Simple proposal for Great Filter: when human intelligence evolved, it also had negative effects: bigger infant head → more dangerous, more painful childbirth, also human children are prematurely born compared to other animals, develop slow, require a lot of care. Hence human intelligence directly caused high maternal risk and high maternal investment, and could it be the cause of the runaway intelligence arms race inside the species? Making it more important for men to compete for women since you could easier lose your mate during birth or she is too tied up in maternal care for another one and so on, so more intelligence means more maternal care / risk means more competition means more use for intelligence and more chance of intelligent genes spreading etc. Hominid women running a risk gamble when hooking up with smart men—more chance you die during labor, but if you win, your son may spread your genes effectively.
My point is: perhaps without intelligence having drawbacks i.e. without having to push that big infant brain through a vagina, there is no runaway arms race of intelligence. A species that does not have this danger of intelligence does have intelligence leading to more sexual competition means it does not develop further intelligence.
Dinosaurs had bigger heads than humans. Even bears can have bigger heads than humans. It seems unlikely that head size is the limiting factor for a Great filter. There seems also no reason why a brain has to be located in the head and not in the torso.
A thought occurred to me that it’s more likely that a brain initially develops near major sensory input channels. Dinosaurs did have secondary brains thought but their function is also proximity based (ie reflex time gets too long for just one brain location in that sized body).
I could guestimate that the primary constraint is eye to brain distance and the other senses are near because of lessened wiring and easier time integrating the information the nearer to a pointlike approximation one gets. That is if the information itself doesn’t require a spesific placing.
Dinosaurs did not give birth and bears don’t have a particularly big head to body ratio—the idea here is specifically that childbirth is hard and dangerous, not simply running around with a big head would be so.
As for the brain, I think having eyes close to mouth is useful to basically every animal, being able to hit food or enemies with the mouth accurately, and eyes came from brains.
There no reason why species on other plants who are intelligent have to give birth. Yes, humans do but to be a great filter it would have to be true more universally.
Precisely. I am trying to say that giving birth means intelligence has a downside, and that could have paradoxically lead to intelligence getting more widespread due to the downside meaning the need for more intense competition.
This is not a possible explanation for the Great Filter.
Hence human intelligence directly caused high maternal risk and high maternal investment, and could it be the cause of the runaway intelligence arms race inside the species?
more chance of intelligent genes spreading
perhaps without intelligence having drawbacks i.e. without having to push that big infant brain through a vagina, there is no runaway arms race of intelligence.
You have this exactly backwards. If intelligence has negative side effects, this means you would expect less intelligence, for basic differential equation reasons. If large-headed women are more likely to give birth to large-headed babies (which die or kill them because of birthing difficulties), then small-headed babies are evolutionarily favored over large-headed babies. (This is why human babies are born so prematurely; that’s the trick that lets you have a big adult head and still survive childbirth. If this trick were not possible, we probably would not be as intelligent as we are.) The selective advantage of intelligence goes down—instead of producing 1.05 times as many children, a smarter person might produce only 1.02 times as many children. In the first case, we obviously get intelligent life faster.
A possible explanation for the Great Filter is that there are planets where smarter animals only produce 0.98 as many children—and thus there are no animals smart enough to significantly alter their environment or make it to space.
But that would need to be a geographic / environmental claim about the planet, and it would need to hold everywhere. On Earth, it seems like one narrow location produced intelligent enough animals. From the unique geographical features of that location, one might suspect that the Cognitive Revolution was a significant filter—but, as with most filter-related things, this is hard to estimate. Was that location only slightly better than other locations, such that other places would have allowed evolution of civilization-creating animals a bit later in geological time (which is immensely later in historical time)? Are locations like that rare on random planets, or could Earth actually have surprisingly few locations that allow the evolution of civilization-creating animals, and that doesn’t matter because you only need one?
The point I am trying to make is what if it is a bit more complicated than negatives or positives. Imagine any trait that increases your chance to find a mate but decreases the chance your mate survives into having another kid. A possible parallel would be having spikes on the back that look very sexy but do awful things to the mothers insides during birth.
