This chapter describes a program of research that, in its initial conception, was not the least bit concerned with cognitive functioning in animals — let alone an argument favoring these processes in nonprimates, such as the rat. An attitude dismissing, or even disavowing, animal cognition has long been prevalent among investigators. It reflects a heritage stemming from Descartes’ dualistic philosophy (on mind and body) and the reaction of the behavioristic school. Mentalistic processes are not to be considered in the analysis of behavior; instead, the bodily reactions of the organism should be studied directly. Adopting this posture, the investigator can ensure public observation and replication of his data and, in so doing, promote the use of a scientific method.