Neanderthals had outsize effect on human biology

[dystopian]

Variations in depression are about 33% genetically heritable. If neanderthal genes are responsible for the genetics depression, that would be interesting. I have speculated that depression is a gene selected to motivate suicide among unproductive or counterproductive members of the tribe, and such a genotype may make more sense in colder climates where resources are scarce and productivity per capita is essential. However, suicide and depression rates among races have only a minor correspondence (at most) to the share of Neanderthal DNA among the races. East Asians have high Neanderthal DNA but low rates of depression or suicide. So the hypothesis seems unlikely. The Nature article reports only a "tiny effect" of each gene identified.

Do you think that the prevalence of ritual suicide in feudal Japan might factor into this? I am not aware of any other culture that embraced such a practice, but I could be wrong.

Seppuku as it's called, was not actually very common as a form of ritual suicide. More often than not it was imposed as a form of "honorable" punishment: the alternative being just to get executed. Voluntary seppuku has often been described as a way of cleansing oneself of shame (such as the shame of being defeated in battle); but in most cases that would not have been the sole motivation. Consider that a samurai defeated in battle might have to choose between the honorable death given by seppuku, or execution at the hands of the enemy (often after being tortured first). Given that, and given that it was restricted to the samurai class and the daimyo (feudal lords) who only represented a minority of Japanese feudal society, I very much doubt one can link modern suicide rates to such a historical phenomenon.

Ritual suicide was/is also not restricted for feudal Japan. For example. it wasn't that long ago that 'Sati', the ritualized suicide of widows (most commonly by immolating themselves on their husband's funeral pyre) was still practiced in India and surrounding areas. Similar practices have been recorded around the world (including among native americans).

 

[KeepTalking]

Do you think that the prevalence of ritual suicide in feudal Japan might factor into this? I am not aware of any other culture that embraced such a practice, but I could be wrong.

Ritual suicide was/is also not restricted for feudal Japan. For example. it wasn't that long ago that 'Sati', the ritualized suicide of widows (most commonly by immolating themselves on their husband's funeral pyre) was still practiced in India and surrounding areas. Similar practices have been recorded around the world (including among native americans).

I didn't know that, very interesting. This certainly seems like it would be more motivated by grief or depression than Seppuku.

 

[Bronzeage]

Do you think that the prevalence of ritual suicide in feudal Japan might factor into this? I am not aware of any other culture that embraced such a practice, but I could be wrong.

Seppuku as it's called, was not actually very common as a form of ritual suicide. More often than not it was imposed as a form of "honorable" punishment: the alternative being just to get executed. Voluntary seppuku has often been described as a way of cleansing oneself of shame (such as the shame of being defeated in battle); but in most cases that would not have been the sole motivation. Consider that a samurai defeated in battle might have to choose between the honorable death given by seppuku, or execution at the hands of the enemy (often after being tortured first). Given that, and given that it was restricted to the samurai class and the daimyo (feudal lords) who only represented a minority of Japanese feudal society, I very much doubt one can link modern suicide rates to such a historical phenomenon.

Ritual suicide was/is also not restricted for feudal Japan. For example. it wasn't that long ago that 'Sati', the ritualized suicide of widows (most commonly by immolating themselves on their husband's funeral pyre) was still practiced in India and surrounding areas. Similar practices have been recorded around the world (including among native americans).

The common thread in ritual suicide is that it is seen as a better alternative to what's going to happen, if you don't kill yourself. In the Roman Empire, a person accused of treason could have their lands seized and their family sold into slavery, after their execution. The traitor might be given the option of suicide and thus preserve their family. This was always a political decision by the Emperor.
The Sati suicide tradition makes one wonder what horrible alternative awaited the widow, if she didn't lay down on her husband's funeral pyre. I have read that this practice was much more likely to be played out if the woman was the young wife of an older man. If the man's adult children wanted immediate access to their father's estate, a young stepmother, who might outlive them could be a problem. This is a great incentive to assisted Sati.

 

[J842P]

I have speculated that depression is a gene selected to motivate suicide among unproductive or counterproductive members of the tribe, and such a genotype may make more sense in colder climates where resources are scarce and productivity per capita is essential.