The important thing is not to calculate if it is a net positive or net negative, but rather what happens? You are a male animal with such a mutation, such as they sexy spiky back, you knock up six females, four give birth to kids with the same spiky back, half them male, other two mothers die during birth. Now your pack / dating pool has a gender imbalance but no matter—you are still attractive, you are the guy with the sexy spiky back so go on outcompeting other males. You end up with more kids than other males, from more females, some of them who died during giving birth. The mole mothers your spiky-back kids kill, the more intense the competition for females becomes, but that is fine for you, you are the attractive guy with the spiky back. Your sons continue the same. See how the spiky back could be a runaway feature? The guy with even bigger spikes has kids who kill even more mothers but still he gets more mates. And so on. The mother-killing aspect of spikes contributes to more intense sexual competition, in which the sexy nature of said spikes works more efficiently.
Does that make sense?
Of course in this case we would probably see females develop spike-resistant insides. Aaaaand maybe that is where the nerds-are-creepy meme came from :-DDD (disregard this last part, just a joke)
See how the spiky back could be a runaway feature?
Until some other species takes over your ecological niche.
I seem to remember hearing about a gene in mice that would ensure that it always gets copied into the offspring if present (leading to rapid growth in the gene pool) but had the unfortunate effect that homozygotes are sterile.* Under random mating, you can calculate the population levels at which the gene frequency is stable,** but under non-random mating, a group where 50% of the parents have this gene could totally annihilate itself (as it would be possible to ensure that every child in the next generation is a carrier, and thus the generation after that will be totally sterile).
But consider this gene without a drawback: if one parent has at least one copy, then the child will, and if both parents each have at least one copy, then the children will have two copies, but the gene is fitness neutral in all permutations. Then we can calculate how many generations it will take for the gene to reach fixation, given random mating.
*Suppose the mechanism was that it would break the other chromosome. This means you’re the only option—unless the other chromosome had the exact same idea, and now there aren’t any functional chromosomes.
**As it turns out, the heterozygote advantage and homozygote disadvantage are both so strong that the only stable levels are 0 and 1. If you drop the heterozygote advantage to something more likely, like a heterozygote having a 55% chance of passing it on to a child, then you get a more interesting answer.
The important thing is not to calculate if it is a net positive or net negative, but rather what happens?
This is a fundamentally mistaken way of looking at evolution. The only important thing is whether it is a selective advantage or disadvantage! Populations roll down the selection gradient, and the assumption that population sizes are the same from year to year is a feature of mathematical models, not reality.
You are good at lowering the probability I give to this hypothesis, and I thank you for that, but it is stil not 0.
First about the second point—my point is more like selective advantages do not mean the fitness of the group, or even the fitness of the parents to be maximized, but solely that of the propagation of the gene in descendants. So, from that angle, a gene killing some parents but still making an animal more sexually succesful can still confer a selective advantage. Depending on the ratio of this two of course. My point is precisely that on the whole it can be hugely destructive for the group.
Of course, and now back to your first point, this weakens the group. This would happen with a spiky back but here is where my metaphor stops being useful. It is intelligence. It begins with the ecological dominance—social competition model. The group was all right before intelligence. Surely a weaker but smarter group can compensate for the group level weakening?
My point is pulling an Occam here. Our best hypothesis is that an unknown factor X launched a runaway IQ based competition inside the hominid species. What if factor X is intelligence itself, basically it killing mothers, thus making the sexual competition of males more vivid? Surely such a reduction of factors is worth pondering? And as a side-effect, whatever group level weakness it would cause wrt other species, they would resolve that because of this intelligence, which according to EDSC was not formerly necessary, but at this point became useful for keeping other species at bay?
