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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. [ABSTRACT FROM AUTHOR]

We present a systematic review and a meta‐analysis comparing the differential outcomes procedure to a nondifferential outcomes procedure among clinical and nonclinical populations. Sixty distinct experiments were included in the systematic review, 43 of which were included in the meta‐analysis. We calculated pooled effect sizes for accuracy (overall accuracy, test accuracy, transfer accuracy) and acquisition outcomes (latency, errors, and trials to mastery). The meta‐analysis revealed significant medium‐to‐large effect sizes for all three accuracy measures (pooled effect size range, 0.57 to 1.30). We found relatively greater effect sizes among clinical populations (effect size = 1.04). The single‐subject experimental literature included in the systematic review was consistent with the findings from the group studies, demonstrating improvements in accuracy and speed of learning for the majority of participants. Moderator and subgroup analyses suggest that discrimination difficulty may induce relatively larger differential outcomes effects. The results indicate that the differential outcomes procedure can be a valuable addition to reinforcement‐based interventions. [ABSTRACT FROM AUTHOR]

This introduction to a special issue of Learning and Motivation on the topic of nonhuman animal social behavior briefly describes each of the research and review articles comprising it as they relate to several considerations broadly relevant to the study of nonhuman animal social behavior: its definition, the controlling variables of such behavior, methodological issues, and the relation of social behavior principles to general learning principles. The authors of these articles examine such questions as the reinforcement and stimulus control of animal social behavior, behavioral economics of animal social behavior, imitation learning, the nature of social reinforcement and its relation to other types of reinforcement, self-awareness, and neurogenetic variables related to social behavior. Species include rats, mice, monkeys, pigeons, dogs, and primates, and the methods vary from visual observation in natural and laboratory settings to computer-managed contingencies on social behavior of animals in highly controlled laboratory settings. [ABSTRACT FROM AUTHOR]

The differential outcomes procedure uses reinforcement unique to each alternative in a conditional discrimination, leading to faster and more accurate learning relative to non-differential outcomes procedures. In this study, the differential outcomes procedure was used to teach novel tacts of musical instrument sounds to children with autism. For one set of instruments, response-specific reinforcers were used in combination with social reinforcement. For the other set, reinforcers were provided non-differentially. Two out of three participants showed enhanced learning in the differential outcomes condition, providing some support of the differential outcomes procedures as a useful tool for teaching individuals with autism. Future research into the differential outcomes effect is warranted to identify the procedural and individual factors that predict its effectiveness. [ABSTRACT FROM AUTHOR]

In concurrent schedules, reinforcers are often followed by a brief period of heightened preference for the just-productive alternative. Such 'preference pulses' may reflect local effects of reinforcers on choice. However, similar pulses may occur after nonreinforced responses, suggesting that pulses after reinforcers are partly unrelated to reinforcer effects. McLean, Grace, Pitts, and Hughes (2014) recommended subtracting preference pulses after responses from preference pulses after reinforcers, to construct residual pulses that represent only reinforcer effects. Thus, a reanalysis of existing choice data is necessary to determine whether changes in choice after reinforcers in previous experiments were actually related to reinforcers. In the present paper, we reanalyzed data from choice experiments in which reinforcers served different functions. We compared local choice, mean visit length, and visit-length distributions after reinforcers and after nonreinforced responses. Our reanalysis demonstrated the utility of McLean et al.'s preference-pulse correction for determining the effects of reinforcers on choice. However, visit analyses revealed that residual pulses may not accurately represent reinforcer effects, and reinforcer effects were clearer in visit analyses than in local-choice analyses. The best way to determine the effects of reinforcers on choice may be to conduct visit analyses in addition to local-choice analyses. [ABSTRACT FROM AUTHOR]

Catania’s Operant Reserve (COR; Catania, 2005) is a computational model of operant behaviour. In COR, responding depletes the reserve while reinforcement replenishes the reserve. The replenishment to the reserve depends on the location of responses within the most recent inter-reinforcement interval. The rule that maps replenishment to the responses within an inter-reinforcement interval is given by a delay-of-reinforcement gradient (DOR). Previous research (Berg and McDowell, 2011) found that non-linear DORs produce sigmoidal response rates on single variable-interval schedules while a linear DOR produces hyperbolic response rates. Berg and McDowell took these sigmoidal response rates as evidence against the viability of COR for modelling variable-interval performance. However, Berg and McDowell did not consider the effect of the slope of each DOR. The present conjecture is that the response rates from COR can be made hyperbolic by manipulating the area under the DOR. Our results show that the manipulation of the area under the DOR allows COR to produce hyperbolic response rates regardless of the parametric form of the DOR. Hence, if COR is to be used to model single variable-interval performance, the reinforcement effect over time should be taken into consideration through the manipulation of the area under the DOR. [ABSTRACT FROM AUTHOR]

