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
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