Investigating the Impact of Stimulus Equivalence on Children's Food Choice and Preference / Investigando o Impacto da Equivalência de Estímulos na Escolha e Preferência de Alimentos por Crianças / Investigando el Impacto de la Equivalencia de Estímulos en la Elección y Preferencia de Alimentos por Niños

Abstract This study investigated the influence of character on food's choices. Eleven preschool children were trained to form two equivalent stimulus classes, each comprising one a cartoon character, a geometric shape, and an abstract symbol. One class had a liked character and the other a disliked character. Three preference tests were conducted where the children had to choose between two identical packages with samples of the same snack, differing only by the label. In Test 1 the labels were symbols of the same class as the liked and disliked characters; in Test 2 the choice was between the symbol of the same class as the disliked character and a new symbol; and in Test 3 children chose between the symbol of the equivalence class with the liked character and the logo of a known brand. Most children chose first, and reported to like more, the snack labeled with the symbol of the same class as the liked character. They also chose, and reported to like more, the snack labeled with a new stimulus over the symbol of the same class as the disliked character. These results confirmed that stimulus equivalence is a useful paradigm to investigate formation of preference for brands.

Resumo Esta pesquisa investigou a influência de personagens em escolhas alimentares. Doze crianças pré-escolares formaram inicialmente duas classes de estímulos equivalentes, cada uma contendo um personagem, uma forma geométrica e um símbolo abstrato. Uma das classes continha um personagem de que a criança gostava e a outra de que a criança não gostava. Três testes de escolha alimentar foram conduzidos nos quais o participante deveria escolher entre duas embalagens idênticas com o mesmo alimento, diferindo somente o rótulo. No Teste 1, os rótulos continham os símbolos da classe do personagem atrativo e não atrativo; No Teste 2, a escolha era entre o símbolo da classe do personagem não atrativo e um símbolo novo; e no Teste 3 a escolha era entre o símbolo da classe do personagem atrativo e o logo de uma marca conhecida. A maioria das crianças escolheu e demonstrou preferência pelo alimento com o símbolo equivalente ao personagem de que gostava. Também escolheram e disseram gostar mais do alimento com o símbolo novo no rótulo ao invés do que continha o símbolo equivalente ao personagem não atrativo. Os resultados apontam a equivalência de estímulos como uma abordagem útil para investigar a formação de preferência por marcas.

Resumen Este estudio investigó la influencia de los personajes en la elección de alimentos. 12 niños preescolares formaran dos clases de estímulos equivalentes, contiendo a un personaje infantil, una forma geométrica, y a un símbolo abstracto. Una clase tenía un personaje que le gustaba al niño y la otra un personaje que no le gustaba. Tres testes de preferencia fueron conducidos, en los que los niños tenían que escoger entre dos pedazos de la misma galleta, diferenciándose sólo por la etiqueta en el recipiente. En el Test 1, las etiquetas eran símbolos equivalentes al personaje que favorito y al que no le gustaba; en el Test 2, la elección fue entre el símbolo equivalente al personaje que no le gustaba y un símbolo nuevo; y en el Test 3, nos niños escogían entre el símbolo equivalente al personaje favorito y el logotipo de una marca conocida. La mayoría de los niños escogió primero, y prefirieron, la galleta etiquetada con el símbolo equivalente al personaje favorito. También escogieron, y prefirieron, la galleta etiquetada con el estímulo nuevo que con el símbolo equivalente al personaje que no les gustaba. Estos resultados confirmaron que la equivalencia de estímulos es un paradigma útil para investigar la formación de preferencia por las marcas.

Equivalência de estímulos e ciúme: efeito de história pré-experimental / Stimulus equivalence and jealousy: effect of pre-experimental history

A formação de classes de estímulos equivalentes tem sido usada como modelo experimental para investigar uma série de fenômenos comportamentais, tais como o desenvolvimento de comportamento simbólico e a transferência de funções que os eventos ambientais adquirem por meio de relações condicionais. O objetivo deste estudo consistiu em analisar o efeito de estímulos com alto grau afetivo pré-experimentalmente constituído, na formação de classes de equivalência estabelecidas em contexto experimental, quando as relações emergentes podem se caracterizar por um conflito na escolha dos estímulos. Participaram 17 estudantes universitários que foram submetidos ao procedimento de escolha de acordo com modelo e aos testes das relações emergentes, para formar quatro classes de equivalência com quatro estímulos cada. Verificou-se que 10 dos 17 participantes formaram as classes equivalentes e observou-se correlação positiva entre o desempenho no Teste de Equivalência e o escore na Escala de Ciúme Romântico, sugerindo que a história pré-experimental referente ao envolvimento afetivo interferiu no desempenho dos participantes. O efeito de interferência provavelmente é devido ao conflito entre contingências: uma que controla o responder diante de relações condicionais pré-experimentalmente estabelecidas, envolvendo estímulos com alto valor afetivo, e outra estabelecida no contexto experimental.

