Formation Of Stimulus Classes Research Articles

Expansion of arbitrary stimulus classes and function-transfer measured by sorting performances.

Sorting (SRT) and matching-to-sample (MTS) tests have measured the formation of arbitrary stimulus classes. This experiment used SRT and MTS tests to document the expansion of class size. Thirty-two participants learned 12 conditional discriminations with a linear series training structure (A➔B➔C➔D➔E). SRT tests documented the formation of 5-member classes by 17 of the participants. Thereafter, 6-member class expansion was implemented by FC training. Nine of these 17 participants showed class expansion when tracked with a sequence of an SRT, MTS, and a final SRT test, and the other 8 showed expansion when tracked with a sequence of MTS and SRT tests. Thus, SRT tests documented class expansion, and the sequence of tests did not influence class expansion. The 15 participants who did not form the 5-member classes learned the baselines for new 3-member classes (A➔B➔C) and formed them as documented by an SRT test. Then, 4-member class expansion was implemented by FB training. Expansion was assessed using the above-mentioned testing sequences. All 15 showed class expansion with 100% correspondence between the SRT and MTS performances. Sorting documented the expansion of arbitrary stimulus classes, while the MTS tests showed that the stimuli also functioned as members of equivalence classes.

Measuring differential nodal distance using the function acquisition speed test

Increasing evidence suggests that the relatedness of stimuli within the Function Acquisition Speed Test (FAST) methodology is sensitive to the learning histories of participants. For example, this method is sensitive to differences in the amount of baseline training provided to establish stimulus equivalence relations using arbitrary stimuli (Cummins et al., 2018a). However, it has not yet been investigated whether the relatedness of stimuli within the FAST varies based on differential nodal distances between stimuli within stimulus classes. If so, the FAST could serve an important adjunct assessment procedure for researchers who wish not only to assess the formation of stimulus classes using traditional methods, such as matching-to-sample, but also the relative relatedness of stimuli within complex stimulus classes (i.e., nodal distance). The current study sought to investigate this possibility. Participants (n = 16) were trained in the formation of two 4-member equivalence classes consisting of arbitrary nonsense syllables. Following this, participants completed three FAST assessments, each of which probed for the relatedness of stimulus pairs of differing nodal distance. Group- and individual-level analyses broadly demonstrated that relatedness varied as a function of nodal distances in pre-trained stimulus classes. However, results also highlighted some limitations of the FAST at the individual level.

Efeito da Formação de Classes de Estímulos Equivalentes e de Procedimentos de Facilitação na Emergência de Analogia

Resumo Buscou-se verificar os efeitos da formação de classes de estímulos equivalentes e de dois procedimentos de facilitação na emergência de respostas de analogia, comparando os resultados obtidos nos testes de analogia de acordo com o procedimento de facilitação e com o fornecimento de instrução. Participaram 30 universitários. Foram ensinadas as relações AB e AC entre figuras abstratas e testadas as relações de simetria, transitividade e analogia. Os participantes que não apresentaram essas relações foram expostos aos procedimentos de facilitação. Doze participantes responderam por analogia antes do procedimento de facilitação, cinco de oito (62%), após Facilitação 1 e três de dez (33%), após Facilitação 2. Dos sete participantes expostos à instrução, seis responderam por analogia. A formação das classes não foi suficiente para a emergência das respostas de analogia e alguns participantes podem ter respondido ao Teste de Analogia sob controle de apenas alguns aspectos dos pares de estímulos.

DISCRIMINAÇÃO SIMPLES E COMPORTAMENTO CONCEITUAL DE POSIÇÃO: INFLUÊNCIA DE DIFERENTES TIPOS DE TREINO

Comportamento conceitual envolve o estabelecimento de classes de estímulos com discriminação interclasses e generalização intraclasse. Esta pesquisa verificou a relação entre o tipo de modificação dos estímulos nos treinos discriminativos e a aquisição de discriminações e de comportamento conceitual de posição. Quinze crianças de 4- 6 anos realizaram tarefas de discriminação simples de posição. Três condições experimentais com treino discriminativo diferente (modificação gradual – MG, múltiplos exemplares – ME e sem modificação - SM dos estímulos utilizados no treino) foram realizadas com todas as crianças. Os participantes deveriam selecionar, em cada condição, o estímulo cujo elemento relacional se localizava dentro, em cima ou à esquerda do elemento de referência. Os treinos foram intercalados com um teste de comportamento conceitual que apresentava estímulos treinados e novos que se diferenciavam apenas com relação à dimensão crítica. Resultados do treino mostraram altos escores nas três condições e menos erros com o Treino MG. Nos testes de comportamento conceitual, desempenhos acima do acaso foram obtidos apenas após o Treino SM. A modificação gradual de estímulos e a utilização de múltiplos exemplares reduziram os erros nos treinos e facilitaram o estabelecimento de discriminações entre estímulos treinados. O treino discriminativo SM com diversas tentativas com os pares de estímulos finais, que diferem apenas na dimensão relevante, produziu comportamento conceitual. Combinar os procedimentos parece, portanto, necessário para acelerar a aquisição das discriminações, prevenir subprodutos dos erros e para gerar controle de estímulos pelas dimensões relevantes. Palavras-chave: aprendizagem sem erro, modelagem de controle de estímulos, múltiplos exemplares, tentativa- e-erro, discriminação de posição, pré-escolares.

