EQUIVALENCE RELATIONS, CONTEXTUAL CONTROL, AND NAMING

Stimulus meaningfulness has been defined by its hedonic valence, denotative (definitional) and connotative (evaluative) properties, and its influence on forming categories called equivalence classes. Positive or negative hedonic value of a meaningful stimulus transfers to the other members of an equivalence class that contains such a stimulus, and also influences likelihood of class formation. The denotative and connotative properties of meaningful stimuli are instantiated by the responses they produced (simple discriminative functions) and by the selection of other related words (conditional discriminative functions). If a meaningless cue acquires one such stimulus control function, and is included in a set of otherwise meaningless stimuli, its inclusion enhances the formation of an equivalence class. These results suggest ways to enhance equivalence class formation in applied settings. When degree of enhancement matches that produced by the inclusion of a meaningful stimulus in a class, class enhancement can be accounted for by the stimulus control functions it serves, as well as its hedonic, denotative, and connotative properties. We also linked equivalence class formation and meaningfulness to semantic networks, relational frame theory, verbal behavior, and naming.

Three experiments identified factors that did and did not enhance the formation of two-node four-member equivalence classes when training and testing were conducted with trials presented in a trace stimulus pairing two-response (SP2R) format. All trials contained two separately presented stimuli. Half of the trials, called within-class trials, contained stimuli from the same class while the other half, called cross class trials, contained stimuli from different classes. On within class trials, making a YES response was correct and making a NO response was wrong. On cross class trials, making a NO response was correct and making a YES response was wrong. In Experiment 1, similar intermediate percentages of participants (about 50%) formed classes, regardless of whether the responses were labeled YES and NO or SAME and DIFF. Response labeling thus did not influence class formation. Regardless of response labels, failures of class formation were primarily due to failure of class-indicative responding produced by within-class transitivity probes. In Experiment 2, only 50% of participants formed classes without prior training, as in Experiment 1, but 100% of participants formed equivalence classes after the establishment of a generalized transitivity repertoire by use of a programmed transitivity induction protocol. Experiment 3 examined two components of the programmed transitivity induction protocol and found that the exclusion of AC trials had no effect on the percentage of participants who formed equivalence classes, while presenting the stimulus sets in randomized order interfered with equivalence class formation. A further analysis found that a number of stimulus control topographies differentiated between individuals who did and did not form equivalence classes. In general, then, these experiments demonstrate that equivalence classes can be formed reliably when training and testing are conducted in an SP2R format, supporting the view that equivalence class formation can account for the development of conceptual categories in natural settings.

\n O processo de envelhecimento pode gerar perdas cognitivas que, se agravadas, podem acarretar o diagnóstico de demência, sendo a Demência de Alzheimer (DA) a mais comum. A DA é uma doença neurodegenerativas que afeta principalmente a memória e a linguagem. Procedimentos de ensino baseados no paradigma de equivalência de estímulos e no ensino por exclusão, apesar de testados com sucesso em diferentes populações com problemas de desenvolvimento, têm gerado poucas pesquisas com idosos com perdas cognitivas. Esta pesquisa apresenta três estudos, com objetivos distintos, mas complementares. O Estudo 1 teve como objetivo avaliar se idosos institucionalizados sem DA formariam classes de estímulos equivalente a partir de um procedimento de ensino de relações condicionais entre palavras ditadas, fotos, nomes impressos de profissões e de graus de parentesco; adicionalmente, pretendia-se verificar que essas relações se mantinham ao longo de um mês, em três testes de manutenção. Cinco idosos institucionalizados passaram pelo ensino de relações arbitrárias, em uma estrutura de treino linear com ensino de novas relações por exclusão. Testes de equivalência foram conduzidos em seguida à Fase de Ensino, e após cinco, 15 e 30 dias. Todos os idosos demonstraram desempenho por exclusão na Fase de Ensino e aprenderam todas as relações com o número mínimo de blocos de ensino programados (exceto uma participante). Todos os idosos apresentaram formação de classes de equivalência. Quatro dos idosos apresentaram manutenção dessas classes em todos os testes de manutenção. O procedimento, portanto, mostrou-se efetivo para esses idosos e gerou formação de equivalência, apesar da sua condição de institucionalização. O Estudo 2 teve como objetivo avaliar se idosos com DA, também institucionalizados, demonstrariam desempenho por exclusão e aprenderiam relações condicionais entre quatro nomes ditados e quatro fotos, em um procedimento de ensino por exclusão. Seis idosas com diagnóstico de DA passaram por tarefas de emparelhamento ao modelo, em que as relações entre modelos ditados e fotos foram ensinadas por exclusão. Apesar de todas as idosas terem respondido por exclusão na primeira apresentação de um estímulo modelo novo e seu comparação correspondente em pelo menos duas das três tentativas em que tal desempenho era possível, apenas duas mantiveram essa relação ao longo das demais tentativas e aprenderam as relações ensinadas. Possíveis motivos para esse desempenho são discutidos. O Estudo 3 avaliou se idosos institucionalizados, com DA e comprometimento cognitivo, formariam classes de equivalência a partir de um ensino de relações arbitrárias com estrutura de treino um-para-muitos, procedimento de dica atrasada e ensino por exclusão. Quatro idosas passaram pelo ensino de relações condicionais entre estímulos visuais (nomes escritos, fotos e nomes de profissões). Todas aprenderam as relações ensinadas com o número mínimo de blocos programados, porém apresentaram dificuldade em formar classes de equivalência e manter tais relações nos testes de manutenção após cinco e oito dias. Os procedimentos de ensino empregados foram eficientes em gerar a aprendizagem das relações, mas tal aprendizagem, nessas idosas, não sustentou a formação e manutenção de classes de equivalência.\n

