The human advantage, I would say, lies in having the largest number of neurons in the cerebral cortex that any animal species has ever managed—and it starts by having a cortex that is built in the image of other primate cortices: remarkable in its number of neurons, but not an exception to the rules that govern how it is put together. Because it is a primate brain—and not because it is special—the human brain manages to gather a number of neurons in a still comparatively small cerebral cortex that no other mammal brain, that is, still smaller than 10 kilograms, would with a viable be able to muster.

Suzana Herculano-Houzel, The human advantage: a new understanding of how our brain became remarkable, Cambridge, Massachusetts, 2016, p. 123