The generalization-across-dimensions model applied to conditional temporal discrimination.

Can simple choice conditional-discrimination choice be accounted for by recent quantitative models of combined stimulus and reinforcer control? In Experiment 1, two sets of five blackout durations, one using shorter intervals and one using longer intervals, conditionally signaled which subsequent choice response might provide food. In seven conditions, the distribution of blackout durations across the sets was varied. An updated version of the generalization-across-dimensions model nicely described the way that choice changed across durations. In Experiment 2, just two blackout durations acted as the conditional stimuli and the durations were varied over 10 conditions. The parameters of the model obtained in Experiment 1 failed adequately to predict choice in Experiment 2, but the model again fitted the data nicely. The failure to predict the Experiment 2 data from the Experiment 1 parameters occurred because in Experiment 1 differential control by reinforcer locations progressively decreased with blackout durations, whereas in Experiment 2 this control remained constant. These experiments extend the ability of the model to describe data from procedures based on concurrent schedules in which reinforcer ratios reverse at fixed times to those from conditional-discrimination procedures. Further research is needed to understand why control by reinforcer location differed between the two experiments.

Can the prosocial benefits of episodic simulation transfer to different people and situational contexts?

Previous research has found that episodic simulation of events of helping others can effectively enhance intentions to help the same person involved and the identical situational context as the imagined scenarios. This 'prosocial simulation effect' is argued to reflect, at least in part, associative memory mechanisms whereby the simulation is reactivated when in the same situation as that imagined. However, to date, no study has examined systematically whether this 'prosocial simulation effect' can be transferred to response scenarios involving different people and/or situational contexts to the imagined scenarios, and if so, whether the degree of overlap with the imagined helping episode modulated the transfer effect. Across two experiments, we systematically varied the overlap of the simulated and response scenarios, both in terms of the persons in need and/or the situational contexts, and whether would influence the magnitude of prosocial simulation effect. Results from both experiments showed that the prosocial simulation effect can be transferred to response scenarios involving different people and situational contexts to the simulated scenarios. However, this finding was primarily driven by response scenarios that had a high degree of overlap to the simulated scenarios. The application of our findings to the practical implementation of simulation to promote prosociality in the real world is discussed.

Human social enrichment is linked with reduced mortality in artificially reared ewe lambs.

Growth of lambs in an artificial rearing system is key to the economic success of sheep-milking farms. Social enrichment in the form of quiet human contact has been shown to increase growth rates of lambs after weaning, perhaps by reducing stress and enhancing immune function. One hundred fourteen artificially reared dairy ewe lambs were assigned either to a Social condition receiving quiet human company in three 20-min segments per day, or a Control condition without quiet human contact. Feeding and housing conditions were otherwise identical. Starting weights for the Social (M = 6.29 kg; SD = 1.19 kg) and Control (M = 6.38 kg; SD = 0.93 kg) lambs were the same, as were their weights after 3 weeks (Mcontrol = 8.89 kg, SD = 2.55 kg, Msocial = 8.63 kg, SD = 2.16 kg). Mortality rates were significantly lower (p = 0.041) in the Social condition (0%) than Control (8%). Thus, social enrichment may be important for the wellbeing of lambs and for economic viability in lamb-rearing.

Divided stimulus control depends on differential and nondifferential reinforcement: Testing a quantitative model.

We investigated the effects of differential and nondifferential reinforcers on divided control by compound-stimulus dimensions. Six pigeons responded in a delayed matching-to-sample procedure in which a blue or yellow sample stimulus flashed on/off at a fast or slow rate, and subjects reported its color or alternation frequency. The dimension to report was unsignaled (Phase 1) or signaled (Phase 2). Correct responses were reinforced with a probability of .70, and the probability of reinforcers for errors varied across conditions. Comparison choice depended on reinforcer ratios for correct and incorrect responding; as the frequency of error reinforcers according to a dimension increased, control (measured by log d) by that dimension decreased and control by the other dimension increased. Davison and Nevin's (1999) model described data when the dimension to report was unsignaled, whereas model fits were poorer when it was signaled, perhaps due to carryover between conditions. We are the first to test this quantitative model of divided control with reinforcers for errors and when the dimension to report is signaled; hence, further research is needed to establish the model's generality. We question whether divided stimulus control is dimensional and suggest it may instead reflect joint control by compound stimuli and reinforcer ratios.

