Análise dos procedimentos de Fading e Exclusão na aquisição de discriminações condicionais e na formação de classes de estímulos equivalentes

Abstract

The aim of this work was to assess the performance on the acquisition of auditory-visual conditional relations and in the emergence of equivalent stimulus classes (pictures and their respective printed and spoken words) of participants exposed to Fading and Exclusion Procedures. Six children between 4 and 5 years of age participated in the study and, after a careful assessment of their reading skills, it was concluded that they could not read and write yet. Matching-to-sample was employed to establish the auditory-visual relations for the Fading in training of incorrect comparison stimuli and for the Exclusion training. Three participants were first exposed to the Fading procedure using two stimuli groups (each group composed of three stimuli pairs made up of written words and their corresponding sounds); subsequently, the same participants were exposed to the Exclusion procedure using two other groups of stimuli. Conversely, the other three participants were first exposed firstly to the Exclusion procedure and then to the Fading procedure. Before exposure to the Fading and Exclusion procedures, participants were exposed to a Preliminary Training for the establishment of conditional relations referring to a set of three stimuli pairs of spoken and printed words, used at Control trials provided during the training with Fading and Exclusion; at these trials, a previously explored (defined) stimulus was the correct comparison stimulus. A general data analysis indicated that more errors occurred during the Preliminary Training condition than during Fading and Exclusion (respectively, 177, 36 and 19 errors), showing that fewer errors took place during the Exclusion condition. The smallest amount of errors during Exclusion was predominant when it was ~he last condition. A molecular analysis of every participant, at each trial, showed different acquisition patterns of conditional relations; during Exclusion,` errors tended to occur mostly in the first trials, while during Fading this tendency shifted to the end of the training, when the comparison stimuli had the same colour intensities . Individual differences as to speed, error accumulation and sudden or gradual acquisition were also noticed. The participants' performances in the equivalence tests revealed that equivalent stimuli classes were generated after both, Fading and Exclusion training conditions; errors that took place in the equivalence test phase were concentrated in the transitivity relations (5 errors), equivalence (7 errors) and in the naming of printed words (2 errors). The emergence of the equivalence and transitivity relations as well as the naming of pictures proved that participants acquired reading comprehension and textual behaviour