Journal of the experimental analysis of behavior最新文献

Tobacco use is the leading cause of death globally and in the United States. After decades of decline, driven by decreases in combusted tobacco use, nicotine product use has increased due to electronic nicotine delivery systems, also known as e-cigarettes or vapes. Preclinical models of nicotine self-administration can serve as important lodestars in the search for effective intervention and prevention tactics. Current variants of the preclinical models have substantial limitations, however. Therefore, we created the rodent electronic nicotine delivery system (RENDS), a novel low-cost nonproprietary nose-only preclinical model of nicotine aerosol self-administration. We confirmed that RENDS sequesters nicotine aerosol in the nose port by measuring fine particulate matter (PM <2.5 microns) generated by e-cigarettes. We also showed that rats robustly self-administer flavored nicotine aerosol, resulting in high blood levels of cotinine (the major nicotine metabolite) and spontaneous somatic withdrawal symptoms. Thus, we provide validation of the operation and function of the RENDS, opening the door to an open-source preclinical aerosol model of nicotine self-administration that is relatively low in cost. Four existing operant chambers can be retrofitted with the RENDS for less than $325/chamber. All RENDS diagrams and plans for custom-designed components are on Open Science Framework (https://osf.io/x2pqf/?view_only=775b55435b8e428f98e6da384ef7889d).

Robots are increasingly used alongside Skinner boxes to train animals in operant conditioning tasks. Similarly, animals are being employed in artificial intelligence research to train various algorithms. However, both types of experiments rely on unidirectional learning, where one partner-the animal or the robot-acts as the teacher and the other as the student. Here, we present a novel animal-robot interaction paradigm that enables bidirectional, or mutual, learning between a Wistar rat and a robot. The two agents interacted with each other to achieve specific goals, dynamically adjusting their actions based on the positive (rewarding) or negative (punishing) signals provided by their partner. The paradigm was tested in silico with two artificial reinforcement learning agents and in vivo with different rat-robot pairs. In the virtual trials, both agents were able to adapt their behavior toward reward maximization, achieving mutual learning. The in vivo experiments revealed that rats rapidly acquired the behaviors necessary to receive the reward and exhibited passive avoidance learning for negative signals when the robot displayed a steep learning curve. The developed paradigm can be used in various animal-machine interactions to test the efficacy of different learning rules and reinforcement schedules.

Due to the undesirable effects of operant renewal for behavioral interventions, recent research has advocated for the advancement of renewal mitigation strategies. One strategy includes the use of extinction cues, which are stimuli used to establish discriminative control over responding in the second context that are subsequently transferred to the initial context. A second strategy involves context fading, which refers to progressively increasing the similarity between the second context and the initial context. The current study evaluated the separate and combined effects of these techniques using a preclinical human laboratory arrangement. Participants were exposed to the extinction cue strategy, the context fading strategy, both strategies, or neither strategy during a three-phase ABA renewal procedure using differential reinforcement of an alternative response combined with extinction. The results indicated that context fading or combining context fading with an extinction cue was effective at mitigating renewal. The use of an extinction cue alone reduced renewal relative to the control group, but this difference was not statistically significant. The results are discussed in terms of methodological and theoretical differences across strategies as well as implications for future research on renewal mitigation strategies.

The role of bidirectional naming in the emergence of analogical relations was investigated in four typically developing children between the ages 5 and 7 years. All participants learned to tact both the categories (clothes, furniture, and vehicles) and relations (same and different) among nine stimuli. They were subsequently tested on analogical responding during which they were presented with two stimuli belonging to the same or different categories and asked to select the comparison that matched the sample. During the last analogy test, we asked participants to tell us why they selected a certain comparison. Relational tact training produced emergent analogical responding in two participants after exposure to relational listener tests, whereas the other two required direct training on baseline analogy relations. All participants met criterion during derived analogy tests in accordance with symmetry and transitivity. The results of this study suggest that participants passed analogy tests by relationally tacting the sample (i.e., speaker) and reacting to its product by selecting the correct comparison (i.e., listener). This supports and extends previous findings suggesting that children must also engage in behaviors consistent with bidirectional naming to respond accurately to analogy tasks.

Following the COVID-19 pandemic, it is vital to understand how major global stressors influence substance use, including cannabis-related outcomes. The Marijuana Purchase Task assesses hypothetical cannabis demand (i.e., relative reinforcing value) and can detect contextual alterations. This study paired prospective cannabis demand assessment with qualitative inquiry to explore how COVID-19 impacted cannabis use behavior. Individuals previously enrolled in a laboratory cannabis administration study opted in to a remote follow-up survey (n = 41, 46% female). Participants were categorized as those who did or did not increase use based on self-reported changes in cannabis flower use and provided contextual explanations regarding pandemic-related influences on cannabis outcomes. General linear models with repeated measures examined mean differences in demand by occasion (i.e., before/during COVID-19), group (i.e., those who did/did not increase use), and their interaction. Those who increased use exhibited significantly higher demand during the pandemic; those who did not increase use exhibited similar demand across time revealing a Group × Time interaction. Thematic analysis contextualized quantitative findings, explaining external influences that affect use and demand (e.g., changes in cost, access, environment). COVID-19 differentially impacted cannabis use and demand, with prepandemic use affecting trajectories. Contextual influences (i.e., availability, free time, income) facilitate the escalation of use under conditions of extreme global stress.

Previous research has demonstrated several procedural modifications that improve the sensitivity of human behavior to relative rates of conditioned reinforcement or S+ production. Denser rates of reinforcement have proved useful in related human operant research, but the influence of denser rates of S+ production has yet to be evaluated. The purpose of the current study was to evaluate how the absolute S+ production rate influenced sensitivity to relative S+ production rate. Thirty undergraduate students were randomly assigned to three groups for which the absolute rate of S+ production varied but the programmed relative rate of S+ production was held constant across groups. Results similar to those of previous research were obtained with many participants; however, the absolute rate of S+ production exerted no systematic effect on sensitivity or the quality of fits of the generalized matching equation. Exploratory analyses suggest that methods ensuring steady-state responding and improving the predictive value of S+ are important directions for future research.

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.