Brain size sets an upper bound on intelligence, but it doesn’t determine it. There are plenty of species with brains much larger than ours that are nevertheless very stupid, and there’s little or no correlation between brain size and intelligence among humans. Since the Boskops appear to have not gone anywhere and not left behind any signs of writing or technology, the logical conclusion is that they weren’t smart enough to have either.
Come on, this isn’t some random other species; these are very near relatives living only 10-30K years ago. Just how much do you think brain architecture changed over that period? Clearly something went wrong with them, but I don’t see why we should assume that would be lower intelligence.
and there’s little or no correlation between brain size and intelligence among humans.
Not exactly true. (Non-paywalled draft paper here). According to that meta-analysis, the correlation between brain volume and intelligence is 0.41 for female adults, 0.37 for female children, 0.38 for male adults and 0.22 for male children.
This was pretty much my response. I’ve read a bit about the issue, and my understanding is that the size of the brain compared to the body is somewhat useful as a rough guide to intelligence on a species level, and that the relative sizes of the different specialized regions of the brain are about as important as overall (relative) size. Neither of those factors could be extrapolated from skull fragments, as far as I know.
Brain size sets an upper bound on intelligence, but it doesn’t determine it. There are plenty of species with brains much larger than ours that are nevertheless very stupid, and there’s little or no correlation between brain size and intelligence among humans. Since the Boskops appear to have not gone anywhere and not left behind any signs of writing or technology, the logical conclusion is that they weren’t smart enough to have either.
Come on, this isn’t some random other species; these are very near relatives living only 10-30K years ago. Just how much do you think brain architecture changed over that period? Clearly something went wrong with them, but I don’t see why we should assume that would be lower intelligence.
Not exactly true. (Non-paywalled draft paper here). According to that meta-analysis, the correlation between brain volume and intelligence is 0.41 for female adults, 0.37 for female children, 0.38 for male adults and 0.22 for male children.
This was pretty much my response. I’ve read a bit about the issue, and my understanding is that the size of the brain compared to the body is somewhat useful as a rough guide to intelligence on a species level, and that the relative sizes of the different specialized regions of the brain are about as important as overall (relative) size. Neither of those factors could be extrapolated from skull fragments, as far as I know.