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Eyewitness misidentifications occur more often than you would think.  Image Courtesy of Š Tavik Morgenstern

Eyewitness misidentifications occur more often than you would think. Image Courtesy of Š Tavik Morgenstern


Giving False Witness

 By: Karen Wiens

The average Joe can wield enormous power over the lives of others if he is a witness to a crime.  Unfortunately, eyewitness accounts can unintentionally send innocent people to jail, sometimes even to death row.  In a survey of cases where DNA evidence proved the innocence of a convicted criminal, mistaken identification contributed to 90 percent of the original convictions.  

Psychologists and law enforcement officials aim to improve methods of lineup administration in an attempt to prevent innocents from paying for the crimes of others.  Cognitive psychology has revealed that factors such as imperfect human memory or investigator influence, unintentional as it may be, can forever change the life of an innocent person. Understanding the role of psychology is leading to changes in procedure and even new computer software for conducting lineups.

While television shows such as Law & Order show a live lineup with the eyewitness behind a one-way mirror as a matter of course, the more typical method is a photo lineup. Though they’re "really sexy in court” according to Otto MacLin, psychology professor in the Eyewitness Laboratory at the University of Northern Iowa, live lineups consume too much time for the average police department. Additionally, it is rare to have the suspect plus five similar individuals incarcerated at the same time. 

In the traditional photo lineup the witness sees all the possibilities at once.  In this “simultaneous lineup,” investigators create a three by two array ("six-pack") of mug shots.  All six fit the verbal description eyewitnesses gave on the scene, say, white male, dark hair, moustache. 

When an eyewitness identifies a suspect in a photo lineup, much of that decision is described by decades-old theories of cognitive psychology.   Two separate forms of face recognition contribute to making a positive identification, a theory termed ‘dual process’ according to Chris Meissner, professor of psychology and criminal justice at the University of Texas at El Paso.  The witness may have that intangible feeling of familiarity.  Alternatively, the witness may specifically remember where he or she knows a person from, such as recalling a high school classmate. 

Some researchers believe that in the “six-pack” simultaneous lineup, the witness is actually comparing the photos to each other, rather than to their mental image of the criminal, to find the “best fit” of the given options.  According to cognitive theory, witnesses rely primarily on their sense of familiarity to pick a mug shot.  The actual criminal may well be fingered, but woe to the unlucky innocent who simply evokes that feeling of familiarity more than the other five.

Psychologists have long recognized the inherent dangers of relying on eyewitness testimony, but only recently have these issues come under public scrutiny.  In 1999, as a result of DNA exoneration studies, the National Institute of Justice commissioned a task force to set uniform guidelines for gathering eyewitness evidence.  These guidelines and subsequent research suggested alternative methods to the simultaneous lineup. 

Each proposed solution, however, has its own pitfalls. If the problem is that witnesses compare photos to each other, then show each mug shot one at a time.  Cognitively, if a witness thinks a later photo may be more like their memory than the current one, they rely less on general familiarity and more on a specific recollection of the suspect.  Some studies show that this method, called a “sequential lineup,” reduces the number of false identifications with only a small reduction in correct responses.   Skeptics say that the method allows for subtle influence by the investigator, either unintentionally lingering a bit or asking leading questions.  

One solution is to run the lineup, whether simultaneous or sequential, more like a double-blind scientific investigation.  In this strategy, neither the experimenter nor the subject of research knows which photo represents the actual subject. This negates the possibility of undue influence, said Mark Phillips, trial consultant at Dispute Dynamics, Inc.  Law enforcement officers, however, aren’t thrilled with this solution, said Ryann Haw, criminal justice instructor at Big Bend Community College in Moses Lake, Wash.  Small departments may have problems finding someone who doesn’t know the suspect’s identity. They may also perceive an implication that they can’t run a fair investigation.

A possible fix is to simply take the lineup administrator out of the picture, a strategy called “low-contact.”  Give the witness instructions, then step away from the immediate vicinity.  This would prevent investigator bias and help relax the witness because they wouldn’t have the intimidation of someone looking over their shoulder.  In mock simultaneous lineups administered to 300 undergraduate students, Haw found a decrease in false identifications from 30 percent to 7 percent using this method.

One way to implement this strategy involves the growing trend of computer technologies.  MacLin at the University of Northern Iowa created a free software program that allows the lineup administrator to assemble the photos and then leave the witness to follow directions given by the program, such as in a video tutorial.   The program, called PC_Eyewitness, allows greater flexibility in creating lineups and documenting the exact lineup procedure for review during court cases.   Eventually, a police officer at the crime scene could use eyewitness descriptions of a suspect to create a photo lineup within ten minutes, by connecting to an internet database of mug shots.  While promising, PC_Eyewitness isn’t in active use yet.  “Police agencies, by and large, are bound by tradition,” said MacLin. 

 Until the use of this type of program is widespread, Haw’s low-contact strategy of moving the lineup administrator away from the witness may be the easiest to implement.  As Haw said, “It’s a major improvement for just moving a chair.”

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