Tomonaga, M. (1999).
Establishing functional classes in a chimpanzee (Pan troglodytes) with
a two-item sequential-responding procedure.
Journal of the Experimental Analysis of Behavior,
72, 57-79.
A 9-year-old female chimpanzee was trained on a two-item
sequential-responding task. Attempts were made with
successive-reversal training to establish functional classes. In
Experiment 1, the subject was exposed to between-session
successive-reversal training in which one of two pairs of stimuli
was reversed, and transfer of reversal responding to the other
pair was tested with nonreinforcement probe trials. She did not show
transfer during the course of reversals. Stimulus control
established in the original training was maintained on
nonreinforcement probe trials. In Experiment 2, within-session
reversals were introduced. She showed transfer from the initially
reversed pair to the other. The results were consistent with
Vaughan's (1988) results with pigeons on successive
discriminations, which indicated the formation of functional
classes. In Experiment 3, crossover and wild-card tests were
conducted to clarify the stimulus control of sequential
responding. The results suggested that the sequential responding
was controlled only by the first stimulus of each pair. To
establish control by both first and second stimuli, trial-unique
stimuli or wild cards were substituted for one of the items of
the lists in Experiment 4. Further transfer tests, in which
stimuli for the two new pairs appeared, were also given to the
subject. She successfully responded to these two merged lists and
reversed the order as the result of reversal training.
Key words: functional classes, sequential responding,
successive-reversal training, stimulus control, screen touch,
chimpanzee