Effects of septal lesion and habit requirement on the acquisition of a CAR in rats

The inordinate difficulty encountered by some investigators (Meyer, Cho, & Wesemann, 1960; D'Amato & Shiff, 1964) while attempting to establish a discriminated lever press avoidance response with rats severely limited the use of discriminated avoidance paradigms and raised several problems of a theoretical nature. The procedure involves training animals to perform a response in the presence of a stimulus (the conditioned stimulus, CS) which signals the occurrence of an aversive stimulus (the unconditioned stimulus, US), which is, generally, shock. The response, either pressing a lever in a Skinner box, or shuttling between two compartments in a shuttle box avoidance situation, terminates the signal and prevents the advent of the US. The efficacy of discontinuous (intermittent) shock as the US in facilitating the acquisition of a discriminated avoidance response (Hurwitz, 1964; D'Amato, Keller, & DiCara, 1964) served only to present additional difficulties for a theoretical explanation of discriminated avoidance behaviors (D'Amato et_al., 1964). This study is a partial attempt to resolve the theoretical questions posed by the effects of discontinuous shock in avoidance situations