This chapter focuses on attempts to understand avoidance learning. The original experiments were first performed in the St. Petersburg laboratory of Pavlovs arch-rival, Vladimir Bekhterev. Researchers there arranged that, if when a signal was given, a dog failed to flex a leg, a shock would be delivered; if the leg was flexed in time, the shock was avoided. In general, these dogs learned quickly to flex the target leg as soon as the signal was given. It took over 30 years before a widely accepted explanation was developed of how the absence of an event could promote learning. A key contribution was the two-factor theory developed by Hobart Mowrer. His studies of avoidance learning and those that followed, mainly by Richard Solomon and his students, laid the foundation for breakthroughs in the study of associative learning in the late 1960s. The chapter also describes research on punishment.

Behavioral psychology was immediately preceded by the reflexology of Russian physiology and the associationism of Thorndike. Physiological reflexology received a sound foundation with the works of Sechenov and Bekhterev, but it was Pavlov who proposed a comprehensive theory of conditioning. Watson’s behavioral formulation defined stimulus and response elements as the substitute to rid psychology of residual mentalistic constructs. Watson’s contemporaries, Holt, Weiss, Hunter, and Lashley, soon restored to behaviorism critical psychological activities. The logical positivist movement expressed an operational spirit and insured the initial success of the behaviorist model. Behavioral psychology expanded beyond the original formulations of Pavlov and Watson. Contemporary reflexology in Russia and in nearby countries expanded to include a wide range of psychological and physiological problems, led by such eminent scientists as Vygotsky, Luria, Konorski, Asratyan, and Beritashvili. In the United States, behaviorism moved through several intellectual stages, through the contributions of Guthrie, Tolman, Hull, and Skinner. A major application of behaviorism was the behavior modification model in clinical settings. Contemporary behaviorism remains a dominant but diffused force in psychology.