Abstract
The concept of negative reinforcement is notoriously difficult to teach to introductory students. Reasons for this difficulty include: surplus meanings associated with the terms negative and punishment, the fact that Skinner (1938, 1953) described two types of reinforcement but only one type of punishment, the tendency that most students have to view reward and punishment in subjective terms, and Skinner's (1 938, 1953) conflicting definitions of reinforcement and punishment. Pointing out to students that there are two types of punishment-positive and negative-as well two types of reinforcement-positive and negative-helps them learn that negative reinforcement is not a synonym for punishment.