The paper which more directly supports the “made them smarter” claim seems to be this. I did somewhat anticipate this—“not much special about the primate brain other than ..”, but was not previously aware of this particular line of research and certainly would not have predicted their claimed outcome as the most likely vs various obvious alternatives. Upvoted for the interesting link.
Specifically I would not have predicted that the graft of human glial cells would have simultaneously both 1.) outcompeted the native mouse glial cells, and 2.) resulted in higher performance on a handful of interesting cognitive tests.
I’m still a bit skeptical of the “made them smarter” claim as it’s always best to taboo ‘smarter’ and they naturally could have cherrypicked the tests (even unintentionally), but it does look like the central claim—that injection of human GPCs (glial progenitor cells) into fetal mice does result in mice brains that learn at least some important tasks more quickly, and this is probably caused by facilitation of higher learning rates. However it seems to come at a cost of higher energy expenditure, so it’s not clear yet that this is a pure pareto improvement—could be a tradeoff worthwhile in larger sparser human brains but not in the mouse brain such that it wouldn’t translate into fitness advantage.
Or perhaps it is a straight up pareto improvement—that is not unheard of, viral horizontal gene transfer is a thing, etc.
The paper which more directly supports the “made them smarter” claim seems to be this. I did somewhat anticipate this—“not much special about the primate brain other than ..”, but was not previously aware of this particular line of research and certainly would not have predicted their claimed outcome as the most likely vs various obvious alternatives. Upvoted for the interesting link.
Specifically I would not have predicted that the graft of human glial cells would have simultaneously both 1.) outcompeted the native mouse glial cells, and 2.) resulted in higher performance on a handful of interesting cognitive tests.
I’m still a bit skeptical of the “made them smarter” claim as it’s always best to taboo ‘smarter’ and they naturally could have cherrypicked the tests (even unintentionally), but it does look like the central claim—that injection of human GPCs (glial progenitor cells) into fetal mice does result in mice brains that learn at least some important tasks more quickly, and this is probably caused by facilitation of higher learning rates. However it seems to come at a cost of higher energy expenditure, so it’s not clear yet that this is a pure pareto improvement—could be a tradeoff worthwhile in larger sparser human brains but not in the mouse brain such that it wouldn’t translate into fitness advantage.
Or perhaps it is a straight up pareto improvement—that is not unheard of, viral horizontal gene transfer is a thing, etc.