* There was a sharp spike in cranial capacity ~200,000 years ago, on the order of 30%
* And, that the large brain was not deleterious despite its large caloric footprint (25% of our calories service the brain) because the “environment of early humans was so clement and rich in resources”
Hawks refutes the first by simply reposting the chart the above (x axis = years before present, y axis = cranial capacity). It’s rather straightforward, I don’t know the paleoanthropology with any great depth, but the gradual rise in hominin cranial capacity has always been a “mystery” waiting to be solved (see Grooming, Gossip, and the Evolution of Language and The Mating Mind: How Sexual Choice Shaped the Evolution of Human Nature). Blakemore may have new data, but as they say, “bring it.” Until then the consensus is what it is (the hominins with the greatest cranial capacities for what it’s worth were Neandertals, and even anatomically modern humans have tended toward smaller cranial capacities since the end of the last Ice Age along with a general trend toward smaller size).