Journal of the experimental analysis of behavior最新文献

Rats responded under a concurrent-chains procedure wherein reinforcement magnitude was varied within sessions and oxycodone's effects on sensitivity to magnitude were evaluated in two experiments. In Experiment 1, the alternative providing the larger magnitude was signaled and effects of acute (0.1–1.0 mg/kg) and chronic (1.0 mg/kg, twice daily) oxycodone administration were examined in female and male rats. Under baseline, sensitivity was slightly higher for females than males. Acute oxycodone decreased sensitivity in both sexes, but females were more susceptible to this effect. Effects of chronic administration on sensitivity were somewhat variable; on average, females showed slight tolerance and males showed slight sensitization to this effect. No physical dependence was noted during withdrawal probes. In Experiment 2, the alternative providing the larger magnitude was not signaled and effects of acute oxycodone were evaluated in a separate group of male rats. Sensitivity was higher under baseline, and larger doses reduced sensitivity to a greater extent in Experiment 2 than in Experiment 1. Taken with previous data on oxycodone's effects on sensitivity to reinforcement delay, oxycodone would be expected to leave impulsive choice unchanged in both sexes. Additional analyses revealed that oxycodone's effects on sensitivity in both experiments were baseline dependent: higher sensitivities were reduced to a greater extent than lower sensitivities.

The effects of punishment rate on response allocation were investigated using a choice procedure where relative reinforcement rates changed rapidly within session. Predictions from a modified version of the direct-suppression model were tested in two separate experiments. In both experiments, sessions were composed of seven unsignaled components, each programming a different reinforcement ratio. In Experiment 1, equal punishment rates were superimposed on the schedule of reinforcement for both responses and absolute punishment rates increased across blocks of sessions. Punishment increased preference for the richer schedule of reinforcement, but the degree of the preference shift was not a function of absolute punishment rates. In Experiment 2, unequal punishment rates were superimposed on the schedules of reinforcement for both responses and relative punishment rates changed across blocks of sessions. Response allocation shifted away from the richer punishment schedule creating a bias toward the option associated with less frequent punishment. The results from both experiments challenged the predictions of the direct-suppression model. Furthermore, fits of the generalized matching law to the data indicated that superimposition of equal or unequal punishment schedules on responses maintained by unequal reinforcement schedules differentially affect the values of sensitivity and bias.

The purpose of this experiment was to explore whether simultaneous access to consequences configures a defining functional feature of coordination. We evaluated whether coordination episodes are maintained when reinforcers are alternately presented to two cooperating rats across these episodes, in contrast to the delivery of reinforcers simultaneously for both rats and independently for each rat. Rat pairs responded under either a tandem fixed-interval (FI) 10-s FI 10-s or a tandem variable-interval (VI) 10-s VI 10-s schedules. In the baseline, lever presses of each rat were individually reinforced according to the tandem FI FI schedule. In two simultaneous reinforcement conditions, reinforcer deliveries depended on coordination episodes under either tandem schedule. In two alternated reinforcement conditions, rats accessed reinforcers in alternation under either tandem schedule. Two main findings are reported: (1) proportions of coordination were consistently higher under the simultaneous than under the alternated reinforcement condition regardless of the type of tandem schedules (FI or VI) and (2) proportions of coordination were similar in the individual and alternated reinforcement conditions. Although the obtained reinforcement rates limit a conclusive evaluation, these findings indicate that the simultaneous delivery of reinforcers (mutual reinforcement) is a critical variable in the operant selection of coordinated responding.

Under rapid-acquisition, concurrent-chains choice procedures, psychomotor stimulants typically decrease the sensitivity of responding to changes in separate dimensions of reinforcement. Across two experiments, pigeons chose between outcomes that differed in terms of reinforcement delay and magnitude (the dimensions involved in delay discounting or “impulsive” choice; Experiment 1) or reinforcement probability and magnitude (the dimensions involved in probability discounting or “risky” choice; Experiment 2). Outcomes associated with each terminal link were varied independently and pseudorandomly across sessions such that in dominated sessions one terminal link was favorable in terms of both dimensions (sooner, larger in Experiment 1 and more likely, larger in Experiment 2) and in trade-off sessions each terminal link was favorable in terms of a different dimension. Response allocation in initial links tracked changes in terminal-link outcomes in a manner that suggests each dimension contributed additively and independently to choice. Methylphenidate decreased sensitivity to all dimensions of reinforcement at a dose (or doses) that did not substantially affect bias or initial-link response rates. The degree to which methylphenidate decreased sensitivity was related to baseline sensitivity for delay and magnitude but not for probability. Baseline dependency may be a more useful approach for predicting drug effects on delay/impulsive, rather than risky, choice.

