According to Jared Diamond's theory, after much research, he determined that there are several elements that separate societies into successful or unsuccessful are:
-Immunity and exposure to germs
-Domestication of animals
-The discovery and use of steel
Diamond places less emphasis on intelligence and more emphasis on how people choose to live. When hunter/gatherer groups decided to settle down and grow their food instead of moving from place to place in search of animals to hunt, their society became more stable.
"What then inevitably follows is the development of specialized labor groups as well as the establishment of hierarchies in ruling parties. Populations thrive under these conditions, and in time empires rise. The stability provides farming societies with powerful advantages over nomadic hunter-gatherer groups,"
"Other impediments to progress included large bodies of water or land barriers such as mountains and deserts."