A utilização do paradigma de equivalência de estímulos para modificar a preferência alimentar

Abstract

STRAATMANN, G. The use of stimulus equivalence paradigm to modify preference food. Dissertation – Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, 2008. The aim of the present study was to verify the acquisition of symbolic properties of facial expressions of emotion for real and fictitious food names in adolescents, using a stimulus equivalence paradigm. In Experiment 1, conditional relations between facial expressions (one of happiness and two expressing emotion neutrality) and real food names were trained by simultaneous matching-to-sample procedure. Three experimental groups differed only on the amount of training (Group 2 and 3 with overtraining). Pictures of facial expressions (Set-A) were related to abstract line drawing stimulus (Set-B and Set-C); C stimuli were related to food names (D). So, the AB, AC and BD relations were trained. Finally, they received the equivalence tests CD/DC. The participants were asked to rate the foods names for pleasantness in the beginning and in the end of the experiment by a questionnaire with fifty food names. These were linked to a five point scale of facial expressions and a preference test that had ten food names selected from the questionnaire. Fifty five participants that were in the fifth grade of public and private schools concluded Experiment I. Thirty five participants demonstrated equivalence (nine in Group 1, eleven in Group 2 and 15 in Group 3). The food trained with the happy face was valued in both final instruments of evaluation of the food preference as more pleasant by sixty six percent of the Group 1 participants and forty five percent of the Group 3. In Group 2, forty five percent valued as more pleasant this food only in the final evaluation of the preference test. The food related to the feminine neutral face showed more positive evaluations in Groups 2 and 3. On the other hand, the food equivalent to the masculine neutral face had a reduction in the food preference test in Groups 2 and 3. Experiment II aimed to verify if the transfer of function would happen if fictitious names of foods related to facial expressions of happiness, neutrality and sadness were used via delayed matching-to-sample procedure. Stimuli of Set-A and Set-D were different from Experiment I and had schematic expressions and fictitious food names (capira, fulito and piteba), respectively. A five point scale questionnaire of schematic expressions was used to value the fictitious names of foods in the beginning and in the end of the experiment. Thirty six participants finished Experiment II and twenty five showed stimulus equivalence. There was a significant interaction between the final evaluations and fictitious food names (p<0,001) in the equivalence group. The participants increased the final evaluations of the food trained with the happy face (capira), maintained almost the same evaluations of the food related with the neutral face (fulito) and considerably reduced the judgments of piteba, which was trained with the sad face. Key-word: Stimulus equivalence. Tranfer of function. Facial expressions. Food preference.