Stimulus Equivalence Research Articles

The interaction of global motion and global form processing on the perception of implied motion: An equivalent noise approach

Global motion and global form are proposed to be processed through functionally differentiated independent channels along dorsal (motion) and ventral (form) pathways. However, more recent studies show significant interactions between these pathways by inducing the perception of motion (implied motion) from presenting the independent frames of static Glass patterns. The mechanisms behind such interaction are not adequately understood with studies showing a larger contribution of either a motion or form processing mechanism. In the current study, we adapted the equivalent noise paradigm to disentangle the effect of internal noise (local processing) and sampling efficiency (global processing) on global motion, global form, and the interaction of both on the perception of implied motion using physically equivalent stimuli. Six visually normal observers discriminated the direction or orientation of random dot kinematograms (RDK), static Glass patterns (Glass), and dynamic Glass patterns (dGlass) whose directions/orientations were determined by the means of normal distributions with a range of direction/orientation variances that served as external noise. Thresholds (τ) showed a consistent pattern across observers and external noise levels, where τGlass > τdGlass > τRDK. Nested model comparisons where the thresholds were related to the external noise, internal noise, and the sampling efficiency revealed that the difference in performance between the tasks was best described by the change in sampling efficiency with invariable internal noise. Our results showed that the higher thresholds for implied motion compared to real motion could be due to inefficient pooling of local dipole orientation cues at global processing stages involving motion mechanisms.

Rule-governed behavior: An ongoing RFT-based operant analysis


 Rule-governed behavior is broadly defined as verbal antecedent stimuli that specify dependence relations between stimuli and events. Since its conception, this definition has supported a relatively rich program of research within the experimental analysis of behavior. Specifically, researchers have sought to explore the extent to which verbal rules are involved in operant behavior, both in the basic and applied domains. However, some have highlighted the need for a more complete understanding of what “specification” means in the context of rule-following and behavior analysis. The current article aims to present an operant account of what it means to understand and follow verbal rules, drawing largely on stimulus equivalence, and focusing in particular on a relational frame theory (RFT) perspective. To this end, we provide an overview of an RFT-based operant account of rule-following as it currently stands, and outline a recent program of experimental research that has utilized this approach to explore the complexities involved in rule-following in the face of competing reinforcement contingencies, a phenomenon typically linked to human psychological suffering. Implications for going forward in developing a more complete operant account of rule-governed behavior in both the basic and applied domains are considered.

자극 등가 관계(Stimulus Equivalence Relations)에 있는 자극들에 대한 청자 반응 훈련이 파생적 청자 반응과 인트라 버벌(Intraverbal) 반응의 출현에 미치는 영향

The purpose of this study was to examine effects of listener training on emergent selection as listener responses and intraverbal as speaker responses using stimuli within equivalent relations. Two 4 to 5 year old children with developmental disabilites participated in the study. A multiple baseline across participants with multiple probes design was used. Stimulus classes used were vocal stimuli of names of occupations, A; visual stimuli representing the occupations, B; vocal stimuli describing functions of the occupations, C; and visual stimuli depicting functions of the occupation, D. Listener training were provided within A-B, C-D relations. Derived listener responses within A-D relation and interverbal as speaker responses within A-C relations were tested. The results showed that the two participants demonstrated targeted emergent listener and intraverbal responses. The results were discussed within stimulus equivalence paradigm.

Naming of Stimuli in Equivalence Class Formation in Children

In the present study, two typically developing 4-year-old children, Pete and Joe, were trained six conditional discriminations and tested for the formation of three 3-member equivalence classes. Pete and Joe did not establish the AC relation within 600 trials and were given two conditions of preliminary training, including naming of stimuli with two different stimulus sets. Pete started with preliminary training with common naming of stimuli, followed by conditional-discrimination training and testing for emergent relations, and continued with preliminary training on individual naming of stimuli, followed by the same training and testing as described previously. Joe experienced the same conditions but in reversed order. Pete responded in accordance with equivalence in the second round in the condition with common naming. In the first round of testing in the condition with individual naming, he responded in accordance with equivalence. In the condition with individual naming, Joe did not respond in accordance with stimulus equivalence but established all of the directly trained relations during training. In the condition with common naming, he responded in accordance with equivalence in the first round of testing. The results from the experiment support earlier findings that both common and individual naming could facilitate the emergence of equivalence classes.

