Equivalence class formation via identity matching to sample and simple discrimination with class-specific consequences

Human participant performances often show evidence of learning untrained relations when conditional discrimination training between physically dissimilar stimuli is conducted. These emergent relations document equivalence 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 have suggested 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 had received 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

A FORMAÇÃO DE CLASSES DE EQUIVALÊNCIA VIA PAREAMENTO POR IDENTIDADE E DISCRIMINAÇÃO SIMPLES COM CONSEQÜÊNCIAS ESPECÍFICAS PARA AS CLASSES

Human participant performances often show evidence of learning untrained relations when conditional discrimination training between physically dissimilar stimuli is conducted. These emergent relations document equivalence 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 have suggested 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 had received 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. Key words: Stimulus equivalence, matching to sample, simple discrimination, outcome-specific reinforcement,differential outcomes effect, mental retardationO 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 paras 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. Palavras-chave: equivalência de estímulos, pareamento ao modelo, discriminação simples, reforçamento específico, efeito de conseqüência específica, retardo menta

Discriminação Simples e Pareamento ao Modelo com Estímulos Bidimensionais em Macacos-Prego Infantes

This study investigated the possibility of teaching repeated shifts of simple discrimination (RSSD) and identity matching to sample (IDMTS) using two-dimensional stimuli in two experimentally naive infant capuchin monkeys (Sapajus sp.; subjects M24 and M25). RSSD training occurred by alternating trials in which only one stimulus was presented (single stimulus trial) with trials in which two or more stimuli were presented simultaneously. The reinforcement probability was gradually reduced in single-stimulus trials, making this training gradually more similar to the IDMTS procedure. Fifty-nine sessions were conducted with subject M24, and 52 sessions were conducted with subject M25 until the criterion was reached. The subjects then underwent IDMTS training, beginning with two choices and gradually moving to four choices. Forty-eight sessions were conducted with M24, and 50 sessions were conducted with M25 until the criterion was reached. The results showed that infant capuchins can acquire these repertoires. The present results were compared to previous studies that used the same kind of task in adult capuchin monkeys and compared to data obtained in the same task using three-dimensional objects as stimuli in adult and infant capuchins.   Keywords: Simple discrimination; identity matching-to-sample; infant capuchin monkeysInvestigou-se a possibilidade de ensinar discriminações simples com mudanças sucessivas nas funções dos estímulos (DSMS) e matching-to-sample de identidade (IDMTS) com estímulos bidimensionais a dois macacos-prego (Sapajus sp.) infantes (M24 e M25) e experimentalmente ingênuos. O treino de DSMS alternou tentativas nas quais apenas um estímulo era apresentado (tentativa com estímulo único) com tentativas com dois ou mais estímulos apresentados simultaneamente. Foi feita uma redução gradual da probabilidade de reforçamento nas tentativas com estímulo único, aproximando esse treino ao de IDMTS. Foram necessárias 52 sessões de treino para M25 e 59 sessões para M24 até que o critério de aprendizagem fosse alcançado. O treino de IDMTS iniciou com dois modelos e duas comparações e continuou até atingir quadro modelos e quatro comparações. Foram necessárias 48 sessões com M24 e 51 com M25 para que as discriminações fossem aprendidas. Os resultados demonstraram que macacos-prego infantes podem adquirir ambos os repertórios. Os resultados são comparados com os de macacos-prego adultos nas mesmas tarefas e com os de macacos-prego adultos e infantes nas mesmas tarefas realizadas com objetos tridimensionais.   Palavras-chave: Discriminação simples; matching-to-sample de identidade; macaco-prego infante

Restricted stimulus control in stimulus control shaping with a capuchin monkey

Teaching the first instances of arbitrary matching-to-sample to nonhumans can prove difficult and time consuming. Stimulus control relations may develop that differ from those intended by the experimenter—even when stimulus control shaping procedures are used. We present, in this study, efforts to identify sources of shaping program failure with a capuchin monkey. Procedures began with a baseline of identity matching. During subsequent shaping trials, compound comparison stimuli had two components—one identical to and another different from the sample. The identical component was eliminated gradually by removing portions across trials (i.e., subtracting stimulus elements). The monkey performed accurately throughout shaping. At a late stage in the program, probe tests were conducted: (1) arbitrary matching trials that had all elements of the identical comparison removed and (2) other trials that included residual elements. During the test, the monkey performed at low levels on the former trials and higher levels on the latter. These results suggested that higher accuracy was due merely to continued control by the residual elements: the target arbitrary matching relations had not been learned. Thus, it appears that procedures that gradually transform identity matching baselines into arbitrary matching can fail by inadvertently shaping restricted control by residual elements. Subsequent probes at the end of the shaping series showed a successful transfer of stimulus control from identity to arbitrary matching after further programming steps apparently overcame the restricted stimulus control

