From the Chronicle of Higher Education

issue dated February 25, 2000

Looking Askance at Eyewitness Testimony


Ronnie Bullock was sentenced to 60 years in jail for

kidnapping and raping a young Illinois girl. Edward Honaker

spent a decade in a Virginia prison for sexually assaulting a

woman at gunpoint. Kirk Bloodsworth was shipped off to

Maryland's death row for raping and strangling a 9-year-old


    All three of those men were convicted in part because

eyewitnesses or victims firmly placed them at the scene of the

crime. But not one of them was guilty. They were among the

first convicts to be exonerated by DNA tests proving that

someone else was responsible.

    Some psychologists believe that such mistakes happen in

thousands of courtrooms every year. But most crimes leave no

DNA traces to rule out the innocent. For more than two

decades, psychological researchers have asked, How could so

many witnesses be wrong, and what can be done about it? Only

recently have they seen their findings influence the way the

criminal-justice system handles eyewitness testimony.

Psychologists have conducted hundreds of studies on errors in

eyewitness identification. In some cases, of course, witnesses

simply lie. But research has shown that flawed police

procedures and the vagaries of memory often lead witnesses to

identify the wrong person, and that credulous jurors too

easily credit their testimony.

    To those familiar with the mountain of evidence about the way

the human mind works, that comes as no surprise. "Why should

people make good eyewitnesses?" asks Gary L. Wells, a

psychologist at Iowa State University who is widely considered

the dean of eyewitness research. In the presence of danger, he

says, "we're wired for fight or flight. What helped for

survival was not a quick recall of details."

The findings of Mr. Wells and his colleagues are finally

gaining currency in the halls of criminal justice. In part

that is due to the gradual acceptance of expert testimony on

eyewitness identification.

    Far more crucial, however, is the growing roster of convicts

cleared by DNA evidence. In 1996, the U.S. Department of

Justice released a report on the first 28 known cases of DNA

exoneration. After studying those and 12 subsequent cases, Mr.

Wells discovered that mistaken eyewitness testimony had played

a part in about 90 percent of the convictions.

Concerned about the high rate of eyewitness error in the DNA

cases, U.S. Attorney General Janet Reno invited him to a

meeting in early 1997. As a result of their conversation, the

department's National Institute of Justice asked Mr. Wells and

five fellow scholars to join a panel of law-enforcement

officials, criminal-defense lawyers, and prosecutors created

to write guidelines for handling eyewitness testimony.

The guide, published in October, gave scholars the opportunity

to show that human memory is not a highly reliable tool for

determining guilt in the courtroom. For example, contrary to

popular belief, people under stress remember events no better

than, and often less well than, they do under ordinary

circumstances. Witnesses also perceive time as moving more

slowly during traumatic events. That, in turn, leads them to

overestimate how much time they had to notice details, a key

factor of their credibility in court. And studies have found

that witnesses to a crime are so distracted by the presence of

a weapon -- a phenomenon called "weapon focus" -- that they

remember little else with accuracy.

    Researchers cannot ethically recreate the trauma of real

crimes. But plenty of field research suggests that witnesses

are apt to misidentify people.

For example, many studies have tested the ability of

convenience-store clerks and bank tellers to recall customers

they encountered in non-stressful situations. Around a third

of the time, the employees wrongly identified faces from

"lineups" that did not include the person they had actually


    In addition, all sorts of factors inhibit our ability to

recognize and recall facial detail. For instance,

psychologists have established that most of us have more

difficulty recognizing people of a different race. And memory

deteriorates very quickly over time.

    Elizabeth F. Loftus, a psychologist at the University of

Washington and a pioneer in research on false memory, has

discovered that it's remarkably easy to alter one's

recollection without realizing it. Human beings are highly

susceptible to incorporating "post-event information" --

newspaper articles, comments by police, conversations with

other witnesses -- into their recollections.

    Witnesses also have been known to identify as criminals people

they recognized from some other encounter, a process called

"transference." In one bizarre example, an Australian

psychologist and memory researcher named Donald Thomson was

himself once identified by a rape victim as her attacker. Not

only was his alibi airtight -- he was being interviewed on

live television at the time -- but she had mistaken him for

the rapist because she had seen his face on her television

screen during the assault.

    Of course, policymakers can't do much to improve the flaws in

our memories. So scholars like Mr. Wells, who wanted to reduce

eyewitness mistakes, began to focus on things that the justice

system can control -- particularly police procedures.

One of the biggest problems with eyewitness identification,

researchers have found, is that uncertain witnesses are often

prompted to finger the person whom police have detained, even

when the suspect is not the same person they spotted at the

scene. Witnesses viewing a lineup tend to assume that police

have caught the person they saw. So they think their job is to

find the face that most resembles the description they gave to


    The police sometimes exacerbate that tendency by designing

lineups poorly. Imagine a witness to a liquor-store robbery

who says the robber was white, stocky, and bearded. Based on

that description, the police identify a suspect and ask the

witness to look at a lineup of live individuals or at a spread

of photos (known as a "six-pack").

    Too often, say researchers, the "distractor" faces used by

police do not closely match the witness's description, or the

suspect's photo looks different from the others. If the

suspect stands out in any way -- if his is the only color

photo in the six-pack, for instance -- the witness is far more

likely to say, "That's the guy."

