Up or down: the influence of upcoming reinforcement on consummatory and operant behavior

Research has shown that animal subjects that are given a chance to consume a low-valued substance will consume less of it if a high-valued substance will soon be available than they would if the low-valued substance were to remain available (negative consummatory contrast). Research has also shown that subjects that lever press for a low-valued reinforcer will press the lever more often for that reinforcer if they will soon be able to lever press for a high-valued reinforcer than they would if they continue to press for the low-valued reinforcer (positive induction). The present study investigated these different changes in behavior across 3 experiments. The results suggest that the occurrence of contrast or induction does not depend on the type of substances that are used. We argue that further investigation of the contrast vs. induction issue is warranted because it has empirical, theoretical, and applied implications.     

Suppression of operant behavior and schedule-induced licking in rats

The first experiment studied the effects of punishment on rats' lever pressing maintained by a fixed-interval schedule of food reinforcement and on the associated schedule-induced licking. When licking was followed by shock, licking was suppressed but lever pressing was largely unaffected. When lever pressing was followed by shock, lever pressing was suppressed but licking was unaffected. In both cases, the punished behavior recovered its previous unpunished level when the shocks were discontinued. In a second experiment, the rats' lever pressing was maintained by a variable-interval schedule of food reinforcement under which polydipsic licking also developed. Both lever pressing and licking were partially suppressed during a stimulus correlated with occasional unavoidable electric shocks. With a higher shock intensity, both behaviors were suppressed further. Both lever pressing and licking recovered their previous levels when shocks were discontinued. These results show that schedule-induced licking, which has been described as adjunctive behavior, can be suppressed by procedures that suppress reinforced lever pressing, an operant behavior.     

Aldactazide-induced consummatory and operant responding to sodium by rats.

The effects of intraperitoneal injections of Aldactazide-A on rats' consumption of water and saline solution (.51M NaCl) were tested in two experiments. During the treatment sessions, the rats showed a substantial increase in saline consumption and in lever pressing to a cue light to obtain the saline, as compared with their negligible intake before the injections and after the injections had been discontinued. The results indicate that both the drinkometer and operantbox measures are sensitive to the natroexigenic effects of Aldactazide.     

Spontaneous recovery of consummatory behavior, but not of consummatory successive negative contrast

Five experiments were designed to study spontaneous recovery (SR) in two situations involving consummatory behavior: consummatory successive negative contrast (cSNC) and consummatory extinction (cE). SR of consummatory suppression should occur if incentive downshift induces an egocentric memory encoding information about the emotional reaction to the downshift that is counterconditioned or extinguished during exposure to the downshifted reward. SR of cSNC failed to occur after resting periods of 24, 96, or 336 h interpolated following complete (Experiment 1) and incomplete (Experiment 2) recuperation of consummatory behavior, and was not induced by the opioid-receptor antagonist naloxone (2 mg/kg), known to enhance cSNC (Experiment 3). However, SR of consummatory behavior occurred across sessions in cSNC (Experiment 3) and cE (Experiments 4-5). Furthermore, naloxone facilitated cE without affecting SR (Experiments 4-5). These results are discussed in relation to evidence for the development of an egocentric memory of the aversive downshift experience in consummatory situations.     

Measurement of consummatory behavior in honey bees

Consummatory behavior in honey bees can be measured by recording contact of the proboscis with sucrose solution in the food cup of an automatic feeder, and the behavior can be instrumentalized by arranging for contact of the proboscis with the food cup to activate the feeder. Illustrative free-operant and discrete-trials data are presented.     

Scaling relative incentive value in consummatory behavior

Surprising downshifts from more preferred (training incentive) to less preferred incentives (test incentive) are usually accompanied by emotional activation and suppression of conditioned behavior in rats. Two experiments were designed to determine whether consummatory behavior is similarly affected by downshifts of equal proportions. Within limits, the degree of consummatory responding during incentive downshift was similar with equal ratios of test concentration to training concentration. Thus, 32–4% and 16–2% downshifts (1:8 test/training ratios) caused similar levels of consummatory behavior, despite differences in the absolute concentrations of the solutions involved in the downshift. An interpretation based on sensory contrast was discarded because of the long intervals between training and test solutions (40 min and 24 h in Experiments 1 and 2, respectively). It is suggested that Weber’s law regulates behavioral suppression after reward downshifts. A theoretical framework for the interpretation of these data is presented.     

Improved techniques for the measurement of consummatory behavior in fishes

Improvements on a technique for the study of consummatory behavior and appetitive conditioning in fishes are described: a target-strike detector module easily incorporated into conventional relay programming equipment, a liquid-food formula highly attractive to goldfish and carp, a reliable Teflon-headed syringe plunger capable of handling gritty foods, and a silent food-pumping system.     

Disrupted patterns of consummatory behavior in rats with fornix transections

The feeding and drinking behavior was examined in male rats with fornix transections and sham-operated control rats. Total food and water consumption was recorded but supplemented by a pattern analysis of feeding and drinking behavior. The behavior of the rats was continuously monitored during four hour morning and afternoon sessions under ad lib access and during a two hour session following adaptation to a restricted access feeding schedule. Rats with fornix transections were more active and exhibited increased frequencies of rearing, eating and drinking. The increased meal frequency in rats with fornix transections was accompanied by decreased meal durations and a reduction in the length of intermeal intervals. Total food and water consumption was unaffected by fornix transection as were the duration of sleep bouts and the frequencies of grooming, sleeping and carrying shavings. Fornix transections also reduced food carrying and food hoarding but only under conditions of restricted food access. The results suggest that fornix transection does not alter major homeostatic regulatory mechanisms nor does it alter the components of feeding and drinking behavior. Fornix transection alters, instead, the organization of microregulatory feeding and drinking patterns.     

Derived relational responding as generalized operant behavior

The major aim of the present study was to demonstrate that derived relational responding may be viewed as a form of generalized operant behavior. In Experiment 1, 4 subjects were divided into two conditions (2 in each condition). Using a two-comparison matching-to-sample procedure, all subjects were trained and tested for the formation of two combinatorially entailed relations. Subjects were trained and tested across multiple stimulus sets. Each set was composed of novel stimuli. Both Conditions 1 and 2 involved explicit performance-contingent feedback presented at the end of each block of test trials (i.e., delayed feedback). In Condition 1, feedback was accurate (consistent with the experimenter-designated relations) following exposure to the initial stimulus sets. When subjects' responding reached a predefined mastery criterion, the feedback then switched to inaccurate (not consistent with the experimenter-designated relations) until responding once again reached a predefined criterion. Condition 2 was similar to Condition 1, except that exposure to the initial stimulus sets was followed by inaccurate feedback and once the criterion was reached feedback switched to accurate. Once relational responding emerged and stabilized, response patterns on novel stimulus sets were controlled by the feedback delivered for previous stimulus sets. Experiment 2 replicated Experiment 1, except that during Conditions 3 and 4 four comparison stimuli were employed during training and testing. Experiment 3 was similar to Condition 1 of Experiment 1, except that after the mastery criterion was reached for class-consistent responding, feedback alternated from accurate to inaccurate across each successive stimulus set. Experiment 4 involved two types of feedback, one type following tests for mutual entailment and the other type following tests for combinatorial entailment. Results from this experiment demonstrated that mutual and combinatorial entailment may be controlled independently by accurate and inaccurate feedback. Overall, the data support the suggestion, made by relational frame theory, that derived relational responding is a form of generalized operant behavior.