Some people believe that altruism has evolved through helping your relatives or through helping others to help you in return. I was thinking about it; on the surface the idea looks good—if you already have this system in place, it is easy to see how it benefits those involved—but that doesn’t explain how the system could have appeared in the first place. Anyone knows the standard answer?
Imagine that you are literally the first organism who by random mutation achieved a gene for “helping those who help you”. How specifically does this gene increase your fitness, if there is no one else to reciprocate?
Or imagine that you are literally the first organism who by random mutation achieved a gene for “helping your siblings”. How specifically does this gene increase your fitness, or the fitness of the gene itself, if your siblings do not have a copy of this gene?
In other words, it seems simple to explain how these kinds of altruism can work when they are already an established system, but it is more difficult to explain how it could work when it is new.
And this all is a huge simplification; for example, I doubt that “helping those who help you” could be achieved by a single mutation, since it involves multiple parts like “noticing that someone helped you”, “remembering the individual who helped you” and “helping the individual who helped you in the past”. Plus the problem of how to start this chain of mutual cooperation.
My guess is that… nygehvfz pbhyq unir ribyirq guebhtu frkhny fryrpgvba. Yrg’f rkcynva vg ol funevat sbbq jvgu bguref. Svefg, vaqvivqhnyf abgvpr jub vf tbbq ng tngurevat sbbq, naq gurl ribyir nggenpgvba gbjneqf tbbq sbbq pbyyrpgbef. Gung znxrf vzzrqvngr frafr orpnhfr vg vapernfrf fheiviny bs gur puvyqera, vs gurl nyfb trg gur trarf tbbq sbe tngurevat sbbq. Nsgre guvf nggenpgvba rkvfgf jvguva gur fcrpvrf, gur arkg fgrc pbhyq or fvtanyyvat: vs lbh unir fbzr rkgen sbbq lbh qba’g npghnyyl arrq, oevat vg naq ivfvoyl qebc vg arne bgure vaqvivqhnyf, fb gung bguref abgvpr lbh unir zber sbbq guna lbh pna rng. Ntnva, guvf znxrf vzzrqvngr frafr, orpnhfr vg znxrf lbh zber nggenpgvir. Abgvpr ubj arvgure “urycvat lbh eryngvirf” abe “urycvat gubfr jub uryc lbh” jnf arprffnel gb ribyir urycvat vaqvfpevzvangryl. Npghnyyl, gubfr pbhyq unir ribyirq yngre, nf shegure vzcebirzragf bs be nqqvgvbaf gb gur vaqvfpevzvangr urycvat.
My first thoughts reading your post are
1) You start WAY TOO LATE IN THE GAME. You are essentially talking about altruism as a conscious choice which means you are well into the higher mammals.
Virtually every sexually reproducing creature devotes resources to reproduction that could have been conserved for individual survival. As you move up in complexity, you have animals feeding their young and performing other services for them. As would be expected with all evolved cooperation, the energy and cost you expend raising your young produces a more survivable young and so is net cost effective at getting the next generation going, which is pretty much what spreads genes.
How big of a leap is it from a mama bird regurgitating food into her baby’s mouth to you helping your neighbor hunt for wooly mammoth?
If you were the first organism to get the gene to feed your babies or do whatever expanded their survivability, then obviously that is how that gene propagates, your babies have the gene.
As you get to the more complex forms of altruism of primates and humans, you also get to strong feedback mechanisms against non-cooperators and free-riders. The system may not be perfect but I think it allows a path from feeding babies or burying eggs in the sand to modern altruism in humans where no wierd “how do we start this” behaviors bump up to stop things.
If the immediate consequences of the genetic change in question aren’t terribly deleterious then that first organism may very well have offspring, even without it conferring any particular advantage. And now those offspring do have siblings who share the gene.
[EDITED to add: oops, saw Viliam’s comment in Recent Comments and replied to it without noticing others had also done so making the same point.]
If you have a gene that makes you help you siblings, your offspring are reasonably likely to get it too, which benefits their siblings (also your offspring).
I feel like this increases the amount of lucky coincidence needed. Not only I have to randomly get the right mutation, but I also need to have many children (surviving to the age when they can help each other) for reasons completely unrelated to having the mutation. Actually, the mutation may be a bit harmful in the second step, because I may give some of my resources to my siblings instead of my children.
Unfortunately, I am not familiar enough with mathematical models of evolution to evaluate how much this extra burden weighs against your hypothesis.
It seems to me that it doesn’t weigh against it very much. A genetic change that causes a not-too-big increase in altruistic behaviour towards likely kin is unlikely to hurt your chances of survival and reproduction a lot.