    Lineups are also fraught with the possibility of mistaken

identity, researchers report, because of our tendency to

overlook differences in facial appearance among people not of

our race. Not only are white witnesses, say, more likely to

mistake one black suspect for another (and vice versa), but

police officers may overestimate the degree to which the

distractors they choose match the suspect's description.

Recently, Mr. Wells has raised the alarm about the way a

witness's confidence can be manipulated. Witnesses are easily

influenced during and after the lineup -- by talking with

other witnesses or police interviewers -- to be more certain

of their choice than their recall warrants. Police

investigators, for example, may praise a witness for "picking

the right guy" out of the lineup.

    That taint frequently makes its way to the jury box.

Understandably, jurors put a lot of stock in a witness who can

point to the defendant and say, "He's the one. I'll never

forget his face." But scholars have learned that the degree of

confidence during trial is a poor predictor of a witness's

accuracy. And, they warn, jurors ought to be particularly

skeptical if they learn that a witness professed more

confidence on the witness stand than in the squad room.

Recall, they say, doesn't improve over time.

    Until recently, the criminal-justice system made little use of

those findings. Defense lawyers, of course, have embraced and

exploited them at least since the 1980's. But according to

Brian L. Cutler, a psychologist at Florida International

University, they have rarely been able to use the research to

cross-examine eyewitnesses or police.

    "Defense lawyers have no special training -- they don't know

what questions to ask," says Mr. Cutler. "If they do ask the

right questions, how well-equipped are jurors to evaluate the

questions?" Unfortunately, jurors cling to a belief that "the

way memory works is a matter of common sense," he says. "It

just isn't so."

    "People expect it's like videotape, that we attend equally

well to everything out there," says Roy S. Malpass, a

psychologist at the University of Texas at El Paso who served

on the Justice Department panel. In fact, he says, "we're

highly selective."

    No one knows how often eyewitness error leads to false

convictions, but some scholars have taken a stab at the

question. In their book Mistaken Identification: The

Eyewitness, Psychology, and the Law (Cambridge University

Press, 1995), Mr. Cutler and Steven D. Penrod, of the

University of Nebraska at Lincoln, do some courtroom

calculations: If just 0.5 percent of America's yearly 1.5

million convictions for serious crimes are erroneous -- a rate

suggested by some studies -- then other research allows the

authors to infer that well over half of those defendants, or

around 4,500 innocent people, are convicted on false

eyewitness testimony.

    All that may change now that the nation's top law-enforcement

officials have created new guidelines for police conduct. The

Justice Department report, "Eyewitness Evidence: A Guide for

Law Enforcement," reads like a primer on eyewitness research.

Among other things, it instructs investigators who assemble a

lineup to:

* Select "distractors" that match the witness's description,

even simulating tattoos or other unusual features if


* Remind the witness that the suspect they saw may not even

be in the lineup, and that the lineup is intended to clear the

innocent as much as it is to identify the guilty.

* Avoid any comments that might influence the witness's


* Ask for and record the witness's degree of certainty


* Photograph or film lineups to make the police more

accountable to the defense.

    Before they can take their new influence for granted,

psychologists say, there is more to be done. For one thing,

police officers and prosecutors need to be educated about the

guidelines, which do not have the force of law. But Mr. Wells

and others believe that both groups will embrace them once

defense lawyers in the courtroom begin to hold the guidelines

up as the gold standard of diligent police work.

    The social scientists didn't win every battle. Despite their

urgings, law-enforcement officials on the Justice Department

panel batted down two key suggestions for improving police

lineups. Research suggests that lineups are more accurate when

they are double-blind -- in other words, when the investigator

in charge doesn't know which person is the suspect -- and

sequential -- when the witness sees faces one at a time.

According to participants, police representatives nixed the

former idea, because logistically it would be difficult to

round up investigators who didn't know who the suspect was.

More important, they said, it would be a tough sell to their

fellow cops, because it smacks of mistrust and requires them

to cede control of an investigation to someone else.

    After scholars lost the battle to include double-blind

procedures, participants say, they gave up on demanding

sequential lineups. Without the first precaution, they

explained, sequential lineups might be even more vulnerable to

manipulation than simultaneous lineups are.

    John Turtle, a panel member and a psychologist at the Ryerson

Polytechnic Institute, in Toronto, believes that he has a

high-tech solution to all those concerns. He has developed

computer software that purports to take the bias out of the

photo-spread lineups, which constitute about 80 percent of

those in the United States and virtually all of those in


    All a police investigator would need to do is scan a photo of

the suspect into a computer and sit the witness down in front

of the screen. The machine would then automatically choose

photos of others who match the witness's description from a

large database, and offer standardized, neutral instructions

that wouldn't nudge the witness toward a particular response.

    Psychologists deny they are imputing bad faith to police

investigators. It's human nature, they say, to want your

results to match your expectations. The scholars are simply

urging police officers to treat their procedures for handling

witnesses with all the care of scientific experiments. "Human

memory is a form of trace evidence, like blood or semen or

hair, except the trace exists inside the witness's head," says

Mr. Wells. "How you go about collecting that evidence and

preserving it and analyzing it is absolutely vital."