Eye movements along the establishment of functional stimuli classes.

The present study analyzed the eye movement patterns of five typically developed adults who were exposed to a series of simple discrimination training tasks with reversals in the contingencies of reinforcement that led to the formation of functional stimulus classes. Two studies were planned. In Study 1, two visual stimuli were used to carry out one training phase and three consecutive reversals. In Study 2, the phases were repeated but four-stimuli functional classes were established. In the second study, the selective observing responses to stimuli of functional classes following the reversal of the first stimulus were analyzed. The results showed shifts in the duration of observing responses as the discriminative functions of the stimuli were established and reversed. Unlike the existing literature, our study reveals that some participants maintain longer observing responses to S- than to S+. Moreover, following the reversal of the first stimulus, observing responses to all other stimuli of the same functional class change immediately and accordingly. These findings deepen our understanding of discriminative stimulus control and shed light on the role of observing responses to stimuli composing functional classes.