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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.

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 superstitionoccurs 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.

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.

Pairing discriminative stimuli with unique reinforcers provides an additional cue to correct responding. In the current study, we evaluated the effectiveness of the differential outcomes procedure in teaching novel tacts and facilitating transfer of tacts to novel discriminative stimuli. Four children diagnosed with developmental or intellectual disability were taught a unique pair of related tacts both under a differential outcomes condition and under a nondifferential outcomes condition where the reinforcers were uncorrelated with the sample stimuli. In the former, the different outcomes were two forms of the same reinforcer. Three out of four participants met the mastery criterion sooner under the differential outcomes condition. Two participants also generalized to novel stimuli under the differential outcomes condition. When we tested for the inclusion of the reinforcers in the stimulus class, three participants demonstrated the acquisition of emergent stimulus–outcomes and response–outcomes relations. The study provides support for the use of the differential outcomes procedure as a cost-effective means of enhancing the acquisition of discriminated responses in an applied setting.

It is widely assumed that reinforcers are biologically relevant stimuli, or stimuli that have been associated with biologically relevant stimuli. However, brief, arbitrary stimuli have also been reported to have reinforcement‐like effects, despite being unrelated to biologically relevant stimuli like food. The present study explored the potential reinforcement‐like effects of brief stimuli across 5 experiments. In Experiments 1 through 4, pigeon subjects responded for food reinforcement and brief stimulus presentations in a 2‐component multiple schedule. Neither baseline response rates nor resistance to change during disruption tests were systematically greater in a component with versus without brief stimulus presentations. Increasing the rate and duration of brief stimulus presentations in Experiment 4 did not reveal reinforcement‐like effects when compared directly with food. In Experiment 5, pigeons chose between independent terminal links in a concurrent‐chains procedure. Across conditions, varying the location, duration, and rate of brief stimulus presentations in the terminal links had no systematic effects on preference. In contrast, varying rates of food reinforcers resulted in large and reliable shifts in preference. Therefore, the present study found no systematic evidence that brief stimuli unrelated to food reliably increase response rates, resistance to change, or preference. These data demonstrate the value of systematic replication, and a behavioral momentum approach to assessing potential reinforcement‐like effects.

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.

We introduce to behavior analysis a way of analyzing choice behavior that exploits recent developments in nanoeconomics, financial economics, and econometrics. A response return, modeled on an economic return, is the log differenced count of responses allocated to each of two alternatives during a short time window, compared with that in the immediately preceding window. The response return is a new dependent variable which offers a novel and useful way of looking at operant behavior, especially at the molecular level of analysis. The response–return seriesis a near‐instantaneous measure of an organism's dynamic preferences for each of two alternatives. Analyzing such a series requires time‐analytic techniques, including Auto‐Regressive Conditional Heteroskedastic (ARCH) models. We illustrate these techniques by analyzing choices between combinations of arithmetic and exponential variable‐interval schedules with pigeon subjects. All response–return series were well‐fitted by one of three ARCH‐family models. The fitted models were differentially sensitive to transition versus steady‐state data samples. The particular insights that the ARCH analyses offer are improved understanding of the effects of the instantaneous effects of reinforcers and their absence, of how the distribution of reinforcers in time affects choice, and of the differences between choice in transition and at steady state.

We advocate for rank‐permutation tests as the best choice for null‐hypothesis significance testing of behavioral data, because these tests require neither distributional assumptions about the populations from which our data were drawn nor the measurement assumption that our data are measured on an interval scale. We provide an algorithm that enables exact‐probability versions of such tests without recourse to either large‐sample approximation or resampling approaches. We particularly consider a rank‐permutation test for monotonic trend, and provide an extension of this test that allows unequal number of data points, or observations, for each subject. We provide an extended table of critical values of the test statistic for this test, and both a spreadsheet implementation and an Oracle® Java Web Start application to generate other critical values at https://sites.google.com/a/eastbayspecialists.co.nz/rank-permutation/.

