# Why haven't falling populations sparked a Darwinian increase in birth rates? **URL:** \ **Category:** Great Debates\ **Created:** [January 25, 2006, 6:38am UTC](https://boards.straightdope.com/t/why-havent-falling-populations-sparked-a-darwinian-increase-in-birth-rates/341526 "2006-01-25T06:38:03Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Rodgers01](https://avatars.discourse-cdn.com/v4/letter/r/b19c9b/32.png) [@Rodgers01](https://boards.straightdope.com/u/Rodgers01)\ **Post date:** [January 25, 2006, 6:38am UTC](https://boards.straightdope.com/t/why-havent-falling-populations-sparked-a-darwinian-increase-in-birth-rates/341526/1 "2006-01-25T06:38:03Z")
There has been a lot of discussion about falling birth rates and the accompanying population decline in various parts of the world. But why haven’t all these gloom and doom forecasts inspired, on some sub-conscious level, a Darwinian boost to the birth rate in some of these societies? I’ll admit I only have a pop culture understanding of Darwin, so maybe I’m completely wrong here, but according to Darwinian theory shouldn’t these societies begin compensating for the population loss? Especially in societies that stereotypically have very strong ethnic/racial/cultural identities – on a Darwinian level, how could the Japanese, for example, allow their kind to start disappearing? Or how about the Quebecois – they are supposedly obsessed with maintaining their distinctive language and culture, but their percentage of the population in Canada is falling, and still they have among the lowest birthrates in the country. So what’s the Darwinian/evolutionary explanation for this? Is it possible that this is a sign that human beings on the whole are actually moving past race/ethnicity/culture – that even if their own group is declining, there are still plenty of other people around, and they’re not concerned enough for that “survival of the race” instinct to kick in? Or is it simply that education/culture/birth control/career trump Darwin? ---
**Author:** ![Marley23](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Marley23](https://boards.straightdope.com/u/Marley23)\ **Post date:** [January 25, 2006, 7:03am UTC](https://boards.straightdope.com/t/why-havent-falling-populations-sparked-a-darwinian-increase-in-birth-rates/341526/2 "2006-01-25T07:03:46Z")
> [@Rodgers01](#): > > but according to Darwinian theory shouldn’t these societies begin compensating for the population loss? I admit I haven’t read _Origin of Species_ all the way through, but I’m pretty sure the answer is no. > [@Rodgers01](#): > > they’re not concerned enough for that “survival of the race” instinct to kick in? Evolution isn’t about instinct and I’m sure it doesn’t posit any kind of drive to keep the race or species alive. It’s about the process by which a species changes and adapts over time. ---
**Author:** ![Rodgers01](https://avatars.discourse-cdn.com/v4/letter/r/b19c9b/32.png) [@Rodgers01](https://boards.straightdope.com/u/Rodgers01)\ **Post date:** [January 25, 2006, 7:18am UTC](https://boards.straightdope.com/t/why-havent-falling-populations-sparked-a-darwinian-increase-in-birth-rates/341526/3 "2006-01-25T07:18:03Z")
> [@Marley23](#): > > Evolution isn’t about instinct and I’m sure it doesn’t posit any kind of drive to keep the race or species alive. It’s about the process by which a species changes and adapts over time. So according to the theory, the whole changing/adapting/survival of the fittest is just a matter of biological chance, without an element of psychological competition, drive, instinct, etc.? My understanding of Origin of Species is that it was just biological, but isn’t there also a theory of social Darwinism? ---
**Author:** ![Marley23](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Marley23](https://boards.straightdope.com/u/Marley23)\ **Post date:** [January 25, 2006, 7:25am UTC](https://boards.straightdope.com/t/why-havent-falling-populations-sparked-a-darwinian-increase-in-birth-rates/341526/4 "2006-01-25T07:25:05Z")
> [@Rodgers01](#): > > So according to the theory, the whole changing/adapting/survival of the fittest is just a matter of biological chance, without an element of psychological competition, drive, instinct, etc.? I won’t explain a book I haven’t finished, especially when we have real experts on it on this board. I just don’t think evolution really applies to the population phenomenon you’re talking about for the reason I gave. > [@](#): > > My understanding of Origin of Species is that it was just biological, but isn’t there also a theory of social Darwinism? There’s such a thing, yes, but it really hasn’t got anything to do with evolution and Darwin sure didn’t come up with it. It’s sort of an attempt to apply competitive ideas to social institutions. ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [January 25, 2006, 7:36am UTC](https://boards.straightdope.com/t/why-havent-falling-populations-sparked-a-darwinian-increase-in-birth-rates/341526/5 "2006-01-25T07:36:33Z")
