Journal of the experimental analysis of behavior最新文献

Midsession reversal examines behavioral flexibility by requiring animals to reverse a discrimination midway within a session. This reversal behavior is controlled by changing temporal factors over the session. We tested behavioral flexibility in pigeons by reversing the contingencies within a session from a visual matching-to-sample (MTS) task to a non-matching-to-sample (NMTS) task. To examine how visual context influenced the reversal, the stimuli were assigned according to two different mapping conditions. In the bounded mapping condition, different stimuli exclusively appeared in either the MTS or NMTS for half of the session, and in the unbounded condition, the stimuli appeared across both the MTS and NMTS halves of a session. In the unbounded condition, pigeons showed a modest switching function, from matching to non-matching, at the reversal boundary. In contrast, in the bounded condition, the pigeons learned the contingences faster and to a higher accuracy and exhibited a more precise switching function at the reversal. The latter outcome suggests there was little or no temporal interference, as the different visual contexts allowed the MTS and NMTS tasks to be segregated within a session. These contrasting results show that reversal interference in the midsession reversal task is influenced by context and temporal factors, with corresponding implications for behavioral flexibility.

Rats are a social species, often used as a research model to study social behavior. However, isolating the factors (i.e., environmental stimuli, experiences with social interactions, novelty, etc.) that influence rats' social behavior can be difficult in many existing social choice assessments. A procedure that may help researchers investigate these variables more systematically is the olfactory choice procedure. The present set of experiments used a free-operant olfactory choice procedure to assess individually housed female rats' preference for social and nonsocial scents. In Experiment 1, rats ran daily sessions in which a response to a nose-poke port produced either a social or nonsocial scent. A response to a second nose-poke port produced a control scent. In Experiment 2, the same female rats could respond in one nose-poke port to produce a social scent and in a second port to produce a nonsocial scent. The results from Experiment 1 indicate that rats prefer social and nonsocial scents over a control scent and that this preference persists across a location reversal and 100+ daily sessions. Although there were individual differences, group results from Experiment 2 suggest that rats prefer social and nonsocial scents relatively equally.

Antecedent stimulus prevalence can affect detectability. Two contrasting effects have been reported in humans. The low-prevalence effect is when participants are less likely to report the presence of the target stimulus when it occurs with low prevalence. Recently, an opposite effect has been discovered in which participants are more likely to report the presence of low-prevalence stimuli. There is little if any research on stimulus prevalence with nonhuman animals; therefore, the present study investigated prevalence effects in rats to extend species generality, determine which effect would occur, and identify controlling variables. Rats were trained to press left and right levers conditional on the flash rate of the sample stimulus (1 or 5 Hz). A between-group, within-subject comparison in which the two flash rates were not always equally prevalent was employed. Low-prevalence stimuli were underreported, systematically replicating the low-prevalence effect. Rats initially trained under the unequal-prevalence condition failed to acquire or took longer to acquire high accuracy with the low-prevalence stimulus but quickly achieved high accuracy with the high-prevalence stimulus. Subsequent training under equal-prevalence conditions remediated these effects, and prior training under equal prevalence seemed to offer a protective effect from later decreases in stimulus prevalence.

The amount of time that organisms spend on a variable-interval schedule of a concurrent pair before departing to the other one (i.e., the dwell time on the schedule) follows an exponential distribution, meaning that the probability of switching to the other schedule does not increase or decrease throughout the visit. This appears to reflect an innate behavioral pattern and implies that concurrent-schedule performance can be modeled using continuous-time Markov chains. In the two-alternative case, the behavior of a Markov chain is completely determined by the leaving rates from each alternative (i.e., the number of departures per unit of time), so finding expressions for these leaving rates should suffice to completely characterize changeover behavior in concurrent schedules. Such expressions can be derived from the matching law in combination with either the mathematical principles of reinforcement or Baum's laws of allocation, induction, and covariance. The resulting equations are assessed in the particular case of concurrent variable-interval schedules using a large data set from a published study that systematically manipulated both the relative and the overall rates of reinforcement, resulting in excellent fits. The performance of the model is also assessed against that of competing models, proving to be superior in most cases.

Concepts can be taught by presenting examples and nonexamples and giving the learner feedback on whether they accurately identify the examples, but it is not clear how to select examples and nonexamples. Specifically, the degree to which examples and nonexamples should differ is unknown. Six experiments were conducted to compare conceptual learning for four stimulus sets (three sets of arbitrary stimuli and one set of biological stimuli) across up to three practice conditions: (a) nonexamples that were relatively similar to the examples, (b) nonexamples that were relatively dissimilar to the examples, and (c) examples only. Conceptual learning was measured before and after practice using tests with examples and nonexamples that were not used during practice. Including nonexamples in practice increased the likelihood of conceptual learning relative to including only examples. Using nonexamples that were more similar to the examples resulted in the most robust conceptual learning. Adding new but conceptually irrelevant features to the testing stimuli disrupted conceptual learning but less so when the practice included nonexamples that were more similar to the examples. The efficacy and efficiency of instruction for conceptual learning were affected by features of the stimuli used to practice and test conceptual learning.

