An Application of the Species-Specific Defense Reaction Hypothesis

Abstract

Acquisition of lever pressing by rats required to escape and avoid unsignalled shock in a test chamber equipped with 2 response levers was examined. Similarity of the arbitrary lever press to one of the S’s species-specific defense reactions (SSDR) to shock —flight—was manipulated by raising and lowering sliding hatches directly above and behind each response lever. Specific sequences of manipulating abortive escape routes proved critical, but results generally support Bolles’ assertion that learning an avoidance response is facilitated if the required response is a SSDR to the aversive stimulus —or at least closely resembles one. In addition, data on escape and avoidance lever-holding during successive portions of the session verify, with only minor qualification, Bolles’ account of the importance of freezing, another Ssdr, in the acquisition of the lever-press avoidance response.