"Incan men were not in the process of becoming conscious when Pizarro encountered them (whatever Jaynes says contrary)."
So interestingly, the Inca's had this belief that when the emperor died his mummy would still be wheeled out as an immortal (but not unable to speak) Lord. And it would be a female partner that would act as interpreter.
Similarly: "As the empire expanded, the role of the most powerful Inca mummies—known as illapa—grew beyond simple ancestor worship. When an Inca emperor died, his successor inherited his power, but not his worldly belongings; these were understood to follow the dead emperor into the afterlife. His family members would then tend to his mummified body, ensuring he was kept in luxurious style even in death.
When the illapa were taken out and assembled together, the new Inca emperor would sometimes show his own power by taking his place and sitting stone-like among his dead predecessors. But these powerful Inca mummies weren’t just male, Heaney emphasizes; instead, *they were often preserved in male-female pairs. In order to claim power, a would-be emperor had to marry a prominent Inca woman, sometimes even a relative*
“There was a duality in both Inca and Andean understanding of the universe—that it is male and female together, with their respective powers and abilities, that creates the empire,” he says."
That is a remarkably similar to Egyptian treatment of the pharaoh, thanks for sharing.
In the previous post I argued that Bicameral Breakdown (or The Fall) also required genetic change, or in other words it would not have been 0-1 in a single generation. One of my primary issues with Jaynes is he argues there was 0 introspection as late as Egyptians building pyramids. I think introspection led to recursion, which in turn led to our flexible thinking. I think it's likely we got to flexible thinking and started building megaliths before shedding parts of the bicameral mindset. I mean, many people still do hear voices (especially if you include childhood imaginary friends); we still have the imprint.
I'm on board with the idea of women leading the ritual shift into consciousness, but I have doubts it required Y chromosome changes to enact. I think what we're seeing here is effect, not causal.
The null hypothesis I see is that the Holocene involved warfare much like historical warfare, which tended to kill men disproportionately and reward their survivors with outsized opportunities to breed, but moreso because we were very new at it. The 6kya massive swing could still be triggered by a quasi-memetic shift to consciousness, as your snake theory posits. The tribes achieving consciousness would then typically win in violent warfare with non-conscious tribes, slaying their men and capturing their women.
That 6kya peak is certainly still dramatic evidence of a incredibly sharp change in a short period of time, which fits the young consciousness hypothesis from your snake theory well. Also fits the creationist narrative that the world started 6kya disturbingly tightly, in a way that implies maybe there's some poetic truth to that, too.
From a timing perspective, 6kya may work better as an effect, tbh. One problem with the effect model is that the bottleneck is so consistent, and my understanding of social organization is that it is quite path dependent. It seems there would be some regions that would avoid the bottleneck if it were due to changing social organization because there were so many different social organizations. Did they all include massive (and fairly short-lived) sex-linked reproductive differences? Looking forward to more papers on the subject, which I assume will come at some point. Was there a mid-Holocene bottleneck in Australia as well? (There is a somewhat related It would be interesting to correlate that with the spread of snake worship and the Pama-Nyungen language family, which can both be dated fairly well. If there is a bottleneck, does come before or after those cultural changes?
Also, wait for the piece on the Y chromosome and theory of mind :) A few lines of evidence says the two are related
So yeah, lots of uncertainty, and I hope other people (like yourself) provide input on whether this makes more sense as a cause or effect.
Reading this article had me wonder if the Y Chromosome selection bottleneck could be explained by the idea of "proactive aggression" discussed in The Goodness Paradox. Could be be an interesting synthesis. Perhaps it played out like the snake-venom cult gradually indoctrinates men. The ones who navigate the ritual and become more prosocial then band together and commit acts of planned murder against the more violent anti-social men. Perhaps they even use threats of violence to force the ritual on men, and the ones who fail to develop the "analogue I" as a result are then murdered. Kinda dovetails with the spread of the male rite-of-passage idea too. All wild speculation. Any thoughts?
