Can anyone be hypnotized, or only certain people?
Using standardized induction
scripts and classical induction techniques, some people are found to be
markedly more hypnotizable than others. Aside from a requisite minimum
intelligence for language and capacity to follow instructions, there are
some other stable characteristics that seem to relate to hypnotizability,
though they do not appear to relate directly to anything that we ordinarily
consider personality traits (such as the stereotype of gullibility and
An exceptionally skillful operator
can individualize their approach and thereby reduce the number of 'un-hypnotizable'
or 'resistant' subjects quite a bit, but there are still some people that
respond much more easily than others to hypnotic suggestion, especially
with regard to 'deep trance' phenomena. This responsiveness appears to
show high test-retest reliability, even after many years.
There are 12 standard tests
in the SHSS (Stanford Hypnotic Susceptibility Scale) which measure how
well a subject conforms to the behavior of a classically hypnotized person.
By these scales, about 5% of people are classically un-hypnotizable, most
people show moderate scores, and about 10%are hypnotizable to extreme
depths and show the classical deep trance phenomena such as somnambulism,
visual and auditory hallucinations, and ability to remain deeply in hypnosis
with eyes open.
As mentioned, hypnotizability
does not appear to show any obvious correlation with any of the usual personality
traits or characteristics. Not only is gullibility not directly correlated,
but gender, extraversion/introversion, and neurotic tendencies have also
been shown not to correlate well with hypnotizability.
There is some tentative evidence
that physiological response to suggestion is influenced by certain forms
of sensory deprivation or isolation. For example, see Barabasz and Gregson,
"Antarctic wintering--over, suggestion and transient olfactory stimulation:
EEG evoked potential and electro-dermal responses." in Biological Psychology.
9(4):285-95, 1979 Dec.
EEG evoked potential and electro-dermal
responses to real and suggested olfactory stimulation were recorded on
a team of nine men who wintered -overat Scott Base, Antarctica. Multi-variate
analysis of variance findings indicated some consistent trends despite
adverse conditions and marked inter-individual differences. Consistent
with studies of secondary afferentation olfaction-related EEGs were evidenced
in the occipital area (O1and O2) as well as the temporal area (T3 and
T4). Skin conductance (SC) showed significant responses for real and suggested
odorants pre and post wintering-over. Suppression of EEG amplitudes for
real and suggested stimuli was evidenced prior to wintering-over. Following
wintering-over experience suppression of EEG amplitudes for real stimuli
showed a decrease while suppression increased for suggested stimuli. The
implications of the suggestion findings are discussed in possible explanation
of the apparent conflict between different sources of information about
human responses to isolation in the Antarctic environment.