Still, it seems unlikely that if we did not observe homosexuality, researchers would be stroking their chins and saying, “Hmm, we should figure out why there is no large minority of our population that is exclusively attracted to members of the same sex. I mean, isn’t that weird? How would that sort of thing evolve?”
This is a really important principle. You haven’t explained a thing if you wouldn’t be confused by that thing’s absence.
ETA: This point is very similar to one of Eliezer’s observations:
Your strength as a rationalist is your ability to be more confused by fiction than by reality. If you are equally good at explaining any outcome, you have zero knowledge.
There is a subtle distinction, though. In that post, the emphasis is on noticing when your theory contradicts a reported fact. Eliezer points out that you should either modify your theory or deny the reported fact. You shouldn’t fall into the common failure mode of concocting some improbable scenario in which the fact could have occurred without contradicting the theory.
I take Alicorn’s point to be about noticing when your theory neither contradicts nor implies a reported fact. The emphasis here is on avoiding the failure mode of convincing yourself that the reported fact is just what you would expect to happen, given your theory.
I just did that, and while there are a lot of hits, I did not find anything but speculation on the matter. For example, this was the first freely available scientific paper I found on Google Scholar addressing the question. I looked at a few others but they were much the same. There are many speculations—it would be too much to call them theories—but if there is actual evidence settling the matter, or even just substantially favouring some hypotheses above others, I did not find it.
On the wider internet the firsttwo hits are junk. Seriously written, but junk. The third reports a test of the theory that homosexual men provide extra care for their relatives. It finds that in the one culture studied such an effect is present but not enough to offset the evolutionary cost of not reproducing oneself. The fourth reports another test of the kin support hypothesis, that failed to support it.
So, I have looked, and found no successful evolutionary explanation of homosexuality.
Did you have some expectation about what that Google search would find, or were you just suggesting that it would be informative one way or another on the subject?
You may already be aware of thesepapers by Andrea Camperio-Ciani. The first one made a pretty big splash a few years back.
Certainly not evolutionary psychology—just good old fashioned genetics (pedigree analysis). And not an explanation of why homosexuality evolved, but a plausible explanation of why natural selection has not ruthlessly eliminated it.
To my mind, the big problem with evolutionary psychology is that it displaces this very straightforward kind of science. It achieves success, not by finding truth, but rather by finding an appealing story. Kinda like religion.
To my mind, the big problem with evolutionary psychology is that it displaces this very straightforward kind of science.
To my mind, the big problem with evolutionary psychology is that it tries to boil everything down to advantages to DNA—and usually pays insufficient attention to the possibility that memes are what have benefitted instead.
To my mind, the big problem with evolutionary psychology is that it displaces this very straightforward kind of science. It achieves success, not by finding truth, but rather by finding an appealing story. Kinda like religion.
To put it mildy: I did not think this was a good argument.
Touche. It is possible to explain almost anything ex post. Moreover, it’s really unclear (and what I’ve read does not address) how a gene that causes someone to not reproduce gets passed on. Assuming that just you have the gene and your relatives don’t, it’s beneficial. But if you all have the gene, that’s a very different story. A gene that causes me to sacrifice myself to save my brothers is conditional—it doesn’t matter unless the need arises. A gene that causes me to prefer non-procreative sex doesn’t seem conditional in the same way—it simply prevents me and anyone who has it from reproducing.
In short, while one can rationalize the behaviour as advantageous ex post, it’s rather hard to actually put that together cogently, and it’s a very long way from getting rid of, “largely accidental” as an alternative explanation.
I will admit bias on this issue, having dated a woman with a lesbian identical twin.
Homosexuality could be controlled by environmental factors and appear at a good rate for kin selection while being genetically present in more people.
Here’s a more straightforward fictional example: In Elcenia, there’s a type of natural magic-user called “lights”. They have healing magic—really heavy-duty healing magic, equal to or better than modern Earthly care in most respects and infinitely cheaper. However, lights can’t heal themselves or each other, so it’s not such a great thing to be a light—you’re much more likely than the people around you to die of disease or injury. But it’s really, really useful to have a close family member who’s a light, because they’ll heal you when you get sick or hurt. So what happens in practice is most people in species where lights appear have the necessary genetic component, but only about 1-2% of the population depending on region encounter enough ambient magic in the womb to turn into actual lights.
I get the underlying theory just fine. It’s a neat fictional example, but (and I’m not familiar with the underlying fiction) it would probably be extremely fitness-enhancing. A male light would probably be incredibly high status and have little difficulty producing offspring. If it were purely genetically determined, it seems like it’d be pretty hard to sustain—no one would want it for their own children. If it were recessive, it might work out better, but there still seems a substantial problem of free-loading.
Thus, this evolutionary explanation for homosexuality partly undermines itself: it’s genetic, but it’s not quite genetic and there’s other stuff going on that determines whether or not it gets activated. So it’s either genetics (actively-selected) + environmental factors or genetics (random noise) + environmental factors. That’s not a very clear case for kin selection, to say the least.
My claim isn’t that it couldn’t possibly be related to kin selection. It’s that, like many ev-psych claims, the evidence for “or something else is going on” is far too strong to make a definitive claim, particularly because the outcome is the exact opposite of what you’d expect from simpler evolutionary theory. Otherwise, you risk combining two theories in a way that can explain far too many outcomes. Any individual who fails to reproduce can divert resources to his siblings. You could just as easily say many negative traits that don’t show up with absolute consistency are also advantageous. This seems like a stretch.
In retrospect I will admit that this example detracted from my overall point and was poorly chosen.
