Willingness to produce disadvantageous outcomes in cooperative tasks is modulated by recent experience.

Cooperative behavior represents a situation in which individuals sometimes act in a way that produces a gain to another at a cost to themselves. This may be explained by a history of repeated interactions with others in which such behavior has resulted in reciprocal cooperation from others. Sometimes, even with reciprocal cooperation, gains and costs are unbalanced between partners. In this case, there is evidence that people may present an aversion to both disadvantageous and advantageous distributions of gains. In other words, they may act in such a way as to ensure an equal outcome among all group members. Aversion to inequity that benefits oneself (advantageous inequity (AI) aversion) may be more dependent on social and cultural cues than aversion to inequity that benefits others (disadvantageous inequity (DI) aversion). Using both between-subjects (Experiment 1) and within-subjects (Experiment 2) manipulations, the influence of recent experience with AI on participants' willingness to produce DI was explored within the context of a two-player card game. In initial game phases, the percentage of trials in which the participant experienced AI was manipulated. In subsequent game phases, participants had the opportunity to produce DI to themselves. The results from both experiments suggest that aversion to DI is reduced by recent experience with AI. This procedure allows social influences on DI to be tested, which may be important for providing a psychological explanation of cultural differences in aversion to DI.

Practical Considerations for Researchers at Teaching-Focused Colleges.

Growth in the discipline of behavior analysis depends on research production in basic, translational, and applied areas from a variety of perspectives and research groups. Although doctoral programs in behavior analysis prepare students to become productive researchers, leading behavior-analytic journals tend to publish articles from a more circumscribed set of researchers than might be expected given the recent growth in the field. One reason may be that as new researchers graduate from their training programs, they take positions in very different environments from those of their training, such as teaching-focused colleges or clinical settings. Establishing and maintaining research production in these settings may be challenging due to practical concerns that could be alleviated by recommendations from researchers with experience in those settings. In this article, we identify some of the research challenges faced by early-career behavior analysts working at small teaching-focused colleges and offer practical advice for new researchers in those settings based on our experience. Additionally, we hope this article serves as a catalyst for established researchers working in a variety of settings to share their experiences and wisdom with new researchers in the field.

Reciprocity With Unequal Payoffs: Cooperative and Uncooperative Interactions Affect Disadvantageous Inequity Aversion.

Cooperation among unrelated individuals can evolve through reciprocity. Reciprocal cooperation is the process in which lasting social interactions provide the opportunity to learn about others' behavior, and to further predict the outcome of future encounters. Lasting social interactions may also decrease aversion to unequal distribution of gains - when individuals accept inequity payoffs knowing about the possibility of future encounters. Thus, reciprocal cooperation and aversion to inequity can be complementary phenomena. The present study investigated the effects of cooperative and uncooperative interactions on participants' aversion to disadvantageous inequity. Participants played an experimental task in the presence of a confederate who acted as a second participant. In reality, the participant interacted with a computer programed to make cooperative and uncooperative choices. After interacting with a cooperative or uncooperative computer, participants chose between blue cards to produce larger gains to the computer and smaller for him/her or green cards to produce equal and smaller gains for both. Results confirmed our first hypothesis that uncooperative interactions would produce aversion to disadvantageous inequity. Lastly, half of the participants were informed that points received during the experiment could be later exchanged for money, and half were not. Results indicated that information about monetary outcomes did not affect aversion to inequity, contradicting our second hypothesis. We discuss these results in the light of theories of reciprocal cooperation, inequity aversion, and conformity.

Expansion of Sidman's theory: The inclusion of prompt stimuli in equivalence classes.

