“Brain tissue can only be laid down at a constant rate during development, so if you want a bigger brain, you have to take…
“Brain tissue can only be laid down at a constant rate during development, so if you want a bigger brain, you have to take longer to produce it. There are no shortcuts. This means that, at least in mammals, you have to have longer periods of gestation and lactation if you want to evolve a larger brain. And since a computer is no use without software, you also have to have a longer period of socialization (essentially the time between weaning and the start of reproduction) in order to allow the brain to fine tune its ability to deal with all the subtleties of the dynamic, constantly shifting social world. Neuroimaging studies of humans suggest that it takes a surprisingly long time (around 20-25 years) for the brain to figure out how to handle the complexities of our social world.”— Dunbar, Robin. Human Evolution. London: Pelican Books, 2014.