The first organism with the genetic change doesn’t need to be exceptionally well supplied with offspring or anything. (Unless this is an r-selected species for which surviving at all is exceptionally lucky; in that case, it needs to be about as lucky as the bearer of any other not-too-dramatic genetic change has to be.)
Maybe it doesn’t help when you’re the only one, but that doesn’t matter; your species is one that has multiple children, and the mutation was so small it occurred in multiple children? … And if that’s too high a complexity penalty, there could be an alternative: say it is a trait which got spread due to a resource boom in a population (the resource boom makes it likely for even disadvantaged mutations to survive), and then individuals with the trait managed to find each other and be more fit?
Doesn’t this suffer from a similar problem as group selection?
Imagine that the first mutant gets lucky and has 20 children; 10 of them inherited the “help your siblings” genes, and 10 of them did not. Does this give an advantage to the nice children over the non-nice ones? Well, only in the next generation… but then again, some children in the next generation will have the gene and some will not… and this feels like there is always an immediate disadvantage that is supposed to get balanced by an advantage in the next generation, except that the next generation also has an immediate disadvantage...
Uhm, let’s reverse it. Imagine that everyone has the “help your siblings” gene, in the most simple version that makes them take a given fraction of their resources and distribute it indiscriminately among all siblings. Now we get one mutant that does not have this gene. Then, this mutant has an advantage over their siblings; the siblings give resources to mutant, not receiving anything in return. Yeah, the mutant is causing some damage to the siblings, reducing the success of their genes. But we don’t care about genes in general here, only about the one specific “don’t help your siblings” allele; and this allele clearly benefits from being a free-rider. And then it reproduces with some else, who is still an altruist, and again 50% of the mutant’s children inherit the gene and get an advantage over their siblings.
So we get the group-selectionist situations where families of nice individuals prosper better than mixed families, but within each mixed family the non-nice individuals prosper better. This would need a mathematical model, but I suspect that unless the families are small, geographically isolated, and therefore heavily interbreeding, the nice genes would lose to the non-nice genes.
Your siblings is not a reproductively isolated population (hopefully=)). The relevant question is if the helpers are more or less fit relative to the population as a whole. So in your example, where the helpers give up something and get back less, the gene goes extinct.
But start instead of just zero-sum redistribution with something like that trust game where you send money through a slot and whatever amount you send the other guy gets triple. But it’s multiplayer and simultaneous. So the helpers give up some amount, let’s say x each and every family member gets three times what the average participant gave up. If half of the family members are helpers then everyone gets 3x/2. Which is more than x, so now the gene gives a fitness advantage.
Let’s ignore the details of genetic reproduction, and simply assume that if both parents have a trait, all children have it; if no parent has a trait, no children have it; and if one parent has it, exactly 50% of children have it. Let’s assume all families have the same size. (These are quite unrealistic assumptions to make calculation simple.)
Let’s suppose that being nice to all your siblings has a cost c (for example, if without reciprocation it would reduce your survival rate by 5%, then c = 0.05), and that being supported by all your siblings provides a benefit b (for example, if without helping any your siblings but being helped by all of them would increase your survival rate by 10%, then b = 0.10). We can assume 0 < c < b.
So, the current generation contains a fraction p of adult individuals who have the sibling-helping trait. Let’s assume they form pairs randomly (because the trait is so new they haven’t developed its detectors yet). On average, there will be p^2 “helper-helper” families, 2×p×(1-p) “helper-nonhelper” families, and (1-p)^2 “nonhelper-nonhelper” families.
In “nonhelper-nonhelper” families, children’s survival rate will be 1 (the default survival rate before the helper mutation appeared). In “helper-helper” families, children’s survival rate will be 1+b-c. In “helper-nonhelper” families, the 1⁄2 of helper children will have survival rate 1+b/2-c (they only get half the help, but pay the full cost), and the 1⁄2 of nonhelper children will have survival rate 1+b/2 (they get galf the help at no cost). Now all these values together have to be normalized to 1, to get the proportions in the next generation.
next generation helpers ratio = (p + pb/2 - pc/2 + ppb/2) / (p + pb/2 - pc/2 + ppb/2 + 1 - p + pb/2 - ppb/2) = (p + pb/2 - pc/2 + ppb/2) / (1 + pb—pc/2) … which for obscure mathematical reasons is always greater than p
Well, assuming that I made no mistake during the calculation, and that my simplified assumptions about heritability of traits didn’t diverge from reality too much (two reasons why I hesitated to do the calculations myself)… I am more or less convinced this could work.
