Reinforcement History Research Articles

Multiple-pair training enhances transposition in pigeons

We studied transposition in pigeons by training them to select the smaller (or the larger) of a pair of circles. In training, different groups of pigeons were given one pair, two pairs, or three pairs of circles along the size dimension. Testing included two stimulus pairs for which, according to theoretical postdiscrimination generalization gradients, transposition should decrease from one-pair to two-pair to three-pair training. On the basis of the results of our earlier study (Lazareva, Wasserman, & Young, 2005) and contrary to these predictions, we expected that transposition should increase from one-pair to two-pair to three-pair training. We found that multiple-pair discrimination training enhanced transposition, which, on average, rose from 47% (one-pair training) to 52% (two-pair training) to 64% (three-pair training). In addition, we found that the overall similarity of the testing pair to the training pair(s) modulated the strength of relational responding. These results demonstrate that encountering multiple instances of a rule leads to stronger relational learning, even when reinforcement history predicts the opposite trend. These results also provide strong evidence against stimulus generalization as the sole determinant of relational responding in transposition.

Tipo de reforçador como variável moduladora dos efeitos da história em humanos

Para investigar como o tipo de reforçador afeta o comportamento em FI após diferentes histórias de reforço, universitários foram expostos a FR ou DRL, que liberavam pontos por pressionar um botão. Alguns participantes trocavam pontos por fotocópias (Condição 1), por dinheiro (Condição 2) ou apenas recebiam os pontos (Condição 3). Subseqüentemente, todos foram expostos a FI. O FR produziu taxas de respostas altas e constantes independentemente do tipo de reforçador utilizado. O FI produziu taxas altas para os participantes das Condições 1 e 2 e baixas para os participantes da Condição 3. O DRL produziu baixas taxas que aumentaram durante o FI subseqüente. Os resultados sugerem que tanto contingências históricas quanto presentes controlaram o comportamento dos participantes e que o tipo de reforçador pode favorecer o responder em taxa alta e constante sob FI após exposição a uma contingência de FR.

Individual differences in reinforcement learning: Behavioral, electrophysiological, and neuroimaging correlates

During reinforcement learning, phasic modulations of activity in midbrain dopamine neurons are conveyed to the dorsal anterior cingulate cortex (dACC) and basal ganglia (BG) and serve to guide adaptive responding. While the animal literature supports a role for the dACC in integrating reward history over time, most human electrophysiological studies of dACC function have focused on responses to single positive and negative outcomes. The present electrophysiological study investigated the role of the dACC in probabilistic reward learning in healthy subjects using a task that required integration of reinforcement history over time. We recorded the feedback-related negativity (FRN) to reward feedback in subjects who developed a response bias toward a more frequently rewarded (“rich”) stimulus (“learners”) versus subjects who did not (“non-learners”). Compared to non-learners, learners showed more positive (i.e., smaller) FRNs and greater dACC activation upon receiving reward for correct identification of the rich stimulus. In addition, dACC activation and a bias to select the rich stimulus were positively correlated. The same participants also completed a monetary incentive delay (MID) task administered during functional magnetic resonance imaging. Compared to non-learners, learners displayed stronger BG responses to reward in the MID task. These findings raise the possibility that learners in the probabilistic reinforcement task were characterized by stronger dACC and BG responses to rewarding outcomes. Furthermore, these results highlight the importance of the dACC to probabilistic reward learning in humans.

Reduced hedonic capacity in major depressive disorder: Evidence from a probabilistic reward task

Objective Anhedonia, the lack of reactivity to pleasurable stimuli, is a cardinal feature of depression that has received renewed interest as a potential endophenotype of this debilitating disease. The goal of the present study was to test the hypothesis that individuals with major depression are characterized by blunted reward responsiveness, particularly when anhedonic symptoms are prominent. Methods A probabilistic reward task rooted within signal-detection theory was utilized to objectively assess hedonic capacity in 23 unmedicated subjects meeting DSM-IV criteria for major depressive disorder (MDD) and 25 matched control subjects recruited from the community. Hedonic capacity was defined as reward responsiveness – i.e., the participants’ propensity to modulate behavior as a function of reward. Results Compared to controls, MDD subjects showed significantly reduced reward responsiveness. Trial-by-trial probability analyses revealed that MDD subjects, while responsive to delivery of single rewards, were impaired at integrating reinforcement history over time and expressing a response bias toward a more frequently rewarded cue in the absence of immediate reward. This selective impairment correlated with self-reported anhedonic symptoms, even after considering anxiety symptoms and general distress. Conclusions These findings indicate that MDD is characterized by an impaired tendency to modulate behavior as a function of prior reinforcements, and provides initial clues about which aspects of hedonic processing might be dysfunctional in depression.