I haven't read The Goodness Paradox (though it looks great), but Antonio Benítez-Burraco has a 4-stage model of self-domestication (https://www.sciencedirect.com/science/article/abs/pii/S0271530920300288), where proactive aggression only comes into play in the last 10,000 years. This fits really well with both the Y chromosome stuff, as well as the Snake Cult timeline. Essentially men come into their own, and their first order of business is to stage a coup to depose women, and kill any weak men. Myths reflect this as well. The Greeks have their 4 ages of man. The Golden Age is essentially Eden. No aging or death, and living at one with nature. Agriculture is introduced in the Silver Age. The men are idiots, dependent on women. Then comes the Bronze Age, which would correspond with organized violence. Then comes the Iron Age, with more of the same (but with better technology). Or take the Bible, the first generation after Adam and Eve you get Cain and Abel: the invention of murder. If you haven't read my two most recent posts on diffusion, which include a bunch of other examples of men staging a coup against women. On the right, you see that transition glorified to this day: https://twitter.com/NapoleonBonabot/status/1568753353748004866
Relating it to the Y chromosome, it's weird that the bottleneck is so early. Before the invention of the horse-raider pastoralist lifestyle, or bronze weapons. Before the spread of Proto-Indo-Europeans. These people came AFTER the bottleneck, which makes it so surprising. But maybe that is just the widescale stuff. Maybe violence increased locally (and everywhere) 10-5kya as men became better at planning for the future.
>Perhaps they even use threats of violence to force the ritual on men, and the ones who fail to develop the "analogue I" as a result are then murdered.
At least genetically, this isn't required. Those without an analogue I could just be 5% worse at gathering food and securing mates which would be a huge disadvantage over several generations.
The 6000 years number here is fascinating, as it's the number you get when you count up the years in the Old Testament genealogies. We laugh at Biblical literalists for saying that "the world is only 6000 years old"
And yet. That 6000 years does appear to be quite significant in the history of humanity.
And right there, still in Genesis but after the creation story, you have a whole host of stories about... men, chosen by God, reproducing with multiple women, and heading up semi-nomadic "households" of hundreds, or even thousands of people once you count up all the menservants and maidservants and associated relatives. Everybody homes in on Abraham, the first in that chosen line, as having one declared-by-God son, Isaac, with his elderly wife Sarah. But in the actual account of Abraham's life, he has children with *three* different women: Isaac from Sarah, Ishmael from Hagar, and then after Sarah dies, he takes a wife or a concubine named Keturah and has six more sons. Eight sons with three women.
What's even more interesting in that whole series of tales is, you've already got a culture that favors male primogeniture for inheritance, but you've got this mysterious *other* thing: the blessing. Jacob dupes his brother Esau out of, not just his birthright (material inheritance), but *also* out of their father's *blessing*. It's their mother Rebecca who engineers this. They're selecting for something else here. Not brute strength, possibly intelligence or self-awareness, maybe even Noetic perception: the capacity to hear God speak.
If you wanted to restate one of Vladimir Lossky's assertions in the most vulgar, oversimplified way: the story of Genesis and the rest of the OT, is the story of God conducting a selective breeding program to finally achieve the pinnacle of humanity: a woman pure enough to bear the incarnate God without being consumed. The burning bush: The Theotokos.
Hairy temper-prone beasts like Esau had to be weeded out. By his own mother!
Jacob himself has a passel of offspring, with at least four women: Rachel, Leah, and two of their slave girls. And yet, over and over we see God's favor following the offspring of women who are barely fertile: Sarai, who has only one child at an advanced age, Rebecca, who has only the one set of twins, Rachel, who has Joseph, and then after begging God for more children for years and years, dies giving birth to Benjamin. There's a lot of this in the genealogies of Christ. The Theotokos is herself the only child of older parents.
If there's something being selected for there, it's definitely not female fertility!
Yeah, the world certainly isn't 6,000 years old, but the world as we know it may be, and that is what myths are about, what we know. There is very strong evidence that the Holocene transition was truly the beginning of a new age, genetically as well as technologically. Many simply didn't make it. Even if one thinks that the bottleneck isn't selection... most male lineages really didn't make it, and that can be described as world-ending.
>"the capacity to hear God speak"
What do you make of the Fall though. Seems that people started out with the ability and then lost it. There is also the strange line in Genesis about the Sons of God taking the Daughters of Man as wife. I'm open to that being a memory of when men were significantly more schizophrenic, and that we have been evolving to hear god less, so to speak.
>God conducting a selective breeding program
Dune to an even greater extent. I'm struck by how closely it follows the Snake Cult I laid out. Women have rituals and do a breeding program until there is a man who can survive them. The rituals even involve psychedelic wyrm juice.
