Although Tolman was firmly behaviorist in his methodology, he was not a radical behaviorist like B. F. Skinner. In his studies of learning in rats, Tolman sought to demonstrate that animals could learn facts about the world that they could subsequently use in a flexible manner, rather than simply learning automatic responses that were triggered off by environmental stimuli. In the language of the time, Tolman was an "S-S" (stimulus-stimulus), non-reinforcement theorist: he drew on Gestalt psychology to argue that animals could learn the connections between stimuli and did not need any explicit biologically significant event to make learning occur. This is known as latent learning. The rival theory, the much more mechanistic "S-R" (stimulus-response) reinforcement-driven view, was taken up by Clark L. Hull.