Transitive inference in non-human animals: An empirical and theoretical analysis

Transitive inference has long been considered one of the hallmarks of human deductive reasoning. Recent reports of transitive-like behaviors in non-human animals have prompted a flourishing empirical and theoretical search for the mechanism(s) that may mediate this ability in non-humans. In this paper, I begin by describing the transitive inference tasks customarily used with non-human animals and then review the empirical findings. Transitive inference has been demonstrated in a wide variety of species, and the signature effects that usually accompany transitive inference in humans (the serial position effect and the symbolic distance effect) have also been found in non-humans. I then critically analyze the most prominent models of this ability in non-human animals. Some models are cognitive, proposing for instance that animals use the rules of formal logic or form mental representations of the premises to solve the task, others are based on associative mechanisms such as value transfer and reinforcement and non-reinforcement. Overall, I argue that the reinforcement-based models are in a much better empirical and theoretical position. Hence, transitive inference in non-human animals should be considered a property of reinforcement history rather than of inferential processes. I finalize by shedding some light on some promising lines of research.

Intention, Choice, and the Medial Frontal Cortex

The medial frontal cortex (MFC) has been identified with voluntary action selection. Recent evidence suggests that there are three principal ways in which the MFC is an essential part of the neural circuit for voluntary action selection. First, the MFC represents the reinforcement values of actions and is concerned with the updating of those action values. Because it is particularly concerned with the rate at which action values should be updated, it mediates the influence that the past reinforcement history has over the next choice that is made and it may determine the learning rate. The MFC's representation of action value does not just reflect the potential reward associations of an action but instead represents both the reward and effort costs that are intrinsic to the action. Second, the MFC is important when an exploratory action is generated in order to obtain more information about action values and the environment. Third, the MFC is critical when conflicting information in the immediate environment instructs more than one possible response. In such situations the MFC exerts an influence over how actions will be chosen by other motor regions of the brain.

Euthymic Patients with Bipolar Disorder Show Decreased Reward Learning in a Probabilistic Reward Task

Bipolar disorder (BPD) features cycling mood states ranging from depression to mania with intermittent phases of euthymia. Bipolar disorder subjects often show excessive goal-directed and pleasure-seeking behavior during manic episodes and reduced hedonic capacity during depressive episodes, indicating that BPD might involve altered reward processing. Our goal was to test the hypothesis that BPD is characterized by impairments in adjusting behavior as a function of prior reinforcement history, particularly in the presence of residual anhedonic symptoms. Eighteen medicated BPD subjects and 25 demographically matched comparison subjects performed a probabilistic reward task. To identify putative dysfunctions in reward processing irrespective of mood state, primary analyses focused on euthymic BPD subjects (n = 13). With signal-detection methodologies, response bias toward a more frequently rewarded stimulus was used to objectively assess the participants' propensity to modulate behavior as a function of reinforcement history. Relative to comparison subjects, euthymic BPD subjects showed a reduced and delayed acquisition of response bias toward the more frequently rewarded stimulus, which was partially due to increased sensitivity to single rewards of the disadvantageous stimulus. Analyses considering the entire BPD sample revealed that reduced reward learning correlated with self-reported anhedonic symptoms, even after adjusting for residual manic and anxious symptoms and general distress. The present study provides preliminary evidence indicating that BPD, even during euthymic states, is characterized by dysfunctional reward learning in situations requiring integration of reinforcement information over time and thus offers initial insights about the potential source of dysfunctional reward processing in this disorder.

The contribution of Relational Frame Theory to the development of interventions for impairments of language and cognition.

