Interrogations-and-Confessions-Handbook

Suggestibility: Empirical Findings 405
The resisters were found to be significantly more intelligent and less suggestible
than the alleged false confessors. A particularly significant finding was the difference
between the two groups in the type of suggestibility that related to the
ability to resist interrogative pressure. These were the Shift and Yield 2 scores
on the GSS 1.
I identified two limitations with the study. First, the number of subjects in
each group was very small. Secondly, part of the difference in suggestibility
between the two groups could have been influenced by the differences in IQ
between the two groups. Sharrock (1988) goes further and states that the difference
in the IQ between the two groups ‘accounts for most of the difference
in their suggestibility’ (p. 220). Sharrock’s bold statement seems to have been
based on the erroneous assumption that, since there is a certain negative relationship
between IQ and suggestibility, this is likely to have mediated the
differences in suggestibility between the alleged false confessors and resisters.
I take the view that suggestibility is mediated by a number of factors, intelligence
being only one of them. However, Sharrock raised an important point,
which warranted a study where the IQ of the two groups are controlled for.
In an attempt to investigate Sharrock’s observation, I extended and replicated
the 1984 study (Gudjonsson, 1991c). The resisters and alleged false confessors
were different to those used in the 1984 study and the number of subjects
in each group was much larger than in the previous study. Perhaps most importantly,
however, the two groups of subjects were matched with respect to age,
sex, intelligence and memory capacity. The study also had the advantage over
the 1984 study in that the subjects had all completed both the GSS 1 and the
GCS. Thus, both suggestibility and compliance were measured. It was hypothesized
that, even with intelligence and memory capacity controlled for, the two
groups would still show significant differences with regard to suggestibility and
compliance, the main difference being related to the ability of subjects to resist
interrogative pressure, as measured by the GCS and the Yield 2 and Shift parts
of the GSS 1.
The most important finding was that highly significant differences emerged
between alleged false confessors and resisters after their intelligence and memory
capacity had been controlled for. This has important implications for the
assessment of retracted confession cases. First, it demonstrates that the assessment
of suggestibility and compliance, which are theoretically construed as
overlapping characteristics (Gudjonsson, 1989c), contributes to discriminating
between the two groups largely independently of the subjects’ level of intelligence.
In other words, intelligence may be an important factor in differentiating
between alleged false confessors and retractors, but other factors, such
as suggestibility and compliance, are also important and should not be underestimated.
Secondly, the present findings are a clear warning to clinicians
carrying out a forensic assessment. That is, even though suggestibility and intelligence
are modestly correlated, it is erroneous to assume that differences in
suggestibility and compliance are largely or necessarily mediated by differences
in intelligence, as Sharrock (1988) postulated.
The mean suggestibility scores in this recent study are very similar to those
found in the 1984 study for alleged false confessors and resisters. Furthermore,