And if this all at least sounds not-impossible enough to invest resources into pondering or testing, it could generate a Great Filter hypothesis, namely that intelligence needs to be advantageous for the offspring but at some level harmful to parents (dangerous birth, maternal care) to launch such an arms race, it would basically predict that any alien species without the special difficulties of Earth mammals and their problems of pushing a big head through a vagina would not have this arms race.
I’m not sure, but I think your model assumes intelligence is mostly (entirely?) useful for males. Actually, females also have a complex bunch of roles, since they need to take care of themselves and their children and make alliances to get help from both males and females.
You might be interested in Mother Nature by Sarah Hrdy.
Actually it is notable that women and men have such similar intelligence. Women and men are quite easy to distinguish physically in a variety of ways, but there is probably way ( I don’t believe one has been discovered) to reliably distinguish a woman from a man based purely on how their minds work. Minds are a lot more like livers, kidneys and eyeballs (effectively identical in each sex) than like body shape, genitals or hair distribution. I haven’t heard this said before, but this would seem to suggest that minds are NOT primarily to get us laid, that they do not evolve from sexual selection, but rather arise from natural selection (survival of the fittest).
Of course, but “useful” is different from “increases reproductive fitness”, and the basic assumption is that the selective pressure of intelligence came from competition inside the species. It is sort of difficult for me to imagine what kind of competition can happen between ancestral females to increase reproductive fitness (and not simply to have a better life, these two are different things). Let’s assume for now it is not for higher quantity of children, nor for higher quality sperm thus the genetic quality of children (it does not really require much of a competition, it is cheap), what else is left? Largely the upbringing and life of those children. Am I on the right track there that it is more about what happens to the children once they are born? Are the get resources invested by the genetic father, by the tribe, by the chieftain, by the queen, by whoever, what status they get and so on? As this sounds vaguely possible for I just don’t know to visualize it. (Sort of Cersei Lannister situation, push children into high status positions?)
I have to check on this, but I think competition can go all the way to low status female’s children being killed. Even if it doesn’t go that far, less access to food/more stressed mothers mean that the children of a low status mother are more likely to be less capable adults.
Yep, higher-status female apes sometimes kill lower-status female apes’ babies. One of the reasons why female cliques are so important even when females typically do not use them to kill other adult females.
In humans, you see how some women have the instinct to touch other women’s babies, and how those mothers are usually scared like shit. Touching other womens’ babies is a female status move. -- That’s because as a female ape you couldn’t realistically defend yourself and your baby from a group of female apes; you would be completely in their mercy. So another female ape touching your baby reminds you of your relative positions in the tribe.
Yes, altruism can pretty easily be part of the picture. Kin selection and all that. Or, we can simply say that if a gene makes a male mate with 2x as many females but also makes 20% of the females die with the child dying too, it still propagates. And it still increases sexual competition by unbalancing gender ratios thus if it was in itself a sexual competition advantage, now it is on the relative level stronger.
Or, we can simply say that if a gene makes a male mate with 2x as many females but also makes 20% of the females die with the child dying too, it still propagates.
Propagates for a very short while. If you initial population was stable (which means that each female had, on the average, two children which survive until they breed), introducing a mutation which kills off 20% of the females during birth is likely to lead to this population dying out pretty quickly. Yes, you’ll have lots of males around, but they can’t give birth.
Imagine any trait that increases your chance to find a mate but decreases the chance your mate survives into having another kid.
This is practically the definition of a trait that is chosen through sexual selection rather than survival of the fittest. Believe it or not, those big boobs are net negatives at helping women survive, but they sure attract a lot of male attention. The antlers on deer and moose, the tail on a peacock, these all hurt the survival chances of the creatures carrying them, but females dig them so whaddyagonnado. Riding motorcycles, driving fast sports cars, and spending all your money on diamonds and hotel suites are none to helpful at surviving, but great ways to get a certain kind of laid.
“more intelligence means … means more competition means more use for intelligence”
Seems to me there is always enough competition in the nature. It’s not like without difficult childbirth our species would have become completely lazy and its evolution would stop.