The baseline rate of a reinforced target response decreases with the availability of response-independent sources of alternative reinforcement; however, resistance to disruption and relapse increases. Because many behavioral treatments for problem behavior include response-dependent reinforcement of alternative behavior, the present study assessed whether response-dependent alternative reinforcement also decreases baseline response rates but increases resistance to extinction and relapse. We reinforced target responding at equal rates across two components of a multiple schedule with pigeons. We compared resistance to extinction and relapse via reinstatement of (1) a target response trained concurrently with a reinforced alternative response in one component with (2) a target response trained either concurrently or in separate components from the alternative response across conditions. Target response rates trained alone in baseline were higher but resistance to extinction and relapse via reinstatement tests were greater after training concurrently with the alternative response. In another assessment, training target and alternative responding together, but separating them during extinction and reinstatement tests, produced equal resistance to extinction and relapse. Together, these findings are consistent with behavioral momentum theory-operant response-reinforcer relations determined baseline response rates but Pavlovian stimulus-reinforcer relations established during training determined resistance to extinction and relapse. These findings imply that reinforcing alternative behavior to treat problem behavior could initially reduce rates but increase persistence. [ABSTRACT FROM AUTHOR]

Six pigeons worked on concurrent exponential variable-interval schedules in which the relative frequency of food deliveries for responding on the two alternatives reversed at a fixed time after each food delivery. Across conditions, the point of food-ratio reversal was varied from 10 s to 30 s, and the overall reinforcer rate was varied from 1.33 to 4 per minute. The effect of rate of food delivery and food-ratio-reversal time on choice and response rates was small. In all conditions, postfood choice was toward the locally richer key, regardless of the last-food location. Unlike the local food ratio which changed in a stepwise fashion, local choice changed according to a decelerating monotonic function, becoming substantially less extreme than the local food ratio soon after food delivery. This deviation in choice appeared to result from the birds' inaccurate discrimination of the time of food deliveries; local choice was described well by a model that assumed that log response ratios matched food ratios that were redistributed across surrounding time bins with mean time t and a constant coefficient of variation. We suggest that local choice is controlled by the likely availability of food in time, and that choice matches the discriminated log of the ratio of food rates across time since the last food delivery. [ABSTRACT FROM AUTHOR]

Abstract: Six pigeons responded on a four-key concurrent variable-interval schedule in which a 27:9:3:1 distribution of reinforcers between the keys changed every 10 reinforcers. Their behaviour quickly came under the control of this changing four-way reinforcer ratio. However, preference between a pair of keys depended not only on the relative reinforcer rates on those keys, but also on the absolute levels of those rates. This contradicts the constant-ratio rule that underpins the matching approach to choice, but is predicted by a contingency-discriminability model that assumes that organisms may occasionally misattribute reinforcers to a response that did not produce them. Reinforcers produced strong preference pulses, or transient increases in responding on the just-reinforced key. Despite accurate tracking of the reinforcer ratio, reinforcers obtained late in components and from leaner keys still produced strong pulses, suggesting both extended and local control of behaviour. Patterns of switching between keys were graded and similarly controlled by the reinforcer rates on each key. Whether considered in terms of switching, local preference pulses, or extended preference, behaviour was controlled by a rapidly changing four-way reinforcer ratio in a graduated, continuous manner that is unlikely to be explained by a simple heuristic such as fix-and-sample. [Copyright &y& Elsevier]