Mediated Generalization and Stimulus Equivalence

From the 1930s to the 1970s a large number of experimental studies on mediated generalization were published, and this research tradition provided an important context for early research on stimulus equivalence. Mediated generalization and stimulus equivalence have several characteristics in common, notably that both traditions seek to experimentally investigate derived responding among arbitrarily related stimuli in human participants. Although studies of stimulus equivalence are currently being regularly published, few studies investigate mediated generalization in humans today, and the research tradition is mainly of historical interest. The current article will give an account of the origin, the development, and the demise of research on mediated generalization, including a presentation of publication trends, experimental methodology, and the conceptual context research on mediated generalization took place within. Finally, some thoughts on the demise of mediated generalization and its relevance for modern research on stimulus equivalence and other types of derived responding are presented, including reflections on the observability of explanatory variables and the use of inferential statistics.

ACA game for individuals with Autism Spectrum Disorder

This article presents a computerized application for the literacy of children with Autistim Spectrum Disorder (ASD) in Portuguese language, which has PECS (Picture Exchange Communication System) using pictographs related to Activities of Daily Living (ADLs). ADLs can be considered as skills learned in childhood and include self-care and personal hygiene activities. The purpose of this article is to show the validation activities of the ACA game that was designed for individuals with autism. Using these PECS is also expected to familiarize the children with the activities they have to carry out every day. The literacy methodology used encourages the teaching of rudimentary skills through the technique of stimulus equivalence. We used the TEACCH teaching program, which is generally suggested for children with ASD, for promoting the learning with independence, autonomy and functionality. Elementary Tetrad (Technology, Mechanics, Story, and Aesthetics) is presented for the creation of an educational game, taking into account the communication deficits, socialization and repetitive behaviors that children with autism present. After analyzing the collected data, it was possible to verify that the ACA application mainly helps in the recognition of images, perceiving the vocabulary gain of the children. This perception was observed by 28 autistic participants in the study. Some of them, who were already in the process of literacy, had an improvement in reading as well.

Enhanced Equivalence Projective Simulation: A Framework for Modeling Formation of Stimulus Equivalence Classes.

Formation of stimulus equivalence classes has been recently modeled through equivalence projective simulation (EPS), a modified version of a projective simulation (PS) learning agent. PS is endowed with an episodic memory that resembles the internal representation in the brain and the concept of cognitive maps. PS flexibility and interpretability enable the EPS model and, consequently the model we explore in this letter, to simulate a broad range of behaviors in matching-to-sample experiments. The episodic memory, the basis for agent decision making, is formed during the training phase. Derived relations in the EPS model that are not trained directly but can be established via the network's connections are computed on demand during the test phase trials by likelihood reasoning. In this letter, we investigate the formation of derived relations in the EPS model using network enhancement (NE), an iterative diffusion process, that yields an offline approach to the agent decision making at the testing phase. The NE process is applied after the training phase to denoise the memory network so that derived relations are formed in the memory network and retrieved during the testing phase. During the NE phase, indirect relations are enhanced, and the structure of episodic memory changes. This approach can also be interpreted as the agent's replay after the training phase, which is in line with recent findings in behavioral and neuroscience studies. In comparison with EPS, our model is able to model the formation of derived relations and other features such as the nodal effect in a more intrinsic manner. Decision making in the test phase is not an ad hoc computational method, but rather a retrieval and update process of the cached relations from the memory network based on the test trial. In order to study the role of parameters on agent performance, the proposed model is simulated and the results discussed through various experimental settings.

The Continuity of Context: A Role for the Hippocampus.