Quantitative Indices of Student Social Media Engagement in Tertiary Education: A Systematic Review and a Taxonomy.

Recent studies have evaluated the use of social media as learning aids in tertiary education. Emerging research in this area has focused primarily on non-quantitative approaches to student social media engagement. However, quantitative engagement outcomes may be extracted from student posts, comments, likes, and views. The goal of the present review was to provide a research-informed taxonomy of quantitative and behavior-based metrics of student social media engagement. We selected 75 empirical studies comprising a pooled sample of 11,605 tertiary education students. Included studies used social media for educational purposes and reported student social media engagement outcomes (source databases: PsycInfo and ERIC). We used independent raters and stringent interrater agreement and data extraction processes to mitigate bias during the screening of references. Over half of the studies (52%, n = 39) utilized ad hoc interviews and surveys to estimate student social media engagement, whereas thirty-three studies (44%) used some form of quantitative analysis of engagement. Based on this literature, we present a selection of count-based, time-based, and text-analysis metrics. The proposed taxonomy of engagement metrics resulting provides the methodological basis for the analysis of social media behavior in educational settings, particularly, for human operant and behavioral education studies. Implications for future research are discussed. Supplementary Information: The online version contains supplementary material available at 10.1007/s10864-023-09516-6.

Is superstitious responding a matter of detectability? A replication of Killeen (1978).

Organisms may sometimes behave as if a contingency exists between behavior and consequences, even if this is not actually the case. Killeen (1978) suggested that such superstition occurs because of factors that bias subjects to behave "superstitiously" rather than because of failures of discrimination. We systematically replicated Killeen's experiment and compared contingency discrimination between different consequences. Six pigeons responded in a matching-to-sample procedure in which a response-independent or response-dependent stimulus change, food delivery, or blackout occurred. The pigeons reported whether the consequence was response dependent or response independent by choosing between two side keys. Discrimination was strongest after stimulus changes, weaker after blackouts, and weakest after food deliveries. These differences persisted even after additional training, suggesting asymmetries that may reflect differences in the disruptive effects of different consequences on remembering and/or behavioral mnemonics. Importantly, the pigeons were not biased to report response-dependent consequences unless that response was consistent with locational biases; that is, they behaved "superstitiously" when there was a reason to be biased to do so. These findings corroborate Killeen's and demonstrate that behavior may deviate from contingencies not necessarily because subjects cannot discriminate those contingencies but because they are biased to behave otherwise.

Revaluation of overselected stimuli: Emergence of control by underselected stimuli depends on degree of overselectivity.

Stimulus overselectivity describes strong control by one stimulus element at the expense of other equally relevant elements. Research suggests that control by underselected stimuli emerges following extinction of the overselected stimulus ("revaluation") and the emergence is larger when overselectivity is greater. We compared such revaluation effects with a control compound or condition in two experiments. Human participants chose between compound S+ and S- stimuli. Then, to assess control by compound-stimulus elements, participants chose between individual elements in a testing phase without feedback. The S+ element chosen most often (the overselected element) underwent revaluation, during which choice of that element was extinguished and choice of a novel element reinforced. Thereafter, participants completed a retesting phase. Revaluation reduced choice of the overselected element. Choice of the underselected element decreased for participants with low overselectivity but increased for participants with high overselectivity. This was not the case for a control compound that did not undergo revaluation (Experiments 1 and 2) or in a control condition in which the overselected element continued to be reinforced during revaluation (Experiment 2). These findings suggest that overselectivity levels may modulate revaluation effects, and they also highlight the importance of the contingency change in postrevaluation changes in stimulus control.

Not bird-brained: Chickens use prior experience to solve novel timing problems.

Despite differences between bird and human brain anatomy, birds have recently demonstrated capacities thought to be uniquely human, including planning and problem-solving. Many avian demonstrations of 'complex' behaviors rely on species-specific behavior (e.g., caching, tool use), or use birds who have evolved largely in similarly undomesticated circumstances (e.g., pigeons). In the present experiment, we asked how a species domesticated thousands of years ago, chickens (Gallus gallus domesticus), used past experience to navigate novel problems in the double-bisection task. The double-bisection task which has been used extensively with pigeons, allowing a comparison of signatures of chicken and pigeon performance on the same task. Our findings revealed chickens, like pigeons, show flexible learning that is sensitive to the broader context in which events occur. Further, as with pigeons, our chickens' patterns of performance could be divided into two distinct categories which may reflect differences in the specific behaviors in which organisms engage during a timing task. Our findings demonstrate remarkable similarity in how chickens and pigeons use past experience to navigate novel problems. Further, these findings add to a growing body of knowledge suggesting the simplest forms of learning common across species-operant and respondent conditioning-are more flexible than is typically assumed.

