Toward a theory of “hypnotic” behavior: Replication and extension of experiments by barber and co-workers (1962–65) and Hilgard and Tart (1966)

Abstract
Responses to test suggestions (e.g., hallucination and amnesia) were assessed under the following treatments: motivational instructions alone; hypnotic procedure with motivational instructions; and imagination-control. Comparisons were made across independent groups, each tested under one treatment, and also within the same Ss tested twice under various combinations of the treatments. Although Ss were suggestible under the imagination-control treatment, both the motivational instructions alone and the hypnotic procedure given together with the motivational instructions raised suggestibility above the control level. The hypnotic-motivational treatment tended to produce an increment in suggestibility which went slightly beyond that attributable to the motivational instructions. The latter increment is interpreted as due to the slightly greater effectiveness of the hypnotic procedure in defining the situation as one in which unusual manifestations, such as hallucination and amnesia, are within Ss' capabilities and definitely expected by E.