This paper describes a classroom activity to demonstrate to undergraduate psychology students studying learning principles the principle of negative reinforcement. The students (n=25) were either enrolled in an introductory psychology course at a business college or the students (n=21) were enrolled in an educational psychology course at a state university. In the experiment the class instructor and a volunteer student role play a simulated spousal situation in which capitulation to the spouse's anger and unreasonable demands serves to negatively reinforce this behavior. Evaluation following the demonstration in two classes indicated that students overwhelmingly found the demonstration useful in understanding the concept of negative reinforcement, found the demonstration to be a useful learning experience, found the demonstration was effective in holding their attention, felt the demonstration should be used in future classes, and reported they enjoyed the demonstration. (DB)