POLYDIPSIA INDUCED IN THE RAT BY A SECOND‐ORDER SCHEDULE 1

Abstract

Drinking was studied in rats pressing a bar on a second‐order schedule in which every third completion of a 1‐min fixed interval was followed by food presentation. A brief flash of light signaled the completion of each fixed‐interval component. The rats drank not only after the food presentations but also after presentations of the light flash alone. A high rate of steady drinking followed intervals terminated by a food presentation. Drinking that followed intervals terminated by a light flash alone was of comparable rate, but characteristically interrupted by bar pressing. When 250‐mg food pellets were used instead of 45‐mg pellets, both drinking and bar‐pressing rates increased substantially.