The present comments concern Michael's concept of motivative variables, and the implications of that concept for our understanding of the nature of reinforcement as well as the extinction of responses maintained through positive and negative reinforcement. We note that both extinction and altering motivative variables decrease responding, but…

Mand training is often a primary focus in early language instruction and typically includes mands that are positively reinforced. However, mands maintained by negative reinforcement are also important skills to teach. These include mands to escape aversive demands or unwanted items. Another type of negatively reinforced mand important to teach…