Stimulus equivalence is defined as the ability to relate stimuli in novel ways after training in which not all of the stimuli had been directly linked to one another. Sidman (2000) suggested all elements of conditional discrimination training contingencies that result in equivalence potentially become class members. Research has demonstrated the inclusion of samples, comparisons, responses, and reinforcers in equivalence classes. Given the evidence that all elements of a conditional discrimination become part of the class, the purpose of this study was to determine if class-specific prompts would also enter into their relevant equivalence classes. Experiment 1 investigated the inclusion of prompts in an equivalence class using abstract stimuli with neurotypical students enrolled in higher education courses. Experiment 2 systematically replicated Experiment 1 using meaningful stimuli and individuals diagnosed with autism spectrum disorder. The results of both experiments demonstrated that class-specific prompts became part of equivalence classes with the other positive elements of the contingency. The results are discussed in terms of class expansion and the potential impact on equivalence-based instruction.

An update on the search for symmetry in nonhumans.

Sidman et al.'s (1982) failure to find evidence for symmetry (bidirectional associations between stimuli) in monkeys and baboons set the stage for decades of work on emergent relations in nonhumans. They attributed the failure to the use of procedures that did not (1) promote stimulus control based on the relation between the sample and correct comparison and (2) reduce control by irrelevant stimulus features. Previous reviews of symmetry in nonhumans indicated that multiple exemplar training and successive matching might encourage appropriate stimulus control. This review examined 16 studies that investigated symmetry in 94 subjects, including pigeons, rats, capuchin monkeys, and baboons. Several studies used alternative training procedures to minimize sources of irrelevant stimulus control, and many combined multiple exemplar training with other procedural modifications. Symmetry was observed in approximately 30% of subjects. Studies that reported the strongest evidence for symmetry used successive matching-to-sample procedures that included training on both symbolic and identity relations, and studies finding mixed evidence employed alternative methods. These studies highlight the challenge in creating training procedures that promote symmetry and the need to assess the underlying sources of control on positive demonstrations.

The establishment of auditory-visual equivalence classes with a go/no-go successive matching-to-sample procedure.

The current study evaluated the effectiveness of a go/no-go successive matching-to-sample procedure (S-MTS) to establish auditory-visual equivalence classes with college students. A sample and a comparison were presented, one at a time, in the same location. During training, after an auditory stimulus was presented, a green box appeared in the center of the screen for participants to touch to produce the comparison. Touching the visual comparison that was related to the auditory sample (e.g., A1B1) produced points, while touching or refraining from touching an unrelated comparison (e.g., A1B2) produced no consequences. Following AB/AC training, participants were tested on untrained relations (i.e., BA/CA and BC/CB), as well as tacting and sorting. During BA/CA relations tests, after touching the visual sample, the auditory stimulus was presented along with a white box for participants to respond. During BC/CB relations tests, after touching the visual sample, a visual comparison appeared. Across 2 experiments, all participants met emergence criterion for untrained relations and for sorting. Additionally, 14 out of 24 participants tacted all visual stimuli correctly. Results suggest the auditory-visual S-MTS procedure is an effective alternative to simultaneous MTS for establishing conditional relations and auditory-visual equivalence classes.

Thematic Matching as Remedial Teaching for Symbolic Matching for Individuals with Autism Spectrum Disorder.

Matching-to-sample (MTS) is often used to teach symbolic relationships between spoken or printed words and their referents to children with intellectual and developmental disabilities. However, many children have difficulty learning symbolic matching, even though they may demonstrate generalized identity matching. The current study investigated whether training on symbolic MTS tasks in which the stimuli are physically dissimilar but members of familiar categories (i.e., thematic matching) can remediate an individual's difficulty learning symbolic MTS tasks involving non-representative stimuli. Three adolescent males diagnosed with autism spectrum disorder were first trained on symbolic MTS tasks with unfamiliar, non-representative form stimuli. Thematic matching was introduced after the participants failed to learn 0, 2 or 4 symbolic MTS tasks and before additional symbolic MTS tasks were introduced. After exposure to thematic matching, accuracy on symbolic MTS tasks with novel stimuli increased to above chance for all participants. For two participants, high accuracy (> 90%) was achieved on a majority of these sessions. Thus, thematic matching may be an effective intervention for students with limited verbal repertoires and who have difficulty learning symbolic MTS tasks. Possible explanations for the facilitative effect of thematic matching are considered and warrant further investigation.