AA: this is a perfect example of why it is difficult to take your seriously sometimes. This is a prototypical example of a 'just-so' story. And all of this is not to say that a selectionist hypothesis is ispo facto a just-so story, it's more a of a criticism regarding the quality of the proposed hypothesis. Your hypothesis, as stated, is practically unfalsifiable. It rests on assumptions with no empirical support - e.g. colder climates require more cooperation . It would be better to try to formulate your hypothesis in the context of a precise population model. You could easily modify or borrow from current frequency-dependent selection models, for example, and see what sorts of testable predictions you could generate. You could try to look for at least basic support in model organisms of which there are many to choose from in the ethological literature. Also, your hypothesis implicitly assumes group-selection, which is problematic to say the least, and that is even recognizing a recent resurgence in support of such a paradigm, including from non-other than E.O. Wilson... The point being that group selection is controversial and theoretically problematic for eusocial insects, so it is likely a seriously intractable problem for a mammalian species. All of this tells me you have very little background in the rather rich tradition of ethological and sociobiological research where these sorts of models and hypotheses would be encountered. And to me, that seems to be a rather large hole in your background given your rather robust knowledge of the psychometric literature.

I hope you will take my two-cents as being in good faith. I am not one of the people on this board who have started to knee-jerk reject your ideas because I find them politically incorrect. I cringe when your threads end up in pseudo-science. I think you are absolutely right that race is a valid concept in human biology, using Ernst Mayr's definition, and your detractors in that specific regard have not been able to even approach a coherent rebuttal to your arguments, at least not on this board. However, most of your ideas about explaining the origin of the racial categories that could be argued to exist seem woefully sophomoric to me. Although, I must admit, I have mostly abandoned my in the field of evolutionary biology, ethology, and human biology.

 

[dystopian]

I hope you will take my two-cents as being in good faith. I am not one of the people on this board who have started to knee-jerk reject your ideas because I find them politically incorrect.

People dont have react that way to his ideas because they're not politically correct. People react that way because he only has one idea which he's tried to push in dozens of different threads he's started. He's a bit like that racist uncle who keeps randomly ranting about immigrants; the first time he does it you listen to him and consider what he has to say... maybe even try to address his argument... but by the twentieth familydinner he ruined, you know all the tells and can't help but shut it all out.

I cringe when your threads end up in pseudo-science. I think you are absolutely right that race is a valid concept in human biology, using Ernst Mayr's definition, and your detractors in that specific regard have not been able to even approach a coherent rebuttal to your arguments, at least not on this board.

The problem isn't with stating that there are biological differences between different groups of people. The problem isn't even so much with trying to define race even though there's no clear genetic borders between populations and instead a continuous gradation in gene frequences making any given race definition an arbitrary construct despite the fact that said race will have significant genetic differences with another sufficiently distant but also arbitrary race. The problem is with the significance he attributes to the differences, and the undoubtedly prejudiced conclusions he tries to push; and how these conclusions are the driving force behind his obsessive need to keep broaching the exact same topic in dozens of different threads. Nobody would be batting an eye if someone simply suggested that there were biological differences between the groups we tend to think of as races as nothing more than a harmless observation... but the motivation is key.

 

[ApostateAbe]

I have speculated that depression is a gene selected to motivate suicide among unproductive or counterproductive members of the tribe, and such a genotype may make more sense in colder climates where resources are scarce and productivity per capita is essential.

AA: this is a perfect example of why it is difficult to take your seriously sometimes. This is a prototypical example of a 'just-so' story. And all of this is not to say that a selectionist hypothesis is ispo facto a just-so story, it's more a of a criticism regarding the quality of the proposed hypothesis. Your hypothesis, as stated, is practically unfalsifiable. It rests on assumptions with no empirical support - e.g. colder climates require more cooperation . It would be better to try to formulate your hypothesis in the context of a precise population model. You could easily modify or borrow from current frequency-dependent selection models, for example, and see what sorts of testable predictions you could generate. You could try to look for at least basic support in model organisms of which there are many to choose from in the ethological literature. Also, your hypothesis implicitly assumes group-selection, which is problematic to say the least, and that is even recognizing a recent resurgence in support of such a paradigm, including from non-other than E.O. Wilson... The point being that group selection is controversial and theoretically problematic for eusocial insects, so it is likely a seriously intractable problem for a mammalian species. All of this tells me you have very little background in the rather rich tradition of ethological and sociobiological research where these sorts of models and hypotheses would be encountered. And to me, that seems to be a rather large hole in your background given your rather robust knowledge of the psychometric literature.