More broadly: consider genetic drift and the probability of reaching fixation. For neutral mutations, their probability of fixation is the rate at which they are introduced, and they will reach fixation at 4*population-size generations. For primate species, the population size is always pretty small, low hundreds of thousands or millions; generation turnover tends to be something like 10 years, and early primates can date back as much as 60 million years, so it can encompass a lot of drift. If we imagine that kin altruism is neutral until you have at least a few relatives and the relevant mutation keeps happening once in every few hundred thousand individuals, it’s not at all unlikely that it will appear repeatedly and then drift up to the threshold where fitness gains start appearing, and then of course, now that it’s no longer neutral, it’ll be quickly selected for at the rate of its gain.
Richard Dawkins’ 1976 book The Selfish Gene contains, among other things, some interesting discussions about how many altruistic behaviors might have arisen through natural selection.
Or imagine that you are literally the first organism who by random mutation achieved a gene for “helping your siblings”. How specifically does this gene increase your fitness, or the fitness of the gene itself, if your siblings do not have a copy of this gene?
Even if being the first one to have that gene would make you have fewer children than average, (half of) your children will have the gene too and they would help each other and benefit from that and as a result you’d still have more grandchildren than average.
Or imagine that you are literally the first organism who by random mutation achieved a gene for “helping your siblings”
That’s not how genes work. There isn’t a single gene for “helping your siblings”.
Imagine that you are literally the first organism who by random mutation achieved a gene for “helping those who help you”. How specifically does this gene increase your fitness, if there is no one else to reciprocate?
Genes don’t need to help the individual that carries it. Genes are as Richard Dawkins famously said selfish.
It doesn’t make sense to focus on only one organism. Natural selection is a stochastic process.
Genes that don’t help the only organism that carry it get doublicated all the time.
A random gene on the Y chromosome of Genghis Khan that didn’t have strong effects would now be carried by millions of people without the gene being responsible for it.
BTW, I was just browsing JSTOR and saw this:
Life history, habitat saturation and the evolution of fecundity and survival altruism. S. Lion and S. Gandon, Evolution, v. 64 n. 6 (2010), pp. 1594-1606. If you would like to, I could relate the substance (it is a tiny bit inconvenient for me to do right now, or I would have.)
I suggest reading Henrich’s book The Secret of our Success. It describes a path to increased altruism that doesn’t depend on any interesting mutation. It involves selection pressures acting on culture.
Some people believe that altruism has evolved through helping your relatives or through helping others to help you in return. I was thinking about it; on the surface the idea looks good—if you already have this system in place, it is easy to see how it benefits those involved—but that doesn’t explain how the system could have appeared in the first place. Anyone knows the standard answer?
Imagine that you are literally the first organism who by random mutation achieved a gene for “helping those who help you”. How specifically does this gene increase your fitness, if there is no one else to reciprocate?
Or imagine that you are literally the first organism who by random mutation achieved a gene for “helping your siblings”. How specifically does this gene increase your fitness, or the fitness of the gene itself, if your siblings do not have a copy of this gene?
In other words, it seems simple to explain how these kinds of altruism can work when they are already an established system, but it is more difficult to explain how it could work when it is new.
And this all is a huge simplification; for example, I doubt that “helping those who help you” could be achieved by a single mutation, since it involves multiple parts like “noticing that someone helped you”, “remembering the individual who helped you” and “helping the individual who helped you in the past”. Plus the problem of how to start this chain of mutual cooperation.
My guess is that… nygehvfz pbhyq unir ribyirq guebhtu frkhny fryrpgvba. Yrg’f rkcynva vg ol funevat sbbq jvgu bguref. Svefg, vaqvivqhnyf abgvpr jub vf tbbq ng tngurevat sbbq, naq gurl ribyir nggenpgvba gbjneqf tbbq sbbq pbyyrpgbef. Gung znxrf vzzrqvngr frafr orpnhfr vg vapernfrf fheiviny bs gur puvyqera, vs gurl nyfb trg gur trarf tbbq sbe tngurevat sbbq. Nsgre guvf nggenpgvba rkvfgf jvguva gur fcrpvrf, gur arkg fgrc pbhyq or fvtanyyvat: vs lbh unir fbzr rkgen sbbq lbh qba’g npghnyyl arrq, oevat vg naq ivfvoyl qebc vg arne bgure vaqvivqhnyf, fb gung bguref abgvpr lbh unir zber sbbq guna lbh pna rng. Ntnva, guvf znxrf vzzrqvngr frafr, orpnhfr vg znxrf lbh zber nggenpgvir. Abgvpr ubj arvgure “urycvat lbh eryngvirf” abe “urycvat gubfr jub uryc lbh” jnf arprffnel gb ribyir urycvat vaqvfpevzvangryl. Npghnyyl, gubfr pbhyq unir ribyirq yngre, nf shegure vzcebirzragf bs be nqqvgvbaf gb gur vaqvfpevzvangr urycvat.