Introduction: Behavior Analysis, Language and Stimulus Equivalence According to behaviour analysis, human language is verbal behaviour, emerging from the social contingencies operating in the verbal community. This perspective on cognitive functioning constitutes a very different approach to human language than that found in mainstream cognitive psychology and in many conceptualisations of language pathology. The conventional approach to the study of language has tended to focus on the symbolic nature of words. Language-able humans are said to be able to manipulate (Clark, 1994), or to use words to refer to objects, events, or relations (Premack, 1976). For the behaviour analyst, however, concepts such as refer and symbol manipulation remain undefined and therefore are not deemed useful in explaining human language. For behaviour analysis the of a word is established through the contingencies that control the emission of the word as an instance of verbal behaviour (Skinner, 1957). For example, the arbitrary vocal dinner has meaning only to the extent that it occasions appropriate behaviour (appropriate being defined by the social contingencies). Originally, behavioural researchers assumed that the meaning of a word was established in much the same way, as are control processes in nonhuman species. In essence, this conceptualisation of symbolic meaning defined symbols as discriminative stimuli. However, both non-behavioural and behavioural psychologists have questioned whether it is possible to accommodate the sheer flexibility of symbolic relations using the principle of discriminative control (cf. Hayes & Hayes, 1989). For instance, it has often been asked how an explanatory framework, which focuses on a history of previous reinforcement, can account for the fact that language-able humans respond appropriately to sentences that they have never previously heard (Chomsky, 1959). This is precisely the crucial question that a growing number of behavioural researchers have focused on in recent years. Specifically, the investigation of the phenomenon termed stimulus has allowed behaviour analysts to explore the behavioural processes whereby stimuli come to control behaviour in new ways in the absence of explicit reinforcement (see Sidman, 1994, for an extensive review). Stimulus equivalence has normally been studied using the matching-to-sample (MTS) procedure. When a subject is taught a series of related conditional discriminations, using the MTS format, the stimuli that enter into these discriminations become related to each other in new ways, without explicit teaching and/or reinforcement. For example, a subject might be taught, given a novel visual sample A1, to select the form B1, from an array containing B1, B2 and B3 (these visual forms are often abstract shapes or nonsense syllables that bear no formal relationship to each other). At the same time, the subject may also be trained, given the sample A1, to select another visual form C1, from an array containing C1, C2 and C3. Without additional training or explicit reinforcement, the subject may derive other relations among the stimuli; therefore the stimuli are said to be members of an equivalence class, and they show the properties of reflexivity, symmetry and transitivity. Reflexivity is inferred from generalised identity matching (e.g. without any training, given A1 as a sample, the subject picks A1 and not A2 or A3 from an array). Symmetry: If the subject is trained, given A1 to pick B1, then the functional reversibility of this trained relation emerges without any direct reinforcement (given B1, pick A1). Transitivity: If a subject is trained 'given A1 pick B1' and 'given B1 pick C1', the relation 'given A1, pick C1' emerges without any training or reinforcement. The phenomenon of equivalence appears to be readily observed in the human species, whereas great difficulty has been encountered in attempting to demonstrate the effect in non-humans (e. …

The translation of basic behavioral research to school psychology: A citation analysis.

In recent years, school psychology has entered into new era of accountability where scientifically-based practices are not only encouraged, but are mandated by law (IDEA, 2004). For school-based practitioners, this means documenting the rationale and empirical support for behavior change procedures in the classroom. Failing to do so is not only poor practice of school psychology, it may also have legal ramifications. Thus, it is of no surprise that the field of school psychology has turned to applied behavior analysis due to its rich empirical support, behavioral assessment methodology, and function-based approaches to solving behavioral concerns (Kratochwill & Martens, 1994). Vollmer and Northup (1997) suggest that one of the key aspects of applied behavior analysis that makes it complimentary to school psychology is its foundation in the basic principles of behavior. In The Technology of Teaching, Skinner remarked that a really effective educational system cannot be set up until we understand the processes of learning and teaching (Skinner, 1968, p. 95). Skinner's views on education continue to resonate today as practitioners and applied researchers alike attempt to pinpoint the active treatment ingredient responsible for behavior change through an understanding of the basic behavioral processes at play in successful behavior change program. As any practicing school psychologist can attest, the classroom ecology is extremely complex, with multiple schedules of reinforcement operating at any given time (Martens & Kelly, 1993). For instance, within any classroom, many students will be exposed to behavior support plans, Individualized Education Programs (IEPs), direct instruction programs, behavior altering medication for behavioral concerns, differing reinforcement histories, etc. With such confounding variables, it becomes very difficult to truly understand what is accounting for the observed behavior change after an intervention is implemented. Thus, it is not always readily apparent which procedures are responsible for behavior change during intervention implementation. One of the fundamental attributes of behavioral research is its reliance on parsimony in understanding behavior change (Johnston & Pennypacker, 1993). While it is easy to monitor gains in the classroom without an understanding of the controlling behavioral processes, this oversight is not only dangerous to the long-term sustainability of the intervention, it actually does disservice to the field. When an intervention works, the most we can walk away with is an understanding of what works with that individual in that setting for that target behavior. In sum, the generalizability of the intervention across students, time, settings, and responses is compromised. However, with an understanding of the basic behavioral principles at play, one can individually tailor the intervention to account for these individual and situational differences. The avenue to accomplishing true understanding of the behavioral principles implicated in academic or academic-related behavior is through form of research termed bridge or research. This approach to research is characterized by simple replications of laboratory studies to applied situations and clinical populations (Lerman, 2003). In essence, translational research affords the researcher greater deal of experimental control (i.e., akin to laboratory setting), while still being directed toward an applied problem. Yet, despite the seemingly critical need for relationship between basic and applied research, the disconnect between the two continues to widen (Mace, 1994; Mace & Wacker, 1994). While researchers have demonstrated much success translating basic experimental research to applied settings (Iwata, 1991), many practitioners and school psychologists may feel that basic research is too esoteric for their settings. …

