r/science Oct 17 '21

New study helps explain why increasing population densities are linked to decreasing fertility rates Anthropology


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u/DiarrheaMonkey- Oct 18 '21

No mention of the effect that I've long seen taken as given in academic writing touching on urbanization and population growth/decline. That is that in rural settings, particularly agricultural ones, children are a source of labor, while in urban settings, children are entirely a cost.

Also, more urbanized nations are, on average, more economically developed, and routinely eventually implement social security-type programs. This alleviates the need for one (usually male) child to remain in their birth location in order to provide for the parents in their old age.

Lastly, related to that, and somewhat to the thesis discussed in the article, is infant and childhood mortality. More developed economies have significantly lower childhood mortality, and thus fewer children are required for the safe assumption that 1 will survive to adulthood.


u/runmeupmate Oct 18 '21

Decline of religion is also important


u/Lykanya Oct 18 '21

I wonder how much of those are true, or post-fact rationalisations by the people attempting to study this phenomenon.

Refer to rat Utopia experiments, none of the factors you mention there are relevant to any degree as they got provided with everything required, and yet had a very similar trajectory as density increased.

Similarly, none of what this new study talks about is also relevant, the rats weren't competing for anything, other than space. (Maybe space is indeed, the reason)

There is something about population density that impacts us at some deep psychological level and shapes behaviour, this is something that should be explored instead of focusing on socioeconomic explanations only in my view.

This is all unconscious, and as such impossible to determine by asking people for reasons, they will rationalise their behaviour as being choices or sequential to events.


u/Savekennedy Oct 18 '21

I mean you could ask 10 random people and they probably would all give you a valid reason for why living in cities decreases fertility rates.


u/PantsOnHead88 Oct 17 '21

Without reading the article, I assume it goes like this: Population density goes up. Demand goes up. CoL go up. People decide they’re not willing to take the QoL downgrade to afford a family.


u/whiskey_bud Oct 18 '21

That’s not what the article says whatsoever. It focuses on competitiveness in dense vs sparse and harsh vs safe environments. Really has nothing to do with quality of life.


u/JackJack65 Oct 18 '21

The correlation is hardly surprising though, as those in dense/safe environments have the lowest fertility rate, but also the highest level of education and access to contraceptives.


u/PantsOnHead88 Oct 18 '21

First off, I literally started the comment with “without reading the article” and then you turn around and tell me that’s not what the article says. I wonder why?

Second, take a walk around any major city in NA and ask 20-40 year olds who aren’t having kids why they’re not having kids and they’ll tell you it is unaffordable. The number of young educated people I’ve had tell me that they’ve given up on ever owning a home or starting their own family for this precise reason is rather upsetting.


u/Act-Math-Prof Oct 18 '21

Why comment if you haven’t read the article?


u/whiskey_bud Oct 18 '21

Maybe don’t comment with total speculation if you haven’t read the article?


u/Hefty-Barber-8256 Oct 18 '21 edited Oct 18 '21

Or to put it in different terms, productivity goes up and the available workforce shrinks as wages rise enough to feed children through school.

Edit,"shrinks" is not exactly right, but the ratio of working children decreases.


u/Gopherbashi Oct 18 '21

"The mid-year population divided by land area provided the population density metric per country"

This feels like an overly-simplistic way of looking at the information, when something like urban density seems more relevant for this type of analysis.


u/Hot_Plastic_883 Oct 18 '21

I think polluting your fresh water supplies beyond a point of return is what’s gonna get humans in the end.

How stupid is that?

Even the great lakes have so many PCBs at the bottom you cannot get a dredging permit in any of the great lakes. Insane


u/Riviz Oct 18 '21

People made too crowd around other people dont want to make more people. Makes sense to me


u/TO_Commuter Oct 18 '21

“Broadly, I’m interested in how people compete with one another, and how environmental factors influence competitive strategies,” explained study author Amanda Rotella (@AMRotella), a lecturer at Kingston University London. “Population density has been previously found to be related to fertility rates in human populations, however, little research has been done on why population density and fertility rates are related.”

The study does hand waving correlations. RIP


u/HellHound989 Oct 18 '21

This is new?

Several studies were done back in the 60s and 70s that already proved this. Look up the behavioral sink studies (Milligan Mouse Utopia stuff)

/sigh, stay stupid sub


u/brberg Oct 18 '21

Like most psychological research done in 60s and 70s, Calhoun's work on mice was methodologically questionable, poorly documented, and dubiously replicable. It probably shouldn't be cited as proof of anything about mice nowadays, let alone people.


u/Hot_Plastic_883 Oct 18 '21

Did you know that wolves will have as many puppies depending on how much game is in the area?


u/madrid987 Oct 27 '21

High density development in Spain must have caused serious low birth rates.


u/who_that_guy227 Oct 18 '21

Are you high on illegal marijuana, is this the new Americana?


u/acatisadog Oct 18 '21

Let's be honest :

- increasing density of population increase the cost of accomodation by a lot. Where I live the price of houses/appartments rise by 5 to 7% PER YEAR. It can be hard for a couple to afford a 3 bedrooms appartment, mainly if they win minimum wage or slightly above.

- People are more feminists in urban areas than rural ones ; it's not just a cliché, I've lived in both and it's what I think. In urban areas women are more interested in pursuing studies imo and are happy living alone while in rural areas having children is higher in their lists of ambitions, and they enjoy the tought of being mother more, maybe (I'm not sure) because rural areas doesn't have such a high imperative to have two jobs per couple to get by