American ethologist John Calhoun conducted a series of amazing experiments in the 60s and 70s of the twentieth century. As experimental D. Calhoun invariably chose rodents, although the ultimate goal of research has always been to predict the future for human society. As a result of numerous experiments on colonies of rodents, Calhoun formulated a new term, "behavioral sink", denoting the transition to destructive and deviant behavior in conditions of overpopulation and overcrowding. With his research, John Calhoun gained some fame in the 60s, as many people in Western countries experiencing the post-war baby boom began to think about how overpopulation would affect social institutions and each person in particular.
His most famous experiment, which made an entire generation think about the future, he conducted in 1972 with the National Institute of Mental Health (NIMH). The purpose of the experiment "Universe-25" was to analyze the effect of population density on the behavioral patterns of rodents. Calhoun has built a veritable paradise for mice in a laboratory setting. A tank was created, measuring two by two meters and a height of one and a half meters, from which the subjects could not get out. Inside the tank, a constant comfortable temperature for mice (+20 ° C) was maintained, food and water were abundant, and numerous nests for females were created. Every week, the tank was cleaned and maintained in constant cleanliness, all necessary safety measures were taken: the appearance of predators in the tank or the occurrence of massive infections were excluded. The experimental mice were under constant supervision of veterinarians, their health status was constantly monitored. The system for providing food and water was so well thought out that 9, 500 mice could eat at the same time without experiencing any discomfort, and 6144 mice could consume water without experiencing any problems. There was more than enough space for the mice, the first problems of lack of shelter could arise only when the population reached over 3, 840 individuals. However, there have never been such a number of mice in the tank, the maximum population size was recorded at 2200 mice.
The experiment started from the moment four pairs of healthy mice were placed inside the tank, which took very little time to get used to, to realize what kind of mouse fairy tale they were in, and to start multiplying at an accelerated rate. Calhoun called the period of development phase A, but from the moment the first calves were born, the second stage began. This is the stage of exponential growth of the population in the tank under ideal conditions, the number of mice doubled every 55 days. Starting from day 315 of the experiment, the population growth rate slowed down significantly, now the number doubled every 145 days, which marked the entry into the third phase C. At that moment, about 600 mice lived in the tank, a certain hierarchy and a certain social life were formed. Physically less space than it was before.
A category of “outcasts” appeared, who were expelled to the center of the tank, they often became victims of aggression. The group of "outcasts" could be distinguished by the bitten tails, torn hair and traces of blood on the body. The outcasts consisted, first of all, of young individuals who did not find a social role for themselves in the mouse hierarchy. The problem of the lack of suitable social roles was caused by the fact that in ideal tank conditions, mice lived for a long time, aging mice did not make room for young rodents. Therefore, aggression was often directed at new generations of individuals born in the tank. After the expulsion, the males broke down psychologically, showed less aggression, did not want to protect their pregnant females and play any social roles. Although from time to time they attacked either other individuals from the society of "outcast", or any other mice.
Females preparing for birth became more and more nervous, as as a result of increased passivity among males, they became less protected from accidental attacks. As a result, the females began to show aggression, often fight, protecting the offspring. However, paradoxically, aggression was not directed only at others, and no less aggressiveness was manifested in relation to their children. Often, females killed their young and moved to the upper nests, became aggressive hermits and refused to breed. As a result, the birth rate has dropped significantly, and the mortality rate of young animals has reached significant levels.
Soon the last stage of the existence of the mouse paradise began - phase D or the death phase, as John Calhoun called it. This stage was symbolized by the emergence of a new category of mice called "beautiful". These included males showing uncharacteristic behavior for the species, refusing to fight and fight for females and territory, showing no desire to mate, and inclined to a passive lifestyle. The "beautiful" only ate, drank, slept and peeled their skins, avoiding conflicts and performing any social functions. They received such a name because, unlike most other inhabitants of the tank, their bodies did not have traces of fierce battles, scars and torn hair, their narcissism and narcissism became legendary. Also, the researcher was struck by the lack of desire among the "beautiful" to mate and reproduce, among the last wave of births in the tank, "beautiful" and single females, refusing to reproduce and fleeing to the upper nests of the tank, became the majority.
The average age of a mouse in the last stage of the existence of a mouse paradise was 776 days, which is 200 days higher than the upper limit of reproductive age. The mortality rate of young animals was 100%, the number of pregnancies was insignificant, and soon it was 0. Endangered mice practiced homosexuality, deviant and inexplicably aggressive behavior in conditions of an excess of vital resources. Cannibalism flourished with an abundance of food at the same time, females refused to raise their young and killed them. The mice rapidly died out, on the 1780th day after the start of the experiment, the last inhabitant of the "mouse paradise" died.
Anticipating a similar catastrophe, D. Calhoun, with the help of his colleague Dr. H. Marden, conducted a series of experiments in the third stage of death. Several small groups of mice were removed from the tank and relocated to equally ideal conditions, but also in conditions of minimal population and unlimited free space. No crowding and intraspecific aggression. In fact, the "beautiful" and single females were recreated the conditions under which the first 4 pairs of mice in the tank multiplied exponentially and created a social structure. But to the surprise of scientists, "beautiful" and single females did not change their behavior, refused to mate, reproduce and perform social functions related to reproduction. As a result, there were no new pregnancies and the mice died of old age. Similar similar results were observed in all resettled groups. As a result, all experimental mice died in ideal conditions.
John Calhoun created the theory of two deaths from the results of the experiment. The "first death" is the death of the spirit. When there was no place for newborns in the social hierarchy of "mouse paradise", there was a lack of social roles in ideal conditions with unlimited resources, an open confrontation between adults and young rodents arose, and the level of unmotivated aggression increased. A growing population, an increase in crowding, an increase in the level of physical contact, all this, according to Calhoun, has led to the emergence of individuals capable of only the simplest behavior. In an ideal world, in safety, with an abundance of food and water, and the absence of predators, most of the individuals only ate, drank, slept, and looked after themselves. A mouse is a simple animal, for him the most complex behavioral models are the process of courting a female, reproduction and caring for offspring, protecting territory and cubs, participating in hierarchical social groups. The psychologically broken mice refused all of the above. Calhoun calls this rejection of complex behavioral patterns "the first death" or "death of the spirit." After the first death, physical death ("second death" in Calhoun's terminology) is inevitable and is a matter of a short time. As a result of the “first death” of a significant part of the population, the entire colony is doomed to extinction even in the conditions of “paradise”.
Calhoun was once asked about the reasons for the appearance of a group of "beautiful" rodents. Calhoun drew a direct analogy with a person, explaining that a key feature of a person, his natural destiny, is to live in conditions of pressure, tension and stress. The mice, who abandoned the struggle, chose the unbearable lightness of being, turned into autistic "beauties" capable of only the most primitive functions, eating and sleeping. The "handsome men" abandoned everything difficult and demanding of stress and, in principle, became incapable of such strong and complex behavior. Calhoun draws parallels with many modern men, capable of only the most routine, daily actions to maintain physiological life, but with an already dead spirit. This is reflected in the loss of creativity, the ability to overcome and, most importantly, to be under pressure. Refusal to accept numerous challenges, escape from stress, from a life of complete struggle and overcoming - this is the "first death" in the terminology of John Calhoun, or the death of the spirit, after which the second death inevitably comes, this time of the body.
Perhaps you still have a question why D. Calhoun's experiment was called "Universe-25"? This was the twenty-fifth attempt by the scientist to create a paradise for mice, and all previous ones ended in the death of all experimental rodents ...