# Universe 25 mouse social experiment **URL:** \ **Category:** In My Humble Opinion\ **Created:** [August 13, 2023, 3:49am UTC](https://boards.straightdope.com/t/universe-25-mouse-social-experiment/988492 "2023-08-13T03:49:40Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![HoneyBadgerDC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/honeybadgerdc/32/1033_2.png) [@HoneyBadgerDC](https://boards.straightdope.com/u/HoneyBadgerDC)\ **Post date:** [August 13, 2023, 3:49am UTC](https://boards.straightdope.com/t/universe-25-mouse-social-experiment/988492/1 "2023-08-13T03:49:40Z")
I was reading a little bit about a social experiment a scientist did with some mice. I find it hard to believe that he reported on it accurately. He provided them with an ideal environment and at the beginning of the experiment the population peaked, he described all kinds of bad behaviors they developed, and they stopped reproducing and eventually almost all of them died out. Why would they have not reverted back to normal behaviors as the population density declined? ---
**Author:** ![Czarcasm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/czarcasm/32/4050_2.png) [@Czarcasm](https://boards.straightdope.com/u/Czarcasm)\ **Post date:** [August 13, 2023, 3:54am UTC](https://boards.straightdope.com/t/universe-25-mouse-social-experiment/988492/2 "2023-08-13T03:54:52Z")
Could you please provide a link to this experiment? ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [August 13, 2023, 3:56am UTC](https://boards.straightdope.com/t/universe-25-mouse-social-experiment/988492/3 "2023-08-13T03:56:56Z")
I went googling and found a couple of links. > **[Universe 25, 1968–1973](https://www.the-scientist.com/foundations/universe-25-1968-1973-69941)** > > A series of rodent experiments showed that even with abundant food and water, personal space is essential to prevent societal collapse. > **[Behavioral sink](https://en.wikipedia.org/wiki/Behavioral_sink)** > > "Behavioral sink" is a term invented by ethologist John B. Calhoun to describe a collapse in behavior which can result from overcrowding. The term and concept derive from a series of over-population experiments Calhoun conducted on Norway rats between 1958 and 1962. > In the experiments, Calhoun and his researchers created a series of "rat utopias" – enclosed spaces in which rats were given unlimited access to food and water, enabling unfettered population growth. Calhoun coined the term "behavi Ca... The first article seems to answer your question: > [@The Scientist Magazine](#): > > Eventually Universe 25 took another disturbing turn. Mice born into the chaos couldn’t form normal social bonds or engage in complex social behaviors such as courtship, mating, and pup-rearing. Instead of interacting with their peers, males compulsively groomed themselves; females stopped getting pregnant. Effectively, says Ramsden, they became “trapped in an infantile state of early development,” even when removed from Universe 25 and introduced to “normal” mice. Ultimately, the colony died out. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [August 13, 2023, 4:22am UTC](https://boards.straightdope.com/t/universe-25-mouse-social-experiment/988492/4 "2023-08-13T04:22:09Z")
Not a lot of details in the links but it sounds like a population density problem. Unlimited food and water assumes those are the only needs animals have. Density problems with livestock show up with behavioral problems and I think I remember something about swine starting to bite at the ears and tails of their fellow future pork chops when kept in too tight of a space despite otherwise ideal conditions. It also sounds eerily like the mythological Mouseville in the Green Mile. Nonsense performed in the name of science is nothing new. ---
**Author:** ![crowmanyclouds](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crowmanyclouds/32/19884_2.png) [@crowmanyclouds](https://boards.straightdope.com/u/crowmanyclouds)\ **Post date:** [August 13, 2023, 4:28am UTC](https://boards.straightdope.com/t/universe-25-mouse-social-experiment/988492/5 "2023-08-13T04:28:15Z")
Speaking of nonsense, > Death Squared: The Explosive Growth and Demise of a Mouse Population > by John B Calhoun MD > (Section on Behavioral Systems, Laboratory of Brain Evolution & Behavior, > National Institute of Mental Health, > 9000 Rockville Pike, Bethesda, Maryland 20014, USA) > > I shall largely speak of mice, but my thoughts are > on man, on healing, on life and its evolution. > Threatening life and evolution are the two deaths, > death of the spirit and death of the body. Evolution, in terms of ancient wisdom, is the acquisition > of access to the tree of life. This takes us back to > the white first horse of the Apocalypse which with > its rider set out to conquer the forces that > threaten the spirit with death. Further in Revelation (ii.7) we note: ‘To him who conquers I will > grant to eat the tree’ of life, which is in the > paradise of God’ and further on (Rev. xxii.2): > ‘The leaves of the tree were for the healing of > nations.’ > This takes us to the fourth horse of the > Apocalypse (Rev. vi.7): ‘I saw … a pale horse, > and its rider’s name was Death, and Hades > followed him; and they were given power over a > fourth of the earth, to kill with the sword and with > famine and with pestilence and by wild beasts of > the earth’ (italics mine). This second death has > gradually become the predominant concem of > modern medicine. And yet there is nothing in the > earlier history of medicine, or in the precepts > embodied in the Hippocratic Oath, that precludes > medicine from being equally concerned with > healing the spirit, and healing nations, as with > healing the body. Perhaps we might do well to > reflect upon another of John’s transcriptions > (Rev. ii. 1): ‘He who conquers shall not be hurt > by the second death.’ > **[procrsmed00338-0007.pdf](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1644264/pdf/procrsmed00338-0007.pdf)** ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [August 13, 2023, 12:10pm UTC](https://boards.straightdope.com/t/universe-25-mouse-social-experiment/988492/6 "2023-08-13T12:10:37Z")
Back to the OP’s question as I understand it … If you assume all mouse / rat behavior is utterly instinctive then you’d expect that as population declined from crazy-making crowded, the animals would revert to the instinctual behaviors appropriate to the more normal density. Even if the older rats/mice did not, their offspring would robotically follow their instinctual programming appropriate to the density they grew up in. etc. If we assume instead that at least some behaviors are learned, that as social animals they are “raised” by their community of older animals, if not by their two particular bio-parents, then it makes sense that as the population dclines the newborns will be being socialized by older animals from the crazy era. Given enough time equals enough generations of animals, could the community regenerate a more “normal” rat / mouse society? Sure, at least in principal. Social norms are as subject to evolution as are genetics. There’s no guarantee the animals would regenerate exactly the same society as one that never went through the crazy-making population boom. But since rat/mouse genetic nature is slow-changing, we’d expect to find their eventual social arrangements, once stabilized, would be not too far off from other colonies raised in isolation. But what if the population decline turns into a crash? Below a certain number of animals, they don’t get the chance to have all the additional generations it takes to regenerate a society. Is any of the above factual? I don’t know for certain. But I find the idea that rats / mice are utterly robotic instinct-followers per my first paragraph highly unbelievable. For insects or amoeba? Sure. For mice / rats? No way. Which makes the rest of my surmise really the only logical alternative; the rest is details. I’ve often commented about humanity that all it takes is for one entire generation not to be taught to read, and all our accumulated knowledge will be lost forever. As a thought experiment of course it depends on an unrealistic exaggeration. But it concisely points out that we’ve built a lot of layers of civilization atop the raw material of “human nature”. And all of that could be stripped away by a big enough cataclysm, leaving a very different sort of humanity in its wake. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [August 14, 2023, 11:38am UTC](https://boards.straightdope.com/t/universe-25-mouse-social-experiment/988492/7 "2023-08-14T11:38:07Z")
> [@LSLGuy](#): > > If we assume instead that at least some behaviors are learned, that as social animals they are “raised” by their community of older animals, if not by their two particular bio-parents, then it makes sense that as the population dclines the newborns will be being socialized by older animals from the crazy era. Many species of animal have been observed to exhibit culture, i.e. behaviors that an individual learns from its social group (as opposed to behaviors that are transmitted genetically, i.e. instinct). Rats have made it onto the list: > **[Animal culture | Rat culture](https://en.wikipedia.org/wiki/Animal_culture#Rat_culture)** > > Notable research has been done with black rats and Norwegian rats. Among studies of rat culture, the most widely discussed research is that performed by Joseph Terkel in 1991 on a species of black rats that he had originally observed in the wild in Israel. Terkel conducted an in-depth study aimed to determine whether the observed behavior, the systematic stripping of pine cone scales from pine cones prior to eating, was a socially acquired behavior, as this action had not been observed elsewh Tho... If rats exhibit culture, then it seems likely that mice do too. ---
