Forensics Journal - Stevenson University 2010 | Page 31

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In the aggregate, the DePaulo, et al. (2003) study included data from
120 independent samples obtained from 116 studies. Based on their
results, they addressed the question: “Do people behave differently
when they are lying compared with when they are telling the truth?”
and concluded:

TABLE 1
Comparison of Reid Predictions and DePaulo et al. (2003)
Observed Behaviors (adapted from Blair and Kooi, 2004)
BEHAVIORS

REID MODELa

DEPAULO ALL
STUDIES

Posture Changes

+

0.05

Illustrators

The combined results of 1,338 estimates of 158
cues to deception are reported. Results show that
in some ways, liars are less forthcoming than truth
tellers, and they tell less compelling tales. They
also make a more negative impression and are
more tense. Their stories include fewer ordinary
imperfections and unusual contents. However,
many behaviors showed no discernible links, or
only weak links, to deceit. Cues to deception were
more pronounced when people were motivated
to succeed, especially when the motivations were
identity relevant rather than monetary or material. Cues to deception were also stronger when
lies were about transgressions (p. 74).

–

–0.14 *

Adaptors (Fidgeting)

+

0.16 *

Feet/Leg Movements

+

–0.09

Eye Contact

–

0.01

Duration

–

–0.03

Latency

+

0.02

Rate

–

0.07

Pitch

–

0.21 *

A + value indicates deceptive subjects exhibited more of a behavior.
A – value indicates deceptive subjects engaged in less of a behavior
than truthful subjects.
* p < 0.05
a

THE BLAIR AND KOOI (2004) ANALYSIS
In order to understand limitations of conclusions offered by Blair and
Kooi (2004) regarding the efficacy of the Reid Technique for detecting deception, it is important to consider evidence evaluated by Blair
and Kooi (2004) relative to what is taught in the Reid Technique. As
noted previously, the Reid Technique trains investigators to focus on
three behavioral response domains – verbal, non-verbal, and paralinguistic. While DePaulo, et al. (2003) included research from all three
in their study, unfortunately, Blair and Kooi (2004) chose to focus
only on what they termed “non-verbal” indicators of deception (in
Reid’s terms, non-verbal and paralinguistic), justifying their choice by
stating that, “Because most existing research about the detection of
deception has focused on nonverbal indicators, this paper will focus
on nonverbal indicators of deception” (p. 77).

Taken together, these select results suggest very little support for the
Reid Technique; only three of the nine cues are statistically significant, and one of them, “pitch,” is contrary to what is suggested by
Reid. Unfortunately, by limiting consideration to only two of the
three focal response domains, Blair and Kooi (2004) provide at best a
weak test of the Reid Technique’s efficacy. In other words, excluding
the verbal response domain ignores the richness of information available to investigators who would also pay attention to a subject’s verbal
behavior, and according to the Reid Technique, use this information
in conjunction with other data to make a determination of credibility.

Based on their limited focus, Blair and Kooi (2003) identified nine
cues to deception on which to judge support for the Reid Technique.
These cues are shown in Table 1, along with predictions based on
the Reid Technique, and aggregate effect sizes from DePaulo, et al.
(2003). This table partially reproduces the one found in Blair and
Kooi (2004, p. 81):

IMPLICATIONS OF THE DEPAULO, ET AL. (2003) STUDY
FOR THE REID TECHNIQUE – REVISITED
Of the 158 cues to deception identified by DePaulo, et al. (2003),
88 of them were reported in three or more empiri