I think some of us azb posters might be able this theory wrong.Brains. Humans sorted out fire and eating meat and spending less time on just surviving. That ended up with more protein, more time to work on things like painting, language development. Brains grew larger with more use and more food, and now here we are with The Kardashians and rap and needing laws to figure out what a girl or a boy is LOL. We developed a bit too much I think or starting down the slope going the other way.