Tracking moment-to-moment change in input and detecting change sufficient to require altering behavior is crucial to survival. Here, we discuss how the brain evaluates change over time, focusing on the hippocampus and its role in tracking context. We leverage the anatomy and physiology of the hippocampal longitudinal axis, re-entrant loops, and amorphous networks to account for stimulus equivalence and the updating of an organism's sense of its context. Place cells have a central role in tracking contextual continuities and discontinuities across multiple scales, a capacity beyond current models of pattern separation and completion. This perspective highlights the critical role of the hippocampus in both spatial cognition and episodic memory: tracking change and detecting boundaries separating one context, or episode, from another.

An overview of key papers preceding Sidman equivalence.

In behavior analysis, research on stimulus equivalence has been an area of high activity for more than 45 years. Murray Sidman's contribution was crucial in the development of this field, and, thus, it seems informative to highlight the experiments that were necessary in the development of the descriptive model of equivalence relations and behavior. The purpose of this paper is to provide an overview of the significant work that gave the historical context for Sidman and colleagues' conceptualization of stimulus equivalence as it was presented in 1982. This article emphasizes the 31 papers and chapters written by Sidman and colleagues that focus on research questions within stimulus control. The chapters and papers are organized according to their dimensions in behavior analysis and according to whether they can be categorized as instruction programs or experimental studies. The issues discussed regarding these papers and chapters include types of stimuli, matching, discriminations, and others. Collectively, this early work influenced methods and considerations about stimulus control issues that have been important to the development of stimulus equivalence.

Role of Physician’s Personality on their Drug Prescription Behavior

Physicians Prescription behavior is the results of 4P's namely Product, Physicians, Promotion, and Patient's expectation. In today's world of evidence-based medicine with ever-growing demand in patient expectations, physician- Patient-centric managing a pathological condition is gaining acceptance from the normal disease management approach. Like all citizenry is Unique; similarly, physicians also possess a singular personality that responds differently even to an equivalent stimulus. Aiming for better patient care and Patient expectations, research work across the world has been administered for identifying the perfect physician personality traits right from selection of specialty, knowledge dissemination during the study period, and managing patients during the Practice sessions. However, there's little, or no research conducted thus far, in understanding the "Physician's personality" make-up focussing on their motives, values, preferences in their professional practice. Understanding "physician's personality" traits will lay a robust foundation for developing effective medico-marketing initiatives from the pharmaceutical industry with the assistance of smart and customized marketing initiatives resulting in a healthy environment for physician-Pharma association towards adopting better therapeutic interventions for patient benefit. This review is an effort to specialize in the research work done thus far in understanding the impact of "physician's personality" aimed toward improving patient care. Further research in understanding "Physician's personality" and its role in physicians prescribing decisions will help the Pharma industry towards developing much needed medico-marketing initiatives with optimal utilization of resources towards disseminating the latest therapeutic interventions to the physicians for better patient care which is the stepping stone for Physician-patient centric management.

IMXQB-80: A Quillaja brasiliensis saponin-based nanoadjuvant enhances Zika virus specific immune responses in mice

Vaccine adjuvants are compounds that enhance/prolong the immune response to a co-administered antigen. Saponins have been widely used as adjuvants for many years in several vaccines – especially for intracellular pathogens – including the recent and somewhat revolutionary malaria and shingles vaccines. In view of the immunoadjuvant potential of Q. brasiliensis saponins, the present study aimed to characterize the QB-80 saponin-rich fraction and a nanoadjuvant prepared with QB-80 and lipids (IMXQB-80). In addition, the performance of such adjuvants was examined in experimental inactivated vaccines against Zika virus (ZIKV). Analysis of QB-80 by DI-ESI-ToF by negative ion electrospray revealed over 29 saponins that could be assigned to known structures existing in their congener Q. saponaria, including the well-studied QS-21 and QS-7. The QB-80 saponins were a micrOTOF able to self-assembly with lipids in ISCOM-like nanoparticles with diameters of approximately 43 nm, here named IMXQB-80. Toxicity assays revealed that QB-80 saponins did present some haemolytical and cytotoxic potentials; however, these were abrogated in IMXQB-80 nanoparticles. Regarding the adjuvant activity, QB-80 and IMXQB-80 significantly enhanced serum levels of anti-Zika virus IgG and subtypes (IgG1, IgG2b, IgG2c) as well as neutralized antibodies when compared to an unadjuvanted vaccine. Furthermore, the nanoadjuvant IMXQB-80 was as effective as QB-80 in stimulating immune responses, yet requiring fourfold less saponins to induce the equivalent stimuli, and with less toxicity. These findings reveal that the saponin fraction QB-80, and particularly the IMXQB-80 nanoadjuvant, are safe and capable of potentializing immune responses when used as adjuvants in experimental ZIKV vaccines.