We conducted a series of studies on the effects of synchronous reinforcement. Study 1 presented 30 participants with their high-preference (HP) music, identified via a conjugate assessment, for walking on a treadmill during three synchronous reinforcement (SYNC) components. The results indicated that HP music produced schedule control of walking speed for 20 participants (66.7%). In addition, 80% of the participants who displayed schedule control also displayed variable walking speeds when music was withheld. Study 2 extended Study 1 by providing 30 new participants with their low-preference (LP) music, again using the same conjugate assessment, for walking on a treadmill during the same three SYNC components. The results indicated that LP music produced schedule control of walking to (a) avoid music for 13 participants (43.33%) and (b) access music for two participants (6.67%). Study 3 compared group results across components for HP and LP participants from Studies 1 and 2, respectively. The results indicated that that the HP group walked significantly faster than the LP group during three components; however, heart rates did not differ statistically between the two groups for any component. The results across the studies indicate that both positive and negative synchronous reinforcement with music increased the walking speeds and heart rates of participants.

The effects of the magnitude of reinforcement on the resistance to change of humans engaged in a computer task were examined in two experiments. In each, responding was disrupted by increasing the force requirement of the required response. In Experiment 1, the participants were exposed to a multiple variable-interval (VI) VI schedule of reinforcement. Responses meeting the VI requirement resulted in the addition of a monetary value to the computer screen. At the end of each session, the monetary value was exchanged for real money. In Experiment 2, snacks or money provided at the time earned were the reinforcers. There was no differential resistance to change as a function of reinforcer magnitude in either experiment. These findings led to Experiment 3, in which the participants from Experiment 2 were exposed to schedules arranging different reinforcement rates using as reinforcers snacks, money at the time it was earned, and points exchangeable for money at the session's end. There was greater resistance to change in the VI component with a higher reinforcement rate. The results are discussed in relation to the varied effects of reinforcer magnitude on both response rates and resistance to change.

The purpose of the current study was to compare the efficacy and efficiency of video-based observational learning (OL) with traditional match-to-sample (MTS) training to establish three 3-member equivalence classes of abstract visual stimuli with adult participants. Video models used during OL depicted a first-person perspective of a computer screen with modeled on-screen movements of a mouse cursor making comparison selections. Adult participants in the OL-mixed group received training in which the video models depicted progressive increases in correct responding of modeled baseline relations across five blocks of trials. Participants in the OL-expert group received identical training except that the models always depicted 100% correct responding across the five modeled trial blocks. Participants in the MTS group actively responded while completing five blocks of traditional MTS training. Posttest results showed that OL-mixed training resulted in the highest mean percentage of class-consistent responding and yield of equivalence classes relative to traditional MTS and the OL-expert group despite minimal differences in total duration during training. Across the groups, nearly all who successfully demonstrated equivalence class formation during the computerized posttest also showed generalization of class-consistent responding during the card sorting posttest. The results showed that OL-mixed training was most effective and that the procedures were similarly efficient.

The present study analyzed the eye movement patterns of five typically developed adults who were exposed to a series of simple discrimination training tasks with reversals in the contingencies of reinforcement that led to the formation of functional stimulus classes. Two studies were planned. In Study 1, two visual stimuli were used to carry out one training phase and three consecutive reversals. In Study 2, the phases were repeated but four-stimuli functional classes were established. In the second study, the selective observing responses to stimuli of functional classes following the reversal of the first stimulus were analyzed. The results showed shifts in the duration of observing responses as the discriminative functions of the stimuli were established and reversed. Unlike the existing literature, our study reveals that some participants maintain longer observing responses to S– than to S+. Moreover, following the reversal of the first stimulus, observing responses to all other stimuli of the same functional class change immediately and accordingly. These findings deepen our understanding of discriminative stimulus control and shed light on the role of observing responses to stimuli composing functional classes.

This study was an investigation of the utility of behavioral economic demand curves (quantitative models showing how consumption changes with price) in assessing acceptance of hypothetical HIV vaccines among sexual and gender minorities (SGMs). Two experiments used simulated purchase tasks (hypothetical scenarios measuring purchasing decisions). SGMs were recruited through Reddit and LGBTQ+ community organizations across the United States. In Experiment 1, participants were randomly assigned to nine instructional sets combining varying vaccine administration modes (oral, mucosal, or subcutaneous) with different dosage schedules (one dose, two doses, or one dose annually). Experiment 2 examined how bundling HIV vaccines with one of nine health commodities affected demand. Participants also responded to questions assessing demographics, HIV risk behaviors, experiences of racial discrimination, and trust in institutions. The results demonstrated that the exponentiated demand equation effectively modeled vaccine acceptance across conditions (median R² = 0.92). Contrary to expectations, vaccine characteristics had a minimal influence on demand (Q₀: R² = 0.007; log α: R² = 0.001). Instead, individual factors significantly influenced demand intensity (consumption when price = 0; Q₀) and price sensitivity (sensitivity of consumption to increasing price; α). Significant predictors of Q₀ included injection drug use history, experiences of racial discrimination, and trust in science. Low household income was the strongest predictor of log α. Bundling HIV vaccines with other health commodities showed subtle effects on acceptance, with condoms and dental examinations significantly differing from the reference category. These findings suggest that behavioral economic approaches can inform policy decisions about pricing, bundling strategies and targeted interventions to maximize HIV vaccine uptake among SGMs who face disproportionate HIV risk without requiring exposure to non-market-ready vaccines.