Avoidance of timeout from response-independent food: effects of delivery rate and quality

In three experiments, a rat's lever presses could postpone timeouts from food pellets delivered on response-independent schedules. In Experiment 1, the pellets were delivered at variable-time (VT) rates ranging from VT 0.5 to VT 8 min. Experiment 2 replicated the VT 1 min and VT 8 min conditions of Experiment 1 with new subjects. Finally, subjects in Experiment 3 could postpone timeouts from delivery of pellets that differed in quality rather than quantity (unsweetened versus sweetened pellets). In general, response rates and success in avoiding increased as a function of the rate and quality of the pellets. Also, performance efficiency increased as the experiments progressed, that is, the avoidance response occurred later and later in the response-timeout interval. The results support the conclusion that timeout from reinforcement has functional properties similar to those of more commonly studied aversive stimuli (e.g., shock).     

Dissociations among ABA, ABC, and AAB recovery effects

In a human predictive learning experiment, the strengths of ABA, ABC, and AAB recovery effects after discrimination reversal learning were compared. Initially, a discrimination between two stimuli (X+, Y−) was trained in Context A. During Phase 2, participants received discrimination reversal training (X−, Y+) either in Context A (Group AAB) or in Context B (Group ABA, Group ABC). Testing occurred in the reversal context and in a neutral context (Group AAB, Group ABC) or in the reversal context and in the acquisition context (Group ABA). Recovery effects were similar in ABA and ABC procedures, whereas no AAB recovery effect occurred. Furthermore, the rate of discrimination reversal learning during Phase 2 was unaffected by whether training was conducted in the same or in a different context as initial learning. Results indicate that contextual stimuli are processed before interfering information is presented. These representations, however, do not acquire the ability to control performance.     

The effects of signaling stimulus presentation during noncontingent reinforcement

The effects of signaling the return of items or attention during treatment with noncontingent reinforcement were examined. First, functional analyses showed that the problem behavior exhibited by 2 teenagers with developmental disabilities was sensitive to social positive reinforcement. Next, delivery of the stimulus that maintained problem behavior on a fixed-time (FT) schedule was compared to a condition in which the removal of the stimulus during the same FT schedule was immediately preceded by a statement indicating that the stimulus would be returned and the initiation of a digital timer. Results show that the FT schedule reduced problem behavior, and the addition of an informative statement and a timer further decreased problem behavior.     

IRT-stimulus contingencies in chained schedules: implications for the concept of conditioned reinforcement

Two experiments with pigeons investigated the effects of contingencies between interresponse times (IRTs) and the transitions between the components of 2- and 4-component chained schedules (Experiments 1 and 2, respectively). The probability of component transitions varied directly with the most recent (Lag 0) IRT in some experimental conditions and with the 4th (Lag 4) IRT preceding the most recent one in others. Mean component durations were constant across conditions, so the reinforcing effect of stimulus change was dissociated from that of delay to food. IRTs were longer in the Lag-0 than in the Lag-4 conditions of both experiments, thus demonstrating that stimulus change functioned as a reinforcer. In the Lag-0 conditions of Experiment 2, the Component-1 IRTs increased more than the Component-2 IRTs, which in turn increased more than the Component-3 IRTs. This finding runs counter to the conditioned-positive-reinforcement account of chained-schedule responding, which holds that the reinforcing effect of stimulus change should vary in strength as an inverse function of the delay to the unconditioned reinforcer at the end of the chain because conditioned reinforcement is due to first- or higher-order classical conditioning. Therefore, we present other possible explanations for this effect.     

A model for residence time in concurrent variable interval performance

A component-functions model of choice behavior is proposed for performance on interdependent concurrent variable-interval (VI) variable-interval schedules based on the product of two component functions, one that enhances behavior and one that reduces behavior. The model is the solution to the symmetrical pair of differential equations describing behavioral changes with respect to two categories of reinforcers: enhancing and reducing, or excitatory and inhibitory. The model describes residence time in interdependent concurrent VI VI schedules constructed from arithmetic and exponential distributions. The model describes the data reported by Alsop and Elliffe (1988) and Elliffe and Alsop (1996) with a variance accounted for of 87% compared to 64% accounted for by the Davison and Hunter (1976) model and 42% by Herrnstein's (1970) hyperbola. The model can explain matching, undermatching, and overmatching in the same subject under different procedures and has the potential to be extended to performance on concurrent schedules with more than two alternatives, multiple schedules, and single schedules. Thus, it can be considered as an alternative to Herrnstein's quantitative law of effect.     

