In the book, in chapter 6, it talks about 4 types of contingencies. In the book it talks about how in operant conditioning there are two types of possible outcomes also known as consequences. One being reinforcers and one being punishers. There are contingencies of reinforcers and contingencies of punishers. In the chart below it gives you the basics in the four types. In this situation you have to focus on if something is being presented or withdrawn to determine if it is a positive or negative reinforcement.