A multivariate analysis is concerned with more than one dependent variable simultaneously. Models that generate event records have a privileged status in a multivariate analysis. From a model that generates event records, we may compute predictions for any dependent variable associated with those event records. However, because of the generality that is afforded to us by these kinds of models, we must carefully consider the selection of dependent variables. Thus, we present a conditional compromiseheuristic for the selection of dependent variables from a large group of variables. The heuristic is applied to McDowell's Evolutionary Theory of Behavior Dynamics (ETBD) for fitting to a concurrent variable‐interval schedule in‐transition dataset. From the parameters obtained from fitting ETBD, we generated predictions for a wide range of dependent variables. Overall, we found that our ETBD implementation accounted well for various flavors of the log response ratio, but had difficulty accounting for the overall response rates and cumulative reinforcer effects. Based on these results, we argue that the predictions of our ETBD implementation could be improved by decreasing the base response probabilities, either by increasing the response latencies or by decreasing the sizes of the operant classes.

The study and use of punishment in behavioral treatments has been constrained by ethical concerns. However, there remains a need to reduce harmful behavior unable to be reduced by differential‐reinforcement procedures. We investigated whether response‐contingent presentation of a negative discriminative stimulus previously correlated with an absence of reinforcers would punish behavior maintained by positive reinforcers. Across four conditions, pigeons were trained to discriminate between a positive discriminative stimulus (S+) signaling the presence of food, and a negative discriminative stimulus (S‐) signaling the absence of food. Once learned, every five responses on average to the S+ produced S‐ for a duration of 1.5 s. S+ response rate decreased for a majority of pigeons when responses produced S‐, compared to when they did not, or when a neutral control stimulus was presented. In Condition 5, choice between two concurrently presented S+ alternatives shifted away from the alternative producing S‐, despite a 1:1 reinforcer ratio. Therefore, presenting contingent S‐ stimuli punishes operant behavior maintained on simple schedules and in choice situations. Development of negative discriminative stimuli as punishers of operant behavior could provide an effective approach to behavioral treatments for problem behavior and subverting suboptimal choices involved in addictions.

Organisms that behave so as to forfeit a relatively higher overall rate of reinforcement in favor of a relatively lower rate are said to engage in suboptimal choice. Suboptimal choice has been linked with maladaptive behavior in humans. Melioration theory offers one explanatory framework for suboptimal choice. Melioration theory suggests behavior is controlled by differences in local reinforcer rates between alternatives. Vaughan (1981) arranged two experimental conditions in which maximizing the overall rate of reinforcement required behavior that was compatible, or incompatible, with melioration. Vaughan found pigeons allocated more time to a locally richer alternative even when doing so resulted in suboptimal choice. However, Vaughan did not show whether these effects could systematically reverse and did not provide within‐session data to show that choice across short time spans remains under the control of differences in local reinforcer rates. The present study used pigeons to replicate and extend Vaughan's findings. We investigated shifts in overall‐ and within‐session choice across repeated conditions, according to arranged local contingencies. Behavior systematically followed changes in local contingencies for most pigeons. Within‐session data suggests that, providing differences in local reinforcer rates are discriminated, pigeons will allocate more time to a locally richer alternative, even if this leads to suboptimal choice. These findings facilitate the more confident use of similar procedures that investigate how melioration contributes to suboptimal choice.

Models that generate event records have very general scope regarding the dimensions of the target behavior that we measure. From a set of predicted event records, we can generate predictions for any dependent variable that we could compute from the event records of our subjects. In this sense, models that generate event records permit us a freely multivariate analysis. To explore this proposition, we conducted a multivariate examination of Catania's Operant Reserve on single VI schedules in transition using a Markov Chain Monte Carlo scheme for Approximate Bayesian Computation. Although we found systematic deviations between our implementation of Catania's Operant Reserve and our observed data (e.g., mismatches in the shape of the interresponse time distributions), the general approach that we have demonstrated represents an avenue for modelling behavior that transcends the typical constraints of algebraic models.