Effects of brief post-sample cues signaling presence or absence of reinforcers in delayed matching-to-sample.

When short-term memory is assessed in the delayed matching-to-sample (DMTS) procedure, performance is better when cues signal larger reinforcer magnitudes or higher reinforcer probabilities for correct responding. Previous studies demonstrating signaled-magnitude or signaled-probability effects presented cues for a prolonged period during the sample stimulus and/or retention interval. The present study asked whether a signaled-probability effect would occur with brief post-sample cues that signaled the presence or absence of reinforcement. Five pigeons responded in a DMTS task in which sample stimuli were sometimes followed by a 0.5-s cue signaling that reinforcers would either be available or not available in the current trial, and the retention interval varied from 0.5 s to 20 s. A reliable signaled-probability effect was found when reinforcers were arranged independently and for all correct responses, whereas a smaller, less systematic effect was found when reinforcers were arranged dependently and probabilistically. These findings highlight the importance of reinforcement contingencies and contingency discriminability in remembering, and add to the evidence showing that cues signaling differential reinforcement in DMTS may affect processes during the retention interval and comparison phase, rather than attention to the sample stimulus.

Machine learning with a snapshot of data: Spiking neural network 'predicts' reinforcement histories of pigeons' choice behavior.

An accumulated body of choice research has demonstrated that choice behavior can be understood within the context of its history of reinforcement by measuring response patterns. Traditionally, work on predicting choice behaviors has been based on the relationship between the history of reinforcement-the reinforcer arrangement used in training conditions-and choice behavior. We suggest an alternative method that treats the reinforcement history as unknown and focuses only on operant choices to accurately predict (more precisely, retrodict) reinforcement histories. We trained machine learning models known as artificial spiking neural networks (SNNs) on previously published pigeon datasets to detect patterns in choices with specific reinforcement histories-seven arranged concurrent variable-interval schedules in effect for nine reinforcers. Notably, SNN extracted information from a small 'window' of observational data to predict reinforcer arrangements. The models' generalization ability was then tested with new choices of the same pigeons to predict the type of schedule used in training. We examined whether the amount of the data provided affected the prediction accuracy and our results demonstrated that choices made by the pigeons immediately after the delivery of reinforcers provided sufficient information for the model to determine the reinforcement history. These results support the idea that SNNs can process small sets of behavioral data for pattern detection, when the reinforcement history is unknown. This novel approach can influence our decisions to determine appropriate interventions; it can be a valuable addition to our toolbox, for both therapy design and research.

A quantitative analysis of the effects of alternative reinforcement rate and magnitude on resurgence.

Resurgence occurs when a previously reinforced and then extinguished target response increases due to a worsening of reinforcement conditions for an alternative response. We conducted four crowdsourcing experiments to evaluate effects of alternative-reinforcer rate and magnitude on resurgence with humans. Contingent on an alternative response, we manipulated across groups either the rate of point delivery (Experiment 1) or number of points delivered per reinforcer (Experiments 2-3). Experiment 4 arranged combinations of high- or low-rate and high- or low-magnitude alternative reinforcement across four groups. When extinguishing alternative responding across experiments, we observed resurgence of target responding with relatively high rates of alternative reinforcement but differences in reinforcer magnitude did not influence resurgence. A quantitative model based on the concatenated matching law, Resurgence as Choice in Context (RaC2), provided a poor fit to the data, generally underpredicted target responding, and could not account for data from control groups experiencing extinction of target responding in the absence of alternative reinforcement. We then fit a modified version of RaC2 borrowing an assumption from theories of choice that suggest some proportion of reinforcers are misallocated between responses - this modified version of RaC2 provided a better account of these findings.

Bringing the past into the present: Control by exteroceptive stimuli and key-peck location in a concurrent-chains procedure.