Evidence for response membership in stimulus classes by pigeons.

Response membership in pigeons' stimulus-class formation was evaluated using associative symmetry and class expansion tests. In Experiment 1, pigeons learned hue-hue (AA) and form-form (BB) successive matching plus a modified hue-form (AB) task in which reinforcement was contingent upon a left versus right side-key response after the positive AB sequences. On subsequent BA (symmetry) probe trials, pigeons responded more often to the comparisons on the reverse of the positive than negative AB sequences and, more importantly, preferentially pecked the side key consistent with symmetry after the reversed positive sequences. In Experiment 2, the original three baseline tasks were supplemented by dot-white (CC) successive matching in which reinforcement was contingent upon a left versus right side-key response after the positive CC sequences. Class expansion was then tested by presenting nonreinforced CA and CB successive matching probes. Comparison response rates were mostly nondifferential on CA probes but were uniformly higher on CB probes that consisted of the C samples and B comparisons from the same, hypothesized class. Together, these results provide evidence that responses can become members of stimulus classes, as predicted by Urcuioli's (2008) theory of pigeons' stimulus-class formation and Sidman's (2000) theory of equivalence.

Membership of Defined Responses in Stimulus Classes.

Sidman (2000) has suggested that in addition to conditional and discriminative stimuli, class-consistent defined responses can also become part of an equivalence class. In the current study, this assertion was tested using a mixed-schedule procedure that allowed defined response patterns to be "presented" as samples in the absence of different occasioning stimuli. Four typically developing adults were first trained to make distinct response topographies to two visual color stimuli, and then were taught to match those color stimuli to two different form-sample stimuli in a matching task. Three separate tests were given in order to determine whether training had established two classes each comprised of a response, a color, and a form: a form-response test in which the forms were presented to test if the participants would make differential responses to them; and two response-matching tests to test if the participants would match visual stimulus comparisons to response-pattern samples. Three of the four participants showed class-consistent responding in the tests, although some participants needed additional training prior to passing the tests. In general, the data indicated that the different response patterns had entered into a class with the visual stimuli. These results add to a growing literature on the role of class-consistent responding in stimulus class formation, and provide support for the notion that differential responses themselves can become a part of an equivalence class.

Contextual influences on resistance to disruption in children with intellectual disabilities.

Training context can influence resistance to disruption under differing reinforcement schedules. With nonhumans, when relatively lean and rich reinforcement schedules are experienced in the context of a multiple schedule, greater resistance is found in the rich than the lean component, as described by behavioral momentum theory. By contrast, when the schedules are experienced in separated blocks of sessions (i.e., as single schedules), resistance is not consistently greater in either component. In the current study, two groups of 6 children with intellectual disabilities responded to stimuli presented in relatively lean or rich components. For both, reinforcers were delivered according to the same variable-interval reinforcement schedule; additionally, the rich component included the delivery of response-independent reinforcers. The Within group was trained on a multiple schedule in which lean and rich components alternated regularly within sessions; the Blocked group was trained on two single schedules in which sessions with either the lean or rich schedule were conducted in successive blocks. Disruption tests presented a concurrently available alternative stimulus disrupter signaling the availability of tangible reinforcers. All 6 Within participants showed greater resistance to disruption in the rich component, consistent with behavioral momentum theory. By contrast, there was no consistent or significant difference in resistance for Blocked participants. This finding is potentially relevant to the development of interventions in applied settings, where such interventions often approximate single schedules and include response-independent reinforcers.

Evaluation of resistance to change under different disrupter conditions in children with autism and severe intellectual disability.

Translational research inspired by behavioral momentum theory in the area of developmental disabilities has shown effects in individuals over a range of functioning levels. In the current study, behavioral momentum was assessed in 6 children diagnosed with autism and severe intellectual disability. In a repeated measures design, participants were exposed to relatively rich versus lean reinforcement contingencies in a multiple schedule with food reinforcers. This was followed by exposure to each of four disrupting conditions: prefeeding, presentation of a concurrent alternative stimulus, presentation of a movie, and the presence of a researcher dispensing response-independent reinforcers on a variable-time schedule. Consistently greater resistance to disruption in the component with the richer schedule occurred with the alternative stimulus disrupter but not with the other disrupters. These results suggest parameters that may be more (or less) effective if behavioral momentum inspired techniques are to be exploited in therapeutic environments.