> [@Rodgers01](#): > > So according to the theory, the whole changing/adapting/survival of the fittest is just a matter of biological chance, without an element of psychological competition, drive, instinct, etc.? My understanding of Origin of Species is that it was just biological, but isn’t there also a theory of social Darwinism? [Social Darwinism](http://en.wikipedia.org/wiki/Social_Darwinism) is not a scientific theory and has nothing to do with biological evolution and nothing to do with any psychological desire to increase population so as to avoid extinction. And yes, biological evolution is predicated on random changes in genetic makeup filtered by the requirement that the organism be able to survive in its environment long enough to reproduce. There is no postulated drive to maintain a population in the Darwinian model. ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [January 25, 2006, 8:38am UTC](https://boards.straightdope.com/t/why-havent-falling-populations-sparked-a-darwinian-increase-in-birth-rates/341526/6 "2006-01-25T08:38:50Z")
Even if we have a drive to keep up the population, we are also greatly overpopulated; especially by Stone Age ( or earlier ) standards, which is when such an instinct would have evolved. Any such instinct would be unlikely to kick in until we lose most of the current population. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 25, 2006, 9:01am UTC](https://boards.straightdope.com/t/why-havent-falling-populations-sparked-a-darwinian-increase-in-birth-rates/341526/7 "2006-01-25T09:01:05Z")
If falling populations result in under-exploited resources and niches, then that’s something I think we could expect an evolutionary response to. Not ‘response’ in the sense that things happen because they are planned, but rather that when the various forces _restraining things from happening_ are relaxed, _things tend to happen_. ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [January 25, 2006, 9:08am UTC](https://boards.straightdope.com/t/why-havent-falling-populations-sparked-a-darwinian-increase-in-birth-rates/341526/8 "2006-01-25T09:08:36Z")
> [@Mangetout](#): > > If falling populations result in under-exploited resources and niches, then that’s something I think we could expect an evolutionary response to. Not ‘response’ in the sense that things happen because they are planned, but rather that when the various forces _restraining things from happening_ are relaxed, _things tend to happen_. Except that evolution is sloooow. It’ll be a long time before anything happens, and by that time the trends could be different. ---
**Author:** ![Martin\_Hyde](https://avatars.discourse-cdn.com/v4/letter/m/47e85d/32.png) [@Martin\_Hyde](https://boards.straightdope.com/u/Martin_Hyde)\ **Post date:** [January 25, 2006, 9:41am UTC](https://boards.straightdope.com/t/why-havent-falling-populations-sparked-a-darwinian-increase-in-birth-rates/341526/9 "2006-01-25T09:41:10Z")
> [@Rodgers01](#): > > So according to the theory, the whole changing/adapting/survival of the fittest is just a matter of biological chance, without an element of psychological competition, drive, instinct, etc.? My understanding of Origin of Species is that it was just biological, but isn’t there also a theory of social Darwinism? Well, the thing is Darwin never posited that animals were actively causing themselves to evolve over time, he (correctly) never thought any animals had that sort of mental capacity. One early view was that, for example, a giraffe’s long neck was explained by the giraffe wanting leaves from higher trees. It stretched it’s neck upwards vainly to try and reach the leaves, and through some process which they couldn’t explain, this passed on to their children and their children’s neck grew longer. This view isn’t _all_ that stupid considering the science of the times. But ultimately it is not correct, the giraffe gets the longer neck because long ago the members of the origin species that had longer necks had a better chance of reproducing, and this trait just become more and more exaggerated as longer and longer necks became more and more beneficial. Darwin did believe “instinct” to a degree came in, in that animal societies were often structured such that the stronger male got with the females and thus the weaker males genes didn’t get passed on. Social Darwinism isn’t very adequately named since the core theories behind social Darwinism predate Darwin’s published works and are based in largepart on guys like Malthus who were actually dead long decades before Darwin’s Origin of the Species. Darwin did espouse some views that might be considered as supportive of eugenics. He did feel that humans as a species should try to pass on desireable traits, but he never believe that there should be governmental or political processes to implement something like that. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 25, 2006, 10:19am UTC](https://boards.straightdope.com/t/why-havent-falling-populations-sparked-a-darwinian-increase-in-birth-rates/341526/10 "2006-01-25T10:19:05Z")
