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Identification of the actual culprit jumps 40% when proper photo array procedures are followed

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A news team in Pittsburgh decided to test how well witnesses to a crime can identify an unknown culprit.  After staging a crime (where another student stole a laptop from in front of the classroom), the students were put in two groups, both of which saw the same 6 photographs.  The first group was shown a ‘traditional’ photo array, where they viewed all the photos together and were not told that the culprit “may or may not” be there.  The second group was shown the photos sequentially — one at time — and were told both that the true culprit “may or may not” be there and that the police would continue to investigate whether an identification was made or not.  

Tellingly, in the first group, 8 out of 10 picked the same man and identified him as the thief.  Problem was, not only did that man not steal the laptop, the actual thief was not in the array.  

The second group was shown pictures one at a time which included the actual culprit.  Before viewing the photos, the students were told that “the suspect may or may not be in this sequence of photos, so don’t feel compelled to make an identification. Rest assured that regardless of whether you make an identification, the police will continue to investigate this case.”  In that group, 60% correctly identified the thief, and 40% were unable to make an identification at all.

While not a perfect experiment, this shows the value of the procedures recommended by the Department of Justice when administering photo arrays: they should be administered by someone who has no knowledge of who the suspect is, the witnesses should be warned the person “may or may not” be present, that they should not feel compelled to identify anyone, and that the police will continue to investigate regardless of whether they can or cannot make an identification.  These simple procedures are win-win: the percentage of incorrect identifications falls dramatically, and the identifications which are made are much more likely to be accurate.  

The Pennsylvania Innocence Project supports the institutionalization of the Department of Justice protocols for eyewitness identifications.  To learn more about the causes of wrongful convictions, contact the Pennsylvania Innocence Project at

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