It must have been something that predates arable farming (sowing seeds on acres), just timeline wise humanity spread before farming became a thing. On the othe

It must have been something that predates arable farming (sowing seeds on acres), just timeline wise humanity spread before farming became a thing. On the other hand I don't think that this must be a one-factor kind of a game changer thing. I could totally think that two to three changes occured in the food chain (meat, starches, food preservation, improved social skills), that combined amplified each other's effect and lead to the development.