Noted, thanks. A quick internet search seems to confirm your point, but I'm not totally convinced yet. I note here:
"the actual causes of low milk supply at the molecular level inside a breast’s epithelial tissue are still unknown...
Interestingly, the change in breast size (breast volume) from pre-pregnancy to lactation can be an indicator of how well the breast performs during lactation"
I wonder whether there is an indirect link, and not all fat is the same — so maybe the breast grows specialised fat to feed the milk-producing epithelial cells, which normal fat can't do (hence obese women with big breasts don't make more milk).
Also the research is probably done on typical western women with only one or two babies to feed. Being able to feed many more hungry babies in a collective cave tribe might be different.
Fat doesn't produce milk, breast tissue does. And increase in breast tissue would mean more milk production. Males also have a small amount of breast tissue hence they can lactate as you noted earlier.
Another theory I think makes sense is that breast cleavage looks like butt cleavage which men find attractive. As we transitioned to waking upright it became a desirable trait. There is another ape that has a similar thing, a red patch on the female's chest that mimics the red of the buttocks when they're ovulating.
I realise fat doesn't produce milk. But the milk-producing epithelial cells can't make milk from nothing — they need nutrients and energy, so maybe they get that partly from the adjacent fat cells, if they're the right type.
They make milk from blood. Fat cells have mo mechanism to supply nutrients, they are storage that is transported via the blood stream. It doesn't matter where those stores are and, as we've discussed, the amount of fatty tissue in the breast isn't correlated with milk supply
Fat is needed for lactation, but not locally. Many mammals have nipples without local fat storages. As a result, it’s clear that female human breasts are sexual ornaments. The question is why it appeared there in humans, and I don’t know the answer. Linking it to bipedalism sounds like a valid hypothesis.
Skimmed the beginning. Stopped when you claim that the penalty to evolution is just too big to justify breasts.
That is the very way sexual ornaments work. They need to be expensive, otherwise they don't signal mate value. "very expensive" is not a bug, it's a feature.
I get your point but I think we will have to agree to disagree on it.
You should force yourself to keep reading when you're confronted by something that you disagree with (otherwise you remain stuck in your bias).
It seems you didn't get to, "there has to be an evolutionary reason WHY men like the look of breasts." – an underlying practical purpose, which is what makes it attractive, even if evolution may then lead to these features being magnified in order to exaggerate the claim about the underlying practical use.
But this is not a challenge. This is an opinion that is against currently accepted facts.
Right now my prior is that it’s an ornament and it’s pretty strong. To open my mind to alternative hypotheses, I need to either lower my prior (hear good arguments why it’s not an ornament), or lower the cost of alternative explanations (right now your post is very long).
If you either substantiate that it can’t be an ornament, or summarize the rest, I (and others) will be more likely to read
Noted, thanks. A quick internet search seems to confirm your point, but I'm not totally convinced yet. I note here:
"the actual causes of low milk supply at the molecular level inside a breast’s epithelial tissue are still unknown...
Interestingly, the change in breast size (breast volume) from pre-pregnancy to lactation can be an indicator of how well the breast performs during lactation"
https://www.milkgenomics.org/?splash=do-larger-breasts-make-more-milk
I wonder whether there is an indirect link, and not all fat is the same — so maybe the breast grows specialised fat to feed the milk-producing epithelial cells, which normal fat can't do (hence obese women with big breasts don't make more milk).
Also the research is probably done on typical western women with only one or two babies to feed. Being able to feed many more hungry babies in a collective cave tribe might be different.
Fat doesn't produce milk, breast tissue does. And increase in breast tissue would mean more milk production. Males also have a small amount of breast tissue hence they can lactate as you noted earlier.
Another theory I think makes sense is that breast cleavage looks like butt cleavage which men find attractive. As we transitioned to waking upright it became a desirable trait. There is another ape that has a similar thing, a red patch on the female's chest that mimics the red of the buttocks when they're ovulating.
I realise fat doesn't produce milk. But the milk-producing epithelial cells can't make milk from nothing — they need nutrients and energy, so maybe they get that partly from the adjacent fat cells, if they're the right type.
They make milk from blood. Fat cells have mo mechanism to supply nutrients, they are storage that is transported via the blood stream. It doesn't matter where those stores are and, as we've discussed, the amount of fatty tissue in the breast isn't correlated with milk supply
Fat is needed for lactation, but not locally. Many mammals have nipples without local fat storages. As a result, it’s clear that female human breasts are sexual ornaments. The question is why it appeared there in humans, and I don’t know the answer. Linking it to bipedalism sounds like a valid hypothesis.
I've had some more thoughts on this. IMO there’s no way that evolution would encumber women with breasts purely as sexual ornaments:
https://www.facebook.com/david.thorp.144/posts/pfbid02T3WgxL1H2wYduX3xmovfevRHUfTrZVChcXX4Mu6pdVSRL8H6g6Fpm5JXZ2KvcoL6l
Skimmed the beginning. Stopped when you claim that the penalty to evolution is just too big to justify breasts.
That is the very way sexual ornaments work. They need to be expensive, otherwise they don't signal mate value. "very expensive" is not a bug, it's a feature.
I get your point but I think we will have to agree to disagree on it.
You should force yourself to keep reading when you're confronted by something that you disagree with (otherwise you remain stuck in your bias).
It seems you didn't get to, "there has to be an evolutionary reason WHY men like the look of breasts." – an underlying practical purpose, which is what makes it attractive, even if evolution may then lead to these features being magnified in order to exaggerate the claim about the underlying practical use.
I love being challenged.
But this is not a challenge. This is an opinion that is against currently accepted facts.
Right now my prior is that it’s an ornament and it’s pretty strong. To open my mind to alternative hypotheses, I need to either lower my prior (hear good arguments why it’s not an ornament), or lower the cost of alternative explanations (right now your post is very long).
If you either substantiate that it can’t be an ornament, or summarize the rest, I (and others) will be more likely to read