I hope you will take my two-cents as being in good faith. I am not one of the people on this board who have started to knee-jerk reject your ideas because I find them politically incorrect. I cringe when your threads end up in pseudo-science. I think you are absolutely right that race is a valid concept in human biology, using Ernst Mayr's definition, and your detractors in that specific regard have not been able to even approach a coherent rebuttal to your arguments, at least not on this board. However, most of your ideas about explaining the origin of the racial categories that could be argued to exist seem woefully sophomoric to me. Although, I must admit, I have mostly abandoned my in the field of evolutionary biology, ethology, and human biology.

Thanks. I don't have much sympathy with the accusation of "just-so story" in relation to evolutionary biology, as it seems to be of little use other than discouraging the presentation of uncomfortable hypotheses (not that this hypothesis makes you uncomfortable). You say the hypothesis is unfalsifiable. But I falsified it in my last half of the post that you snipped out, the half that seemingly everyone else likewise overlooked.

[...] However, suicide and depression rates among races have only a minor correspondence (at most) to the share of Neanderthal DNA among the races. East Asians have high Neanderthal DNA but low rates of depression or suicide. So the hypothesis seems unlikely. The Nature article reports only a 'tiny effect of each gene identified.

Scientific progress requires speculation. Many hypotheses are put on the table, many of them are explored, and, if they conflict with the evidence, they are discarded. If they line up with the evidence, then they are accepted. And they all begin as "just so stories." That is a slur that has long unjustly burdened the field of evolutionary psychology, a way of saying, "We don't like your hypothesis, and you were stupid to put on the table, so don't put it back on the table until you have fully conclusive evidence behind it." That isn't typically the way science works.

 

[Canard DuJour]

I have speculated that depression is a gene selected to motivate suicide among unproductive or counterproductive members of the tribe, and such a genotype may make more sense in colder climates where resources are scarce and productivity per capita is essential.

LOL!

 

[dystopian]

I have speculated that depression is a gene selected to motivate suicide among unproductive or counterproductive members of the tribe, and such a genotype may make more sense in colder climates where resources are scarce and productivity per capita is essential.

LOL!

Nice catch. Talk about putting the cart in front of the horse... people don't get depressed because they're unproductive... they get unproductive because they're depressed.

 

[ApostateAbe]

LOL!

Nice catch. Talk about putting the cart in front of the horse... people don't get depressed because they're unproductive... they get unproductive because they're depressed.

So why do people get depressed?

 

[fromderinside]

Nice catch. Talk about putting the cart in front of the horse... people don't get depressed because they're unproductive... they get unproductive because they're depressed.

So why do people get depressed?

Trick question? They're unproductive.

 

[ApostateAbe]

What reasons are most typically observed? Granted, some people get depressed no matter what, but many people get depressed temporarily for seemingly consistent reasons. Notice that depression and low self-esteem are often regarded as synonymous, though they don't logically need to be.

 

[dystopian]

What reasons are most typically observed? Granted, some people get depressed no matter what, but many people get depressed temporarily for seemingly consistent reasons. Notice that depression and low self-esteem are often regarded as synonymous, though they don't logically need to be.

You're confusing depression as a clinical condition with the state of feeling bad for a little while; and you also don't seem to understand *why* low-self esteem is often considered synonymous. Clinical depression is a mental disorder that has low self-esteem as one of its core conditions. It has a wide range of causes; absolutely none of which support your ridiculous notion that suicidal thoughts among depressed individuals are an evolutionary trait meant to weed out unproductive members of society. Any trait that leads to a *higher* rate of death is *less* likely to get passed on. There is no evolutionary mechanism that produces suicidal behavior in members of a species on the basis that those members are a burden. The only way to accomplish the culling of unproductive members of a society through evolutionary means is for populations with a tendency to *ostracize/exclude/bully/kill/leave-to-their-fate* the unproductive members to have a higher chance of surviving and passing on their genes. You could maybe explain the origins of bullying that way. Maybe. This selected-for bullying then leads people to depression, and then possibly to suicidal thoughts. However, this is a poor explanation because pushing people like that is a high-risk behavior where the rewards (getting rid of a less than productive member of society) aren't worth the risks (creating violent feuds between individuals and bloodlines, alienating empathetic individuals, targeting people who actually are productive, etc).