> [@Der Trihs](#): > > Except that evolution is sloooow. It’ll be a long time before anything happens, and by that time the trends could be different. Adaptation is usually quite slow; populations expanding to exploit unoccupied (or recently vacated) niches and unexploited resources (to which they may not be fully adapted) can be quite quick. Admittedly, this isn’t the whole of the picture, but it’s definitely part of it. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [January 25, 2006, 10:46am UTC](https://boards.straightdope.com/t/why-havent-falling-populations-sparked-a-darwinian-increase-in-birth-rates/341526/11 "2006-01-25T10:46:34Z")
> [@Der Trihs](#): > > Except that evolution is sloooow. It’ll be a long time before anything happens, and by that time the trends could be different. There is nothing that requires evolution to be “slow”. Depending on the enviornmental pressure and the variability within a given speceis, it can be “slow” or “fast”. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [January 25, 2006, 10:59am UTC](https://boards.straightdope.com/t/why-havent-falling-populations-sparked-a-darwinian-increase-in-birth-rates/341526/12 "2006-01-25T10:59:49Z")
> [@Rodgers01](#): > > So what’s the Darwinian/evolutionary explanation for this? Is it possible that this is a sign that human beings on the whole are actually moving past race/ethnicity/culture – that even if their own group is declining, there are still plenty of other people around, and they’re not concerned enough for that “survival of the race” instinct to kick in? Maybe, but I doubt it’s on a conscious level. Natural selection operates on populations. For all intents and purposes, the species _Homo sapiens_ is one population. > [@](#): > > Or is it simply that education/culture/birth control/career trump Darwin? The human population, as a whole, is growing faster than it ever has. If certain cultures within that population die out, then those culture didn’t have the necessary aspects to ensure their survival. Do not confuse that with Social Darwinism, which **David Simmons** has already identified as a debunked hypothesis. Some cultures will prove to be better than others at ensuring the survival of their memebers, but all members still belong to the species _Homo sapiens_. ---
**Author:** ![Evil\_Captor](https://avatars.discourse-cdn.com/v4/letter/e/f17d59/32.png) [@Evil\_Captor](https://boards.straightdope.com/u/Evil_Captor)\ **Post date:** [January 25, 2006, 2:11pm UTC](https://boards.straightdope.com/t/why-havent-falling-populations-sparked-a-darwinian-increase-in-birth-rates/341526/13 "2006-01-25T14:11:00Z")
> [@Rodgers01](#): > > Or is it simply that education/culture/birth control/career trump Darwin? Ding ding ding. Evolution, or “Darwin” as you call it, doesn’t operate on the individual basis. There’s a well-developed instinct in people to mate and to have offspring, but apparently in most cases, there’s no instinct to have any particular number of offspring … that’s often a rational decision based on individual needs. Of course, a nation might start a program to encourage its members to reproduce more robustly, but as long as the underlying economics that make for few or no children don’t change, it won’t work. Look at Catholicism, which encourages its members to be fruitful and multiply, and forbids not only abortion but birth control. It works in countries where having lots of kids is perceived as being an advantages – the Third World, roughly speaking, but it doesn’t work in the US, where the birthrate hovers right at the replacement rate, and it most especially doesn’t work in the home of Catholicism, Italy, where the birth rate is 1.23 children per woman, the second lowest in the western world. [The Italian government is even bribing women to have a second child](http://www.doki.net/tarsasag/novedelem/upload/novedelem/document/birth_rate_in_Italy.htm). All evolution says is that traits which are successful in a given population will over many generations, become spread throughout the population, even if the trait is just fractionally more successful than other traits. It doesn’t say any individual members or groups within that population will change their behavior on its behalf. ---
**Author:** ![Evil\_Captor](https://avatars.discourse-cdn.com/v4/letter/e/f17d59/32.png) [@Evil\_Captor](https://boards.straightdope.com/u/Evil_Captor)\ **Post date:** [January 25, 2006, 2:16pm UTC](https://boards.straightdope.com/t/why-havent-falling-populations-sparked-a-darwinian-increase-in-birth-rates/341526/14 "2006-01-25T14:16:02Z")
There is one ray of hope for currently depopulation countries. After the Black Death in Europe, there was a huge baby boom, because everyone who lived through it inherited a great deal of land and so forth (whatever it was that passed for wealth in those times) from their dead relatives … with one in three people in Europe dead of plague, there was a lot of inheriting going on. I don’t know that this will occur in the depopulating countries, because the economic system is very different now. Time will tell. ---
