ABSTRACT
Any organism in even the most sterile environment is faced with a continual and multifaceted stream of stimulus events. To discover the laws governing behavioral adjustments to the exigencies of an environment, Pavlov (1927, pp. 110-113) and subsequent investigators have used compounds of two separable stimuli (e.g., tone + light) as a laboratory model for the array of innocuous events that antedate a biologically significant stimulus (e.g., Hull, 1943; Kehoe & Gormezano, 1980; Razran, 1965,1971; Wickens, 1954, 1959, 1965). One major result of research with compound stimuli has been the discovery that the level of response acquisition to a given conditioned stimulus (CS) depends not only on its own degree of contiguity with the unconditioned stimulus (US) but also on the intensive, associative, and temporal characteristics of other CSs in a compound (e.g., Kamin, 1968,1969a, 1969b; Wagner, Logan, Haberlandt, & Price, 1968). At a descriptive level, it appears that the learning process is selective as to which components of a compound will gain associative strength and thus gain the capacity to evoke responding. The present chapter reviews the contribution to this research literature made by investigations with the rabbit nictitating membrane response (NMR) and eyeblink response (EBR) preparations.