Yeah, I don't think a *strict* noetic perception-selection perfectly fits the storyline. But-- what makes Jacob better than Esau? Esau's hairy (why, why is this important?? It's brought up more than once), he's prone to outbursts of temper, and he's not a long-term thinker. Jacob is kind of a weasel. He tricks his brother out of all his inheritance, and then has to flee to his kinsman for many years before he can risk coming back home, rightly afraid Esau will murder him. Esau cannot be accused of self-awareness here. So: intelligence? Self-awareness? The hair thing though: are we selecting people who are *less* animal-like?
Tangent: is this some kind of fragmentary cultural memory of contact with other hominids?
There's also this weird side-plot, where Jacob marries his cousins (inbreeding = selection), and this is good, but Esau marries a couple of unrelated local women, who are a terrible grief to his mother (yay nasty MIL dynamic preserved in the oldest myths!), and then finally marries a slightly more acceptable third wife... who is the daughter of Ishmael, and therefore a cousin.
But... receptiveness to divine messages really does seem to be a part of it. Right down the line, you see, over and over, that God talks to these people. He talks to Abraham, talks to Jacob (wrestles with him!), talks to Moses, talks to David... they're not favored by God because of their wonderful ethics or righteousness. They do some really terrible things. It's not until way down the line that you start getting people who are both righteous *and* hearken to the voice of God. Mary comes from a whole family of such people. Her kinswoman Elisabeth, on meeting her, is possessed by the spirit of God and prophesies. Elisabeth's husband Zachariah gets told his wife will have a son and he's to name him John, and he *argues with God* about this and gets struck mute until John is born. I would not, from that, jump to the conclusion that the people in this genetic line were getting less noetically perceptive over time. They do seem to become better people, though.
That doesn't mean the population at large wasn't selecting for less perception. Maybe it's what makes the story of God's special people Israel different: preserving that thread, while simultaneously adapting to changing conditions. One of the huge themes of the Bible is that these are God's people, *brought out* of the mass of humanity, blessed, forbidden to intermarry with the surrounding peoples... kept separate.
Dune, of course, is a cynical ripoff of the messiah story. I don't think it has anything useful to say here.
There's also a curious phenomenon *that repeats* in those stories, where eg when Abraham and Sarai are traveling in a foreign land, she pretends to be his sister (she actually is his half-sister, so this is a half-truth), and *not* his wife, so that the inhabitants of the land will not kill Abraham in order to take his beautiful wife. They *do* take Sarai, and then there are some regrets all around because God rains bad fortune on them or somesuch, and then they're upset about the lie.
This tale repeats, almost exactly, with Isaac and Rebecca.
So, what exactly is going on in these accounts?
Was this literally just what happened in the ancient world? If you traveled to another land in search of food, during a famine, you had to give up your womenfolk to the local strongman... and if you were married, they'd kill you and take your wife?
...that does sound rather like the "most violent man gets all the women" thing. But it's interesting that in the stories of God choosing his lineage, that practice is avoided, just barely, *more than once*.
I think that a bottleneck with consciousness is consistent with local strongmen (the first to forethought) to be extremely polygamous. Take Herakles, who is an Adam figure (the Scythians said he was their progenitor, the first man), who beds 50 Amazonians.
I'm interested in connected the Y chromosome bottleneck to EToC for the same reason I went after the diffusion of pronouns: it's good to make predictions that can falsify or limit a model. Y chromosome selection in the last 10,000 years is the most extreme form of EToC; I agree that it doesn't necessarily have to be part of EToC
As for a change in temperature, it doesn't make sense because it applies to entire continents. The difference in temperature is greater between North Africa and Siberia than it is between the Ice Age and now. So if it had to do with end of ice age climate change, why aren't the effects more regional, or present when humans expanded from Africa to Siberia?
One of the hypothesis for agriculture being invented a bunch of times in the last 10,000 years is that the climate was relatively stable. Historically speaking, during the Neolithic, it was changing *less* than usual.
Selection wouldn't mean mass graves. Could have dramatic reduction in genetic diversity with just a 1% increased survival of those with Y chromosomes conducive to self-awareness, recursive language, or whatever else became important in the Neolithic. No need for mass violence. That is, however, what other models use to explain the bottleneck.
"Incan men were not in the process of becoming conscious when Pizarro encountered them (whatever Jaynes says contrary)."
