The phenomenon of sensory preconditioning was presented by Brogden (1939) with the implicit assumption that its quantitative variation and the independent variables to which it is functionally related are similar to those of conditioning. Brogden (1950) reported briefly about two experiments on sensory preconditioning in which variation in the number of preconditioning training trials appeared to have no differential effect upon the magnitude of the phenomenon. Because of the fundamental relation of amount of training to amount of conditioning, it was assumed that there were errors of some kind in the experiments, rather than that sensory preconditioning differs in respect to this relationship from standard conditioning. Hoffeld, Thompson, and Brogden (1958) studied the stimuli time relations during preconditioning training for conditions of 0, .5, 1, 2, and 4 sec, precedence of tone over light and found maximum sensory preconditioning to tone for 4 sec. precedence. Since these results are not compatible with the results on time relations