The search for symmetry: 25 years in review.

It has been 25 years since the publication of Sidman et al.'s (1982) report on the search for symmetry in nonhuman animals. They attributed their nonhuman subjects' failure to the absence of some critical experiences (e.g., exemplar training, control of location variables, and generalized identity matching). Since then, species ranging from rats to chimpanzees have been tested on symmetry, and the results have been equivocal. Twenty-four investigations of symmetry in nonhumans are reviewed to determine whether the underlying factors first addressed by Sidman et al. (1982) have been verified and whether new factors have been identified. The emergent picture shows that the standard procedures as typically implemented on a three-key apparatus are insufficient by themselves to produce emergent symmetry in nonhumans. Recent successful demonstrations of symmetry in sea lions and pigeons have clarified certain important stimulus control variables (i.e., select and reject control) and suggest avenues for future research. Reliable symmetry may be achievable with nonhumans if training and test procedures that encourage compatible stimulus-control topographies and relations are designed.

REVERSAL LEARNING SET AND FUNCTIONAL EQUIVALENCE IN CHILDREN WITH AND WITHOUT AUTISM.

To evaluate whether children with and without autism could exhibit (a) functional equivalence in the course of yoked repeated-reversal training and (b) reversal learning set, 6 children, in each of two experiments, were exposed to simple discrimination contingencies with three sets of stimuli. The discriminative functions of the set members were yoked and repeatedly reversed. In Experiment 1, all the children (of preschool age) showed gains in the efficiency of reversal learning across reversal problems and behavior that suggested formation of functional equivalence. In Experiment 2, 3 nonverbal children with autism exhibited strong evidence of reversal learning set and 2 showed evidence of functional equivalence. The data suggest a possible relationship between efficiency of reversal learning and functional equivalence test outcomes. Procedural variables may prove important in assessing the potential of young or nonverbal children to classify stimuli on the basis of shared discriminative functions.

A NOVEL METHOD FOR TEACHING THE FIRST INSTANCES OF SIMPLE DISCRIMINATION TO NONVERBAL CHILDREN WITH AUTISM IN A LABORATORY ENVIRONMENT.

A novel method for initiating discrimination training with nonverbal children combines a delayed S+ procedure that requires children to refrain from responding to either of 2 physically different choice stimuli until a prompt stimulus is added onto 1 of the choices, and a delayed prompting procedure that presents the same 2-choice stimulus display, but stimuli are initially added onto both choices. After a short delay, the added stimulus on the S- is removed, and the choice of the S+ is thus prompted. If the children learn to observe and respond to the defining features of the S+ choice stimulus, then they may respond to the S+ prior to the added-stimulus removal. Implementation was successful with 8 nonverbal children who had not previously exhibited simple simultaneous discrimination, suggesting a useful methodology for initiating discrimination training with populations for whom verbal instruction is ineffective.

Failure to replicate the 'work ethic" effect in pigeons.

We report six unsuccessful attempts to replicate the "work ethic" phenomenon reported by Clement, Feltus, Kaiser, and Zentall (2000). In Experiments 1-5, pigeons learned two simultaneous discriminations in which the S+ and S- stimuli were obtained by pecking an initial stimulus once or multiple (20 or 40) times. Subsequent preference tests between the S+ stimuli and between the S- stimuli mostly revealed indifference, on average, between the S+ from the multiple-peck (high-effort) trials and the S+ from the one-peck (low-effort) trials, and likewise between the two respective Sstimuli. Using a slightly different procedure that permitted assessment of the relative aversiveness of low versus high effort, Experiment 6 again revealed a pattern of indifference despite showing that pigeons took considerably longer to begin pecking on high- than on low-effort trials. Our findings call into question the reliability of the original findings and the sufficiency of the hypothesized within-trial contrast mechanism to produce them.