The formation of stimulus equivalence classes has been used as an experimental model to investigate a series of behavioral phenomena, such as the development of symbolic behavior and transfer of functions that environmental events acquire through conditional relations. The aim of this study was to analyze the effect of stimuli with high pre-experimentally constituted affective grade in the formation of equivalence classes established in an experimental context, when the emergent relations can be characterized by a conflict in choosing stimuli. Participants were 17 college students exposed to matching to sample procedure and the tests of emergent relations to form four equivalence classes with four stimuli each. The results showed that 10 out of 17 participants formed equivalence classes, and positive correlation was observed between the performance on the Equivalence Test and the score on the Romantic Jealousy Scale, suggesting that the pre-experimental history related to emotional involvement interfered with participants' performance. The interference effect is probably due to the conflict between contingencies: one that controls responses to pre-experimentally established conditional relations involving stimuli with high emotional value, and another one, established in the experimental setting.

Transferencia de funciones sintácticas artificiales entre estímulos relacionados por equivalencia: Un estudio de potenciales cerebrales relacionados con eventos / Transfer of artificial syntax functions among equivalence - related stimuli: An event - related brain potentials study

La formación de clases de equivalencia entre estímulos ha sido propuesta en el campo del Análisis Experimental del Comportamiento como un prerrequisito conductual para el lenguaje. Adicionalmente, existe evidencia de que la transferencia de función entre estímulos equivalentes podría explicar la adquisición de estructuras sintácticas simples. No obstante, la simplicidad de las funciones sintácticas estudiadas no capturó la complejidad combinatoria de la gramática natural. Si la transferencia de funciones en clases de equivalencia es un modelo posible del desarrollo de estructuras gramaticales, debería ser verificado en contextos más válidos para el estudio del lenguaje. Los objetivos del trabajo realizado fueron los siguientes: (1) analizar la transferencia de funciones sintácticas en clases de equivalencia en un contexto válido para el estudio de la adquisición de reglas gramaticales, utilizando para ello el paradigma de gramáticas artificiales y (2) analizar los potenciales cerebrales relacionados con el procesamiento de esta transferencia de función, en secuencias gramaticales y no gramaticales. Se encontró evidencia comportamental de transferencia de función en un subgrupo de los sujetos experimentales. El potencial P600, típicamente asociado al costo de integración sintáctica en contextos lingüísticos, fue observado en estos sujetos ante: violaciones gramaticales con estímulos originales de la gramática artificial y secuencias con estímulos relacionados por equivalencia (gramaticales y no gramaticales). Se interpretó que el procesamiento de las secuencias artificiales implicó mecanismos neurobiológicos similares a los asociados a la sintaxis del lenguaje y que el patrón de actividad P600 observado puede ser explicado por el aumento del costo de integración de los estímulos al contexto previo.

Stimulus equivalence class formation has been proposed as a behavioral prerequisite for language within the field of experimental analysis of behavior. Additionally, there is evidence that transfer of function among equivalent stimuli may explain acquisition of simple syntactic structures. However these experiments analyzed sequence functions that did not capture the complexity and versatility of natural grammar. If transfer of function between stimuli that belong to the same equivalence classes is indeed a useful model for the development of grammatical structures, then we should be able to verify it in a more valid context for the study of language. Artificial grammar learning tasks have been applied to the study of several aspects of language acquisition, from word segmentation to phrase structure and syntax rules. Furthermore, it has been shown that patterns of brain activity during processing of artificial grammars resemble those observed in language syntax processing. In particular, structural violations of language sentences and artificial grammar sequences both activate Broca's area. Therefore, artificial grammars provide a valid paradigm to study the learning of syntactic functions. The main objectives of the current work were: (1) to analyze transfer of function within equivalence classes in a valid context for the study of syntax acquisition, applying the artificial grammar paradigm and (2) to analyze brain potentials related to the transfer of function in grammatical and ungrammatical sequences. Fifteen subjects were trained to form two three-stimulus equivalence classes and then performed an artificial grammar learning task. One stimulus from each equivalence class was included as an item in the artificial grammar categories. During a test stage, subjects were asked to classify new artificial grammar sequences as grammatical or ungrammatical, while their EEG activity was registered. Half of these new sequences were built using the original training items and the other half contained equivalence-related stimulus. Subjects were assigned to two groups according to their performance in this test stage. Those participants whose percentage of correct responses was above 50 % were considered to pass, while those below were assigned to the fail group. We found behavioral evidence of transfer of function in the pass subgroup. These participants were able to correctly discriminate grammatical from un grammatical sequences that were built using original or equivalence-related stimulus. Event-Related potential Analysis of the EEG signal indicated a posteriorly distributed positivity with a topography and time-course similar to the P600 potential. Within linguistic contexts, P600 is interpreted as the neural correlate of prediction and integration costs during syntax processing. It has been proposed that sentence comprehension depends on predictive mechanisms that combine lexical, semantic and syntactic information from linguistic input to anticipate future words. Processing of incoming stimuli is facilitated by pre- activation, allowing rapid integration to previous context. However, when the input does not match predictions, this integration becomes slower and more difficult, requiring additional neural resources. The P600 has been considered and index of increased integration costs, generated by unfulfilled predictions of word category and morphology based on previous context. In the present experiment, the P600 was observed after: grammar violations with the original artificial grammar lexicon and artificial sequences containing equivalence-related stimulus (both grammatical and ungrammatical). Results showed that artificial grammar processing involved neurobiological mechanisms that are similar to those associated in natural grammar processing. We interpreted the observed P600 pattern in terms of an increased stimulus integration cost, both in the case of grammatical and ungrammatical equivalence-related stimulus. Even though we consider that transference of function and equivalence class formations are by themselves insufficient to explain the complexity of natural grammar, we propose that this processes might be relevant to its acquisition and evolution, constituting a behavioral prerequisite for language development.