We recently found that initial-link stimuli signaling trial outcomes (signals) in a concurrent-chains procedure exerted imperfect control during initial and terminal links. Here, we conducted a follow-up experiment to investigate further such imperfect control. Five pigeons worked on a concurrent-chains procedure in which one alternative led to a terminal link ending in a smaller-sooner reinforcer delivery, and the other in a larger-later reinforcer. During initial links of some trials, compound stimuli (signals) signaled the trial outcome. We assessed control by signal dimensions in Conflicting trials, in which the dimensions signaled conflicting outcomes. Unlike our previous experiment, signals remained present during terminal links. During initial links, preference favored the signaled key in Signaled trials, and the key signaled by the dimension exerting stronger control in Conflicting trials, suggesting strong signal control. Initial-link choice also depended on trial outcomes; preference was overall biased towards the smaller-sooner key. Terminal-link responding was primarily controlled by the key peck producing terminal-link entry, although some weak signal control was also evident. Thus, signal control during initial and terminal links was enhanced, and control by key-peck location during terminal links persisted, when signals remained present during terminal links. This suggests that our previous findings were partly related to temporal separation between signals and trial outcomes, and to history effects producing strong control by key-peck location.

Modeling choice across time: Effects of response-reinforcer discriminability.

This experiment asks whether timing is affected by animals' discrimination of response-reinforcer contingencies, and if so, how this effect can be understood. Six pigeons were trained on a procedure in which concurrent-schedule reinforcer ratios between left and right keys changed at 30 s after the last reinforcer. One stimulus signaled a reinforcer-ratio reversal from 9:1 to 1:9 on that key, and the other stimulus signaled the inverse reversal, with the key on which these stimuli occurred randomized. Across conditions, the physical difference between the stimuli signaling the two responses was varied and the directional changes in the reinforcer ratio signaled by each stimulus were reversed. Choice changed appropriately across time when the two stimuli were discriminable, and points of subjective equality fell with decreasing stimulus difference. A model which assumed that reinforcers obtained in time bins were redistributed across other time bins according to ogivally changing standard deviations, and between response locations according to an ogivally changing redistribution measure, accounted well for the data. This model was shown to be preferable to one in which across-time redistributions were scalar, and across-location redistribution was constant. These results show the critical importance of stimulus-response-reinforcer discriminability to measures of timing.

Extending a misallocation model to children's choice behavior.

Nonhuman animal models show that reinforcers control behavior through what they signal about the likelihood of future events, but such control is generally imperfect. Imperfect control by the relation between past and likely future events may result from imperfect detection of those events as they occur, which result in imperfect detection of the relation between events. Such an approach would suggest the involvement of more complex psychological processes like memory in simple operant learning. We extended a research paradigm previously examined with nonhuman animals to test the ability of a quantitative model that assumes imperfect control by the relation between events arises because of (a) occasional misallocation of reinforcers to the wrong response, causing imperfect control by the relation between events; and (b) a tendency to explore or exploit which is independent of the relation between events. Children played a game in which one of two different responses could produce a reinforcer. The likelihood of a reinforcer for the same response that produced the last one varied across three conditions (.1, .5, .9). As with nonhuman animal models, children's choices followed these probabilities closely but not perfectly, suggesting strong control by what one reinforcer signals about subsequent reinforcers. Choice was well described by the quantitative model. This same model also provides a good description of nonhuman animal-model data, suggesting fundamentally similar mechanisms of control across species. These findings suggest reinforcers control behavior to the extent the relation between reinforcers can be detected-that is, simple operant learning may be more complex than is typically assumed. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Pigeons prefer to invest early for future reinforcers.

Five pigeons were trained in a series of conditions in which food was delivered after 25 responses, but only when a different (Investing) response had been made before the 25 responses had been completed. If an Investing response was not made, the 25 responses ended in blackout. In various conditions, effective Investing responses either had to be made before the first of the 25 responses, or anywhere within the 25 responses; and effective Investing responses either resulted in a stimulus change or did not. Pigeons Invested even when the consequences were temporally and spatially distant, but Investing was most likely when it produced an immediate stimulus change. When given the choice, pigeons preferred to make Investing responses at the beginning of a trial. These findings again demonstrate that behavior may be maintained by events that are separated in time and space from the present.

On the "Strength" of Behavior.

