And at least in nature’s case, I reiterate that the improvement process was several orders of magnitude harder than the one-brain process.
If we take “time” as a proxy for “difficulty” we have:
Origin of life: 3500 MYA.
Origin of brains: 600 MYA.
Origin of chimp-human split: 7 MYA.
According to those figures, scaling brains up a few thousand times was much easier than making one in the first place. Scaling one up by a factor of 3 was much, much easier.
As for modern big human brains, the main examples I know of arise from giantism and head binding.
If we take “time” as a proxy for “difficulty” we have:
Origin of life: 3500 MYA.
Origin of brains: 600 MYA.
Origin of chimp-human split: 7 MYA.
According to those figures, scaling brains up a few thousand times was much easier than making one in the first place. Scaling one up by a factor of 3 was much, much easier.
As for modern big human brains, the main examples I know of arise from giantism and head binding.