posted on March 25, 2013 11:13
| Dr. Gary Wells, professor of psychology at Iowa
State University, who has studied witness identification since the mid-1970s, spoke during Black Hills State University's recent Black Hills Research Symposium.
In 1985, Kirk Bloodsworth was convicted and sentenced to the Maryland gas chamber for the brutal rape and murder of a 9-year-old girl. In 1993, the former marine walked out of the Maryland prison, the first inmate in the nation on death row to be exonerated by DNA.
Bloodsworth is not alone, said Dr. Gary Wells, a professor of psychology at Iowa State University. Wells, who has studied witness identification since the mid-1970s, recently spoke to a group of Black Hills State University students, faculty, staff, community members and local law enforcement. His talk was part of University’s annual Black Hills Research Symposium.
As of last month, there were 302 full exonerations based on DNA testing and of those 226 cases were from mistaken eyewitness identification, Wells said.
The memory does not work like a video system, he said. “We process the gist of our world, not the details of the world.”
Wells is also the director of social science for the American Judicature Society’s Institute of Forensic Science and Public Policy with a research interest in the integration of cognitive and social psychology as it relates to the law. He has completed extensive research on lineup procedures and the reliability and accuracy of eyewitness identification.
Since the 70s, experimental psychologists have been “blowing the whistle” on the legal system’s identification methods based on the results of several controlled experiments, Wells said. However, it wasn’t until decades later when law enforcement started taking notice.
“Not until the mid-1990s when forensic DNA testing came along that we began to see a change in things,” Wells said. “The legal system is now paying attention partly because they are dealing with all these DNA exonerations.”
While DNA testing has helped exonerate many innocent people, it is a just a small fraction of the mistaken identification cases, Wells said.
“When we go back to look at the cases of people claiming their innocence the vast majority of these cases there was no biological evidence collected – they have no chance of proving their innocence with DNA. “Only five percent of these cases have DNA trace evidence that can trump a mistaken eyewitness identification, and it takes something as definite as DNA to trump an eyewitness identification.”
While Wells admits that eyewitness identification is a key tool for law enforcement, he said there are ways the legal system can use psychological science to improve the method.
Wells suggested three changes that could help reduce the number of mistaken identifications: proper selection of “fillers” in lineups; preliminary admission that the suspect may not be in the lineup; and double-blind testing. Double-blind testing, used in scientific experiments, means that neither the witness nor the person administering the lineup test know which member is the actual suspect.
This prevents any conscious or subconscious influence of the witness, Wells said.
“There is a natural tendency to verbally influence identification,” he said. Wells said he first decided to enforce the double-blind testing after observing a lineup procedure where witness didn’t say anything for a long time and the officer said, “I noticed you paused on suspect three.”
Wells said law enforcement agency agencies also need to select lineups of suspects that fit the witness description and inform witnesses that the suspect may not be in the lineup.
“That is the problem with relative judgment – someone is always going to look more like the perpetrator than the other people in the lineup, even when the real perpetrator is not there,” he said.
Most of the DNA-exoneration cases have occurred because the actual perpetrator was not present to be identified,” he said.
There has been a lot of improvement and law enforcement agents adopting changes, Wells said.
In 2000, there were no law enforcement agencies doing double-blind testing. In 2013, 38 percent had adopted the change. The psychological reforms are legally required by all law enforcement agencies in New Jersey, North Carolina, Ohio and Connecticut, and there are state-wide recommendations in several other states.
Wells noted that there is still a long way to go in making changes