Análise do Controle de Estímulos resultante da Manipulação do número de escolhas em Treino Discriminativo com Macacos-Prego (Sapajus Sp.)

Previous studies evaluated the effect of presenting multiple copies of an S- on simple simultaneous discrimination S+/S- train­ing. The present study evaluated whether some control by the nominal features of the stimuli develops in this kind of procedure, in addition to control by the singularity of the S+ (Experiment I). The present study also qualitatively evaluated stimulus control relations produced in this kind of procedure (Experiment II). In Experiment I, capuchin monkeys (Sapajus sp.) underwent discriminative training with three different trial types (two, four, and nine choices). A stimulus control test evaluated whether performance could be maintained when the discriminations learned in the three different trial types where presented in a two-choice procedure. The results showed clear control by the nominal features of the stimuli. In Experiment II, a mask procedure was used to identify the established stimulus control relations (select and/or reject control). The results showed solid reject control for both subjects, with select control also present for one of the subjects. The present study contributes to the research area by presenting a more detailed analysis of stimulus control that is ap­plicable to several studies on the manipulation of the number of choices in discriminative training.Estudos anteriores avaliaram o efeito da apresentação de múltiplas cópias de S- em treino de discriminação simples simul¬tânea S+/S-. O presente estudo avaliou se, nesse tipo de procedimento, algum controle pelas características nominais dos estímulos se desenvolve, além do controle pela singularidade do S+ (Experimento I). Adicionalmente, o presente estudo avaliou qualitativamente as relações de controle produzidas neste tipo de procedimento (Experimento II). No Experimento I, macacos-prego (Sapajus sp.) foram submetidos a treino discriminativo com três tipos diferentes de tentativas (duas, quatro e nove escolhas). Um teste de controle de estímulos avaliou se o repertório aprendido podia ser mantido quando os estímulos utilizados nos três tipos de tentativa eram apre¬sentados na forma de duas escolhas. Os resultados apontam claramente controle pelas características nominais dos estímulos. No Ex¬perimento II, o procedimento de máscara foi utilizado para identificar as relações de controle (por seleção e/ou rejeição) desenvolvidas. Os resultados mostram sólido controle por rejeição para ambos os sujeitos, com controle por seleção também presente para um dos sujeitos. O presente trabalho contribui no sentido de aprofundar a análise do controle de estímulos em estudos sobre a manipulação do número de escolhas em treino discriminativo

DISCRIMINAÇÃO SIMPLES COM ESTÍMULOS AUDITIVOS EM MACACOS-PREGO

A part of human symbolic behavior can be characterized in terms of generalized relational discriminative repertoires. The capuchin monkey (Sapajus sp.) has been used as an animal model to investigate the acquisition of generalized relational discriminative repertoires. It has been shown that this species can learn some of such repertoires (e.g., Identity Matching-to-Sample and Generalized Identity) with visual stimuli. However, little is known about the auditory discriminative capabilities of capuchin monkey, and even less on his intermodal discriminatory repertoire. This study aims to evaluate the acquisition of auditory simple discrimination with three monkeys, using a Go/No-Go procedure. The subjects were exposed to seven pairs of auditory stimuli, each pair comprising one S+ and one S-. The criterion used to change the training pair was reaching discriminative index equal or above 80% in five consecutive sessions. All subjects learned the seven discriminations tasks showing evidence of learning-set across exposition to stimulus sets. These results show the capability of the capuchin monkey to learn auditory simple discriminations in experimental context and enable new studies that seek to teach auditory-visual discrimination for this species. Keywords: Auditory simple discrimination, learning-set, capuchin monkey. Parte do que chamamos de comportamento simbólico no ser humano pode ser caracterizado em termos de repertórios discriminativos relacionais generalizados. O macaco-prego (Sapajus sp.) vem sendo utilizado como modelo animal para investigar a aquisição de repertórios discriminativos relacionais generalizados. Tem sido demonstrado que essa espécie pode aprender alguns desses repertórios (e.g., Matching-to-Sample de identidade e Identidade Generalizada) com estímulos visuais. No entanto, pouco se sabe sobre as capacidades discriminativas auditivas do macaco-prego e, menos ainda, sobre seu repertório discriminativo intermodal. O presente estudo procurou avaliar a aquisição de discriminação simples auditiva com três macacos-prego, utilizando um procedimento do tipo Go/No-Go. Os sujeitos foram expostos a sete pares de estímulos sonoros, com um S+ e um S- cada. O critério adotado para a mudança de par foi a obtenção de um índice discriminativo maior ou igual a 80% em cinco sessões consecutivas. Todos os sujeitos concluíram o treino com indícios de learning-set. Estes resultados mostram a capacidade do macaco-prego em aprender repertório discriminativo simples auditivo em contexto experimental e viabilizam novos estudos que buscam ensinar discriminação auditivo-visual para essa espécie. Palavras-chave: Discriminação simples auditiva, learning-set, macaco-prego.

