After viewing a crime or event,
eyewitnesses are asked to identify the
perpetrator from a list of suspects.
Unfortunately, eyewitness memory is
unreliable, and lineups often contain
some form of bias.
Currently there are two lineups styles that
law enforcement can use with witnesses:
› Simultaneous
› Sequential
Witnesses can also be shown only a
picture of the suspect. This is called a
Showup.
Simultaneous- all suspects featured in the
lineup are shown at once.
› Higher identification rate: Both positive and
false identification
› Potential for comparative judgments—
choosing the face who looks “most like” the
perpetrator
1 2 3
4 5 6
Sequential- The people featured are
shown one at a time, and the witness
must say whether or not the person
currently shown is the perpetrator.
› Lower Identification rate: Both positive and
false identifications
Witnesses would
see a suspect
photo one at a
time in a format
such as this.
1
Most police municipalities do not have formal rules or guidelines about which type of lineup to use, or how to interact with witnesses.
Most memory researchers recommend using a sequential lineup.
The prevailing theory is that sequential presentation reduces false identifications, without concurrently reducing true identifications.
In the present research, we propose a third type of lineup--slideshow.
The witness can view each face as many times as needed, however only one face is on the screen per time.
Each picture is shown for 6 seconds before the presentation automatically moves on to the next picture.
The slideshow runs on a continuous loop until the witness makes a decision.
The witness picks a starting point at
random.
› This is accomplished by selecting a card at
random with a colored shape on it.
› This shape corresponds to one of the shapes
we have associated with each of the
suspects.
› When no picture is obviously first or last we can control for possible sequence effects.
To identify the suspect, the witness
confirms the name
and color of the
shape.
Example: “Blue Star”
The slideshow lineup will produce the
same number of correct IDs as the
simultaneous lineup.
› Current thinking is that simultaneous lineups
produce more IDs because witnesses have
time to compare all the faces and “pick the
closest one”.
› We hypothesize that the benefit will still exist
with multiple exposures but no opportunity to
directly compare faces.
101 general psychology students from
the University of Mary Hardin-Baylor
participated in our experiment.
The experiment was double-blind
› Neither witnesses nor proctors knew who the
suspects were in the lineups.
We split participants into 3 groups:
› Simultaneous Lineups(31)
› Sequential Lineups (32)
› Slideshow Lineups (38)
We showed a 45 second video of a
mock car jacking to all participants.
They were given two 5-minute
questionnaires to create a delay
between the video and the lineup.
A target present lineup was shown
containing 6 suspects.
› Target present means the true suspect was
present in the lineup.
The participant’s selection was
accompanied by a self-evaluated
confidence level based on their
selection.
› The confidence ratings varied from 0-100%.
The simultaneous and slideshow lineups
produced a similar rate of correct
identifications, supporting our hypothesis.
The sequential lineup produced a mean
correct ID rate of 31%.
› This challenges previous findings suggesting
that sequential presentation of a lineup does
not significantly reduce the likelihood of correct identifications.
So far, we have supported the
hypothesis that simultaneous and
slideshow presentation of a target-
present lineup produces similar results.
Next, we need to see what happens with
target-absent lineups.
We hope that slideshow presentation of
a target-absent lineup will lead to fewer
false identifications than simultaneous
presentation of a target-absent lineup.
This would create a lineup format that
merges the benefits of both simultaneous
and sequential presentation.
Sponsor: Trent Terrell Ph.D
Co-researchers:
› Thomas Via
› Kristina Zufall
› Hope Underwood
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