My first thoughts reading your post are 1) You start WAY TOO LATE IN THE GAME. You are essentially talking about altruism as a conscious choice which means you are well into the higher mammals.
Virtually every sexually reproducing creature devotes resources to reproduction that could have been conserved for individual survival. As you move up in complexity, you have animals feeding their young and performing other services for them. As would be expected with all evolved cooperation, the energy and cost you expend raising your young produces a more survivable young and so is net cost effective at getting the next generation going, which is pretty much what spreads genes.
How big of a leap is it from a mama bird regurgitating food into her baby’s mouth to you helping your neighbor hunt for wooly mammoth?
If you were the first organism to get the gene to feed your babies or do whatever expanded their survivability, then obviously that is how that gene propagates, your babies have the gene.
As you get to the more complex forms of altruism of primates and humans, you also get to strong feedback mechanisms against non-cooperators and free-riders. The system may not be perfect but I think it allows a path from feeding babies or burying eggs in the sand to modern altruism in humans where no wierd “how do we start this” behaviors bump up to stop things.
If the immediate consequences of the genetic change in question aren’t terribly deleterious then that first organism may very well have offspring, even without it conferring any particular advantage. And now those offspring do have siblings who share the gene.
[EDITED to add: oops, saw Viliam’s comment in Recent Comments and replied to it without noticing others had also done so making the same point.]
If you have a gene that makes you help you siblings, your offspring are reasonably likely to get it too, which benefits their siblings (also your offspring).
I feel like this increases the amount of lucky coincidence needed. Not only I have to randomly get the right mutation, but I also need to have many children (surviving to the age when they can help each other) for reasons completely unrelated to having the mutation. Actually, the mutation may be a bit harmful in the second step, because I may give some of my resources to my siblings instead of my children.
Unfortunately, I am not familiar enough with mathematical models of evolution to evaluate how much this extra burden weighs against your hypothesis.
It seems to me that it doesn’t weigh against it very much. A genetic change that causes a not-too-big increase in altruistic behaviour towards likely kin is unlikely to hurt your chances of survival and reproduction a lot.
The first organism with the genetic change doesn’t need to be exceptionally well supplied with offspring or anything. (Unless this is an r-selected species for which surviving at all is exceptionally lucky; in that case, it needs to be about as lucky as the bearer of any other not-too-dramatic genetic change has to be.)
Maybe it doesn’t help when you’re the only one, but that doesn’t matter; your species is one that has multiple children, and the mutation was so small it occurred in multiple children? … And if that’s too high a complexity penalty, there could be an alternative: say it is a trait which got spread due to a resource boom in a population (the resource boom makes it likely for even disadvantaged mutations to survive), and then individuals with the trait managed to find each other and be more fit?
… Just conjecture, though.
Doesn’t this suffer from a similar problem as group selection?
Imagine that the first mutant gets lucky and has 20 children; 10 of them inherited the “help your siblings” genes, and 10 of them did not. Does this give an advantage to the nice children over the non-nice ones? Well, only in the next generation… but then again, some children in the next generation will have the gene and some will not… and this feels like there is always an immediate disadvantage that is supposed to get balanced by an advantage in the next generation, except that the next generation also has an immediate disadvantage...
Uhm, let’s reverse it. Imagine that everyone has the “help your siblings” gene, in the most simple version that makes them take a given fraction of their resources and distribute it indiscriminately among all siblings. Now we get one mutant that does not have this gene. Then, this mutant has an advantage over their siblings; the siblings give resources to mutant, not receiving anything in return. Yeah, the mutant is causing some damage to the siblings, reducing the success of their genes. But we don’t care about genes in general here, only about the one specific “don’t help your siblings” allele; and this allele clearly benefits from being a free-rider. And then it reproduces with some else, who is still an altruist, and again 50% of the mutant’s children inherit the gene and get an advantage over their siblings.
So we get the group-selectionist situations where families of nice individuals prosper better than mixed families, but within each mixed family the non-nice individuals prosper better. This would need a mathematical model, but I suspect that unless the families are small, geographically isolated, and therefore heavily interbreeding, the nice genes would lose to the non-nice genes.
Your siblings is not a reproductively isolated population (hopefully=)). The relevant question is if the helpers are more or less fit relative to the population as a whole. So in your example, where the helpers give up something and get back less, the gene goes extinct.