**Author:** ![Omar\_Little](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/omar_little/32/269_2.png) [@Omar\_Little](https://boards.straightdope.com/u/Omar_Little)\ **Post date:** [August 14, 2023, 3:37pm UTC](https://boards.straightdope.com/t/universe-25-mouse-social-experiment/988492/8 "2023-08-14T15:37:45Z")
When certain rules are placed within a society and this results in societal norms changing and those rules are enforced over multiple generations, even if the rules are lifted the societal norms will continue to exists it may take something else to force the societal norms to change. Example: China’s one child policy which began in 1980 that limited families to only having one child. This was enforced with monetary fines, withholding of government benefits and in many cases forced abortions. This policy continued til 2016 (36 years) when the government permitted families to have two children. However, birthrates did not increase. So China increased the policy to permit three children per family in 2021, and eliminated the fines for families that exceed the limit. The birth rate in China has continued to fall at about 2.2% per year since 2016. It has become a societal norm to have only one child, if you are going to have a child at all. If China wants to see their population increase, they are going to have to offer incentives to have more children, or punishments for having so few children. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [August 14, 2023, 7:31pm UTC](https://boards.straightdope.com/t/universe-25-mouse-social-experiment/988492/9 "2023-08-14T19:31:05Z")
Good example. Thank you. Another possible factor in China’s situation is the decline in birthrates seen in every society as it urbanizes and enrichens itself. Pre- the one-child policy, most Chinese were peasants, where more kids = more security in old age. Now that the policy has been rescinded, one heck of a lot of Chinese are (sub-)urban. And especially the folks in the prime childbearing age range. Children in that scenario are much more a cost- and hassle-center for you now than they are a retirement elder-care asset for future you 40-60 years later. Or at least that’s what’s been seen in nearly every industrializing / urbanizing society for the last 150-ish years. That’s _not_ meant to pooh-pooh your point that social norms a) evolve, and are b) sticky. I’m just pointing out another way in which the Chinese government are trying to push a string here and will need _big_ incentives to make it work. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [November 25, 2024, 1:05pm UTC](https://boards.straightdope.com/t/universe-25-mouse-social-experiment/988492/10 "2024-11-25T13:05:46Z")
This experiment came up in a web comic ( [Freefall](http://freefall.purrsia.com/), if you must know). I’d never heard of it except indirectly, since I’d heard the results discussed before. Anyway, I got to wondering: Has anyone tried to reproduce it? ---
**Author:** ![Pardel-Lux](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pardel-lux/32/20182_2.png) [@Pardel-Lux](https://boards.straightdope.com/u/Pardel-Lux)\ **Post date:** [November 25, 2024, 1:26pm UTC](https://boards.straightdope.com/t/universe-25-mouse-social-experiment/988492/11 "2024-11-25T13:26:17Z")
[**John Calhoun**](https://en.wikipedia.org/wiki/John_B._Calhoun) designed several artifical environements for mice and rats, if that counts as replication. Here is a recent article from _The Guardian_ about Universe 25: > **[The ‘mad egghead’ who built a mouse utopia](https://www.theguardian.com/science/2024/nov/21/the-mad-egghead-who-built-a-mouse-utopia-john-b-calhoun)** > > The long read: John Calhoun designed an apartment complex for mice, to examine the effects of overcrowding. It was hailed as a groundbreaking study of social breakdown, but is largely forgotten. So what happened? I don’t understand what is so hard to believe about his findings: the offspring of people affected by severe trauma exhibit the influence of that trauma in their behaviour and it shows in their biochemistry. **[Cite](https://www.research.va.gov/currents/1016-3.cfm)**, one of many. Just search for “epigenetics of holocaust survivors” if you want more. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [November 25, 2024, 1:37pm UTC](https://boards.straightdope.com/t/universe-25-mouse-social-experiment/988492/12 "2024-11-25T13:37:09Z")
> [@Pardel-Lux](#): > > [**John Calhoun**](https://en.wikipedia.org/wiki/John_B._Calhoun) designed several artifical environements for mice and rats, if that counts as replication. No it doesn’t. Replication means _some other_ researcher performs the same experiment to see if they get the same results.