Sorry, this is how I parsed your argument. I am not sure what exactly are you saying is the bad thing that could happen to species that would be similar to humans, only would have no problem giving childbirth to children with huge heads.
My point is more like the runaway arms race of intelligence is pretty tricky to figure out. Sure, one thing is clear—if it only happened inside one species, the selective pressure was inside the species: not adaptation to the environment (that would predict a world where we have 70 IQ chimp servants) but something inside the species, and given that it has to be a pressure, a do-or-not-reproduce kind of pretty tough stuff, and being nice and empathic with each other is not a pressure, it must be some kind of a competition. So far it is not a new idea, but a rehearsal of the most popular hypotheses.
Now, my point is simply you got a factor inside the hominid species, a factor X, which leads to the runaway arms race of intelligence, an Y. My point is, what if they are the same?
It is Occam and Solomonoff at work here. Usually we assume two variables, an unknown factor X launched a runaway arms race of intelligence, Y competition inside the human-hominid species.
So why not ponder the possibility that X = Y ? What if intelligent offspring killing / tying up mothers due to big heads led to males more intensely IQ-compete for the women who were not dead nor tied up with a child or three?
Interesting.
1 compared to what animals?
2 what does your theory predict regarding infanticide/cannibalism in intelligent species?
3 at what level of reproduction effort would childbearing remain viable, given a lifespan of twenty max and high children mortality?
4 …genes effectively—in what way? Polygamy?
primates 2. no idea, must think about it, how did you localize it in hypothesis space i.e. why does it sound interesting at all? 3. no idea, this is really where I lack the training, but will think about it, but it is probably a complex math problem including ever longer gestation periods and all that 4. yes clearly
2 well, if a trait has some visible manifestation, what prevents the offspring from being eaten before reaching reproductive age? Competition still works. 3. I don’t know, too. Just thought someone might give it their best shot. 4. If only the sons can use it effectively, then does it not mean that daughters having this gene would be outcompeted, dying in childbirth always (if it’s a dominant allele) or a fixed % of times (if it’s not), and so the allele will just reach some equilibrium in the population? And the ‘intelligent’ males will seek to have children from ‘not-intelligent’ females, since some offspring is strictly better than zero? (That’s probably what Vaniver said.)
Simple proposal for Great Filter: when human intelligence evolved, it also had negative effects: bigger infant head → more dangerous, more painful childbirth, also human children are prematurely born compared to other animals, develop slow, require a lot of care. Hence human intelligence directly caused high maternal risk and high maternal investment, and could it be the cause of the runaway intelligence arms race inside the species? Making it more important for men to compete for women since you could easier lose your mate during birth or she is too tied up in maternal care for another one and so on, so more intelligence means more maternal care / risk means more competition means more use for intelligence and more chance of intelligent genes spreading etc. Hominid women running a risk gamble when hooking up with smart men—more chance you die during labor, but if you win, your son may spread your genes effectively.
My point is: perhaps without intelligence having drawbacks i.e. without having to push that big infant brain through a vagina, there is no runaway arms race of intelligence. A species that does not have this danger of intelligence does have intelligence leading to more sexual competition means it does not develop further intelligence.
Was this considered?
Dinosaurs had bigger heads than humans. Even bears can have bigger heads than humans. It seems unlikely that head size is the limiting factor for a Great filter. There seems also no reason why a brain has to be located in the head and not in the torso.
A thought occurred to me that it’s more likely that a brain initially develops near major sensory input channels. Dinosaurs did have secondary brains thought but their function is also proximity based (ie reflex time gets too long for just one brain location in that sized body).
I could guestimate that the primary constraint is eye to brain distance and the other senses are near because of lessened wiring and easier time integrating the information the nearer to a pointlike approximation one gets. That is if the information itself doesn’t require a spesific placing.
Dinosaurs did not give birth and bears don’t have a particularly big head to body ratio—the idea here is specifically that childbirth is hard and dangerous, not simply running around with a big head would be so.
