Wilkes Barre Times-Leader, PA
05-22-06
Putting police lineups under study
By Tom Avril
Inquirer Staff Writer
In 2001, New Jersey became the first state to adopt two scientifically based
methods for its police lineups, designed to prevent witnesses from picking the
wrong person.
Whenever possible, lineups are now "double-blind": The officer running it doesn't
know who among the half-dozen people is the suspect, so there's no chance of
leading the witness.
Also, witnesses now look at possible suspects one at a time, deciding in each
case whether that person is the offender before moving on to the next.
In traditional lineups - looking at all the candidates at once - people tend to pick
whichever person looks most like the offender. That's a serious problem if the
actual offender isn't there.
In laboratory simulations, with actors portraying criminals, the new procedures
can reduce mistakes. But whether they work in real life is hard to say. During the
last year, research with actual police and suspects has yielded mixed results.
The key problem: with real crimes, researchers don't know whether a witness has
picked the right person if they don't know for sure who that is.
"You don't really know whether the culprit is in the lineup," says Roy Malpass,
professor of psychology and criminal justice at the University of Texas, El Paso.
Most felonies, for one thing, do not yield the scientific certainty of DNA evidence.
Yet police departments rely on eyewitness' memory for tens of thousands of
cases each year, so a few have experimented with various lab-based methods to
make the real-world system as good as possible.
The double-blind technique is a no-brainer, says Gary Wells, an Iowa State
University psychologist who's studied lineup errors for more than 20 years. It's
standard practice for scientific and medical research - why not police?
Most studies would never get published if they weren't double-blind, Wells says.
"But we could put people to death based on what would be considered to be a
lousy experiment that would never get published."
Another recommended method is to warn witnesses that the real culprit might not
be in the lineup, so they don't feel obligated to pick someone.
Still another is for police to pick good "fillers" - lineups of people who resemble
the suspect. If the suspect stands out for any reason, the witness is more likely to
pick him, even if he's innocent.
Yet scientists do not agree on whether the sequential method, used in New
Jersey and a handful of police departments elsewhere, is an improvement.
In the first head-to-head study of the new and old methods, Illinois witnesses of
sequential lineups were more likely to pick innocent "fillers" and less likely to pick
the suspected culprits.
Witnesses in the study, conducted by three police departments, did a better job
with traditional, simultaneous lineups.
Yet the research, released in March, was not directly supervised by scientists;
Iowa State's Wells calls it flawed. The traditional lineups may have worked better
because officers knew which person was the suspect, he says. The sequential
lineups, on the other hand, were double-blind.
In a double-blind study in Minnesota, the new method showed promise.
Researchers from Augsburg College found that witnesses looking at people
sequentially picked the police suspect more than half the time. They picked no
one 38 percent of the time, and they incorrectly picked a filler just 8 percent of
the time - half as often as in some studies of the traditional method.
Weighing the success of the different approaches may ultimately be a question of
values, not science. Lab studies suggest the sequential method improves
accuracy when the suspect is not the offender. But when the suspect is the
offender, witnesses don't do as well in picking the bad guy.
So which is the greater social cost - letting a criminal go free or locking up the
wrong person?
In New Jersey, a 2003 survey indicates a fairly smooth transition despite some
early reluctance. Nearly 90 percent of police said they noticed no difference in
the percentage of cases in which a witness identifies a suspect, according to
deputy attorney general Lori Linskey.
Michael P. King, chief of detectives for the Burlington County prosecutor, says he
had no problems with the old system. But he sees the logic of the new one, too.
"It doesn't hurt us at all," he says. "And it can help us in the eyes of the courts. ...
All this is doing is giving us more credibility."