ABSTRACTTreatment integrity is the extent to which interventionists implement treatment procedures as prescribed.  The majority of treatment integrity research involving discrete-trial teaching (DTT) reports an overall score summarizing integrity across procedural components.  Because DTT is a procedure consisting of multiple steps, practitioners may find it helpful to report integrity data separately for each component (i.e., component integrity).  Recent research has found that high levels of overall integrity are not always representative of high integrity for individual treatment components.  The purpose of this study was to assess component integrity of DTT programs occurring in the natural environment with a specific emphasis on identifying integrity errors for an error-correction procedure consisting of remedial trials.  The results showed that high overall levels of integrity did not correspond to high levels of integrity for the remedial trial portion of the error-correction procedures.  We discuss the implications of the results for research and practice.

The extent to which a stimulus exerts control over behavior depends largely on its informativeness. However, when reinforcers have discriminative properties, they often exert less control over behavior than do other less reliable stimuli such as elapsed time. We investigated why less reliable cues in the present often overshadow stimulus control by more reliable cues presented in the recent past, by manipulating the reliability and duration of stimulus presentations. Five pigeons worked on a modified concurrent schedule in which the location of the response that produced the last reinforcer was a discriminative stimulus for the likely time and location of the next reinforcer. In some conditions, either the location of the previous reinforcer, or the location of the next reinforcer, was signaled by a red key light. This stimulus was either Brief, occurring for 10 s starting a fixed time after the most recent reinforcer, or Extended, being present at all times between food deliveries. Brief and Extended stimuli that signaled the same information had a similar effect on choice when they were present, but control by Brief stimuli weakened as time since stimulus offset elapsed. Control was divided among stimuli in the present and recent past according to the apparent reliability of the information signaled about the next reinforcer. More reliable stimuli in the present degraded, but did not erase, control by less reliable stimuli presented in the recent past. Thus, we conclude that less reliable stimuli in the present control behavior to a greater degree than do more reliable stimuli in the recent past because these more reliable stimuli are forgotten, and hence their relation to the likely availability of food cannot be discriminated.

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.

ABSTRACTThe behavioural literature on representativeness is able to provide general rules for selecting representative measurement systems. For example, using shorter intervals between observations will, in general, produce more representative samples. However, applied behaviour analysis would benefit from a data-based method of choosing a measurement system based on estimated duration of behaviour, desired representativeness (i.e., acceptable error), and the parameters of a measurement system likely to be practical in a clinical setting. Computer simulations were used to evaluate the effect of varying overall and bout durations on the representativeness of samples extracted using simulated momentary time sampling (MTS). A set of decision rules, in the form of 3D graphs, from which practitioners could select parameters of MTS, based on estimates of the dimensions of the behaviour (bout duration and overall duration) and acceptable error, were developed. The decision rules were applied to whole-week data sets obtained in a prior study to test their use with naturalistic data.

Three pigeons responded for food reinforcement on multiple variable‐interval schedules in which the total consumption of food was entirely determined by the subjects' interaction with the schedules (a closed economy). The finding of overmatching, where response allocation between components is more extreme than the distribution of reinforcers, was reconfirmed. Generalized‐matching sensitivity decreased from overmatching to undermatching values typical of conventional multiple schedules when food deprivation was increased by decreasing session duration, but not when deprivation was increased by decreasing overall reinforcer rate. Sensitivity also increased from undermatching to overmatching as session duration increased from 100 min to 24 hr, while deprivation was held constant by decreasing overall reinforcer rate. These results can be understood in terms of increases in the value of extraneous reinforcers relative to food reinforcers as deprivation decreases or as the economy for extraneous reinforcers becomes more closed. However, no published quantitative expression of the effects of extraneous reinforcers is entirely consistent with the results.