Revisão Sistemática dos estudos experimentais publicados na “Perspectivas em Análise do Comportamento” de 2010 a 2018


 O presente trabalho apresenta uma revisão sistemática dos artigos experimentais publicados na revista brasileira Perspectivas em Análise do Comportamento (RPAC) desde a sua fundação em 2010 até o ano de 2018. Foram consideradas elegíveis para análise todas as pesquisas experimentais. A análise das 15 pesquisas selecionadas revelou: (1) pequeno número de pesquisas experimentais; (2) humanos como principal tipo de participantes utilizado; (3) preferência por delineamentos intra-sujeitos e por registros computadorizados; (4) prevalência de pesquisas básicas; (5) predominância de pesquisas envolvendo equivalência de estímulos; (6) pouco uso da estatística inferencial; e (7) pouca atenção à generalização, integridade e acordo entre observadores em pesquisas aplicadas. Além dessa visão preliminar sobre o comportamento de pesquisa de analistas do comportamento, os dados obtidos pelo presente estudo sugerem a necessidade de uma maior ênfase experimental.

O ensino de habilidades terapêuticas em FAP: uma revisão de literatura


 Nenhuma revisão enfocou exclusivamente em estudos sobre o ensino de FAP para terapeutas. Investigações sobre o ensino de FAP para terapeutas são fundamentais para a sua implementação e disseminação. Este estudo pretendeu realizar uma revisão de literatura com o objetivo de identificar e analisar os estudos empíricos que descreveram, analisaram ou avaliaram estratégias de ensino para a formação de psicólogos em FAP. A busca dos textos ocorreu na plataforma de bases de dados Periódicos CAPES, na base de dados da PEPSIC e no Catálogo de Teses e Dissertações da CAPES, em um site da FAP e nas referências dos estudos. Categorias de análise foram utilizadas para avaliar a qualidade metodológica dos estudos e as estratégias de ensino utilizadas para o treinamento. Foram encontrados 10 artigos e duas dissertações. Foram identificados dois grupos de pesquisa produtivos vinculados a Universidade de Washington e UFPR. Em relação aos aspectos metodológicos, dois estudos foram correlacionais, dois foram estudos de caso e oito empregaram metodologias experimentais. Dos estudos experimentais, quatro utilizaram delineamentos de sujeito único e outros quatro empregaram delineamentos entre grupos. Observou-se a utilização de vários cuidados metodológicos nos dois tipos de estudos experimentais, sendo que o controle experimental aumentou nos estudos mais recentes. As estratégias de ensino utilizadas foram: supervisão (5); treinamento de habilidades em grupo - modalidade online (2) e modalidade presencial (1); e workshop (2).

Do common elements predict class merger: A test of Sidman's theory of equivalence.

The study presented here investigated the effect of common and uncommon elements on class merger as predicted by Sidman in his reconceptualization of stimulus equivalence suggesting that common elements among contingencies can facilitate emergent performances (1994, 1997, 2000). Eight adult participants were exposed to a procedure that arranged for stimulus-reinforcer correlations in Phase 1 and response-reinforcer correlations in Phase 2 of a 3-phase study. In the common element group, the visual images serving as reinforcers were the same in Phase 1 and Phase 2. In the uncommon elements group, the images serving as reinforcers were different in Phases 1 and 2. In Phase 3, participants were given an opportunity to respond but no feedback was programmed. The results showed that participants' responding was well differentiated in the common element group and undifferentiated in the uncommon elements group. These results are predicted by Sidman's revised formulation of the provenance and scope of equivalence relations. Specifically, these data support Sidman's (1994, 1997, 2000) suggestion that elements of a contingency enter into an equivalence class and common elements among contingencies are sufficient to produce class mergers. The findings highlight an emergent simple discrimination and raise some interesting considerations about the definition of equivalence under the new formulation.