CONTINGENCY TRACKING DURING UNSIGNALED DELAYED REINFORCEMENT

Three experiments were conducted with rats in which responses on one lever (labeled the functional lever) produced reinforcers after an unsignaled delay period that reset with each response during the delay. Responses on a second, nonfunctional, lever did not initiate delays, but, in the first and third experiments, such responses during the last 10 s of a delay did postpone food delivery another 10 s. In the first experiment, the location of the two levers was reversed several times. Responding generally was higher on the functional lever, though the magnitude of the difference diminished with successive reversals. In the second experiment, once a delay was initiated by a response on the functional lever, in different conditions responses on the nonfunctional lever either had no effect or postponed food delivery by 30 s. The latter contingency typically lowered response rates on the nonfunctional lever. In the first two experiments, both the functional and nonfunctional levers were identical except for their location; in the third experiment, initially, a vertically mounted, pole-push lever defined the functional response and a horizontally mounted lever defined the nonfunctional response. Higher response rates occurred on the functional lever. These results taken together suggest that responding generally tracked the response-reinforcer contingency. The results further show how nonfunctional-operanda responses are controlled by a prior history of direct reinforcement of such responses, by the temporal delay between such responses and food delivery, and as simple generalization between the two operanda.

Drug and Reinforcement History as Determinants of the Response-Maintaining Effects of Quinpirole in the Rat

The present study examined the effect of drug and reinforcement history on quinpirole-maintained responding in rats. Quinpirole (0.01, 0.032, or 0.1 mg/kg per injection) was assessed as a reinforcer in experimentally naive rats, as well as in rats trained to self-administer cocaine, remifentanil, ketamine, or food under a fixed ratio 1 schedule of reinforcement. Quinpirole failed to maintain responding in experimentally naive rats, or in ketamine- or food-trained rats. However, robust responding was maintained in rats with a history of cocaine reinforcement, and modest levels of responding were observed in rats with a history of responding for remifentanil. In a second set of studies, the effects of protracted drug histories on quinpirole-maintained responding in food-trained rats were assessed. Rats were maintained with food reinforcement, and different groups of rats were then allowed to respond for saline, quinpirole, and response-contingent cocaine or were administered noncontingent cocaine; all rats were subsequently allowed to respond for quinpirole. Only rats that previously responded for cocaine showed quinpirole-maintained responding; all other conditions failed to establish quinpirole-maintained responding. Although the high levels of quinpirole-maintained responding observed when quinpirole was substituted for cocaine are suggestive of positive reinforcing effects, these response-maintaining effects were highly dependent upon both drug and reinforcement history, suggesting that quinpirole may only function as a reinforcer under very specific conditions. The behavioral effects of quinpirole under these situations represent a novel constellation of actions relative to other drug reinforcers, and they suggest that the direct effects of self-administered quinpirole may be important in establishing the response-maintaining effects.

Compulsive drug seeking by rats under punishment: effects of drug taking history

Abstinence from drug occurs in human addicts for several reasons, including the avoidance of adverse consequences. To explore a model of drug use in the face of adverse consequences in rats through intermittent punishment of drug seeking and to investigate whether the ability to withhold seeking responses depends upon the duration of drug history. Rats were trained under a seeking-taking chained schedule with sucrose or cocaine as reinforcer. Pressing the seeking lever gave access to the taking lever, and a single press on this lever delivered the reinforcer after which the seeking-taking chain recycled. During punishment, half of the seeking links terminated with a mild foot shock without access to the taking link. After a moderate history of reinforcement, punishment of the terminal response in the seeking link suppressed both sucrose- and cocaine-seeking responses. By contrast, rats with an extended cocaine history were more resistant to punishment than those with a moderate cocaine history. This enhanced resistance to punishment was due to a sub-group of rats that showed minimal or no suppression of drug seeking. No differences in suppression of sucrose seeking were observed in animals with moderate versus extended sucrose histories. These results suggest that an extended drug self-administration history decreases the ability of vulnerable rats to suppress their drug seeking.

