Three experiments (N = 60) were performed to assess the reliability and generality of Wright''s finding of a learned drive based on hunger. While some support was found in Exp. I, this result could not be replicated successfully in two other studies. In all three studies Ss'' [naive male Holtzman albino rats] performance on the first consummatory test was contrary to the learned drive hypothesis. It is generally assumed that drives may be learned. While there is substantial evidence to support this assumption in the case of drives based on pain, the bulk of the evidence is negative when appetitional needs are used (Cofer and Appley, 1964). Recently, Wright (1965) has reported that rats consumed greater amounts of liquid food in boxes where they were previously hungry than in boxes where they were previously satiated. Wright attributed his positive result to the use of a within-S type of design. The purpose of the present experiments was to assess the reliability and generality of Wright''s finding. Because our studies employed dry rather than liquid food, they represent systematic replications (Sidman, 1960) rather than replications of the original investigation.
