The present research explored the role of RES manipulation on ongoing Sidman avoidance behavior. Results of the first phase revealed that both experimental drugs significantly altered RES levels in predicted directions after the first measure; however, only stimulated subjects maintained significant differences after 5 days. No activity-level differences were noted in any subjects due to drugs across time. Sidman avoidance data indicated that RES-stimulated subjects showed significant deterioration in avoidance performance as compared to other groups for the first session. Stimulated subjects were also poorer on the second and third sessions, but statistical significance was not obtained because some saline subjects also showed poorer performance. A rank order correlation revealed that a significant negative correlation existed between RES stimulation and avoidance performance, based on changes in RES levels from baseline to the end of the shock program. These data suggest that increased stress resistance due to RES stimulation may reduce the aversive properties of the shock program, thus decreasing motivation for responding. It was concluded that artificial methods of inducing stress resistance by RES stimulation may be a useful therapeutic technique for patients experiencing psychological stress.