Using a computer simulation of three slot machines to investigate a gambler’s preference among varying densities of near-miss alternatives

The present article describes a software program in Visual Basic .NET designed to simulate three slot machines on a computer screen. This software is described in detail regarding utility, downloading, and usage; and data are presented illustrating the software's potential for researchers interested in gambling behavior. A simulation of multiple slot machines such as this enables researchers to evaluate players' preferences across various machines. In the highlighted experiment, 18 recreational slot machine players played the software for extra course credit and a chance at cash prizes. All participants played a version of the simulation in which every 5th response on average was a win, whereas the remaining trials were a loss. However, on those loss trials, a varying distribution of almost wins or near misses (i.e., two winning symbols on the payoff line and the final winning symbol directly above or below the payoff line) were presented in percentages of 15, 30, or 45. While no preferences across the three options could be predicted on the basis of reinforcement history alone, deviations from equal choices across the games were noted and appeared to be the result of the presentations of near-miss losing trials. Implications for a greater understanding of pathological gambling are presented.

Reinforcers following greater effort are preferred: A within-trial contrast effect.

Psychologists who study human behavior often posit underlying mechanisms that are difficult to measure directly. And because humans are known to be complex organisms with complex motivational systems, researchers studying human behavior may avoid asking if there are simpler accounts of the behavior being studied. One such example is the phenomenon known as transposition. This phenomenon is familiar to musicians who after playing a tune in one key can seamlessly transpose the tune to a different key with no apparent change in the melody (the relations among the notes). A similar effect can be shown in rats, when after training them on a simultaneous light-gray (S+) versus dark-gray (S-) discrimination with responding to the light-gray reinforced, rats are tested with the light-gray stimulus and a still lighter-gray stimulus (Sn). In spite of the fact that responding to the S+ had a history of reinforcement and responding to the Sn had not, rats typically choose the Sn over the S+. That is, it appears that they learned to choose the lighter one during training and they continued to choose the lighter one on test trials. That is, it appears that they had learned the relation between the two training stimuli rather than their absolute properties. But Spence (1937) proposed that when organisms learn to respond to a stimulus for reinforcement, the tendency to respond generalizes to other similar stimuli (defining a gradient of stimulus generalization). Similarly, responding to the S- results in a gradient of inhibition around the value of the S- stimulus. According to Spence, it is the algebraic summation of those gradients at each point along the dimension that determines the strength of responding (the net response strength) at other points on the dimension (brightness in the example described). If one assumes that the gradients are convex (i.e., flatter near the training values) then the net gradient typically has its peak value not at the S+ but at a point away from the S+ in the direction away from the S-. This occurs because, given the presumed shape of the gradients, there would be a smaller decline in response strength as one begins to move away from the S+ than there would be a decline in inhibition at that point in the inhibitory gradient (see Spence, 1937). In this way, paradoxically, Spence's theory of learning about the absolute properties of a stimulus can account for an animal's choice of a novel stimulus, never seen before, over the S+ training value, and hence it can account for transposition without appealing to relational learning. Cognitive Dissonance An even more striking example of a presumably complex human behavior that is likely to be influenced by simpler behavioral processes is the supposed human motivation to reduce cognitive dissonance. Cognitive dissonance occurs when there is a discrepancy between one's beliefs and one's behavior. This can occur when one acts in a way that is inconsistent with the way one believes one should act. According to cognitive dissonance theory (Festinger, 1957), one should work to reduce the dissonance and if it is too late to avoid the behavior, one would modify one's beliefs to account for or justify one's behavior. Festinger and Carlsmith (1957) tested this theory by giving subjects a task considered to be boring and then asking them to tell a prospective subject that the task was interesting. In payment for this service, the experimenter would compensate them with a payment (the experimental manipulation) of either $1 or $20. But before carried out their assignment they were asked to fill out a questionnaire that included judgments about the task. Surprisingly, those subjects who were paid $1 judged the task to be more interesting than those who were paid $20. Festinger and Carlsmith explained the difference in terms of an attempt to reduce cognitive dissonance for the subjects paid only $1. For those subjects, the dissonance produced by having engaged in a boring task but having agreed to tell a potential subject that the task was interesting could not be resolved by appealing to the payment of $1. …

Reinforcement history determines the reinforcing effects of quinpirole in the rat

