On the effects of noncontingent food delivery during naturally occurring periods of deprivation and satiation

Four adults diagnosed with moderate to profound mental retardation performed a manual response that was reinforced with food identified from a stimulus preference assessment. During baseline, the response was reinforced on a variable ratio (VR) schedule. Participants were then exposed to noncontingent reinforcement (NCR) plus extinction, and no‐food (i.e., extinction) conditions. A combination multielement and reversal design was used to evaluate intervention effects. For each participant, sessions were conducted both before and after the midday meal during baseline and NCR‐plus‐extinction conditions, thus capitalizing on naturally occurring states of food deprivation and satiation. Results showed that response rates were slightly higher during deprivation sessions than during satiation sessions during NCR‐plus‐extinction and VR schedules for three of the four participants. For three participants, initial NCR schedules did not reduce responding; however, subsequent NCR schedules, which were twice as dense, were effective in reducing response rates. The results are discussed in terms of the development of NCR as a reductive technology and the manipulation of establishing operations applied to the habilitation of individuals with developmental disabilities. The use of a basic experimental preparation as a method of examining decelerative interventions is also addressed. Copyright © 2000 John Wiley & Sons, Ltd.     

Resistance to satiation: Reinforcing effects of food and eating under satiation

It has been shown previously that rats which have learned a response when hungry will continue to make that response when tested satiated, a phenomenon labeled resistance to satiation. Here we showed that rats which were previously trained hungry will learn a new response for the opportunity to consume pellets in a new situation when tested satiated. In four experiments various groups received each of the components of the training given when rats learn an instrumental response when hungry. Rats were placed in the goalbox of a straight alley and given food pellets when hungry or were hungry only in their home cages prior to running a straight alley in the satiated test in Experiment 1. In Experiments 2, 3, and 4 learning of a differential conditioning problem for pellets in S+ (nonreward in S?) was measured in the satiated test. Groups given pellets in their home cages when hungry with or without alley exposure learned to run more rapidly in S+ than in S? in the satiated test phase. The tendency to eat pellets in the apparatus and the reinforcing effect of eating the pellets was larger for rats which ate the pellets when hungry in their home cage than for rats which ate the pellets when satiated in their home cage. Being hungry in the home cage with no pellets was not sufficient to produce eating or running for pellets in the satiated test, indicating that any inherent reinforcing effect of the pellets is not sufficient to produce eating or running, and that incomplete satiation cannot account for the learning. These data indicate that a reinforcing effect of eating pellets under satiation is an important determiner of resistance to satiation.     

Deprivation and satiation: The interrelations between food and wheel running

Two experiments were designed to assess whether depriving rats of food would increase the reinforcement effectiveness of wheel running (Experiment 1) and whether satiation for wheel running would decrease the reinforcement effectiveness of food (Experiment 2). In Experiment 1, a progressive-ratio schedule was used to measure the reinforcement effectiveness of wheel running when rats were deprived or not deprived of food. Completion of a fixed number of lever presses released a brake on a running wheel for 60 s, and the response requirement was systematically increased until the rat stopped pressing or until 8 hr had elapsed. The ratio value reached (and the total number of lever presses) was an inverted-U function of food deprivation (percentage body weight). In Experiment 2, when wheel running preceded test sessions, fewer food-reinforced lever presses were maintained by the progressive-ratio schedule, and responding occurred at a lower rate on a variable-interval schedule. An interpretation of these results is that deprivation or satiation with respect to one event (such as food) alters the reinforcement effectiveness of a different event (such as access to wheel running).