The Effects of Listener and Speaker Training on Emergent Relations in Children With Autism

The current study assessed the use of standard conditional discrimination (i.e., listener) and textual/tact (i.e., speaker) training in the establishment of equivalence classes containing dictated names, tacts/textual responses, pictures and printed words. Four children (ages 5 to 7years) diagnosed with autism were taught to select pictures and printed words in the presence of their dictated names, and to emit the tact or textual response corresponding to a presented picture or printed word. Both speaker and listener training resulted in the formation of stimulus classes for 3 of 4 participants.

Equivalence Class Formation Via Common Reinforcers Among Preschool Children

Equivalence formation, expansion, and reversal were investigated as a result of arbitrary matching associated with specific reinforcers. Four 4- and 5-year-old normal children were taught identity matching with stimuli, A, B, C, and D, and stimulus-specific reinforcement. Then the children were taught two conditional discriminations AB and BC. All subjects showed formation of the ABC stimulus classes; one subject, however, did not show expansion to ABCD classes. This subject was taught to name the D stimuli, he then demonstrated the expanded class. Next, 2 subjects who showed expanded classes were taught identity matching with the reinforcers reversed for the D stimuli. In tests that followed, their matching responses remained consistent with the original equivalence classes. These subjects were then taught to reverse the names for the D stimuli. As a result, the children reversed the classes. The results suggest that class expansion and subsequent reformation of classes may be facilitated when stimulus within each class controls a common naming response.

Naming, the formation of stimulus classes, and applied behavior analysis.

The methods used in Sidman's original studies on equivalence classes provide a framework for analyzing functional verbal behavior. Sidman and others have shown how teaching receptive, name-referent matching may produce rudimentary oral reading and word comprehension skills. Eikeseth and Smith (1992) have extended these findings by showing that children with autism may acquire equivalence classes after learning to supply a common oral name to each stimulus in a potential class. A stimulus class analysis suggests ways to examine (a) the problem of programming generalization from teaching situations to other environments, (b) the expansion of the repertoires that occur in those settings, and (c) the use of naming to facilitate these forms of generalization. Such research will help to clarify and extend Horne and Lowe's recent (1996) account of the role of verbal behavior in the formation of stimulus classes.

Delayed matching to complex samples and the formation of stimulus classes in children.

In two experiments (ns = 3 plus a previously tested child, and 2, respectively), children learned delayed matching with complex samples, each consisting of a form and a printed nonsense word. Forms or printed words were comparison stimuli. For form comparisons, selecting the form identical to that in the preceding sample was reinforced. For printed word comparisons, selecting the word identical to that in the preceding sample was reinforced. During testing, the children then matched the forms and printed words to one another. In subsequent training, the samples were (a) old forms combined with new words or (b) old words combined with new forms. Novel matching performances among forms and words appeared across these training phases. Word-form contiguity in a matching-to-sample context may contribute to the formation of classes of stimuli that may be equivalent.

Matching to complex samples and stimulus class formation in adults with autism and young children.

Adults with autism and young children first learned to match one-element comparison stimuli to two-element sample stimuli. Test conditions then examined whether each of the individual sample elements (a) controlled selections of the comparison stimuli to which they were related during training, (b) were interchangeable with one another as either sample or comparison stimuli, and (c) were interchangeable with the original comparison stimuli. Test data were positive and suggested the formation of three-member stimulus classes. Subsequent experiments demonstrated the formation of four-member classes by (a) adding novel stimuli by training outside the original context; (b) adding novel stimulus elements to the two-element samples used during baseline training; and (c) training with three-element rather than two-element sample stimuli from the outset. Results suggest that acquisition of stimulus classes may be one of the benefits of broad rather than restricted attention to the components of complex stimuli.

Emergent Relations in the Formation of Stimulus Classes by Pigeons

A defining feature of a stimulus class is the presence of untrained (emergent) relations among its members. Three types of emergent relations that define formal stimulus equivalence are reflexivity, symmetry, and transitivity. We find that pigeons can demonstrate all three types of emergent relations. Reflexivity is demonstrated by showing the transfer of identity-matching to new stimuli. Symmetry is demonstrated by showing that positive transfer results when differential food versus no food outcomes (associated with correct responding to comparison stimuli in a conditional discrimination) are substituted for conditional stimuli in a matching task. Transitivity is demonstrated when training with a simple successive hue discrimination is followed by training on a symbolic matching task involving food and no-food samples and line-orientation comparisons, and positive transfer is found when the hues are substituted for the food and no-food events. Finally, pigeons can demonstrate simultaneous evidence for symmetry and transitivity relations. For example, two samples are first associated with a common comparison in many-to-one delayed matching-to-sample. When one of those samples is then associated with a new comparison, evidence for an emergent relation between the remaining sample and the new comparison is found. Overall, the pigeon data provide strong evidence for emergent relations using procedures that result in stimulus class formation.

