Abstract
This study aimed to describe the within-session decreases of rat feeding behavior as a function of cumulative amount of food intake. Rats (N = 16) were trained to obtain food pellets by nose-poke responses into a recessed food tray. Session lengths were 45 minutes. Half of the rats were reinforced by CRF schedule and the other half were reinforced by VI 20-s. Three levels of hunger drive were operated by changing duration of food deprivation. The following results were obtained : 1) Within-session decreases of response rates were well described as liner functions of cumulative amount of food intake under both reinforcement schedules. This means that within-session decreases of response rates could be regarded as a satiation process that progressed proportionally to the cumulative amount of food intake. 2) Effects of drive operation appeared in the differences in slopes of regression lines. This suggests that drive level affects the progress of the satiation process.