These experiments were aimed at extending the finding that the D3-peferring agonist, 7-OH-DPAT, maintained responding in rhesus monkeys with a history of cocaine-reinforced responding, but not in all monkeys with a history of food-reinforced responding (Psychopharmacol. 125:13–22). In the present experiments, the effect of reinforcement history on responding for quinpirole (QPRL) was examined in rats. In one set of studies rats were trained to self-administer cocaine, remifentanil, ketamine, or liquid-food (LF) under an FR1 schedule of reinforcement, and QPRL (0.01, 0.032, or 0.1 mg/kg/inj) was assessed as a substitute reinforcer during 1.5 hour sessions over 7 days. When cocaine history was provided, QPRL maintained robust responding with the highest rates at 0.032 QPRL. However, QPRL was generally no different than saline when responding was previously maintained by LF, remifentanil, or ketamine. A second set of studies assessed the type of cocaine history necessary to establish QPRL-reinforced responding in rats initially trained to respond for LF. Two substitutions were used with rats returned to LF between substitutions. In the first substitution, either saline, 0.032 QPRL, response-contingent, or non-contingent cocaine were delivered. Following interpolated LF, a second substitution was carried out with only QPRL. Rats previously maintained with response-contingent cocaine were now maintained by QPRL; all other rats failed to be maintained by QPRL. Thus, a response-contingent cocaine history was necessary to establish the reinforcing effect of QPRL. Research supported by grants DA20669 and F013771 through NIDA

Towards a behavioral analysis of humor: Derived transfer of self-reported humor ratings.

Recently, behavior analysts have shown considerable interest in the burgeoning research area of derived stimulus relations which, many argue, may provide the foundations for a behavioral account of novel, complex behavior. Typically studied using a matching-to-sample (MTS) procedure, the basic finding is as follows. Suppose, for instance, reinforcement is delivered for selection of comparison B in the presence of the sample A, and for selection of comparison C in the presence of sample B, respectively. Most verbally able humans will now readily reverse these explicitly reinforced conditional discriminations in the absence of further training. That is, they will now select A given B, and B given C in accordance with derived symmetrical, or mutually entailed, stimulus relations. Furthermore, participants will now also select C given A and A given C in accordance with derived transitive and equivalence, or combinatorially entailed, stimulus relations without further training. Following such derived performances, the stimuli are said to participate in an equivalence class (Sidman, 1994) or a relational frame of equivalence (Barnes, 1994; Hayes, Barnes-Holmes, & Roche, 2001). Perhaps what is most interesting about derived stimulus relations such as equivalence is that the test outcomes are not readily predicted from the traditional concept of conditional discrimination; neither A nor C has a direct history of differential reinforcement with regard to the other, and therefore neither stimulus should control selection of the other. Another feature of derived stimulus relations is the transfer of stimulus functions, which has also generated research interest due in part to its implications for understanding a wide range of complex, derived behavior. The transfer of stimulus functions occurs when the function of one stimulus in a derived relation alters the functions of another according to the derived relation between the two, without additional training (see Dymond & Rehfeldt, 2000). To date, the transfer of functions through equivalence relations has been demonstrated with discriminative (e.g., Barnes & Keenan, 1993; Grey & Barnes, 1996; Roche, Barnes-Holmes, Smeets, Barnes-Holmes, & McGeady, 2000; Wulfert & Hayes, 1988), self-discriminative (Dymond & Barnes, 1994, 1997, 1998), consequential (Hayes, Kohlenberg, & Hayes, 1991; Greenway, Dougher, & Wulfert, 1996), and respondent (Dougher Augustson, Markham, Greenway, & Wulfert, 1994; Roche & Barnes, 1997; Roche et al., 2000) stimulus functions in adults and children. For instance, Barnes and Keenan (1993) first trained participants on a series of related conditional discriminations in a MTS format (i.e., A1-B1, A1-C1, A2-B2, A2C2), and then explicitly trained high-rate and low-rate performances on a schedule task in the presence of the two B stimuli (i.e., B1 = low-rate, B2 = high-rate). Subsequently, the researchers demonstrated a transfer of discriminative control over the two types of schedule performance through derived equivalence relations (i.e., C1 = low rate, and C2 = high rate), without any further training. The transfer of stimulus functions may have implications for a contemporary understanding of complex behavior, and the research topics investigated usually reflect this. Several studies have either employed procedures germane to a behavioral analysis of, for instance, self-awareness (e.g., Dymond & Barnes, 1997), sexual arousal (Roche & Barnes, 1997), rule-following (Barnes-Holmes, Healy, & Hayes, 2000), and attitude formation (Grey & Barnes, 1996) or have highlighted similarities between the transfer of functions and complex behavior beyond the laboratory (e.g., Friman, Hayes, & Wilson, 1998; Roche et al., 2000; Wilson & Hayes, 2000). An important issue in much of this research is the development of new procedures to measure the transfer of functions in ways that formally resemble the behavior of interest. …

Stimulus equivalence as a function of training protocol in a connectionist network.