You should try googling ′ “evolutionary psychology” homosexuality’.
Still, it seems unlikely that if we did not observe homosexuality, researchers would be stroking their chins and saying, “Hmm, we should figure out why there is no large minority of our population that is exclusively attracted to members of the same sex. I mean, isn’t that weird? How would that sort of thing evolve?”
This is a really important principle. You haven’t explained a thing if you wouldn’t be confused by that thing’s absence.
ETA: This point is very similar to one of Eliezer’s observations:
There is a subtle distinction, though. In that post, the emphasis is on noticing when your theory contradicts a reported fact. Eliezer points out that you should either modify your theory or deny the reported fact. You shouldn’t fall into the common failure mode of concocting some improbable scenario in which the fact could have occurred without contradicting the theory.
I take Alicorn’s point to be about noticing when your theory neither contradicts nor implies a reported fact. The emphasis here is on avoiding the failure mode of convincing yourself that the reported fact is just what you would expect to happen, given your theory.
Very true.
However, my point was more that this doesn’t exactly conflict with evopsych either.
Of course, the question if evopsych actually does any useful predictions is still open. :)
I just did that, and while there are a lot of hits, I did not find anything but speculation on the matter. For example, this was the first freely available scientific paper I found on Google Scholar addressing the question. I looked at a few others but they were much the same. There are many speculations—it would be too much to call them theories—but if there is actual evidence settling the matter, or even just substantially favouring some hypotheses above others, I did not find it.
On the wider internet the first two hits are junk. Seriously written, but junk. The third reports a test of the theory that homosexual men provide extra care for their relatives. It finds that in the one culture studied such an effect is present but not enough to offset the evolutionary cost of not reproducing oneself. The fourth reports another test of the kin support hypothesis, that failed to support it.
So, I have looked, and found no successful evolutionary explanation of homosexuality.
Did you have some expectation about what that Google search would find, or were you just suggesting that it would be informative one way or another on the subject?
The only theory I’ve seen that makes any sense is radioactive politically.
Pathogenic Hypothesis of Homosexuality
An Evolutionary Look at Human Homosexuality
You may already be aware of these papers by Andrea Camperio-Ciani. The first one made a pretty big splash a few years back.
Certainly not evolutionary psychology—just good old fashioned genetics (pedigree analysis). And not an explanation of why homosexuality evolved, but a plausible explanation of why natural selection has not ruthlessly eliminated it.
To my mind, the big problem with evolutionary psychology is that it displaces this very straightforward kind of science. It achieves success, not by finding truth, but rather by finding an appealing story. Kinda like religion.
To my mind, the big problem with evolutionary psychology is that it tries to boil everything down to advantages to DNA—and usually pays insufficient attention to the possibility that memes are what have benefitted instead.
To put it mildy: I did not think this was a good argument.
Touche. It is possible to explain almost anything ex post. Moreover, it’s really unclear (and what I’ve read does not address) how a gene that causes someone to not reproduce gets passed on. Assuming that just you have the gene and your relatives don’t, it’s beneficial. But if you all have the gene, that’s a very different story. A gene that causes me to sacrifice myself to save my brothers is conditional—it doesn’t matter unless the need arises. A gene that causes me to prefer non-procreative sex doesn’t seem conditional in the same way—it simply prevents me and anyone who has it from reproducing.
In short, while one can rationalize the behaviour as advantageous ex post, it’s rather hard to actually put that together cogently, and it’s a very long way from getting rid of, “largely accidental” as an alternative explanation.
I will admit bias on this issue, having dated a woman with a lesbian identical twin.
Homosexuality could be controlled by environmental factors and appear at a good rate for kin selection while being genetically present in more people.
Here’s a more straightforward fictional example: In Elcenia, there’s a type of natural magic-user called “lights”. They have healing magic—really heavy-duty healing magic, equal to or better than modern Earthly care in most respects and infinitely cheaper. However, lights can’t heal themselves or each other, so it’s not such a great thing to be a light—you’re much more likely than the people around you to die of disease or injury. But it’s really, really useful to have a close family member who’s a light, because they’ll heal you when you get sick or hurt. So what happens in practice is most people in species where lights appear have the necessary genetic component, but only about 1-2% of the population depending on region encounter enough ambient magic in the womb to turn into actual lights.
I get the underlying theory just fine. It’s a neat fictional example, but (and I’m not familiar with the underlying fiction) it would probably be extremely fitness-enhancing. A male light would probably be incredibly high status and have little difficulty producing offspring. If it were purely genetically determined, it seems like it’d be pretty hard to sustain—no one would want it for their own children. If it were recessive, it might work out better, but there still seems a substantial problem of free-loading.
Thus, this evolutionary explanation for homosexuality partly undermines itself: it’s genetic, but it’s not quite genetic and there’s other stuff going on that determines whether or not it gets activated. So it’s either genetics (actively-selected) + environmental factors or genetics (random noise) + environmental factors. That’s not a very clear case for kin selection, to say the least.
My claim isn’t that it couldn’t possibly be related to kin selection. It’s that, like many ev-psych claims, the evidence for “or something else is going on” is far too strong to make a definitive claim, particularly because the outcome is the exact opposite of what you’d expect from simpler evolutionary theory. Otherwise, you risk combining two theories in a way that can explain far too many outcomes. Any individual who fails to reproduce can divert resources to his siblings. You could just as easily say many negative traits that don’t show up with absolute consistency are also advantageous. This seems like a stretch.
In retrospect I will admit that this example detracted from my overall point and was poorly chosen.
That… has a lot of potential.