Two

experiments determined the role that a stimulus associated with extinction plays in the maintenance of the observing response in goldfish. In Experiment,goldfish were trained to respond on either a mixed or a mukiple schedule of reinforcement. By swimming through a light beam at the opposite end of the tank, one group of fish could produce stimuli associated with food (S+) and  extinction (S-).In a second group, fish could terminate presentations of S+ and S-. For both groups, reward was response independent. S+ appeared to maintain the observing response, whereas S played an aversive role. In Experiment 2, goldfish were trained to respond on a multiple schedule of reinforcement. Reward was response dependent. Goldfish terminated S+ at significantly lower rate than S-. The two experiments together show that S- will not support observing even under conditions where response efficiency could be improved by observing. Results are discussed in light of theories of the observing response based on secondary reinforcement, information, and energy savings.