ISU researcher: Rethink crime photo lineups

A study led by Iowa State University psychology professor Gary Wells is offering clear guidelines to law enforcement agencies nationwide on how to administer photo lineups to minimize the chance for eyewitness mistakes, along with the research to back up those recommended practices.

Results released Monday indicate that showing lineup photos to eyewitnesses one at a time, rather than all together, decreases the likelihood that the witnesses will identify the wrong person as a suspect in a crime.

The sequential method did not dramatically improve the rate of positive identification of suspects, Wells said during a phone news conference Monday. But, he said, the “sequential procedures resulted in significantly fewer identifications of innocent people than the simultaneous procedures.”

“This improves the reliability of eyewitness identifications,” he said.

Wells and his companions in the study, including the Innocence Project in New York, are pushing for nationwide reform based on their results.

New Jersey, Wisconsin and North Carolina already have implemented new procedures to improve their eyewitness identification processes. Iowa has not launched any such reform at the state level, but individual jurisdictions are making changes. For instance, the Cedar Rapids Police Department began displaying photos one at a time two years ago, Sgt. Cristy Hamblin said.

Wells said he expects agencies across the country to follow suit.

“In every jurisdiction, law enforcement people want to get the right guy, and they have to step forward like they have in other states,” he said. “This is long overdue.”

Researchers began a deeper analysis into how photo lineups are administered in the 1990s, when advancing DNA technology led to a series of overturned convictions. Seventy-five percent of those exonerations involved mistaken eyewitness identifications, Wells said.

The new study provided eyewitnesses of crimes with laptop computers that took them through the photo lineup procedure. Some viewed all of the photos at the same time and some viewed them one at a time.

Each set of mug shots showed one suspect with five “fillers,” or known innocents. Witnesses picked the actual suspect about a quarter of the time using both methods. But in the simultaneous lineups, the witnesses picked a filler 18 percent of the time, versus just 12 percent for the sequential method.

That means, Wells said, that people seem be more likely to identify an innocent person pictured in a lineup with other people because the witnesses are choosing based on a comparison with other possible suspects.

“When eyewitnesses see them at the same time, they decide who looks the most like the suspect relative to the others in the lineup,” he said.

The study was conducted at the police departments in Austin, Texas; Charlotte-Mecklenburg, N.C.; San Diego; and Tucson, Ariz.

“If we develop new and best practices, that doesn't mean everything we have done for the last 30 years is wrong,” said Rosemary Lehmberg, a prosecutor in Austin. “But we have to keep moving forward.”

The Associated Press contributed to this report.