We investigated the effects that sequences of reinforcers obtained from the same response key have on local preference in concurrent variable-interval schedules with pigeons as subjects. With an overall reinforcer rate of one every 27 s, on average, reinforcers were scheduled dependently, and the probability that a reinforcer would be arranged on the same alternative as the previous reinforcer was manipulated. Throughout the experiment, the overall reinforcer ratio was 1:1, but across conditions we varied the average lengths of same-key reinforcer sequences by varying this conditional probability from 0 to 1. Thus, in some conditions, reinforcer locations changed frequently, whereas in others there tended to be very long sequences of same-key reinforcers. Although there was a general tendency to stay at the just-reinforced alternative, this tendency was considerably decreased in conditions where same-key reinforcer sequences were short. Some effects of reinforcers are at least partly to be accounted for by their signaling subsequent reinforcer locations. [ABSTRACT FROM AUTHOR]

Five pigeons were trained on pairs of concurrent variable-interval schedules in a switching-key procedure. The arranged overall rate of reinforcement was constant in all conditions, and the reinforcer-magnitude ratios obtained from the two alternatives were varied over five levels. Each condition remained in effect for 65 sessions and the last 50 sessions of data from each condition were analyzed. At a molar level of analysis, preference was described well by a version of the generalized matching law, consistent with previous reports. More local analyses showed that recently obtained reinforcers had small measurable effects on current preference, with the most recently obtained reinforcer having a substantially larger effect. Larger reinforcers resulted in larger and longer preference pulses, and a small preference was maintained for the larger-magnitude alternative even after long inter-reinforcer intervals. These results are consistent with the notion that the variables controlling choice have both short- and long-term effects. Moreover, they suggest that control by reinforcer magnitude is exerted in a manner similar to control by reinforcer frequency. Lower sensitivities when reinforcer magnitude is varied are likely to be due to equal frequencies of different sized preference pulses, whereas higher sensitivities when reinforcer rates are varied might result from changes in the frequencies of different sized preference pulses. [ABSTRACT FROM AUTHOR]

Examines the short-and long-term effects of reinforcers on the concurrent preference of pigeons. Analysis on the concurrent variable-interval schedules in switching-key procedure; Effects of the condition on current preference; Factors contributing to the increase of short-term effects.

Abstract: Five pigeons were trained in a procedure in which, with a specified probability, food was either available on a fixed-interval schedule on the left key, or on a variable-interval schedule on the right key. In Phase 1, we arranged, with a probability of 0.5, either a left-key fixed-interval schedule or a right-key variable-interval 30s, and varied the value of the fixed-interval schedule from 5s to 50s across 5 conditions. In Phase 2, we arranged either a left-key fixed-interval 20-s schedule or a right-key variable-interval 30-s schedule, and varied the probability of the fixed-interval schedule from 0.05 to 1.0 across 8 conditions. Phase 3 always arranged a fixed-interval schedule on the left key, and its value was varied over the same range as in Phase 1. In Phase 1, overall preference was generally toward the variable-interval schedule, preference following reinforcers was initially toward the variable-interval schedule, and maximum preference for the fixed-interval schedule generally occurred close to the arranged fixed-interval time, becoming relatively constant thereafter. In Phase 2, overall left-key preference followed the probability of the fixed-interval schedule, and maximum fixed-interval choice again occurred close to the fixed-interval time, except when the fixed-interval probability was 0.1 or less. The pattern of choice following reinforcers was similar to that in Phase 1, but the peak fixed-interval choice became more peaked with higher probabilities of the fixed interval. Phase 3 produced typical fixed-interval schedule responding. The results are discussed in terms of reinforcement effects, timing in the context of alternative reinforcers, and generalized matching. These results can be described by a quantitative model in which reinforcer rates obtained at times since the last reinforcer are distributed across time according to a Gaussian distribution with constant coefficient of variation before the fixed-interval schedule time, changing to extended choice controlled by extended reinforcer ratios beyond the fixed-interval time. The same model provides a good description of response rates on single fixed-interval schedules. This article is part of a Special Issue entitled: SQAB 2012. [Copyright &y& Elsevier]

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. • We investigated how brief cues signaling the presence or absence of reinforcers affect memory performance. • Cues were presented for 0.5 s after the sample in a delayed matching-to-sample procedure. • In reinforced trials, reinforcers were arranged with p =.5 (Expt 1) or for all correct responses (Expt 2). • Accuracy was lower when cues signaled reinforcer absence in Expt 2. This effect was smaller and less systematic in Expt 1. • These findings highlight the role of discriminated reinforcement contingencies in remembering. [ABSTRACT FROM AUTHOR]