Interrogations-and-Confessions-Handbook

368 A Psychology of Interrogations and Confessions
they are less imaginative and creative, which impairs their normal tendency to
confabulate.
SUGGESTIBILITY AND HYPNOTIC SUSCEPTIBILITY
I argued in Chapter 13 that the susceptibility to hypnosis is related to primary
suggestibility, using Eysenck’s conventional classification, whereas interrogative
suggestibility is a special type of suggestibility that is unrelated to suggestibility
of the primary type and only relates to the more elusive category of
secondary suggestibility.
Evidence that interrogative suggestibility differs from susceptibility to hypnosis
comes from six empirical studies. In the first study, Hardarson (1985)
found no significant correlation ( r = 0.15) between scores on the Harvard Group
Scale of Hypnotic Susceptibility and interrogative suggestibility, as measured
by the GSS 1, among 40 Icelandic University students.
In two different experiments, one comprising university students and one
psychiatric patients, Young, Bentall, Slade and Dewey (1987) correlated the
GSS 1 Total Suggestibility score with the Barber Suggestibility Scale (Barber &
Calverley, 1964). The Barber Suggestibility Scale consists of eight test suggestions
that are theoretically related to primary suggestibility. None of the three
scores on the Barber Suggestibility Scale, which comprised the subjects’ responses
to suggestions, their rated subjective involvement in the tasks, and
their verbalized resistance to the suggestions, correlated with interrogative
suggestibility.
Register and Kihlstrom (1988) used a variant of the GSS 1 during an experiment
into hypnosis. The subjects were 40 college students, who had all
completed the Harvard Group Scale of Hypnotic Susceptibility and were interrogated
after hypnotic induction. Negative feedback was not administered;
instead the interrogation questions were repeated without any explicit negative
feedback. No significant difference in interrogative suggestibility was found between
hypnotizable and non-hypnotizable subjects. The authors concluded that
the results
. . . support Gudjonsson’s (1987) hypothesis that interrogative suggestibility is
independent of suggestibility as measured in a hypnotic context (p. 556).
Gwynn and Spanos (1996) cite two studies where interrogative suggestibility,
as measured by the GSS, was not found to be correlated with hypnotizability.
In both studies hypnotizability was measured by the Carleton University
Responsiveness to Suggestion Scale (CURSS). In the first study (Gwynn,
Spanos, Nancoo & Chow, 1995, unpublished manuscript), 120 subjects who
had previously completed the CURSS were administered the GSS. The CURSS
score did not correlate significantly with Yield, Shift or Total Suggestibility. The
second study (Gordon, Gwynn & Spanos, 1993) also involved 120 subjects, who
had previously completed the CURSS. One half of the subjects were later tested
on the GSS. No significant correlation was found between the hypnotizability
score and the GSS scores.