Procedural Variables in Equivalence Classes Research: Contributions to the Study of Symbolic Behavior

Procedures typically used in Experimental Analysis of Behavior for studying equivalence classes formation may constitute an experimental model for studying symbolic behavior. Equivalence classes formation and symbolic behavior are alike in the fact that dissimilar elements, once arbitrarily related, become equivalent, that is, they become substitutable concerning to the control of the repertoires related to them. Difficulties in obtaining equivalence classes with non-linguistic organisms have lead some theorists to speculate that equivalence class formation, and possibly symbolic behavior, is a phenomenon dependent on linguistic functioning. Some studies reported in the literature, however, suggest that difficulties to obtain equivalence classes with non-linguistic organisms may be due to procedural failure to effectively establish stimulus control relations planned by the experimenter. This paper presents a brief review of basic concepts on equivalence relations, discusses some of the possibilities for development of non-coherent stimulus control in equivalence studies, and briefly points to studies of alternative procedures to select stimulus control relations that cohere with the experimentally planned relations

Generalized identity matching-to-sample in Cebus apella

Explored whether or not conditions could be created under which capuchin monkeys (Cebus apella) might display generalized identity matching-to-sample. The authors employed procedures designed to minimize the effects of several variables that past research suggested might interfere with such emergent matching. These included unwanted stimulus control by location, failure to discriminate defining stimulus features, and stimulus novelty. In Experiment 1, two monkeys displayed accurate simple simultaneous discrimination with three sets of three stimuli each, presented in any of nine locations on a touchscreen-equipped computer monitor. In Experiment 2, the same monkeys were exposed to a 0-delay identity matching training procedure involving one of the stimulus sets from Experiment 1. After the identity-matching baseline was established, identity-matching tests were presented with other three-stimulus sets. For certain sets, the critical initial identity-matching test was preceded by a history of simple discrimination reversals involving the stimuli that would appear on the test. Overall, identity-matching test scores were substantially higher than might be expected by \u27chance\u27. In Experiment 3, two additional new stimulus sets were introduced

A note on select- and reject-controlling relations in the simple discrimination of capuchin monkeys (Cebus apella)

Controlling relations in the simple discrimination performances of capuchin monkeys (Cebus apella) were studied in two experiments using a blank-comparison procedure. The main goal was to determine whether monkeys would (a) select an S+ stimulus if another stimulus was substituted for the S- (indicating a select-controlling relation) and (b) reject an S- if another stimulus was substituted for S+ (indicating a reject-controlling relation). In experiment 1, two simple simultaneous discriminations were established, one of which was reversed repeatedly until rapid reversal learning was exhibited. During subsequent probe tests, some behavior was consistent with select- and reject-controlling relations, but there was also substantial variability. To control the variability, the procedures of experiment 2 were designed to establish select- and reject-control relations directly by training with the blank-comparison procedure. On subsequent probe trials, new stimuli were substituted for the blank comparison. Both animals exhibited consistent, reliable select- and reject-controlling relations. These experiments are the first to employ the blank-comparison procedure with non-human subjects. They also demonstrate a reliable method for generating select- and reject-controlling relations for experimental study