Interrogations-and-Confessions-Handbook

42 A Psychology of Interrogations and Confessions
under-represented. In view of these factors Irving warned that generalizing
from the findings might not be justified.
Irving’s Subsequent Research
Irving’s original research at Brighton Police Station has been replicated twice
jointly with his colleague Ian McKenzie (Irving & McKenzie, 1989). In 1986,
six months after the implementation of the Police and Criminal Evidence Act
1984 (PACE) (Home Office, 1985a), which has had radical effects on police interrogation
procedures, Irving and McKenzie replicated Irving’s original study.
The interviews of 68 criminal subjects were observed by McKenzie at Brighton
Police Station. As certain noticeable changes had been detected with the implementation
of PACE, Irving and McKenzie decided to replicate the second study
in 1987, again observing the interviews of 68 suspects. The main methodological
difference between the 1986 and 1987 studies was that more serious cases
were observed in the latter study. One of the main purposes of the replication
studies was to look at the effect that the new legislation might have had on
police interviewing behaviour.
The 1986 study indicated that there had been a dramatic fall in the number
of manipulative and persuasive tactics used by detectives at Brighton Police
Station (Irving & McKenzie, 1989). In the 1979 sample of 60 suspects, a total
of 165 tactics had been used. In 1986 the number of tactics used had fallen
to 42 in 68 cases. This fall in the number of manipulative tactics used by the
police was almost certainly due to the implementation of PACE, which is the
first Act in England that attempted to provide a comprehensive code of police
powers and practices for the investigation of crime (Bevan & Lidstone,
1985).
Between 1986 and 1987 the number of tactics used at Brighton Police Station
rose from 42 to 88, which may have been due to the diminishing of initial
rigidity in applying the new rules or because suspects were being interviewed
about more serious offences. However, the number of tactics observed was still
below that observed in 1979. In the 1986 and 1987 samples, the most persuasive
tactics were used in the more serious cases. Nevertheless, the rate of admissions
for the most serious crimes fell in 1986 and 1987. This left Irving and McKenzie
with confusing findings. They concluded ‘Either some of the essential power
of the tactics used was destroyed by the cumbersome note-taking procedure,
or by the general reduction in the potential of custody conditions to produce
compliance or by a combination of both. The advent of tape recording will partly
resolve these issues because skilled interrogators in serious cases will be able to
get back to their previous standard of performance’ (Irving & McKenzie, 1989,
p. 182).
The main conclusion is that the new Act appears to have markedly reduced
the number of manipulative and persuasive techniques that police officers use
when interrogating suspects, except perhaps in the most serious cases. Interestingly,
there appears to have been no overall effects on the confession rate of
suspects (see Chapter 6). The main limitation of the three observational studies
was the small number of suspects in each study.