 

[ApostateAbe]

What reasons are most typically observed? Granted, some people get depressed no matter what, but many people get depressed temporarily for seemingly consistent reasons. Notice that depression and low self-esteem are often regarded as synonymous, though they don't logically need to be.

You're confusing depression as a clinical condition with the state of feeling bad for a little while; and you also don't seem to understand *why* low-self esteem is often considered synonymous. Clinical depression is a mental disorder that has low self-esteem as one of its core conditions. It has a wide range of causes; absolutely none of which support your ridiculous notion that suicidal thoughts among depressed individuals are an evolutionary trait meant to weed out unproductive members of society. Any trait that leads to a *higher* rate of death is *less* likely to get passed on. There is no evolutionary mechanism that produces suicidal behavior in members of a species on the basis that those members are a burden. The only way to accomplish the culling of unproductive members of a society through evolutionary means is for populations with a tendency to *ostracize/exclude/bully/kill/leave-to-their-fate* the unproductive members to have a higher chance of surviving and passing on their genes. You could maybe explain the origins of bullying that way. Maybe. This selected-for bullying then leads people to depression, and then possibly to suicidal thoughts. However, this is a poor explanation because pushing people like that is a high-risk behavior where the rewards (getting rid of a less than productive member of society) aren't worth the risks (creating violent feuds between individuals and bloodlines, alienating empathetic individuals, targeting people who actually are productive, etc).

I think there is good reason to favor the idea that suicide is an evolutionary mechanism against the unproductive. Genes are the units of selection, and one's genes do not exist in merely one's own organism. They also exist in the whole tribe, and humans tribes competed with other human tribes much like individuals compete with other individuals. If there are too many unproductive members of the tribe, then the tribe would be conquered and killed. If just a few people in the tribe hate you, it hardly matters. If EVERYONE in the tribe hates you, it is likely because you are harming the survival odds of the tribes, and your own genes are better off with you dead! There is likewise something to be said in favor of the evolutionary mechanism of bullying (I didn't think of that). Bullying and suicidal behavior so often go together, and not by accident.

 

[dystopian]

I think there is good reason to favor the idea that suicide is an evolutionary mechanism against the unproductive. Genes are the units of selection, and one's genes do not exist in merely one's own organism. They also exist in the whole tribe, and humans tribes competed with other human tribes much like individuals compete with other individuals.

Genes don't give a shit about tribes; and don't work the way you describe. There is no genetic hivemind; your own genes are never better off with you dead. Genes that make a person more likely to *kill themselves* are not an evolutionary benefit. Period. Why? Because it enhances the chances that the people with those genes will be dead before they can procreate. Therefore, these genes are *unlikely* to be passed on... meaning these traits are likely to DIE OUT. And therefore there is no evolutionary benefit to suicide. Your idea is flat out ridiculous and ignorant of the way selection functions.

 

[ApostateAbe]

I think there is good reason to favor the idea that suicide is an evolutionary mechanism against the unproductive. Genes are the units of selection, and one's genes do not exist in merely one's own organism. They also exist in the whole tribe, and humans tribes competed with other human tribes much like individuals compete with other individuals.

Genes don't give a shit about tribes; and don't work the way you describe. There is no genetic hivemind; your own genes are never better off with you dead. Genes that make a person more likely to *kill themselves* are not an evolutionary benefit. Period. Why? Because it enhances the chances that the people with those genes will be dead before they can procreate. Therefore, these genes are *unlikely* to be passed on... meaning these traits are likely to DIE OUT. And therefore there is no evolutionary benefit to suicide. Your idea is flat out ridiculous and ignorant of the way selection functions.