Abstract Previous research on stimulus equivalence has demonstrated an advantage for one-to-many training protocols over linear procedures when training subjects using a matching-to-sample (MTS) task. In the current study, the relative merits of these training designs were explored in a connectionist simulation of a MTS procedure. Following minimal pre-training, a network was exposed to a series of conditional discrimination-type tasks using a linear or one-to-many training protocol. Following training to criterion, equivalence performance was assessed. The results showed a detrimental effect of linear series training, with substantially more training required to reach criterion performance and subsequent failure to demonstrate equivalence. By contrast equivalence was readily demonstrated using a one-to-many procedure. Possible explanations for this pattern are addressed from a connectionist perspective and application to the human context is discussed. Keywords: stimulus equivalence; training design; connectionism. Introduction Stimulus equivalence is a behavioral effect that would appear to be restricted to language-able humans and is readily demonstrated under a range of conditions in this population (e.g., Barnes, McCullough & Keenan, 1990; Devany, Hayes & Nelson, 1986; Mackay & Sidman, 1984). The effect is typically investigated using a matching-to-sample (MTS) format to expose participants to a series of conditional discriminations using arbitrary stimulus pairings. The stimuli employed may be nonsense syllables or abstract shapes (here alphanumerics are used to denote such stimuli). Training involves the presentation of a set of comparison stimuli from which a target must be selected when a given sample is present. For example, positive reinforcement may be provided for selecting B1 given A1, from the comparisons B1, B2, B3, and C1 given A1, from the comparisons C1, C2, C3. In this case, equivalence is demonstrated when the subject produces C1 given B1, from C1, C2, C3, in the absence of further explicit training. Three properties are required for stimulus equivalence, symmetry, transitivity, and reflexivity, and each of these must be shown by a participant in the absence of direct reinforcement (Sidman & Tailby, 1982). Reflexivity is identity matching and is shown when the stimulus is mapped onto itself; that is when A1 is produced given A1 (i.e. A1-A1). Symmetry is shown when A1 is produced in the presence of B1, following training to produce B1 in the presence of A1 (i.e. A1-B1 therefore B1-A1). To demonstrate transitivity at least three stimuli are involved: if B1 is chosen in the presence of A1, and C1 is chosen in the presence of A1, then C1 may emerge as selected in the presence of B1 in the absence of further training (A1-B1 and A1-C1 therefore B1-C1). The emergence of this untaught response is not predicted by traditional investigations of conditional discriminations (Barnes & Hampson, 1993); the B1 and the C1 stimuli have not acted as discriminative stimuli for choosing each other, and therefore are not predicted to reliably control the selection of the other, yet such control is demonstrated in the derived response. This emergent response indicates that stimuli A1, B1, and C1 have come to participate in an equivalence class and may now be functionally substitutable in appropriate contexts. It has been argued that the language-able human can readily produce this derived response in the experimental setting due to an extended and complex history of reinforcement within a verbal community (e.g. Hayes, 1991; Barnes & Hampson, 1993). The precise nature of this pre-experimental history remains elusive. Given that stimulus equivalence is apparently limited to language-able humans, controlled study of this period in an individual's learning history is precluded, and therefore the precise underpinnings of the effect in the experimental setting remain speculative. …

Assessing Relational Learning Deficits in Perspective-Taking in Children With High-Functioning Autism Spectrum Disorder

Perspective-taking, or the ability to demonstrate awareness of informational states in oneself and in others, has been of recent interest in behavioral psychology. This is, in part, a result of a modern behavioral approach to human language and cognition known as Relational Frame Theory, which views perspectivetaking as generalized operant behavior based upon a history of reinforcement for relational responding. Previous lines of research have developed a behavioral protocol for assessing relational learning deficits in perspective-taking and have implicated the lack of perspective-taking as a basis for the social deficits observed in children with autism. However, no empirical investigations have been conducted on relational learning deficits in perspective-taking with autistic populations. The present paper reports 2 experiments that investigated whether children with autism spectrum disorder demonstrated relational learning deficits in a perspective-taking task as compared to their age-matched typicalill developing peers. We also investigated whether accuracy in perspective-taking correlated with scores on standardized instruments commonly used in the assessment of autism spectrum disorder, and whether relational responding in perspective-taking improves following a history of reinforcement for such responding. Results of Experiment 1 demonstrated statistically significant differences in errors as a function of type of relation, while visual inspection revealed that partiCipants with autism spectrum disorder made more errors than typically developing children on 2 of the 3 types of relations examined. Results of Experiment 2 illustrated that a history of reinforced relational responding improved performance on the perspective-taking task.

