by paper and pencil, but the publisher also provides a
means for computer testing.
The test takers must complete all the items, each of
which has two answer choices. Once the test is com-
pleted, the answers are scored (0 or 1), and they are
reordered by item difficulty. Spans of 10 scores are
averaged, using running means, to yield performance
curves comprising 91 (nonverbal) or 69 (verbal)
points. For example, Items 1 to 10 yield the first run-
ning mean, and Items 2 to 11 yield the second running
mean. In a VIP performance curve, the xvalue of the
performance curve is item difficulty, and the yvalue is
mean performance accuracy (running mean value).
When a line is plotted through the running means,
the resulting performance curve yields distinctive
features that are used to categorize performance. The
first general feature is the slope of the performance
curve. The curves that have a downward slope from
easy to difficult reveal intent to respond correctly.
The flat curves reflect irrelevant responding, and the
upward sloping curves reflect intent to respond
incorrectly. The extent to which these slopes are sus-
tained provide information about application of
effort. The first running mean is also an indicator of
intent, as that point of the curve reflects performance
on the 10 easiest items. These items are easily
answered by young children. The test includes items
that are not easily answered by most individuals so
that a transition from effortful performance to guess-
ing can be observed. The fluctuations in the expected
progression of the performance curve from consis-
tent correct responding to guessing, given the ability
level of the individual, and identify instances of
inconsistent responding. That is, these fluctuations
are meaningful irrespective of the inherent capacity
of the individual to respond correctly.
For classifications of compliant, inconsistent, and
suppressed, it is possible to estimate the intellectual
capacity of the individual. The characteristics of the
performance curve and the number of items correctly
responded to have been correlated with performances
on other intellectual measures. It is noteworthy that
these features are applicable when individuals inten-
tionally choose incorrect answers and are classified as
suppressed.
Validation studies have been reported in four pub-
lished papers and the test manual. Validation and cross-
validation samples have included large numbers of
normal adults, neuropsychology examinees, criminal
defendants, and persons with serious mental illness.The reported classificatory accuracy of the nonverbal
subtest is 66% sensitivity and 90% specificity. The
verbal subtest demonstrates 59% sensitivity and 94%
specificity.Richard I. FrederickSee alsoCompetency to Stand Trial; Detection of
Deception: Use of Evidence in; Detection of Deception
in Adults; Forensic Assessment; Malingering; Personal
Injury and Emotional Distress; Test of Memory
Malingering (TOMM)Further Readings
Frederick, R. I. (2003). The validity indicator profile
(2nd ed.). Minnetonka, MN: NCS Pearson.
Frederick, R. I., Crosby, R. D., & Wynkoop, T. F. (2000).
Performance curve classification of invalid responding on
the Validity Indicator Profile. Archives of Clinical
Neuropsychology, 15,281–300.
Ross, S. R., & Adams, K. M. (1999). Test review: One more
test of malingering? Clinical Neuropsychologist,
13,112–116.VERBALOVERSHADOWING AND
EYEWITNESSIDENTIFICATION
Verbal overshadowing (VO) refers to situations in
which describing a nonverbal experience, such as the
appearance of a face, impairs subsequent recognition.
In the original demonstration of VO, participants
viewed a video of a robbery with a salient perpetrator
and were later asked to recognize the perpetrator in a
photographic lineup, including seven similar distrac-
tors. After viewing the video, half the participants
spent 5 minutes writing a description of the robber,
while the other half performed an unrelated control
task. Remarkably, participants who verbalized the
face were significantly less likely to correctly identify
the target face among others in the lineup.
Since its original demonstration, considerable
research has explored the generality and boundary
conditions of VO. VO has been found to generalize to
a large variety of other visual experiences, including
colors, abstract figures, photographs of mushrooms,
and maps, as well as other sensory modalities, includ-
ing audition (e.g., music and voices) and taste (wines).830 ———Verbal Overshadowing and Eyewitness IdentificationV-Cutler (Encyc)-45463.qxd 11/18/2007 12:44 PM Page 830