Campbell-Tie, Philippa2021-11-242021-11-241992https://hdl.handle.net/10092/103012http://dx.doi.org/10.26021/12146The discovery of discrepancies between human and animal performance on standard reinforcement schedules has resulted in growing interest in the role of verbal behaviour in human operant responding. The verbal control theory states that discrepancies between human and animal responding result from the unique ability of humans to use verbal descriptions of contingencies as rules for the self-instruction of behaviour. In opposition to this theory, the epiphenomenal hypotheses state that verbal behaviour plays no role in mediating nonverbal responding. The present study was designed to examine the verbal control theory, and to explore a related claim that there is a delay of some years between the initial acquisition of language and the development of rule-governed behaviour. Children aged 4.5, 7 and 11 years-old performed a discrete-trials task requiring temporal differentiation of button press duration. Success on this task was compared when children were required to perform either a concurrent verbal or nonverbal interference task. The two interference tasks did not show a differential effect on responding for any age group. While this result fails to support the verbal control theory, support for the opposing epiphenomenal hypotheses is precluded by problems identified with the use of verbal interference tasks. In addition to the interference tasks, children's verbal formulations of the reinforcement contingency were assessed by the presentation of a verbal probe following each trial. For the two older groups of subjects, successful nonverbal performance was correlated with verbal identification of the contingency, while for the youngest group no such relationship was apparent. These results clearly support the claim that following the initial acquisition of language there is a period during which verbal and nonverbal behaviour are dissociated. It is proposed that this hypothesis is not dependent on the overall validity of the verbal control theory.enAll Rights ReservedVerbal behaviorBody languageOperant behaviorTheses / Dissertations