Stimulus Class Formation in Humans and Animals

Previous experiments have investigated the function of using pictures or meaningful stimuli on equivalence class formation. For example, when attempting to form three 5-member classes (A→B→C→D→E), findings have shown that pictures used as C stimuli have increased the probability of producing equivalence class formation relative to when all stimuli in the stimulus set are abstract. The present experiment extends the literature by examining whether the formation of equivalence classes varies as a function of having three (C1, C2, and C3), two (C1 and C2), or one (C1) stimulus as a picture in a set of abstract stimuli. Hence, 60 participants were randomly assigned to 4 different experimental groups: 0-picture group or abstract group (ABS), 1-picture group (1PIC), 2-pictures group (2PIC), and 3-pictures group (3PIC). In addition, we had a reference group with abstract shapes only. The findings from the present experiment showed that 2 of 15 participants in the ABS formed classes. Also, two of 15 participants in the 1PIC formed classes, 8 of 15 participants in the 2PIC formed equivalence classes, and 12 of 15 members in the 3PIC formed classes. The statistical analysis supported the notion that equivalence class formation is a function of the number of pictures in a potential equivalence class.

Equivalence classes are typically established using match to sample (MTS) procedures with single stimuli serving as samples and comparisons. In a recent study, however, equivalence classes were established with samples and comparisons consisting of compound stimuli (i.e., pairs of abstract symbols). One potential problem using compound stimuli during equivalence class formation, however, is that one element may overshadow the other, thereby disrupting class formation. To address this, the current study used two different compound configurations for incorrect (negative) comparisons during MTS. One group of participants was exposed to negative comparison compounds containing stimuli from only one class (referred to as Type 1 trials) while the other group was exposed to negative comparison compounds containing stimuli from both classes (Type 2 trials) along with Type 1 trials. Class formation was assessed with a test block containing single-element-to-single-element, single-element-to-compound, compound-to-single element, and compound-to-compound derived relations trials. A card sorting test with single elements was also conducted. Results showed that class formation was high and equally likely for both groups; therefore, overshadowing did not occur for either group. Thus, Type 2 trials may be unnecessary during class formation with compound stimuli, and their omission would likely increase efficiency of instruction.

THE RELATIONSHIP BETWEEN VERBAL BEHAVIOR AND STIMULUS EQUIVALENCE WAS EXAMINED USING THREE SETS OF CHILDREN DIFFERING IN CHRONOLOGICAL AGE AND VERBAL ABILITY: (1) non-hearing impaired three and four year olds who had verbal skills generally consistent with their chronological ages; (2) partially hearing (severe to profoundly deaf) children who were rated with verbal ages of above 2 years; and (3) partially hearing children (also severely to profoundly deaf) who were rated with verbal ages of below 2 years. All children were taught a series of four conditional discriminations using unfamiliar stimuli. The children were then tested to determine whether classes of equivalent stimuli had formed. Although all the children were able to learn the conditional discriminations equally well and all the verbally-able children (normal and partially hearing) formed equivalence classes, only one of the verbally-impaired children reliably demonstrated stimulus equivalence formation. These results are consistent with the suggestion that stimulus equivalence and human verbal behavior are closely related.

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.

Resumo Relações condicionais pré-experimentais que eliciam respostas emocionais, como ciúme, podem afetar a formação de classes de equivalência? Haveria diferenças entre homens e mulheres? Para abordar essas questões, 19 participantes, de ambos os sexos, foram expostos a treinos e testes para a formação de quatro classes de equivalência, uma delas constituída pelo nome do(a) namorado(a), o nome de mulher/homem desconhecida(o) e duas figuras não-familiares. Após os testes, aplicou-se a Escala de Ciúme Romântico. Os participantes classificados com maior grau de ciúme não formaram as classes de equivalência, independentemente de serem homens ou mulheres. Sugere-se que relações pré-experimentais com funções afetivas interferiram na formação das classes de equivalência em que o nome do namorado(a) deveria ser relacionado ao nome de desconhecido(a).