So interestingly, the Inca's had this belief that when the emperor died his mummy would still be wheeled out as an immortal (but not unable to speak) Lord. And it would be a female partner that would act as interpreter.
Similarly: "As the empire expanded, the role of the most powerful Inca mummies—known as illapa—grew beyond simple ancestor worship. When an Inca emperor died, his successor inherited his power, but not his worldly belongings; these were understood to follow the dead emperor into the afterlife. His family members would then tend to his mummified body, ensuring he was kept in luxurious style even in death.
When the illapa were taken out and assembled together, the new Inca emperor would sometimes show his own power by taking his place and sitting stone-like among his dead predecessors. But these powerful Inca mummies weren’t just male, Heaney emphasizes; instead, *they were often preserved in male-female pairs. In order to claim power, a would-be emperor had to marry a prominent Inca woman, sometimes even a relative*
“There was a duality in both Inca and Andean understanding of the universe—that it is male and female together, with their respective powers and abilities, that creates the empire,” he says."
That is a remarkably similar to Egyptian treatment of the pharaoh, thanks for sharing.
In the previous post I argued that Bicameral Breakdown (or The Fall) also required genetic change, or in other words it would not have been 0-1 in a single generation. One of my primary issues with Jaynes is he argues there was 0 introspection as late as Egyptians building pyramids. I think introspection led to recursion, which in turn led to our flexible thinking. I think it's likely we got to flexible thinking and started building megaliths before shedding parts of the bicameral mindset. I mean, many people still do hear voices (especially if you include childhood imaginary friends); we still have the imprint.
I'm on board with the idea of women leading the ritual shift into consciousness, but I have doubts it required Y chromosome changes to enact. I think what we're seeing here is effect, not causal.
The null hypothesis I see is that the Holocene involved warfare much like historical warfare, which tended to kill men disproportionately and reward their survivors with outsized opportunities to breed, but moreso because we were very new at it. The 6kya massive swing could still be triggered by a quasi-memetic shift to consciousness, as your snake theory posits. The tribes achieving consciousness would then typically win in violent warfare with non-conscious tribes, slaying their men and capturing their women.
That 6kya peak is certainly still dramatic evidence of a incredibly sharp change in a short period of time, which fits the young consciousness hypothesis from your snake theory well. Also fits the creationist narrative that the world started 6kya disturbingly tightly, in a way that implies maybe there's some poetic truth to that, too.
From a timing perspective, 6kya may work better as an effect, tbh. One problem with the effect model is that the bottleneck is so consistent, and my understanding of social organization is that it is quite path dependent. It seems there would be some regions that would avoid the bottleneck if it were due to changing social organization because there were so many different social organizations. Did they all include massive (and fairly short-lived) sex-linked reproductive differences? Looking forward to more papers on the subject, which I assume will come at some point. Was there a mid-Holocene bottleneck in Australia as well? (There is a somewhat related It would be interesting to correlate that with the spread of snake worship and the Pama-Nyungen language family, which can both be dated fairly well. If there is a bottleneck, does come before or after those cultural changes?
Also, wait for the piece on the Y chromosome and theory of mind :) A few lines of evidence says the two are related
So yeah, lots of uncertainty, and I hope other people (like yourself) provide input on whether this makes more sense as a cause or effect.
Looking forward to it. Whether or not I fully agree with the conclusions, this is some fascinating thought-provoking stuff. Keep at it!
Reading this article had me wonder if the Y Chromosome selection bottleneck could be explained by the idea of "proactive aggression" discussed in The Goodness Paradox. Could be be an interesting synthesis. Perhaps it played out like the snake-venom cult gradually indoctrinates men. The ones who navigate the ritual and become more prosocial then band together and commit acts of planned murder against the more violent anti-social men. Perhaps they even use threats of violence to force the ritual on men, and the ones who fail to develop the "analogue I" as a result are then murdered. Kinda dovetails with the spread of the male rite-of-passage idea too. All wild speculation. Any thoughts?
