicates complete equality, i.e. all members of society have exactly the same income or wealth.

Gini index = 1: This indicates complete inequality, i.e. a single person has all the income or wealth, while everyone else owns nothing.

Example:

Say that everyone in a society earns exactly the same amount, say $50,000 per year. The Gini index of that society would be 0. On the other hand, if a single person has all the wealth and everyone else has nothing, the Gini index would be 1.

Gini index for wealth

The Gini index for wealth is calculated similarly to the Gini index for income, but is based on the distribution of wealth within a population. The data typically includes real estate, savings, investments, and other financial or material assets.

Calculation:

Collecting data: Sort households by increasing wealth.

Create Lorenz curve: Graphical representation of the cumulative share of wealth (y-axis) against the cumulative share of households (x-axis).

Calculate area: Determine the area between the Lorenz curve and the equality line.

Gini index: The index is the ratio of the above-mentioned area to the total area under the equality line.

Western values: Gini index for wealth

Wealth inequality is typically higher than income inequality in Western societies. This is because wealth is often concentrated in the hands of a small elite.

Scandinavian countries: Gini values for wealth often range around 0.60 to 0.70. Despite relatively equal income distribution, there is significant disparity in the ownership of real estate and other assets.

Germany: The Gini index for wealth is around 0.75, indicating a very high level of concentration. A large proportion of the population has hardly any wealth, while the richest 10% hold the largest share.

USA: With a Gini index of over 0.80, this country has one of the highest levels of wealth inequality in the Western world. The richest 1% own almost 40% of the total wealth.

Italy and Spain: Values between 0.65 and 0.75 also indicate a significant concentration of wealth.

Criticism and context

Lack of mobility: A high wealth Gini coefficient not only indicates inequality, but also limited opportunities for social advancement.

Accumulation of privilege: high values often mean that wealth is passed down through generations, cementing inequality.

Capitalist dynamics: the wealth Gini index reflects the structural problems of capitalist systems in which capital grows faster than earned income (according to Thomas Piketty).

These figures make it clear that wealth concentration is not only an economic problem, but also a social and political one that fosters social tensions.

Forced social isolation and decay

The focus on individualism and privatised solutions has undermined community structures. People are forced into competitive situations that undermine solidarity. The consequences are loneliness, social exclusion and increasing psychological stress.

Aggression and repression

Like the aggressive mice in Universe 25, the real world is showing an increasing willingness to use violence, fuelled by social inequality. The race for scarce resources such as housing or jobs that secure a living wage creates conflicts, while the rich secure their privileges.

Social criticism: the consequences of neoliberal politics

The developments in Universe 25 remind us that we need to change the social conditions. A policy that accepts homelessness, hunger and social isolation is not sustainable. The focus on economic efficiency and growth at any price does not lead to prosperity, but to social disintegration. Instead, it needs:

• Redistribution of resources: A just society requires the expropriation of wealth accumulated at the expense of the majority.

• Rebuilding community: Social systems must be based on cooperation rather than competition.

• Criticism of the growth concept: Economic growth must not be placed above the good of society.

Conclusion

The Universe 25 experiment was a warning. But instead of learning from these insights, neoliberal capitalism is strengthening the mechanisms that lead to collapse. By interpreting the experiment in a neo-Malthusian and social-Darwinian framework, structural problems are obscured and responsibility is delegated. It ignores the fact that human societies are shaped by discourses, symbolic capital and normative systems that open up far more scope for action. It is time to stop this development and create a society based on solidarity, justice and mutual respect. Otherwise, we risk the same demise as the mice in Universe 25.