For proper understanding, it takes getting out of the perspective that one's own genes exist in one's own organism and nowhere else. Not so. One's genes exist also in one's kin. It is part of Richard Dawkins' theory of the selfish gene, explaining self-destructive altruism. You can get a short review of the theory here:

https://en.wikipedia.org/wiki/The_Selfish_Gene#Altruism_explained

 

[dystopian]

For proper understanding, it takes getting out of the perspective that one's own genes exist in one's own organism and nowhere else. Not so. One's genes exist also in one's kin. It is part of Richard Dawkins' theory of the selfish gene, explaining self-destructive altruism. You can get a short review of the theory here:

https://en.wikipedia.org/wiki/The_Selfish_Gene#Altruism_explained

You *really* don't understand, do you? Altruism has an evolutionary benefit because by treating others well you promote others doing the same *for you*; leading to *your* survival chances going up and therefore the chances of your *genes* passing on going up as well.

That is not even remotely similar to suicidal behavior, which simply doesn't fucking function the same way. It doesn't fucking matter even *if* it were universally true (and it isn't) that "unproductive" people killing themselves is a survival benefit to the group; because there's no mechanism to actually pass the fucking genes on. Dead people don't procreate, and people with a genetic predisposition for depression and suicide are much less likely to procreate than others so the argument that they'd have kids first and THEN kill themselves doesn't work for you. There is no way for this behavior to be passed on genetically. Ergo, you're full of shit; and are trying to hide it by appealing to something *completely fucking different*.

 

[ApostateAbe]

For proper understanding, it takes getting out of the perspective that one's own genes exist in one's own organism and nowhere else. Not so. One's genes exist also in one's kin. It is part of Richard Dawkins' theory of the selfish gene, explaining self-destructive altruism. You can get a short review of the theory here:

https://en.wikipedia.org/wiki/The_Selfish_Gene#Altruism_explained

You *really* don't understand, do you? Altruism has an evolutionary benefit because by treating others well you promote others doing the same *for you*; leading to *your* survival chances going up and therefore the chances of your *genes* passing on going up as well.

That is not even remotely similar to suicidal behavior, which simply doesn't fucking function the same way. It doesn't fucking matter even *if* it were universally true (and it isn't) that "unproductive" people killing themselves is a survival benefit to the group; because there's no mechanism to actually pass the fucking genes on. Dead people don't procreate, and people with a genetic predisposition for depression and suicide are much less likely to procreate than others so the argument that they'd have kids first and THEN kill themselves doesn't work for you. There is no way for this behavior to be passed on genetically. Ergo, you're full of shit; and are trying to hide it by appealing to something *completely fucking different*.

Altruism is sometimes an exchange, but very often it isn't. The plainest examples of altruism are among ant colonies. Most ants cannot reproduce, but they work solely for the reproduction of other organisms within their own colony, because they share the same genes, and the genes are the relevant unit of selection, not the individual ants. The soldiers of some ant species, in fact, can and do function as suicide bombers against enemies. There is no fair exchange in this.

 

[PyramidHead]

I agree with Abe's understanding of kin selection (behaving in a way that benefits a collection of organisms with shared genes, even if it is detrimental to the individual, will result in more of those genes being propagated, just not from that individual).

The problem, however, is conceptual. Not every behavior exhibited by humans serves an important evolutionary purpose, or any evolutionary purpose at all. It is more likely that depression and suicide are simply outcomes of having large, self-aware, complicated brains. It need not have been the case that suicide itself emerged as a result of natural selection. The existence of suicide is perfectly explainable without invoking any particular hypothesis about its genetic usefulness.

I think it is more likely that depression, anxiety, and suicidal ideation are inevitable side effects of conscious awareness, in much the same way that lack of opposable thumbs is an inevitable side effect of having flippers instead of hands. Aquatic organisms couldn't have both underwater mobility AND the ability to manipulate complex tools, so the underwater biome on this planet does not contain any organisms that can use a hammer and chisel to sculpt a likeness of Poseidon. It's not as if there was an evolutionary reason for a clownfish to avoid growing thumbs, it's just that the body plan that had been the most successful in general didn't support that feature. Evolution does not produce optimal solutions, only sufficient ones.

