The prevailing theories of hypnotic susceptibility hold that the ability to experience hypnotic phenomena is a function of either dissociative capacity or of attentional control. However, an upcoming study in the journal Consciousness And Cognition claims to challenge both of these ideas.
The researchers administered the Waterloo-Stanford Group Scale of Hypnotic Susceptibility (Form C), the Dissociative Experiences Scale (normed for non-clinical populations), and a series of cognitive inhibition tasks to 180 study participants. They conclude, decisively, that “the data ruled out even moderate correlations between hypnotic suggestibility and all the measures of dissociation and cognitive inhibition.”
The implications of these findings are uncertain. After all, the idea that hypnotizability exists as a biological or personality trait at all is controversial. From the perspective of those therapists who suspect that everyone is susceptible to some form of hypnotic experience, it is unsurprising that investigations into hypnotic ability should lead to unpredictable and ultimately meaningless results.
But even if we assume the validity of hypnotic susceptibility as an individual trait, then these findings are of questionable value. With regard to dissociation, this study’s findings are not new. Many conflicting studies have found varying levels of relationship between hypnosis and dissociation, which are now generally considered to be related but separate phenomena.
The study’s findings on cognitive inhibition are interesting, but without the use of a reliable measure of inhibitory cognitive control little can be said other than more research in this area may be warranted.
I would be interested to see the operation definitions used in the development of the measures. I take it that the Stanford scale was developed by Hilgard, and is steeped Neo-Dissociation theory. What cognitive measure and the operational definition were used?
You bring up a good point–the opinions and biases of researchers will bias a study. Kirrsch tends to see hypnosis as some sort of cognitive persuasion, and or placebo. Do the rest of the researchers hold this view, at least as an approach to this study?
The general premise of the Ericksonian crowd is that one does not need to use standard inductions, or even to bother framing hypnosis in a high or low manner with most clients–use it and it will work if you persistently adapt your approach to the individual client; a kind of integration of hypnotherapy approaches. Case studies and the word of clients are listed as proof that this conceptual model is correct. However, in today’s world of evidence based practice, this approach may of necessity need to adapt to measures of hypnotizability in order make it more secure in the list of evidence based treatments. So, the debate may continue for the experimental crowd over what the heck hypnosis consists of, but use of measures in clinical practice may be something we should look to as clinicians in order to better represent hypnosis as an intervention in the world of managed care.
Hi Scott, thanks for your comment.
You bring up some very good points about bias. I really don’t know anything about the other authors, but I do know that most published psychological research seems to match the preconceptions of the researchers.
In spite of this, I also agree that hypnosis practitioners, like all psychological practitioners, have to really be diligent about conducting studies and publishing research to protect their ability to practice and receive adequate compensation. Hypnosis is too powerful a tool to risk losing to managed care.
Regarding an operational definition of ‘cognitive inhibition,’ the authors cite theories which attribute hypnotic responding to attention-regulation capacity, and specifically the ability to inhibit attentional response to ambient stimuli. No normed instruments were used to measure cognitive inhibition in this study, which I see as a shortcoming of the study. The research participants were administered “a latent inhibition task, a spatial negative priming task, and a memory task designed to measure negative priming.”
Scott,
You make a pragmatic point about the need to protect the ability to practice. However, to me, the point of research is to learn new things, and to improve our effectiveness with clients, not to prove what we already think is the case. Genuine curiosity to learn is the motivator here.