Interrogations-and-Confessions-Handbook

64 A Psychology of Interrogations and Confessions
low IQ scores obtained and similar to those found for other forensic populations
(Gudjonsson, 1997a). When the memory scores are compared with the norms for
the general population, it is apparent that they fall approximately in the 10th
percentile rank (i.e. more than one standard deviation below the mean for the
general population). That is, they are still within normal limits, but at the lower
end of the normal range for the general population. Since the detainees were
being assessed under very stressful conditions (i.e. while waiting to be interviewed
by the police), is this likely to have impaired their memory performance
on the GSS 2? The conditions under which they were being assessed may have
impaired the memory performance of some of them. Certainly, some of them appeared
to have problems concentrating on the task. However, it is important to
note in this context that the memory scores obtained are slightly higher than
those obtained among defendants tested for court referral assessments (see
Tables 5.7 and 5.8 in Gudjonsson, 1997a). Therefore, the scores obtained among
the detainees may not have been significantly impaired as a result of the testing
being conducted at a police station while they were waiting to be interviewed.
Both groups may have been under stress during the testing and their scores
consequently adversely affected. It is also likely that some detainees’ memory
performance would be more impaired by stress than those of others. No doubt,
individual differences play an important part.
As far as suggestibility is concerned, the Yield, Shift and Total Suggestibility
scores are shown in Table 3.2. The scores are very similar to the mean scores
found for court referrals and fall approximately in the 70th percentile rank
for persons in the general population (Gudjonsson, 1997a). This suggests that,
as a group, detainees tested at police stations are somewhat more suggestible
than persons in the general population (i.e. about 0.5 standard deviation above
the mean). However, these fall well within normal limits and deviate less from
the mean scores of persons in the general population than was found for their
memory scores. This suggests that among police detainees, and the same holds
for court referrals, the memory scores on the GSS 2 deviate more from those
found in the general population than their suggestibility scores (i.e. just over one
standard deviation for the memory scores in contrast to less than 0.5 standard
deviation for the suggestibility scores). These findings do not support the notion,
which is sometimes argued in court by defence counsel, that being detained
at a police station for questioning is inherently so stressful that detainees’
suggestibility is inevitably increased well above their normal level.
It is possible that the elevated suggestibility scores found are due to the
detainees’ impaired intellectual and memory functioning. However, the prorated
Full Scale IQ correlated poorly with both Total Suggestibility (r =−0.23,
p < 0.05) and immediate and delayed recall (r =−0.36, p < 0.001, for both
analysed separately). The reason for the low relationship between suggestibility
and cognitive functioning (IQ and memory) may have been due to the fact
that there were several detainees of very low IQ who were far from being suggestible
on testing; conversely, some intellectually able detainees were highly
suggestible. Therefore, the level of suggestibility of detainees cannot be judged
on the basis of their IQ alone, which is consistent with previous studies involving
different groups of subjects (Gudjonsson, 1992a).