Formation of arbitrary stimulus classes in matching to complex samples: supplementary data.

A follow-up study of work published in 1990 showed that consistent use of Tone-relevant trials during training and testing baselines contributed to the reliable formation of 5-member stimulus classes during matching to sample. With Tone-irrelevant trials during either training or testing 4 of 12 subjects formed such classes, but none did so when such trials were used in both training and testing baselines. This extends our prior work.

Delayed constructed-response identity matching improves the spelling performance of students with mental retardation

We assessed the effects of a computerized matching-to-sample procedure on the spelling performances of three students with mental retardation. Initially, the students could 1) match pictures and printed words to one another, and 2) match pictures and printed words to spoken words. However, they could not construct words to either pictures or spoken words (e.g., touch, in order, the letters s->h->o->e given the spoken-word sample “Shoe”). Word constructions then improved markedly after exposure to delayed constructed-response identity matching (e.g., touch the letters s->h->o->e given the printed-word sample shoe). One subject's oral and written spelling also improved. The results extend previous research by showing multiple positive effects of a computerized spelling intervention. These effects may have occurred in part because of the formation of stimulus classes among pictures, printed words, and spoken words.

Conditional stimulus control of childrens' sequence production.

Normally capable children were first taught to touch in sequence each of a set of five physically dissimilar stimuli (Sequence A). Another set of stimuli was then used to train sequence B. Next, direct training established conditional control of the production of the A sequence and its reversal: in the presence of one printed word, touching the stimuli in the order A1----A2----A3----A4----A5 was reinforced; in the presence of another word, touching the stimuli in the order A5----A4----A3----A2----A1 was reinforced. During probe sessions, the printed words also exercised conditional control over production of the B sequence and its reversal for five of six subjects, suggesting the formation of stimulus classes. Four of these five subjects also performed mixed sequences under conditional control of the words (e.g., A1----B2----A3----B4----A5 and its reversal), verifying that the stimuli which occupied the same position in each sequence were members of the same class.

The Formation of Arbitrary Stimulus Classes in Matching to Complex Samples

This study assessed whether arbitrary stimulus classes would emerge via elements of complex sample stimuli. College students learned matching to sample (AB-D/AC-E) where D and E forms were selected conditionally upon complex tone/color samples (AB and AC). Unreinforced tests were then given to assess emergent relations among the five sets of stimuli (e.g., A-B, D-B, B-C, B-E, and D-E). The test performances for 14 of 18 subjects were consistent with the experimentally defined stimulus classes. These 14 subjects were also given tests with new F forms as sample elements (Test AF-B). Subsequent testing for emergent relations (e.g., F-D and E-F) showed that the classes were expanded to six members each. the study demonstrated that the relations necessary for arbitrary class formation and expansion may be established without explicit training of each. The procedures permitted an analysis of six-member equivalence classes based on relations among elements of complex samples and their respective comparisons.

Emergent simple discrimination established by indirect relation to differential consequences.

Three experiments examined a discrimination training sequence that led to emergent simple discrimination in human subjects. The experiments differed primarily in their subject populations. Normally capable adults served in the first experiment, preschool children in the second, and mentally retarded adults in the third. In all experiments, subjects learned a simple simultaneous discrimination: When visual stimuli A1 and A2 were displayed together, reinforcers followed selections of A1, the S+, but not A2, the S-. The subjects also learned a conditional discrimination taught with an arbitrary visual-visual matching-to-sample procedure. Comparisons were two additional visual stimuli, B1 and B2, and samples were A1 and A2. Reinforcers followed selections of B1 in the presence of A1 and of B2 in the presence of A2. After the simple-discrimination and conditional-discrimination baselines had been acquired, B1 and B2 were displayed alone (without a sample) on probe trials. Subjects had never been taught explicitly how to respond to such displays. Nonetheless, they almost always selected B1, which was involved in a conditional relation with A1, the stimulus that served as S+ on the simple-discrimination trials. This outcome suggested the formation of stimulus classes during conditional-discrimination training. Through class formation, B1 and B2 had apparently acquired stimulus functions similar to those shown by A1 and A2 on simple-discrimination trials, thereby leading to emergent selections of B1 on the probes.

A TEST OF SYMMETRY AND TRANSITIVITY IN THE CONDITIONAL DISCRIMINATION PERFORMANCES OF PIGEONS

In a matching-to-sample context, pigeons were taught two conditional discriminations according to one of three equivalence paradigms: train if A, then select B and if B, then select C; train if B, then A and if B, then C; or train if A, then B and if C, then B. Test trials without reinforcement revealed that the conditional relations did not satisfy the symmetrical and transitive properties of an equivalence relation. Apparently, only specific if... then relations were learned. Contrary to Kendall's (1983) findings, and probably as a consequence of procedural differences, none of the pigeons in the present experiment were observed to emit mediating behavior during the transitivity probe trials. The absence of symmetry and transitivity may be related to the individual stimuli not being reflexive. Behavioral techniques other than the commonly used matching-to-sample technique might better succeed in avoiding unintended stimulus control in the study of the formation of stimulus classes.