**Author:** ![Evil\_Captor](https://avatars.discourse-cdn.com/v4/letter/e/f17d59/32.png) [@Evil\_Captor](https://boards.straightdope.com/u/Evil_Captor)\ **Post date:** [January 25, 2006, 2:18pm UTC](https://boards.straightdope.com/t/why-havent-falling-populations-sparked-a-darwinian-increase-in-birth-rates/341526/15 "2006-01-25T14:18:04Z")
Lemme fix that [link](http://www.doki.net/tarsasag/novedelem/upload/novedelem/document/birth_rate_in_Italy.htm) I put up earlier. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [January 25, 2006, 2:51pm UTC](https://boards.straightdope.com/t/why-havent-falling-populations-sparked-a-darwinian-increase-in-birth-rates/341526/16 "2006-01-25T14:51:51Z")
Humans are the only animals on the planet capable of making a conscious decision _not_ to reproduce, even when conditions might be favorable. At present, social and cultural factors are far more important than “instinct” among humans in determining reproductive behavior. Many animals will refrain from attempting to reproduce if conditions are unfavorable - If there is inadequate food, or if the local population density is so high that it may cause depletion of resources in the near future. Local human population density in many places is far in excess of what could be supported by hunting and gathering, the ecological conditions under which most human evolution took place. _If_ instinctual factors were significant for humans, one would expect a negative feedback from high population densities so that birth rates would decline. This does not seem to occur; although birth rates are declining in some places with high population density (e.g. Europe), they are high in other placess with equally high density. If instinct or raw biological factors were important, one might also expect that birth rates would be correlated with food quality and availabily. This is probably true at very low population densities and low average levels of nutrition. However, at the very high population densities seen today, it is actually the countries where food is most available where birth rates are declining. Again, cultural and social factors appear to trump biological ones in modern societies. ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [January 25, 2006, 3:06pm UTC](https://boards.straightdope.com/t/why-havent-falling-populations-sparked-a-darwinian-increase-in-birth-rates/341526/17 "2006-01-25T15:06:06Z")
> [@Colibri](#): > > Humans are the only animals on the planet capable of making a conscious decision _not_ to reproduce … And also have the capability of having sex without reproducing. Maybe the sexual drive is the instinct and reproduction is a by product, although a crucial one. ---
**Author:** ![Steve\_MB](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/steve_mb/32/5339_2.png) [@Steve\_MB](https://boards.straightdope.com/u/Steve_MB)\ **Post date:** [January 25, 2006, 3:34pm UTC](https://boards.straightdope.com/t/why-havent-falling-populations-sparked-a-darwinian-increase-in-birth-rates/341526/18 "2006-01-25T15:34:13Z")
> [@Rodgers01](#): > > I’ll admit I only have a pop culture understanding of Darwin, so maybe I’m completely wrong here I think that pretty well covers it. In biological terms, species have a range of reproductive stategies from spewing out zillions of young with miniscule parental investment in each individual (e.g. insects) to rearing a few young with heavy parental investment in each (e.g. most mammals). Modern civilization has impelled humans to move even further in the direction of smaller numbers and higher investment in each individual. The evolutionary success of each strategy depends on circumstances. ---
**Author:** ![Steve\_MB](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/steve_mb/32/5339_2.png) [@Steve\_MB](https://boards.straightdope.com/u/Steve_MB)\ **Post date:** [January 25, 2006, 3:37pm UTC](https://boards.straightdope.com/t/why-havent-falling-populations-sparked-a-darwinian-increase-in-birth-rates/341526/19 "2006-01-25T15:37:11Z")
> [@David Simmons](#): > > Maybe the sexual drive is the instinct and reproduction is a by product, although a crucial one. I think that’s clearly the case – instinctive responses are oriented toward the present, not the future. ---
**Author:** ![Spoke](https://avatars.discourse-cdn.com/v4/letter/s/a88e57/32.png) [@Spoke](https://boards.straightdope.com/u/Spoke)\ **Post date:** [January 25, 2006, 3:51pm UTC](https://boards.straightdope.com/t/why-havent-falling-populations-sparked-a-darwinian-increase-in-birth-rates/341526/20 "2006-01-25T15:51:47Z")
Availability of birth control? [Next page](https://boards.straightdope.com/t/why-havent-falling-populations-sparked-a-darwinian-increase-in-birth-rates/341526.md?page=2)