Computerized assessment of food preferences in adolescents in the stimulus equivalence paradigm / Avaliação computadorizada das preferências alimentares em adolescentes no paradigma de equivalência de estímulos / Evaluación computarizada de las preferencias alimentarias de los adolescentes en lo paradigma de la equivalencia de estímulo

In Experiment 1, 71 participants were trained to match three pictures of facial expressions (one that expressed happiness and two that expressed emotional neutrality) to three abstract line drawings and match three healthy food names to the abstract line drawings. The participants were then tested to verify equivalence between facial expressions, abstract pictures, and foods. They were required to rate the foods for pleasantness at the beginning and end of the experiment. The experiment had three different experimental groups that differed only in the amount of training. The foods that were equivalent to the happy and neutral female faces received more positive evaluations than the foods that were equivalent to the neutral male face; however, the data presented high variability. In Experiment 2, schematic faces and fictitious food names were used in a delayed matching-to-sample procedure. The food that was equivalent to the happy face was evaluated as more pleasant, and the food that was equivalent to the sad face was evaluated as less pleasant.

No Experimento 1 foram ensinadas relações entre três expressões faciais (uma de alegria e duas neutras) a três desenhos abstratos e em seguida ensinado a relação de três nomes de alimentos saudáveis aos três desenhos abstratos para 71 participantes. Depois de passar pelo treino das relações, os participantes foram, então, testados para verificar a equivalência entre as expressões faciais, as imagens abstratas e os alimentos. A avaliação da preferência alimentar foi realizada no início e no final do experimento. O experimento teve três diferentes grupos experimentais que diferiam apenas na quantidade de treinamento das relações. Os alimentos equivalentes às expressões faciais de alegria e neutra feminina tiveram avaliações mais positivas do que os alimentos equivalentes à face neutra masculina, no entanto, os dados apresentaram grande variabilidade. No Experimento 2 expressões faciais esquemáticas e nomes fictícios de alimentos foram usados em um procedimento de emparelhamento com o modelo com atraso. O alimento treinado com a face feliz foi avaliado como mais agradável e o relacionado a uma face triste foi avaliado como menos agradável.

En el experimento 1 se enseñaban las relaciones entre los tres expresiones faciales (una de alegría y neutral dos) para tres diseños abstractos y luego enseñó la relación de los tres nombres de los alimentos saludables en tres diseños abstractos a 71 participantes. Después de pasar por la formación de las relaciones, los participantes fueron analizadas para la equivalencia entre las expresiones faciales, las imágenes abstractas y alimentos. La evaluación de la preferencia de alimentos se realizó al inicio y al final del experimento. El experimento consistió en tres diferentes grupos experimentales que diferían sólo en la cantidad de entrenamiento. Los alimentos equivalentes a las expresiones faciales de alegría y mujeres neutral sido objeto de evaluaciones más positivas que los alimentos equivalente a cara neutro masculino, sin embargo, los datos muestran una gran variabilidad. En el Experimento 2 expresiones faciales esquemáticos y nombres fictícios de alimentos fueron utilizados en un procedimiento de igualación a la muestra con retraso. La alimentación equivalente a la cara feliz se evaluó como más agradable y el equivalente a la cara triste se evaluó como menos agradable.