Interrogations-and-Confessions-Handbook

Interrogation Tactics and Techniques 31
factors he considered important included unfamiliarity with the physical environment
of the police station, the effect of confinement on ‘under-arousal’, and
the absence of control that the suspect has over the physical environment.
The ways in which the physical environment can affect the physiological state
of suspects whilst they are in police custody have been discussed in detail by
Hinkle (1961) and Shallice (1974). Social isolation, sensory deprivation, fatigue,
hunger, the lack of sleep, physical and emotional pain, and threats are all factors
that can powerfully influence the decision-making of suspects and the reliability
of their statements. According to Hinkle (1961), these factors commonly result
in impaired judgement, mental confusion and disorientation, and increased
suggestibility. He concludes by stating:
Most people who are exposed to coercive procedures will talk and usually reveal
some information that they might not have revealed otherwise (p. 44).
However,
. . . the personality of a man and his attitude toward the experience that he is
undergoing will affect his ability to withstand it (p. 33).
In my own experience of assessing defendants for a pre-trial examination, many
complain of having had insufficient sleep prior to the interrogation. They often
claim that this seriously impaired their ability to cope with the demands
of interrogation. There is considerable evidence that a lack of sleep impairs
mental functioning, especially if it continues for two or three days (Hinkle,
1961; Mikulincer, Babkoff & Caspy, 1989). Loss of sleep is associated with increased
circadian oscillations (i.e. heart rate irregularity), lack of motivation
to initiate and perform tasks, attentional problems, cognitive confusion and
slowness of thought (Mikulincer, Babkoff & Caspy, 1989). The peak hours for
reported problems occur between four and eight a.m. There is also empirical evidence
that people deprived of sleep are significantly more suggestible, as measured
by the Gudjonsson Suggestibility Scale, than normal controls (Blagrove,
Cole-Morgan & Lambe, 1994). The degree of suggestibility increases with the
amount of sleep deprivation (Blagrove, 1996). This indicates that sleep deprivation
impairs the person’s ability to resist leading questions and interrogative
pressure. It explains why sleep deprivation is apparently effective in breaking
down suspects’ resistance during interrogation.
AMERICAN RESEARCH ON INTERROGATION
In Chapter 2 a number of British studies into interrogation techniques will be
reviewed. In fact, most of the observational research into interrogation techniques
has been conducted in Britain. In contrast, as noted by Leo (1996a),
American researchers have largely failed to directly observe custodial interrogations.
Apart from Leo’s own research (1992, 1994, 1996a) there have only
been two previous American observational studies (Milner, 1971; Wald et al.,