The place of the concept of response strength in a natural science of behavior has been the subject of much debate. This article reconsiders the concept of response strength for reasons linked to the foundations of a natural science of behavior. The notion of response strength is implicit in many radical behaviorists' work. Palmer (2009) makes it explicit by applying the response strength concept to three levels: (1) overt behavior, (2) covert behavior, and (3) latent or potential behavior. We argue that the concept of response strength is superfluous in general, and an explication of the notion of giving causal status to nonobservable events like latent behavior or response strength is harmful to a scientific endeavor. Interpreting EEG recordings as indicators of changes in response strength runs the risk of reducing behavior to underlying mechanisms, regardless of whether such suggestions are accompanied by behavioral observations. Many radical behaviorists understand behavior as a discrete unit, inviting conceptual mistakes reflected in the notion of response strength. A molar view is suggested as an alternative that accounts for the temporally extended nature of behavior and avoids the perils of a response-strength based approach.

Stimulus control depends on the subjective value of the outcome.

Stimuli that provide information about likely future reinforcers tend to shift behavior, provided a reliable relation between the stimulus and the reinforcer can be discriminated. Stimuli that are apparently more reliable exert greater control over behavior. We asked how the subjective value (measured in terms of preference) of reinforcers associated with stimuli influences stimulus control. Five pigeons worked on a concurrent chains procedure in which half of all trials ended in a smaller reinforcer sooner, and the other half in a larger reinforcer later. In Signaled trials, the color and flash duration on the keys in the initial link signaled the outcome of the trial. In Conflicting probe trials, the color and the flash duration signaled conflicting information about the outcome of the trial. Choice in Signaled trials shifted toward the signaled outcome, but was never exclusive. In Conflicting probe trials, control was divided idiosyncratically between the 2 stimulus dimensions, but still favored the outcome with the higher subjective value. Thus, stimulus control depends not only on the perceived reliability of stimuli, but also on the subjective value of the outcome.

Generalizing from the Past, Choosing the Future.

Behavior in the present depends critically on experience in similar environments in the past. Such past experience may be important in controlling behavior not because it determines the strength of a behavior, but because it allows the structure of the current environment to be detected and used. We explore a prospective-control approach to understanding simple behavior. Under this approach, order in the environment allows even simple organisms to use their personal past to respond according to the likely future. The predicted future controls behavior, and past experience forms the building blocks of the predicted future. We explore how generalization affects the use of past experience to predict and respond to the future. First, we consider how generalization across various dimensions of an event determines the degree to which the structure of the environment exerts control over behavior. Next, we explore generalization from the past to the present as the method of deciding when, where, and what to do. This prospective-control approach is measurable and testable; it builds predictions from events that have already occurred, and assumes no agency. Under this prospective-control approach, generalization is fundamental to understanding both adaptive and maladaptive behavior.

Signaled reinforcement: Effects of signal reliability on choice between signaled and unsignaled alternatives.

When reinforcer availability on one alternative of a concurrent schedule is signaled by a discriminative stimulus, responding on that alternative decreases. We investigated how the correlation between signal presentation and reinforcement (signal reliability) affects choice between signaled and unsignaled alternatives. Six pigeons responded in a concurrent schedule, in which reinforcers on one alternative were signaled by a key-color change. Across conditions, the probability of reinforcement following signal presentation varied (the probability in its absence was the complement). As signal reliability increased, response rates and latencies following signal onset on the signaled alternative decreased, whereas responding on the unsignaled alternative remained unchanged. Because the signal did not alter overall reinforcer rates, these findings are consistent with matching theories and research suggesting that responding on one alternative of a concurrent schedule depends on reinforcer, but not response, rates on other alternatives. However, these findings are inconsistent with others demonstrating concomitant changes in responding on signaled and unsignaled alternatives. We consider whether a response-competition account of concurrent performance can explain these discrepancies, and suggest avenues for future studies to investigate the mechanisms underlying effects of signaled reinforcement in concurrent schedules.

Being there on time: Reinforcer effects on timing and locating.

In research on timing, reinforcers often are assumed to influence discrimination of elapsed time. We asked whether changes in choice used to measure timing arise because of joint control by elapsed time and reinforcers, rather than from the direct modification of control by elapsed time by reinforcers. Pigeons worked on a concurrent-choice task in which 1 response was 9 times more likely to produce a reinforcer, reversing between locations when 19 s had elapsed since the marker event. Across conditions, we manipulated the percentage of reinforcers arranged before the probability reversal from 5 to 95%. These changes in reinforcer percentages altered control by location-based elements of the contingency, but not by time-based elements. Choice was well described by a model that assumes that control by the contingency is weakened by generalization across the time and location of reinforcers, and that these generalizations become more likely at later times since a marker. These findings add to a growing body of research that suggests that reinforcers share the same function as other environmental events in determining how the environment controls behavior.