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Cooperation between two pigeons was trained in a systematic replication of an earlier study by Daniel (1942) using rats and electric shock avoidance. After both pigeons were trained separately to eat from a food magazine and to stand on a platform located 45 cm from the food magazine, two stimulus lights were added. Different responses of each pigeon were brought under the stimulus control of the lights. In the presence of one light, magazine approach by one of the pigeons was reinforced and in the presence of the other, standing on the platform was reinforced. These functions were reversed for the other pigeon, that is, the light that was the SD for magazine approach for Pigeon A was the SD for the platform response for Pigeon B. When behavior was under stimulus control, the pigeons were placed together in the study space. Across sessions, the lights were removed gradually, transferring stimulus control to the co-actor’s behavior. Thus, the terminal performance was two interlocking response chains: as one pigeon approached the magazine, the other approached the platform, standing on which operated the feeder for up to 7 s. After one pigeon ate for a duration dependent upon the co-actor’s platform standing, the two switched positions. The results are discussed in relation to the definition of social behavior and the role of basic learning principles in social behavior.