But start instead of just zero-sum redistribution with something like that trust game where you send money through a slot and whatever amount you send the other guy gets triple. But it’s multiplayer and simultaneous. So the helpers give up some amount, let’s say x each and every family member gets three times what the average participant gave up. If half of the family members are helpers then everyone gets 3x/2. Which is more than x, so now the gene gives a fitness advantage.
Here is a toy model:
Let’s ignore the details of genetic reproduction, and simply assume that if both parents have a trait, all children have it; if no parent has a trait, no children have it; and if one parent has it, exactly 50% of children have it. Let’s assume all families have the same size. (These are quite unrealistic assumptions to make calculation simple.)
Let’s suppose that being nice to all your siblings has a cost c (for example, if without reciprocation it would reduce your survival rate by 5%, then c = 0.05), and that being supported by all your siblings provides a benefit b (for example, if without helping any your siblings but being helped by all of them would increase your survival rate by 10%, then b = 0.10). We can assume 0 < c < b.
So, the current generation contains a fraction p of adult individuals who have the sibling-helping trait. Let’s assume they form pairs randomly (because the trait is so new they haven’t developed its detectors yet). On average, there will be p^2 “helper-helper” families, 2×p×(1-p) “helper-nonhelper” families, and (1-p)^2 “nonhelper-nonhelper” families.
In “nonhelper-nonhelper” families, children’s survival rate will be 1 (the default survival rate before the helper mutation appeared). In “helper-helper” families, children’s survival rate will be 1+b-c. In “helper-nonhelper” families, the 1⁄2 of helper children will have survival rate 1+b/2-c (they only get half the help, but pay the full cost), and the 1⁄2 of nonhelper children will have survival rate 1+b/2 (they get galf the help at no cost). Now all these values together have to be normalized to 1, to get the proportions in the next generation.
Ugh, math...
non-normalized next generation helpers = p^2 × (1+b-c) + 1⁄2 × 2×p×(1-p) × (1+b/2-c) = p + pb/2 - pc/2 + ppb/2
non-normalized next generation non-helpers = (1-p)^2 × 1 + 1⁄2 × 2×p×(1-p) × (1 + b/2) = 1 - p + pb/2 - ppb/2
next generation helpers ratio = (p + pb/2 - pc/2 + ppb/2) / (p + pb/2 - pc/2 + ppb/2 + 1 - p + pb/2 - ppb/2) = (p + pb/2 - pc/2 + ppb/2) / (1 + pb—pc/2) … which for obscure mathematical reasons is always greater than p
Well, assuming that I made no mistake during the calculation, and that my simplified assumptions about heritability of traits didn’t diverge from reality too much (two reasons why I hesitated to do the calculations myself)… I am more or less convinced this could work.
More broadly: consider genetic drift and the probability of reaching fixation. For neutral mutations, their probability of fixation is the rate at which they are introduced, and they will reach fixation at 4*population-size generations. For primate species, the population size is always pretty small, low hundreds of thousands or millions; generation turnover tends to be something like 10 years, and early primates can date back as much as 60 million years, so it can encompass a lot of drift. If we imagine that kin altruism is neutral until you have at least a few relatives and the relevant mutation keeps happening once in every few hundred thousand individuals, it’s not at all unlikely that it will appear repeatedly and then drift up to the threshold where fitness gains start appearing, and then of course, now that it’s no longer neutral, it’ll be quickly selected for at the rate of its gain.
Not all information is encoded genetically. Many kinds of information have to be learned from the parents or from society.
Richard Dawkins’ 1976 book The Selfish Gene contains, among other things, some interesting discussions about how many altruistic behaviors might have arisen through natural selection.
That’s not how genes work. There isn’t a single gene for “helping your siblings”.
Genes don’t need to help the individual that carries it. Genes are as Richard Dawkins famously said selfish.
Technically true, but irrelevant in the scenario when there is yet only one organism having the gene. Kill the organism and the gene is gone.
It doesn’t make sense to focus on only one organism. Natural selection is a stochastic process. Genes that don’t help the only organism that carry it get doublicated all the time.
A random gene on the Y chromosome of Genghis Khan that didn’t have strong effects would now be carried by millions of people without the gene being responsible for it.
BTW, I was just browsing JSTOR and saw this: Life history, habitat saturation and the evolution of fecundity and survival altruism. S. Lion and S. Gandon, Evolution, v. 64 n. 6 (2010), pp. 1594-1606. If you would like to, I could relate the substance (it is a tiny bit inconvenient for me to do right now, or I would have.)
I suggest reading Henrich’s book The Secret of our Success. It describes a path to increased altruism that doesn’t depend on any interesting mutation. It involves selection pressures acting on culture.