I haven't read The Goodness Paradox (though it looks great), but Antonio Benítez-Burraco has a 4-stage model of self-domestication (https://www.sciencedirect.com/science/article/abs/pii/S0271530920300288), where proactive aggression only comes into play in the last 10,000 years. This fits really well with both the Y chromosome stuff, as well as the Snake Cult timeline. Essentially men come into their own, and their first order of business is to stage a coup to depose women, and kill any weak men. Myths reflect this as well. The Greeks have their 4 ages of man. The Golden Age is essentially Eden. No aging or death, and living at one with nature. Agriculture is introduced in the Silver Age. The men are idiots, dependent on women. Then comes the Bronze Age, which would correspond with organized violence. Then comes the Iron Age, with more of the same (but with better technology). Or take the Bible, the first generation after Adam and Eve you get Cain and Abel: the invention of murder. If you haven't read my two most recent posts on diffusion, which include a bunch of other examples of men staging a coup against women. On the right, you see that transition glorified to this day: https://twitter.com/NapoleonBonabot/status/1568753353748004866
Relating it to the Y chromosome, it's weird that the bottleneck is so early. Before the invention of the horse-raider pastoralist lifestyle, or bronze weapons. Before the spread of Proto-Indo-Europeans. These people came AFTER the bottleneck, which makes it so surprising. But maybe that is just the widescale stuff. Maybe violence increased locally (and everywhere) 10-5kya as men became better at planning for the future.
>Perhaps they even use threats of violence to force the ritual on men, and the ones who fail to develop the "analogue I" as a result are then murdered.
At least genetically, this isn't required. Those without an analogue I could just be 5% worse at gathering food and securing mates which would be a huge disadvantage over several generations.
The 6000 years number here is fascinating, as it's the number you get when you count up the years in the Old Testament genealogies. We laugh at Biblical literalists for saying that "the world is only 6000 years old"
And yet. That 6000 years does appear to be quite significant in the history of humanity.
And right there, still in Genesis but after the creation story, you have a whole host of stories about... men, chosen by God, reproducing with multiple women, and heading up semi-nomadic "households" of hundreds, or even thousands of people once you count up all the menservants and maidservants and associated relatives. Everybody homes in on Abraham, the first in that chosen line, as having one declared-by-God son, Isaac, with his elderly wife Sarah. But in the actual account of Abraham's life, he has children with *three* different women: Isaac from Sarah, Ishmael from Hagar, and then after Sarah dies, he takes a wife or a concubine named Keturah and has six more sons. Eight sons with three women.
What's even more interesting in that whole series of tales is, you've already got a culture that favors male primogeniture for inheritance, but you've got this mysterious *other* thing: the blessing. Jacob dupes his brother Esau out of, not just his birthright (material inheritance), but *also* out of their father's *blessing*. It's their mother Rebecca who engineers this. They're selecting for something else here. Not brute strength, possibly intelligence or self-awareness, maybe even Noetic perception: the capacity to hear God speak.
If you wanted to restate one of Vladimir Lossky's assertions in the most vulgar, oversimplified way: the story of Genesis and the rest of the OT, is the story of God conducting a selective breeding program to finally achieve the pinnacle of humanity: a woman pure enough to bear the incarnate God without being consumed. The burning bush: The Theotokos.
Hairy temper-prone beasts like Esau had to be weeded out. By his own mother!
Jacob himself has a passel of offspring, with at least four women: Rachel, Leah, and two of their slave girls. And yet, over and over we see God's favor following the offspring of women who are barely fertile: Sarai, who has only one child at an advanced age, Rebecca, who has only the one set of twins, Rachel, who has Joseph, and then after begging God for more children for years and years, dies giving birth to Benjamin. There's a lot of this in the genealogies of Christ. The Theotokos is herself the only child of older parents.
If there's something being selected for there, it's definitely not female fertility!
Yeah, the world certainly isn't 6,000 years old, but the world as we know it may be, and that is what myths are about, what we know. There is very strong evidence that the Holocene transition was truly the beginning of a new age, genetically as well as technologically. Many simply didn't make it. Even if one thinks that the bottleneck isn't selection... most male lineages really didn't make it, and that can be described as world-ending.
>"the capacity to hear God speak"
What do you make of the Fall though. Seems that people started out with the ability and then lost it. There is also the strange line in Genesis about the Sons of God taking the Daughters of Man as wife. I'm open to that being a memory of when men were significantly more schizophrenic, and that we have been evolving to hear god less, so to speak.
>God conducting a selective breeding program
Dune to an even greater extent. I'm struck by how closely it follows the Snake Cult I laid out. Women have rituals and do a breeding program until there is a man who can survive them. The rituals even involve psychedelic wyrm juice.
