ABSTRACT to alter food intake in rats. Rats (n = 23) were trained in a twolever, food-reinforced, discrimination paradigm to press one lever when deprived of food for 3 hr and another lever when deprived of food for 22 hr. Criteria for stimulus control over responding were achieved after a mean of 92 (range = 26-1 75) training sessions. In time course tests, rats were tested when 22, 1 2, 6 and 3 hr food-deprived. As the number of hours of food depnvation decreased