As for the brain, I think having eyes close to mouth is useful to basically every animal, being able to hit food or enemies with the mouth accurately, and eyes came from brains.
There no reason why species on other plants who are intelligent have to give birth. Yes, humans do but to be a great filter it would have to be true more universally.
Precisely. I am trying to say that giving birth means intelligence has a downside, and that could have paradoxically lead to intelligence getting more widespread due to the downside meaning the need for more intense competition.
This is not a possible explanation for the Great Filter.
You have this exactly backwards. If intelligence has negative side effects, this means you would expect less intelligence, for basic differential equation reasons. If large-headed women are more likely to give birth to large-headed babies (which die or kill them because of birthing difficulties), then small-headed babies are evolutionarily favored over large-headed babies. (This is why human babies are born so prematurely; that’s the trick that lets you have a big adult head and still survive childbirth. If this trick were not possible, we probably would not be as intelligent as we are.) The selective advantage of intelligence goes down—instead of producing 1.05 times as many children, a smarter person might produce only 1.02 times as many children. In the first case, we obviously get intelligent life faster.
A possible explanation for the Great Filter is that there are planets where smarter animals only produce 0.98 as many children—and thus there are no animals smart enough to significantly alter their environment or make it to space.
But that would need to be a geographic / environmental claim about the planet, and it would need to hold everywhere. On Earth, it seems like one narrow location produced intelligent enough animals. From the unique geographical features of that location, one might suspect that the Cognitive Revolution was a significant filter—but, as with most filter-related things, this is hard to estimate. Was that location only slightly better than other locations, such that other places would have allowed evolution of civilization-creating animals a bit later in geological time (which is immensely later in historical time)? Are locations like that rare on random planets, or could Earth actually have surprisingly few locations that allow the evolution of civilization-creating animals, and that doesn’t matter because you only need one?
The point I am trying to make is what if it is a bit more complicated than negatives or positives. Imagine any trait that increases your chance to find a mate but decreases the chance your mate survives into having another kid. A possible parallel would be having spikes on the back that look very sexy but do awful things to the mothers insides during birth.
The important thing is not to calculate if it is a net positive or net negative, but rather what happens? You are a male animal with such a mutation, such as they sexy spiky back, you knock up six females, four give birth to kids with the same spiky back, half them male, other two mothers die during birth. Now your pack / dating pool has a gender imbalance but no matter—you are still attractive, you are the guy with the sexy spiky back so go on outcompeting other males. You end up with more kids than other males, from more females, some of them who died during giving birth. The mole mothers your spiky-back kids kill, the more intense the competition for females becomes, but that is fine for you, you are the attractive guy with the spiky back. Your sons continue the same. See how the spiky back could be a runaway feature? The guy with even bigger spikes has kids who kill even more mothers but still he gets more mates. And so on. The mother-killing aspect of spikes contributes to more intense sexual competition, in which the sexy nature of said spikes works more efficiently.
Does that make sense?
Of course in this case we would probably see females develop spike-resistant insides. Aaaaand maybe that is where the nerds-are-creepy meme came from :-DDD (disregard this last part, just a joke)
Until some other species takes over your ecological niche.
I seem to remember hearing about a gene in mice that would ensure that it always gets copied into the offspring if present (leading to rapid growth in the gene pool) but had the unfortunate effect that homozygotes are sterile.* Under random mating, you can calculate the population levels at which the gene frequency is stable,** but under non-random mating, a group where 50% of the parents have this gene could totally annihilate itself (as it would be possible to ensure that every child in the next generation is a carrier, and thus the generation after that will be totally sterile).
But consider this gene without a drawback: if one parent has at least one copy, then the child will, and if both parents each have at least one copy, then the children will have two copies, but the gene is fitness neutral in all permutations. Then we can calculate how many generations it will take for the gene to reach fixation, given random mating.
*Suppose the mechanism was that it would break the other chromosome. This means you’re the only option—unless the other chromosome had the exact same idea, and now there aren’t any functional chromosomes.