The extinction burst is an increase in an operant behavior early in the transition to extinction. A matching-law-based quantitative theory suggests that it results from the elimination of competition from reinforcement-related behavior that accompanies the transition to extinction. This experiment examined the effects of reinforcement magnitude on the extinction burst with rats. Responding produced either 1 pellet or 6 pellets prior to a within-session transition to extinction. Baseline response rates were lower with 6 pellets than with 1 pellet but increased more in the first minute of extinction following 6 pellets. Furthermore, an order effect was observed where rats having first experienced extinction following 1 pellet showed a smaller extinction burst when subsequently trained with 6 pellets—an outcome resulting from a faster deceleration of responding during extinction. The model described the data well, including the order effect, when augmented to include the potential asymmetrical influence of learning to discriminate the continued absence of different magnitudes of reinforcement. We conclude that the approach holds promise by formally incorporating the extinction burst into the corpus of matching theory and serving as an example of the utility of better aligning basic research methods and theorizing with areas of applied concern.

Behavioral economics offers a framework for understanding choice making around public health concerns such as drug use and distracted driving. Such a framework could be beneficial to understanding caregiver choices related to arranging an infant sleep environment. Nonadherence to infant sleep safety guidelines provided by the American Academy of Pediatrics increases the risk of sleep-related infant deaths. The present study adopted a willingness-to-accept purchase task procedure, used in previous research to evaluate variables that predict abstaining from consuming alcohol, to evaluate intention to adhere to recommendations for arranging a safe infant sleep environment. This analysis would inform contingency management incentive scales used to measure caregiver adherence following training caregivers to arrange an infant sleep environment and identify variables that might predict treatment engagement. The results identified incentive sizes, condition duration, and participant variables that predict caregiver adherence. The results can be applied to future investigations that train caregivers to arrange an infant sleep environment.

The development of schedule-induced drinking depends on different variables affecting the food delivered at the end of the interfood interval. There are mixed results concerning the effects of varying magnitude and/or preference of different reinforcers in the development of schedule-induced drinking, with some studies showing higher levels and other studies showing lower levels of drinking. The purpose of this study was to observe how differences in preference for a flavor of equally nutritious food pellets influence the development and maintenance of schedule-induced drinking. Using the operant demand framework, four flavors of food pellets were compared to form two groups: one in which subjects would receive their most preferred flavor and another in which subjects would receive their least preferred flavor. In general, licking rates were lower and magazine-entering rates were higher when the preferred flavor was delivered regardless of the fixed-time schedule used. It is suggested that the value of the reinforcer has a larger influence on the immediately preceding behaviors, which will determine the distribution of competing responses in the interreinforcement intervals. These results are relevant to developing public policies that manipulate the taste of healthy food to increase its consumption.

Obesity may be more prevalent among populations who are of low socioeconomic status, have limited access to nutrient-dense foods, or both. One such population is justice-involved youth. This series of translational experiments builds on previous research on food reinforcement and behavioral demand by (a) assaying demand for snack foods among justice-involved adolescents and (b) evaluating the effect of a nutrition intervention on justice-involved adolescents' demand for healthier alternatives. In Experiment 1, participants completed preference assessments for high- and low-energy-density snack foods and corresponding commodity purchasing tasks. The results indicated significant differences in demand based on energy density and preference. In Experiment 2, justice-involved adolescents received a nutrition intervention. Following intervention, participants repeated preference assessments and commodity purchasing tasks. The researchers used mixed-effects modeling to evaluate the effect of (a) the intervention, (b) participant age, and (c) the amount of intervention received on pre–post differences in demand for healthier alternatives. Results and implications are discussed along with future directions for improving conditions of confinement for justice-involved adolescents.

Different personal information types are shared at different rates during a social-discounting task. However, it is unclear whether differences in social-discounting rates between different personal information types are related to differences in valuing personal information. To assess the value of personal information more directly, 160 university student participants completed four hypothetical purchase tasks (HPT) for protecting identification, health, security, and financial personal information at 17 ascending price points and a social-discounting task for one of those four different personal information types. The results for social discounting partially replicated those of a previous study where discounting rates for health information were higher than those for financial information. The results for the HPT largely mirrored those for the social-discounting task. The demand for protecting financial information was significantly higher relative to the that for the other three types of personal information for most demand indices such as the highest price participants were willing to pay for the protection of personal information (break point) and the price where consumption for personal information protection became elastic (P_max). However, there were no significant relations between social-discounting rate and HPT demand indices. These results show that value may play a role in the observed differences in social-discounting rate for personal information, but additional factors likely contribute to these differences.