In humans, the traits that were enabled by the development of our brains--language, agriculture, technology, etc.--were so incredibly successful at spreading their genes, it didn't matter that our brains also enabled us to be truly, profoundly miserable, in a way that few species on earth can even approach. Depression and suicide were not specifically favored by evolution, they were necessary drawbacks to being clever enough to question one's place in the universe. They weren't solutions to some selection pressure, but selection pressures themselves.

This is probably partly why we have such a strong natural aversion to suicide, and tend to ostracize those who seriously entertain the idea. We have evolved a host of psychological defense mechanisms to help mitigate the existential burden of knowing we will someday die. We couldn't do away with depressive tendencies without sacrificing the intellect that gave us writing and horseback riding, so the only option was to evolve coping strategies. Like anything, they aren't perfect, which is why people still get depressed and kill themselves; just not enough to seriously threaten the evolutionary dominance of the human brain.

 

[fromderinside]

I agree with Abe's understanding of kin selection (behaving in a way that benefits a collection of organisms with shared genes, even if it is detrimental to the individual, will result in more of those genes being propagated, just not from that individual).

The problem, however, is conceptual. Not every behavior exhibited by humans serves an important evolutionary purpose, or any evolutionary purpose at all. It is more likely that depression and suicide are simply outcomes of having large, self-aware, complicated brains. It need not have been the case that suicide itself emerged as a result of natural selection. The existence of suicide is perfectly explainable without invoking any particular hypothesis about its genetic usefulness.

I think it is more likely that depression, anxiety, and suicidal ideation are inevitable side effects of conscious awareness, in much the same way that lack of opposable thumbs is an inevitable side effect of having flippers instead of hands. Aquatic organisms couldn't have both underwater mobility AND the ability to manipulate complex tools, so the underwater biome on this planet does not contain any organisms that can use a hammer and chisel to sculpt a likeness of Poseidon. It's not as if there was an evolutionary reason for a clownfish to avoid growing thumbs, it's just that the body plan that had been the most successful in general didn't support that feature. Evolution does not produce optimal solutions, only sufficient ones.

In humans, the traits that were enabled by the development of our brains--language, agriculture, technology, etc.--were so incredibly successful at spreading their genes, it didn't matter that our brains also enabled us to be truly, profoundly miserable, in a way that few species on earth can even approach. Depression and suicide were not specifically favored by evolution, they were necessary drawbacks to being clever enough to question one's place in the universe. They weren't solutions to some selection pressure, but selection pressures themselves.

This is probably partly why we have such a strong natural aversion to suicide, and tend to ostracize those who seriously entertain the idea. We have evolved a host of psychological defense mechanisms to help mitigate the existential burden of knowing we will someday die. We couldn't do away with depressive tendencies without sacrificing the intellect that gave us writing and horseback riding, so the only option was to evolve coping strategies. Like anything, they aren't perfect, which is why people still get depressed and kill themselves; just not enough to seriously threaten the evolutionary dominance of the human brain.

first I thought "nicely done". Then I thought "wait". Doesn't every life form recognize difference and isn't difference usually treated as an existential threat and isn't that the very definition of genetic drive. So wouldn't a complex thinking life form find recognized difference in themselves or others to which they have no appreciated defense be something that would induce a response something like suicide?

Just sayin'

 

[PyramidHead]

first I thought "nicely done". Then I thought "wait". Doesn't every life form recognize difference and isn't difference usually treated as an existential threat and isn't that the very definition of genetic drive. So wouldn't a complex thinking life form find recognized difference in themselves or others to which they have no appreciated defense be something that would induce a response something like suicide?

Just sayin'

To recognize difference... not sure how many ways that can be interpreted, but there may be a qualitative divide within the spectrum of possible meanings. The field mouse's instinctive understanding that I am one thing and the owl that is trying to eat me is another thing, may be different from having an actual self-concept (and the corresponding ability to ascribe a self-concept onto others). The mouse may do everything in its power to avoid being eaten, including flinging itself off a cliff, but it's probably not a cognitive choice of "falling to my death is probably less unpleasant than being eaten by an owl." So not really suicide in the same sense.