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Bluelighter
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The Universe 25 experiment, conducted by American ethologist John B. Calhoun in 1968, was a famous study on social decay caused by overpopulation. Calhoun placed four pairs of mice into a specially designed 9-foot-square enclosure with unlimited food, water, and nesting material, but limited physical space.
The Phases of Universe 25
The population grew rapidly at first but eventually collapsed due to social breakdown:
The Behavioral Sink
Calhoun coined the term "behavioral sink" to describe the total collapse of normal social behaviors, including mating, parenting, and territorial defense, resulting from high population density. Even when the population dwindled and space opened back up, the mice had lost the social capacity to reproduce, leading to the extinction of the entire colony. While Calhoun warned that human cities could face a similar fate, modern psychologists point out that human social structures are far more adaptable than those of rodents.
Commentary:
Calhoun Replicated The Same Experiments 25 Or 35 Times, And The Results Were The Same Every Time.
The Phases of Universe 25
The population grew rapidly at first but eventually collapsed due to social breakdown:
- Phase A (Adjustment): The mice adapted to the environment and established initial territories.
- Phase B (Exploitation): The population doubled every 55 days, peaking at 2,200 mice, well below the enclosure's maximum capacity of 3,840.
- Phase C (Stagnation): Severe overcrowding disrupted normal social structures. Dominant males became hyper-aggressive or completely passive, while females struggled to protect their nests, leading to a drop in birth rates.
- Phase D (Death Phase): A new generation emerged, dubbed "the beautiful ones." These mice avoided all social interaction, grooming themselves obsessively and showing no interest in mating or fighting.
The Behavioral Sink
Calhoun coined the term "behavioral sink" to describe the total collapse of normal social behaviors, including mating, parenting, and territorial defense, resulting from high population density. Even when the population dwindled and space opened back up, the mice had lost the social capacity to reproduce, leading to the extinction of the entire colony. While Calhoun warned that human cities could face a similar fate, modern psychologists point out that human social structures are far more adaptable than those of rodents.
Commentary:
Calhoun Replicated The Same Experiments 25 Or 35 Times, And The Results Were The Same Every Time.
