In other areas there might be a lack of an animal food supply which is going to cause people to have to sit down and figure out how do we eat. And climate change would be probably top on my list. But there's also other reasons that archaeologists and archaeogenetics people have put out there including the population just growing too large to be a huntering and gathering society. So when you have too many people you have to figure out how to feed them. You also have a feast theory that the clans were more powerful when they would have feasts with lots of food which caused them to have to sit down and make food. Again another reason for a change. You also have the oasis theory that in some parts of the world in the Middle East that there was only so many pockets of water of oasis that was available which caused the hunter and gathering people to come together and sit down.