<< It depends on how you define "cultural leap forard". I don't know to what you are referring but primitive cave paintings and the like do not consititute a great leap forward in my opinion. >> The one thing that doesn't seem to be mentioned: Most of our great tech advances come from research on how to make better weapons (better ways to kill each other or get a leg up on each other). When the Neolithic time came around, people started being concerned with acquiring land and property. The increase of acquired property created the desire to protect said property. The men also wanted their property to be transferred to their children. A woman knows who her children are and a man has to create situations to ensure it. In the hunter-gatherer groups their is no overwhelming concern of who fathered who. The group had to sustain and protect itself. Perceived necessity is the mother of invention. Gawen Harrison