The effects of observational training on the acquisition of reinforcement for listening.

Abstract Experiment 1 investigated the effects of observational training in a social listener reinforcement game on participants' conversational units in non-instructional settings. Experiment 2 tested the effects of multiple exemplar instruction on the development of The participants who had reader/writer levels of verbal were selected because they emitted a low number of and listener exchanges with and did not have empathy as measured in the study. In Experiment 1, data were collected on the number of sequelics, conversational units, wh questions, vocal approvals and vocal disapprovals during 5 minute probe sessions after meeting criterion on each objective of the listener reinforcement game. During intervention, the participants were required to engage in a listener exchange through playing a yoked contingency game where they competed with the experimenter to teach several objectives including I Spy, peer tutoring, textually responding and group instruction. Data showed that the total number of verbal interactions in non-instructional settings significantly increased for both participants. In Experiment 2 multiple exemplar instruction across questions was implemented to teach the participants empathy. The participants responded to 3 questions: What happened? How does the person feel? and What could you do to help? The results showed a significant increase in correct responses to empathy questions. Keywords: autism, empathy, observational training, reinforcement for listening. ********** Many children with autism do not have a history of reinforcement for listening to others. Listening to is a critical component of social experiences that leads to more advanced listener repertoires such as emitting behaviors characterized as empathy. Skinner (1957) proposed a theory on the function of verbal based on operant research. was defined by Skinner as reinforced through the mediation of others (Skinner, 1957, p. 2). is categorized based on function into mands, tacts, intraverbals, autoclitics, echoics, and textual topographies. Skinner (1957) discussed verbal from the point of view of the as mediated by the contingencies of the listener. The listener provides reinforcement for verbal repertoires in the form of providing access to a preferred item or generalized reinforcement. is analyzed through the function of the and is emitted to affect the of a listener. Catania (1998) expanded on Skinner's views and stated that, Verbal involves both listener shaped by its effects on the speaker's behavior, and shaped by its effects on the listener's behavior (Catania, 1998, p. 262) Greer (2002) expands upon Skinner's verbal repertoires. Greer also includes naming, the conversational unit, the learn unit and joint stimulus control as extensions to the operants proposed by Skinner. A conversational unit is defined as one full exchange in which the student emits both a response that is reinforced by the verbal of another person responding as a listener and in turn a listener response by the initial speaker (Greer, 2002, p. 91). Conversational units are directly reinforced by the listener who responds in the role of the (Greer, 1989). Each member must respond as both and listener to complete the conversational unit. Truly social is measured by the presence or absence of conversational units. One emits conversational units because of the reinforcement obtained as both a and a listener (Donley & Greer, 1993; Lodhi & Greer, 1989). The key component of conversational units is the capacity of an individual to be reinforced by listening. If an individual is not reinforced by what another has to say, there will not be a listener exchange, only a sequelic. …

The effect of intruded events on peak time: The role of reinforcement history during the intruded event

Pigeons were studied in an extension of a study by Aum et al. [Aum, S., Brown, B.L., Hemmes, N.S. 2004. The effects of concurrent task and gap events on peak time in the peak procedure. Behav. Process. 65, 43-56] on timing behavior under a discrete-trial fixed-interval (FI) procedure during which 6-s intruded events were superimposed on peak-interval (PI) test trials. In Aum et al., one event consisted in termination of the timing cue (gap trial); the other was a stimulus in the presence of which subjects had been trained to respond under an independent random-interval (RI) schedule of reinforcement (concurrent task trial). Aum et al. found a disruption of timing on concurrent task trials that was greater than that on gap trials. The present study investigated history of reinforcement associated with intruded events as a possible explanation of this earlier finding. After training to peck a side key on a 30-s PI procedure, discrimination training was conducted on the center key in separate sessions; red or green 6-s stimuli were associated with RI 24s or EXT (extinction) schedules. During testing under the PI procedure, three types of intruded events were presented during probe trials--the stimulus associated with the RI (S+) or EXT (S-) schedule during discrimination training, or a gap (termination of the side-keylight). Intruded events occurred 3, 9, or 15s after PI trial onset. Effects of reinforcement history were revealed as substantial disruption of timing during the S+ event and relatively little disruption during the S- event. Intermediate effects were found for the gap event. Results indicate that postcue effects are at least partially responsible for the disruptive effects of the S+ event.