That is exactly what researcher James Calhoun suggested with his groundbreaking studies on rodents - which found many of the same social problems cropping up in artificial and overcrowded 'rat cities' that he created in his lab.
|What happens to a rat's behaviour when it is overcrowded? Image via Pixabay|
The most obvious problem the rats suffered from was overcrowding. Things started off well with a total population of 48 rats across 4 enclosures, but they soon began to breed and multiply despite the limited space. The social structures that emerged were put under pressure, with it hard for any of the rats to defend their territory.
Interestingly, it was not just the size of the physical space that impacted on behaviour, but its layout. With the pen divided into four compartments, two were 'end' compartments with a single entranceway, and the remaining two were of equal size and shape, but had a pair of entrances, joining on to the other pens. The results in the two types of compartment were sharply contrasting. In the end compartments, a single male rat was able to dominate a territory, guarding the single entrance and keeping rivals out. Within these compartments, behaviour was essentially normal.
However in the middle compartments, this wasn't possible. It was here that the rats' behaviour degenerated so disturbingly:
- Male rats formed 'gangs' and attacked females and infants
- Females suffered massively increased birth complications
- Infants were forgotten or abandoned
- Some rats wounded, sexually attacked or even cannibalised other rats.
The rats changed so markedly that their behaviour was unrecognisable compared to rats in a more natural habitat - according to Calhoun, they had "stopped being rats".
What do people (and rats) need?
There will always be doubts about comparing animal experiments to humans, but this study had a huge impact because it seemed to tell us something profound about behaviour and psychological health.
The research strongly suggests that the answer to psychological health is not within our brains but within our environments - if our surroundings are positive, it seems to suggest, the chances of deviant and antisocial behaviours may be greatly reduced.
The social implications of Calhoun's work: 'Letting the Rat out of the Bag'
A similar study with implications for addiction: 'The View from Rat Park'.
Calhoun, J. B. (1962). Population density and social pathology. Scientific American, 206(3), 139–148.
- Was this study unethical?
- Can the rat behaviour in the study be generalised to human behaviour?
- What human environments might be similar to the 'middle compartments' in the study where most harmful behaviour was observed?