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.

Evaluation of transferability of persistence-enhancing effects of reinforcement through stimulus equivalence.

Evaluation of transferability of persistence-enhancing effects of reinforcement through stimulus equivalence.

Effects of preliminary class membership on subsequent stimulus equivalence class formation.

The present study examined the effects of including stimuli previously trained as members of functional classes or equivalence classes on subsequent equivalence class formation, and isolated the effects of preliminary training from those of the acquired function stimuli. Fifty-six adults were assigned to 1 of 5 conditions. The control group (CONT) received no preliminary training prior to the terminal phase. Participants in the other 4 groups learned two 3-member functional classes and two 3-member equivalence classes during the preliminary phase. The terminal equivalence phase trained two 5-member classes (A → B → C → D → E) comprising abstract forms; the C stimuli in the terminal phase were (a) from the preliminary functional classes for 1 group (ACQ-F), (b) from the preliminary equivalence classes for the second experimental group (ACQ-E), (c) pictures of everyday objects for the picture control group (PIC), and (d) novel, unfamiliar stimuli for the preliminary training control group (PRE-CONT). Class formation yields were 100% in the PIC condition and 11% in the CONT condition; however, low yields in the PRE-CONT, ACQ-F, and ACQ-E conditions were unexpected, suggesting that procedural variables in preliminary training account for more of the subsequent effects on class formation than the stimulus control properties of the acquired function stimuli.

Murray Sidman's contributions to clinical behavior analysis.

Murray Sidman was not himself a clinician nor directly involved in clinical research. Nevertheless, his experimental and conceptual work, especially in the area of stimulus equivalence, profoundly influenced the development of clinical behavior analysis. Before his work on stimulus equivalence, clinicians with a behavior analytic world view working with verbally sophisticated humans, were making some progress in understanding clinical phenomena and in developing innovative therapies. However, given the obvious and predominant role of verbal processes in both the development and treatment of clinical problems, that progress was constrained by the existing behavior analytic account of verbal behavior. Most fundamentally, it was hard to understand how, in the apparent absence of direct training, verbal events, even novel verbal events, acquire the functions of the nonverbal events that they stand for or represent. Sidman's work on stimulus equivalence, especially the transfer (transformation) of functions, offered an answer and thereby provided a conceptual framework of symbolic behavior around which clinical behavior analysis could cohere and develop.

Murray Sidman: fostering progress through foundational choices.

The contributions of Murray Sidman to the field of behavior analysis have helped to put the field on a progressive path. In this paper we describe three areas as examples, drawn from the larger set of his notable contributions: the analysis of stimulus equivalence in a way that has fostered a behavior-analytic approach to derived stimulus relations and symbolic meaning; the observation and measurement of individual behavior through time; and his stance against punitive applied methods. In each of these areas Sidman was a dedicated behaviorist, avoiding appeals to mentalistic or transcendental forces, opposing hypothetical mediational accounts, and taking a functional and contextual approach. Clarity of assumptions was at the heart of Sidman's effective scientific practices and there is no reason to think that those same assumptions will not carry us further, as evidence mounts in support of these views on psychological research and practice.

Citations of Murray Sidman's work in JEAB: Evidence of a long and large contribution.

We examined citations of Murray Sidman's publications in the Journal of the Experimental Analysis of Behavior from the journal's inception in 1958 through May 2020. On average, he was cited 35.6 times per year. The rate of citation did not change substantially across time and the cumulative citation count was 2,212. His 10 publications cited most often deal with behavior-analytic research methods, stimulus equivalence, and unsignaled free-operant (or Sidman) avoidance. Our data provide clear evidence of the breadth and depth of Sidman's influence on the experimental analysis of behavior across 7 decades. His contributions were both exceptional and praiseworthy and his legacy will long endure.