ABSTRACT
The research and theorizing reported in this chapter were instigated by prior studies in the rabbit that were remarkable in not reproducing a well-accepted phenomenon of Pavlovian conditioning. The phenomenon of interest is the so-called conditioned diminution of the UR (Kimble & Ost, 1961), which is a reduction in the amplitude of the response to a US that may be specifically attributed to preceding the US by an associated CS. Although the phenomenon has been widely observed in many different subject populations and conditioning preparations (e.g., Fanselow & Bolles, 1979; Fitzgerald, 1966; Kimble & Ost, 1961; Kimmel, 1966), Hupka, Kwaterski, and Moore (1970, Exp. 1) and Grevert and Moore (1970) reported that, in a nictitating-membrane conditioning preparation with the rabbit, preceding the US by an associated CS increased, rather than decreased, the amplitude of response, compared to US-alone occasions.
