The capabilities of ancestral humans increased smoothly as their brains increased in scale and/or algorithmic efficiency. Until culture allowed for the brain’s within-lifetime learning to accumulate information across generations, this steady improvement in brain capabilities didn’t matter much. Once culture allowed such accumulation, the brain’s vastly superior within-lifetime learning capacity allowed cultural accumulation of information to vastly exceed the rate at which evolution had been accumulating information. This caused the human sharp left turn.
This is basically true if you’re talking about the agricultural or industrial revolutions, but I don’t think anybody claims evolution improved human brains that fast. But homo sapiens have only been around 300,000 years, which is still quite short on the evolutionary timescale, and it’s much less clear that the quoted paragraph applies here.
I think a relevant thought experiment would be to consider the level of capability a species would eventually attain if magically given perfect parent-to-child knowledge transfer—call this the ‘knowledge ceiling’. I expect most species to have a fairly low knowledge ceiling—e.g. meerkats with all the knowledge of their ancestors would basically live like normal meerkats but be 30% better at it or something.
The big question, then, is what the knowledge ceiling progression looks like over the course of hominid evolution. It is not at all obvious to me that it’s smooth!
This is basically true if you’re talking about the agricultural or industrial revolutions, but I don’t think anybody claims evolution improved human brains that fast. But homo sapiens have only been around 300,000 years, which is still quite short on the evolutionary timescale, and it’s much less clear that the quoted paragraph applies here.
I think a relevant thought experiment would be to consider the level of capability a species would eventually attain if magically given perfect parent-to-child knowledge transfer—call this the ‘knowledge ceiling’. I expect most species to have a fairly low knowledge ceiling—e.g. meerkats with all the knowledge of their ancestors would basically live like normal meerkats but be 30% better at it or something.
The big question, then, is what the knowledge ceiling progression looks like over the course of hominid evolution. It is not at all obvious to me that it’s smooth!