The purpose of this study was to evaluate the effects of tact and intraverbal training on the establishment of generalized equivalence classes. Seventeen college students were exposed to tact training, listener testing, and intraverbal training (A'B' and B'C') in two experiments. Visual-visual matching-to-sample and intraverbal tests measured performances consistent with the formation of equivalence classes. Generalization was assessed with four novel sets of stimuli. In the second experiment, matching-to-sample tests for baseline relations (AB, BC) were eliminated to control for the possibility that equivalence classes were developed through exposure to these visual stimulus-stimulus relations. Thirteen of 17 participants passed all matching-to-sample and intraverbal posttests. Results suggest that when trained and emergent intraverbal relations were not maintained or were faulty, participants did not respond correctly during matching-to-sample posttests.

Problems with Skinner’s (1957) definition of verbal behavior are raised and one possible solution is presented. It is suggested that the way in which verbal communities shape behavior is distinctive—unlike the physical environment, verbal communities have culturally evolved a system of extremely generalized conditions for reinforcement which allows arbitrary relations to be shaped—and therefore could serve to define verbal behavior and exclude other forms of socially mediated behaviors. The form of “loose” shaping used is described, along with anthropological and sociological equivalents, and a suggestion is made of how it might figure in equivalence class formation. Two terms from Esoteric Buddhism are then used to illustrate this form of shaping. Fuse refers to loose reinforcement and Muzai No Nanase refers to seven ways to reinforce loosely even when one has no material possessions.

The present study investigated whether simple discrimination procedures produce emergent relations that are consistent with functional and equivalence classes. In Experiment 1, 4 normally capable adults were exposed to simple successive discrimination reversal training. Responses to the S+ (A1, B1, and C1) but not S− (A2, B2, and C2) were reinforced. The participants were then exposed to repeated-reversal training, followed by tests of emergent equivalence relations. In Experiment 2, 4 additional adults were exposed to a simple successive discrimination training procedure using differential responses. Response 1 (R1) was reinforced only when emitted in the presence of A1, B1, or C1 (A1-R1, B1-R1, or C1-R1). Response 2 (R2) was reinforced only in the presence of A2, B2, or C2 (A2-R2, B2-R2, or C2-R2). A new response was then trained in the presence of 1 member of each class (A1-R3, A2-R4). A transfer-of-function test was then conducted to verify whether the new responses would be emitted in the presence of B1, B2, C1, and C2. In both experiments, emergent conditional relations were tested using a go/no-go procedure with compound stimuli. In Experiment 1, all of the participants showed functional classes, and 3 showed patterns that are consistent with the formation of equivalence classes. In Experiment 2, all 4 participants showed patterns that are consistent with functional and equivalence class formation. In these experiments, simple discrimination training generated a range of emergent stimulus relations that mirrored those that are indicative of equivalence class formation.

The formation of equivalence classes in individuals with autism spectrum disorder: A review of the literature

AB, BC, CD, and DE were established by conditional discrimination training. Symmetry, transitivity, and equivalence tests were then passed demonstrating the formation of 5-member equivalence classes. These tests were passed even though they were conducted in the absence of baseline relations. A new stimulus (F) was then linked to a class member (A) by stimulus fading conducted in the context of simple discrimination training. Thereafter, subjects passed FB, FC, FD, FE, BF, CF, DF, and EF tests, demonstrating that F functioned as a new member of the A-E class. The expansion of equivalence classes can also be accomplished by the use of simple discrimination training combined with stimulus fading, in addition to the typical use of conditional discrimination training. Equivalence classes, then, can be defined independently of conditional discrimination procedures.

The purpose of the current study was to (1) compare the acquisition of baseline conditional discriminations in younger and older adults, (2) study the effect of the differential outcome procedure (DOP) on the establishment of baseline conditional discriminations, and (3) compare equivalence class formation in younger and older adults. Twenty-four participants, 12 younger adults (20–30 years old) and 12 older adults (67+ years old), participated in the study. In the conditional discrimination training, we gave the participants a break following 180 training trials, and the experimenter evaluated their progress. Participants with overall 50% correct responses or more after those 180 trials continued with the study as planned, with baseline conditional discrimination presented in accordance with the one-to-many (OTM) training structure and serialized training, followed by thinning of programmed consequences across training blocks before a test for the emergence of equivalence classes. If a participant was still training AB-conditional discriminations when the break was presented, with overall correct responses below 50% correct, the participant was exposed to a DOP to evaluate whether such a procedure may facilitate the establishment of the baseline conditional discrimination. Five participants in the older adult group received additional DOP training trials. The results show that two out of the five participants receiving DOP training established the AB baseline conditional discrimination. Neither of those responded in accordance with stimulus equivalence. Two out of the other seven participants in the older adults group and six out of 12 participants in the younger group formed equivalence classes.