When is a failure to replicate not a type II error?

Zentall and Singer (2007) challenge our conclusion that the work-ethic effect reported by Clement, Feltus, Kaiser, and Zentall (2000) may have been a Type I error by arguing that (a) the effect has been extensively replicated and (b) the amount of overtraining our pigeons received may not have been sufficient to produce it. We believe that our conclusion is warranted because (a) the original effect has not been replicated despite multiple attempts to do so and (b) the statement that more extended overtraining may be needed itself suggests that the original effect is not reliable.

A formação de classes de equivalência via pareamento por identidade e discriminação simples com conseqüências específicas para as classes / Equivalence class formation via identity matching to sample and simple discrimination with class-specific consequences

O desempenho de participantes humanos freqüentemente mostra aprendizagem de relações não diretamente ensinadas após o treino de discriminações condicionais entre estímulos fisicamente diferentes. Essas relações emergentes documentam a formação de classes de equivalência. O presente estudo investigou se conseqüências específicas para as classes (i.e., reforçadores específicos usados para cada classe potencial durante o treino) também integram as classes de equivalência. Vários estudos anteriores sugeriram que as conseqüências específicas podem integrar as classes, entretanto, o treino nesses estudos inclui pareamento arbitrário e pareamento por identidade.No presente estudo, duas crianças autistas foram submetidas apenas a treino de reversões de discriminações simples e pareamento por identidade com conseqüências específicas paras as classes potenciais. Então, testes de pareamento arbitrário foram conduzidos. O desempenho das crianças evidenciou a formação de classes nestes testes, a despeito de elas não terem experiência de treino de pareamento arbitrário. Adicionalmente, um dos participantes mostrou evidência de formação de classes após treino de reversões de discriminação simples somente. Esses resultados tanto demonstram que as conseqüências reforçadoras de fato se tornam parte das classes de equivalência, quanto dão suporte à idéia de que equivalência surge das contingências de reforçamento e não é baseada em habilidades lingüísticas.(AU)

Human participant performances often show evidence of learning untrained relations when conditional discrimination training between physically dissimilar stimuli is conducted. These emergent relations documentequivalence class formation. The current study investigated whether class-specific consequences (i.e. the specific reinforcers used for each potential class during training) also join the equivalence class. Several studies havesuggested they do so. However, training in those studies typically included arbitrary matching and identity matching baselines. In the current study, two autistic children were trained on simple discrimination reversals and identity matching with class specific consequences. They were then given arbitrary matching probes. Performances of both children initially showed evidence of class formation on these tests, despite the fact that neither hadreceived training on arbitrary matching. In addition, one of the participants showed evidence of class formation after simple discrimination reversal training alone. These results demonstrate that the reinforcing consequences do in fact become part of the stimulus equivalence class and provide support for the ideas that equivalence (1) arises from reinforcement contingency and (2) is not based upon language skills.(AU)

The role of common reinforced comparison responses in acquired sample equivalence.

Different samples occasioning the same reinforced comparison response in matching-to-sample are interchangeable for one another outside of original training. The present studies were designed to verify the role of these common responses in producing acquired sample equivalence by explicitly varying the presence or absence of this commonality during training. In each of the two experiments, one group of pigeons made the same reinforced choice response following multiple sample stimuli, whereas controls either made different reinforced choices following each sample (Experiment 1) or reinforced choices after only two of four center-key stimuli (Experiment 2). Later, two of the original samples/center-key stimuli were established as conditional cues for new comparison responses, after which the ability of the remaining samples/center-key stimuli to occasion those new responses was assessed. Following common-response training, matching accuracy was higher on class-consistent than on class-inconsistent transfer tests, whereas accuracy in the controls was generally intermediate between these two extremes, a pattern similar to that reported in the human paired-associate literature. These findings confirm that occasioning the same reinforced choice response is one means by which disparate samples become functionally equivalent.