Yes, positive reinforcement and negative reinforcement (a.k.a. punishment), are types of persuasion. An example of positive reinforcement would be giving a person food or money to do something you want them to do - that is the basis of capitalism, and as you indicated, negative reinforcement is the basis of slavery. However, there is an increasing movement of people suggesting that we should alter this paradigm - and perhaps, move toward an economy that is not based on positive or negative reinforcement, but one that is based on the shared gains of the entire community - this is often referred to as communism or socialism.