Religion as schedule-induced behavior

In this article, I argue that a class of religious behaviors exists that is induced, for prepared organisms, by specific stimuli that are experienced according to a response-independent schedule. Like other schedule-induced behaviors, the members of this class serve as minimal units out of which functional behavior may arise. In this way, there exist two classes of religious behavior: nonoperant schedule-induced behaviors and operant behaviors. This dichotomy is consistent with the distinction insisted upon by religious scholars and philosophers between "graceful" and "effortful" religious behaviors. Embracing the distinction allows an explanation of many aspects of religious experience and behavior that have been overlooked or disregarded by other scientific approaches to religion.     

Stimuli, Reinforcers, and the Persistence of Behavior

This article reviews evidence from basic and translational research with pigeons and humans suggesting that the persistence of operant behavior depends on the contingency between stimuli and reinforcers, and considers some implications for clinical interventions.     

Caffeine reinforces flavor preference and behavior in moderate users but not in low caffeine users

The study examined the role of caffeine consumption in caffeine reinforcement. Previous findings have shown that caffeine reinforced flavor preference in moderate caffeine consumers who are caffeine deprived. However, most of these studies have employed rating procedures only, and have not shown the effectiveness of caffeine to reinforce behaviors other than through subjective ratings. Twenty-five participants (15 low caffeine consumers, and 10 moderate caffeine consumers) were each given three exposures to a caffeinated drink, and three exposures to a non-caffeinated drink. Each drink was associated with a particular color. At each session, they were asked to rate the pleasantness of the drink, and choose from distinctively colored sweets. The results showed an increase in the rating of pleasantness for the caffeinated drink in moderate caffeine consumers, but a decrease in rated pleasantness for low caffeine consumers. The opposite effect was seen for the non-caffeinated drink. There was an increase in consumption of the number of sweets with the same color as that of the caffeine-paired drink in the moderate caffeine consumers. These findings suggest that caffeine may serve as a negative reinforcer, and that the alleviation of withdrawal symptoms may be associated with the flavor and appearance of the caffeinated drink.     

Short-term gains, long-term pains: How cues about state aid learning in dynamic environments

Successful investors seeking returns, animals foraging for food, and pilots controlling aircraft all must take into account how their current decisions will impact their future standing. One challenge facing decision makers is that options that appear attractive in the short-term may not turn out best in the long run. In this paper, we explore human learning in a dynamic decision making task which places short- and long-term rewards in conflict. Our goal in these studies was to evaluate how people’s mental representation of a task affects their ability to discover an optimal decision strategy. We find that perceptual cues that readily align with the underlying state of the task environment help people overcome the impulsive appeal of short-term rewards. Our experimental manipulations, predictions, and analyses are motivated by current work in reinforcement learning which details how learners value delayed outcomes in sequential tasks and the importance that “state” identification plays in effective learning.     

Assessing reinforcers under progressive schedule requirements.

Recent research findings suggest that reinforcing stimuli may be differentially effective as response requirements increase. We extended this line of research by evaluating responding under increasing schedule requirements via progressive‐ratio schedules and behavioral economic analyses. The differential effectiveness of preferred stimuli in treating destructive behavior maintained by automatic reinforcement also was examined. Results showed that one of two stimuli was associated with more responding under increasing schedule requirements for the 4 participants. Furthermore, stimuli associated with more responding under increasing schedule requirements generally were more effective in treating destructive behavior than stimuli associated with less responding. These data suggest that progressive‐ratio schedules and behavioral economic analyses may be useful for developing a new technology for reinforcer identification. From a clinical perspective, these results suggest that two reinforcers may be similarly effective for low‐effort tasks and differentially effective for high‐effort tasks.