**As it turns out, the heterozygote advantage and homozygote disadvantage are both so strong that the only stable levels are 0 and 1. If you drop the heterozygote advantage to something more likely, like a heterozygote having a 55% chance of passing it on to a child, then you get a more interesting answer.
This is a fundamentally mistaken way of looking at evolution. The only important thing is whether it is a selective advantage or disadvantage! Populations roll down the selection gradient, and the assumption that population sizes are the same from year to year is a feature of mathematical models, not reality.
You are good at lowering the probability I give to this hypothesis, and I thank you for that, but it is stil not 0.
First about the second point—my point is more like selective advantages do not mean the fitness of the group, or even the fitness of the parents to be maximized, but solely that of the propagation of the gene in descendants. So, from that angle, a gene killing some parents but still making an animal more sexually succesful can still confer a selective advantage. Depending on the ratio of this two of course. My point is precisely that on the whole it can be hugely destructive for the group.
Of course, and now back to your first point, this weakens the group. This would happen with a spiky back but here is where my metaphor stops being useful. It is intelligence. It begins with the ecological dominance—social competition model. The group was all right before intelligence. Surely a weaker but smarter group can compensate for the group level weakening?
My point is pulling an Occam here. Our best hypothesis is that an unknown factor X launched a runaway IQ based competition inside the hominid species. What if factor X is intelligence itself, basically it killing mothers, thus making the sexual competition of males more vivid? Surely such a reduction of factors is worth pondering? And as a side-effect, whatever group level weakness it would cause wrt other species, they would resolve that because of this intelligence, which according to EDSC was not formerly necessary, but at this point became useful for keeping other species at bay?
And if this all at least sounds not-impossible enough to invest resources into pondering or testing, it could generate a Great Filter hypothesis, namely that intelligence needs to be advantageous for the offspring but at some level harmful to parents (dangerous birth, maternal care) to launch such an arms race, it would basically predict that any alien species without the special difficulties of Earth mammals and their problems of pushing a big head through a vagina would not have this arms race.
I’m not sure, but I think your model assumes intelligence is mostly (entirely?) useful for males. Actually, females also have a complex bunch of roles, since they need to take care of themselves and their children and make alliances to get help from both males and females.
You might be interested in Mother Nature by Sarah Hrdy.
Actually it is notable that women and men have such similar intelligence. Women and men are quite easy to distinguish physically in a variety of ways, but there is probably way ( I don’t believe one has been discovered) to reliably distinguish a woman from a man based purely on how their minds work. Minds are a lot more like livers, kidneys and eyeballs (effectively identical in each sex) than like body shape, genitals or hair distribution. I haven’t heard this said before, but this would seem to suggest that minds are NOT primarily to get us laid, that they do not evolve from sexual selection, but rather arise from natural selection (survival of the fittest).
Of course, but “useful” is different from “increases reproductive fitness”, and the basic assumption is that the selective pressure of intelligence came from competition inside the species. It is sort of difficult for me to imagine what kind of competition can happen between ancestral females to increase reproductive fitness (and not simply to have a better life, these two are different things). Let’s assume for now it is not for higher quantity of children, nor for higher quality sperm thus the genetic quality of children (it does not really require much of a competition, it is cheap), what else is left? Largely the upbringing and life of those children. Am I on the right track there that it is more about what happens to the children once they are born? Are the get resources invested by the genetic father, by the tribe, by the chieftain, by the queen, by whoever, what status they get and so on? As this sounds vaguely possible for I just don’t know to visualize it. (Sort of Cersei Lannister situation, push children into high status positions?)
I have to check on this, but I think competition can go all the way to low status female’s children being killed. Even if it doesn’t go that far, less access to food/more stressed mothers mean that the children of a low status mother are more likely to be less capable adults.
Yep, higher-status female apes sometimes kill lower-status female apes’ babies. One of the reasons why female cliques are so important even when females typically do not use them to kill other adult females.
