John B Calhoun with mice and published in 1973. Calhoun designed a habitat for mice that had all the resources needed to survive, basically a “mouse paradise”. There was no need for looking for food, water and shelter as it was all there. There were also no predators, so mice did not need to invest in protection. Calhoun called his experiment “Mortality-Inhibiting Environment for Mice” and is also known as “Universe 25”.
The Universe 25 began with 4 pairs of 48 day old mice and at the beginning the population was growing rapidly. Mice inhabitants doubling on average every 55 days and reached close to 2000 by the day 600! However at that stage the population began to drop. The study ends on the 1500 day with a population of 27 mice (23 females and 4 males, the youngest of which exceeded 987 days of age).
Observing the numbers and population growth and decline is interesting; however that real gem of the study is the behaviour of mice in accordance to the number population. The dominance of particular males was established by the number of offspring: “the most dominant male is the most active one” (p. 84). By the day 300, there were more than three times younger mice than as the socially established older ones.
As mentioned above the population however began to fall at about day 600. Calhoun attempts to examine why that was the case. Males that failed to dominate were observed to be very inactive, did not initiate in interaction and became violent against each other. On the contrarily females withdraw themselves and would hide in boxes above everyone else.
Later, the females that were more “attractive” and exhibited interest from male mice became destructive in their maternal behaviour. They often abandon their youngsters and engaged in aggressive behaviours in order to defend their territory, sort of speak. Additionally male mice that were observed as dominant withdrew and were not interested in reproducing and lacking interest in social roles etc. Males slept, ate, drank and groomed themselves. Because they were not interested in sexual behaviour, the aggressive behaviour ceased.
Calhoun experiment gives a conclusion that when all the available social roles are occupied the competition along with stress will result in a breakdown in complex social behaviours.
Of course the study and the conclusion itself attract a lot of criticism. The major one perhaps is that the environment been not applicable to the real world, however is that not the point of the study? If one was given everything one needs (if this may apply to human individuals) would one want to participate in a society? And how would this theory apply to Sociality and Participatory Sense-Making and of course embodiment? Does over population and its’ outcomes have an effect on creating and maintaining own dynamic identity? In a society of that similar to Mega City (Judge Dredd, 2000AD comics) does Participatory Sense-Making really make sense?
*I mention 2000AD as this study influenced Judge Dredd and Mega City comics.