A reinterpretation of schedule-induced behaviors based on a systematic analysis of behavior.

Confusion exists regarding the criteria to be used in determining whether or not particular behaviors are schedule-induced. Four critical characteristics of schedule-induced behaviors are suggested and a comparison made of the complete range of behaviors exhibited by body weight-reduced rats drinking in response to one of three stimuli. These were (1) a fixed-time food reinforcement schedule, (2) a meal of dry food, and (3) 24 hour water deprivation. Drinking, locomotion, rearing and oral and perioral behaviors occurred in accordance with the defining characteristics of schedule-induced behaviors. Rats in the fixed-time reinforcement condition also deposited significantly greater numbers of fecal boli. Sniffing and food bowl related behaviors occurred as terminal responses for this group. It is concluded that animals which receive reinforcers intermittently maintain high levels of arousal for extended periods, and that the presence of the schedule may mimic conditions experienced by wild rats in non-laboratory settings. In such conditions ambulatory behaviors may be particularly adaptive. In contrast, reinforcing sensory feedback and a stress reducing role may be particularly important in the mediation of oral behaviors (such as drinking) which occur during intermittent reinforcement.