In humans, you see how some women have the instinct to touch other women’s babies, and how those mothers are usually scared like shit. Touching other womens’ babies is a female status move. -- That’s because as a female ape you couldn’t realistically defend yourself and your baby from a group of female apes; you would be completely in their mercy. So another female ape touching your baby reminds you of your relative positions in the tribe.
You really can’t have a kid survive its mother who died in childbirth if the kid is as helpless as here.
UNLESS you have not only competition, but altruism, too.
Yes, altruism can pretty easily be part of the picture. Kin selection and all that. Or, we can simply say that if a gene makes a male mate with 2x as many females but also makes 20% of the females die with the child dying too, it still propagates. And it still increases sexual competition by unbalancing gender ratios thus if it was in itself a sexual competition advantage, now it is on the relative level stronger.
Propagates for a very short while. If you initial population was stable (which means that each female had, on the average, two children which survive until they breed), introducing a mutation which kills off 20% of the females during birth is likely to lead to this population dying out pretty quickly. Yes, you’ll have lots of males around, but they can’t give birth.
This is practically the definition of a trait that is chosen through sexual selection rather than survival of the fittest. Believe it or not, those big boobs are net negatives at helping women survive, but they sure attract a lot of male attention. The antlers on deer and moose, the tail on a peacock, these all hurt the survival chances of the creatures carrying them, but females dig them so whaddyagonnado. Riding motorcycles, driving fast sports cars, and spending all your money on diamonds and hotel suites are none to helpful at surviving, but great ways to get a certain kind of laid.
What does this have to do with great filters?
“more intelligence means … means more competition means more use for intelligence”
Seems to me there is always enough competition in the nature. It’s not like without difficult childbirth our species would have become completely lazy and its evolution would stop.
Sorry, this is how I parsed your argument. I am not sure what exactly are you saying is the bad thing that could happen to species that would be similar to humans, only would have no problem giving childbirth to children with huge heads.
My point is more like the runaway arms race of intelligence is pretty tricky to figure out. Sure, one thing is clear—if it only happened inside one species, the selective pressure was inside the species: not adaptation to the environment (that would predict a world where we have 70 IQ chimp servants) but something inside the species, and given that it has to be a pressure, a do-or-not-reproduce kind of pretty tough stuff, and being nice and empathic with each other is not a pressure, it must be some kind of a competition. So far it is not a new idea, but a rehearsal of the most popular hypotheses.
Now, my point is simply you got a factor inside the hominid species, a factor X, which leads to the runaway arms race of intelligence, an Y. My point is, what if they are the same?
It is Occam and Solomonoff at work here. Usually we assume two variables, an unknown factor X launched a runaway arms race of intelligence, Y competition inside the human-hominid species.
So why not ponder the possibility that X = Y ? What if intelligent offspring killing / tying up mothers due to big heads led to males more intensely IQ-compete for the women who were not dead nor tied up with a child or three?
No. There no evidence that different lineages differ mainly in inside species selection.
Interesting. 1 compared to what animals? 2 what does your theory predict regarding infanticide/cannibalism in intelligent species? 3 at what level of reproduction effort would childbearing remain viable, given a lifespan of twenty max and high children mortality? 4 …genes effectively—in what way? Polygamy?
primates 2. no idea, must think about it, how did you localize it in hypothesis space i.e. why does it sound interesting at all? 3. no idea, this is really where I lack the training, but will think about it, but it is probably a complex math problem including ever longer gestation periods and all that 4. yes clearly
2 well, if a trait has some visible manifestation, what prevents the offspring from being eaten before reaching reproductive age? Competition still works. 3. I don’t know, too. Just thought someone might give it their best shot. 4. If only the sons can use it effectively, then does it not mean that daughters having this gene would be outcompeted, dying in childbirth always (if it’s a dominant allele) or a fixed % of times (if it’s not), and so the allele will just reach some equilibrium in the population? And the ‘intelligent’ males will seek to have children from ‘not-intelligent’ females, since some offspring is strictly better than zero? (That’s probably what Vaniver said.)