Yeah, I don't think a *strict* noetic perception-selection perfectly fits the storyline. But-- what makes Jacob better than Esau? Esau's hairy (why, why is this important?? It's brought up more than once), he's prone to outbursts of temper, and he's not a long-term thinker. Jacob is kind of a weasel. He tricks his brother out of all his inheritance, and then has to flee to his kinsman for many years before he can risk coming back home, rightly afraid Esau will murder him. Esau cannot be accused of self-awareness here. So: intelligence? Self-awareness? The hair thing though: are we selecting people who are *less* animal-like?
Tangent: is this some kind of fragmentary cultural memory of contact with other hominids?
There's also this weird side-plot, where Jacob marries his cousins (inbreeding = selection), and this is good, but Esau marries a couple of unrelated local women, who are a terrible grief to his mother (yay nasty MIL dynamic preserved in the oldest myths!), and then finally marries a slightly more acceptable third wife... who is the daughter of Ishmael, and therefore a cousin.
But... receptiveness to divine messages really does seem to be a part of it. Right down the line, you see, over and over, that God talks to these people. He talks to Abraham, talks to Jacob (wrestles with him!), talks to Moses, talks to David... they're not favored by God because of their wonderful ethics or righteousness. They do some really terrible things. It's not until way down the line that you start getting people who are both righteous *and* hearken to the voice of God. Mary comes from a whole family of such people. Her kinswoman Elisabeth, on meeting her, is possessed by the spirit of God and prophesies. Elisabeth's husband Zachariah gets told his wife will have a son and he's to name him John, and he *argues with God* about this and gets struck mute until John is born. I would not, from that, jump to the conclusion that the people in this genetic line were getting less noetically perceptive over time. They do seem to become better people, though.
That doesn't mean the population at large wasn't selecting for less perception. Maybe it's what makes the story of God's special people Israel different: preserving that thread, while simultaneously adapting to changing conditions. One of the huge themes of the Bible is that these are God's people, *brought out* of the mass of humanity, blessed, forbidden to intermarry with the surrounding peoples... kept separate.
Dune, of course, is a cynical ripoff of the messiah story. I don't think it has anything useful to say here.
An afterthought:
There's also a curious phenomenon *that repeats* in those stories, where eg when Abraham and Sarai are traveling in a foreign land, she pretends to be his sister (she actually is his half-sister, so this is a half-truth), and *not* his wife, so that the inhabitants of the land will not kill Abraham in order to take his beautiful wife. They *do* take Sarai, and then there are some regrets all around because God rains bad fortune on them or somesuch, and then they're upset about the lie.
This tale repeats, almost exactly, with Isaac and Rebecca.
So, what exactly is going on in these accounts?
Was this literally just what happened in the ancient world? If you traveled to another land in search of food, during a famine, you had to give up your womenfolk to the local strongman... and if you were married, they'd kill you and take your wife?
...that does sound rather like the "most violent man gets all the women" thing. But it's interesting that in the stories of God choosing his lineage, that practice is avoided, just barely, *more than once*.
I think that a bottleneck with consciousness is consistent with local strongmen (the first to forethought) to be extremely polygamous. Take Herakles, who is an Adam figure (the Scythians said he was their progenitor, the first man), who beds 50 Amazonians.
I'm interested in connected the Y chromosome bottleneck to EToC for the same reason I went after the diffusion of pronouns: it's good to make predictions that can falsify or limit a model. Y chromosome selection in the last 10,000 years is the most extreme form of EToC; I agree that it doesn't necessarily have to be part of EToC
As for a change in temperature, it doesn't make sense because it applies to entire continents. The difference in temperature is greater between North Africa and Siberia than it is between the Ice Age and now. So if it had to do with end of ice age climate change, why aren't the effects more regional, or present when humans expanded from Africa to Siberia?
One of the hypothesis for agriculture being invented a bunch of times in the last 10,000 years is that the climate was relatively stable. Historically speaking, during the Neolithic, it was changing *less* than usual.
Selection wouldn't mean mass graves. Could have dramatic reduction in genetic diversity with just a 1% increased survival of those with Y chromosomes conducive to self-awareness, recursive language, or whatever else became important in the Neolithic. No need for mass violence. That is, however, what other models use to explain the bottleneck.