This article places in the contemporary context 'A theory of hypnosis based on principles of conditioning and inhibition', published earlier in Contemporary Hypnosis (Barrios, 2001). The commentary is in two parts. Here in Part I, following a succinct summary of the theory, there are two sections: (1) contrasting the theory with three other major perspectives in the fi eld, the Sociocognitive, the Dissociation/Neo-Dissociation, and the Response-Expectancy perspectives as well as with Erickson's strategic approach to therapy; and (2) some of the supporting research subsequent to the theory's fi rst evolution (1969) Key words: conditioning, hypnosis, hypnotic phenomena, inhibition, belief
Summary of the theoryIn the theory (Barrios, 2001) a hypnotic induction is defi ned as the giving of a series of suggestions so that a positive response to a previous suggestion predisposes the subject to respond more strongly to the next suggestion. Hypnosis is defi ned then as the state of heightened suggestibility, also referred to as a state of heightened belief, produced by a hypnotic induction. What occurs during a hypnotic induction to increase suggestibility is a process of conditioning of an inhibitory set. The latter increases responsiveness to suggestion by inhibiting thoughts and stimuli which would contradict the suggested response. The more effective the hypnotic induction, the greater this inhibitory set.It is postulated that at any point in time there are any number of stimuli (both cognitive and sensory) that one can be responsive to, some more strongly than others. This is referred to as the stimulus dominance hierarchy. The various hypnotic and post-hypnotic phenomena can be explained in terms of how the inhibitory set can rearrange the dominant position of a particular stimulus (cognitive or sensory) focused on by the suggestion. Post-hypnotic behaviour changes are explained as produced through a process of higherorder conditioning where the inhibitory set facilitates such conditioning by suppressing any dominant stimuli present (cognitive or sensory) that would interfere with the intended conditioning.From the theory, a number of ways can be deduced for increasing responsiveness to suggestion and thereby increasing the effectiveness of hypnotic induction. These include: the amplifi cation of minute responses to suggestion such as with the use of biofeedback