The starchy carbohydrates were probably not potatoes which are a new world plant and domesticated fairly recently. https://en.wikipedia.org/wiki/Potato https://

The starchy carbohydrates were probably not potatoes which are a new world plant and domesticated fairly recently. https://en.wikipedia.org/wiki/Potato https://en.wikipedia.org/wiki/Potato. The article states: "Dr Karen Hardy and her team at the Autonomous University of Barcelona say that there are five crucial reasons why a starch-rich diet was critical in human development." That suggests that the key is "a starch rich diet" rather than potatoes that enabled larger brains. It would be interesting to know where the starches came from, given that potatoes are not an option.