BRIA 13 3 c How Reliable Are Eyewitnesses?

In a San Diego courtroom, a distraught young woman described her hour of terror at the hands of a rapist. The victim pointed directly at defendant Frederick Daye and stated that he was the offender. "There is no doubt in my mind," she insisted. A second eyewitness testified that he saw Daye push the woman into a car and drive away. The San Diego barber was convicted of rape and sent to prison.

Both men were wrongfully accused by eyewitnesses who were certain they had correctly identified the defendant as the offender. Both men were later cleared of the charges against them and released from prison after serving 16 and 10 years respectively. Their cases serve as vivid proof that eyewitnesses can make horrible mistakes.

The Role of Eyewitness Testimony

Eyewitness testimony occupies a prominent place in the criminal justice system.  According to a 1988 survey of court prosecutors, an estimated 77,000 suspects are arrested each year based on eyewitness testimony. Beyond providing a strong basis for arrest, eyewitness testimony has great impact in the courtroom. 

"It's the most theatrical moment of the trial," says UCLA law professor John Wiley Jr. "Everybody in the jury box looks at the witness, looks at the [eyewitness's] finger and follows the line right to the defendant."

To determine what role eyewitness testimony played in the courtroom, psychologist and memory expert Elizabeth Lofthus conducted an experiment in which subjects served as jurors in a mock trial. First, all jurors heard the same description of the crime, a hypothetical robbery and murder. In one version of the trial, the prosecutor presented only circumstantial evidence. Only 18 percent of the jurors found the defendant guilty. In the second version of the trial the prosecutor presented the same evidence with one addition—an eyewitness. Seventy-two percent of the jurors found the defendant guilty. This led Lofthus to conclude that jurors place enormous value on eyewitness testimony. 

Studies have shown that mistaken eyewitness testimony accounts for about half of all wrongful convictions. Researchers at Ohio State University examined hundreds of wrongful convictions and determined that roughly 52 percent of the errors resulted from eyewitness mistakes. Legal scholar Edwin Borchard studied 65 cases of "erroneous criminal convictions of innocent people." Mistaken eyewitness identification was responsible for approximately 45 percent of Borchard's case studies.

There is no way of telling how many innocent people go to jail due to mistaken eyewitnesses. Most juries arrive at a conviction only after hearing a broad spectrum of evidence against the defendant. Eyewitness testimony is usually only a part of that broad spectrum. San Diego criminologist Ebbe Ebbesen maintains that police and prosecutors "weed out" most unreliable witnesses while others disqualify themselves by expressing doubt about their own perceptions. These factors help prevent convictions of innocent defendants from mistaken eyewitnesses. 

The Brain Is Not a VCR

Eyewitness testimony is powerful because most people believe that the human mind is able to record and store every detail of the events we experience. They believe that these permanently recorded memories, thoughts, and impressions can be retrieved, even from realms of the forgotten and the subconscious. In fact, says psychologist Lofthus, "human memory is far from perfect or permanent and forgetfulness is a fact of life."

Most scientists agree that memories are formed when neurons form connections between brain cells. According to James McClelland, a Pittsburgh brain researcher, "Each neuron represents a little bit of memory," just like a computer holds information in bytes of electronic coding. These bits of information are channeled from the eyes, ears, and other senses to various parts of the brain. Here, the connected neurons are stored in cerebral compartments that can hold as much as 1 quintillion separate memory bits.

These storage compartments are constantly being rearranged by a part of the brain called the limbic system. Like a neurological file clerk, the limbic system tries to "make sense" out of our memories by adding new data and tossing out old or confusing information. As Lofthus describes this process, "Every time we recall an event, we must reconstruct the memory and with each recollection the memory may be changed...Thus our representation of the past takes on a living, shifting reality."

Our brains may hold on to certain peak memories. But between the peaks, our brains fill in the gaps. Dr. Marcel Mesulam, professor of neurology and psychiatry at Northwestern University observes that "your brain may be re-creating something very vivid. But that doesn't prove that what was being re-created was true." 

This neural recollection process takes on particular significance when eyewitnesses to crimes are asked to recall their experience for police investigators, lawyers, or a judge and jury. Most witnesses want to help. Both investigators and witnesses want to see justice served. No one wants to held responsible for the wrongful conviction of an innocent person. In short, most witnesses and criminal investigators have the same goals. In most cases, these common goals can create an effective collaboration to identify a suspect. But these same goals, combined with the fallibility of memory, can create an margin for error in the identification of a suspect.

Psychologist G.H. Wells, an expert in methods used to secure eyewitness testimony, describes the process this way: "The investigator's knowledge of which the suspect creates a dynamic situation in which the investigator can influence the eyewitness to choose the suspect." For example, if the eyewitness makes a tentative choice, the investigator can create a false sense of confidence by confirming the choice. "The eyewitness then becomes convinced that the identification was correct," contends Wells, "and a false certainty begins to take hold."

Elizabeth Lofthus explains the development of false certainty by claiming that "the more people think about an event from the past, the more confident they become in their memories. The problem is that they get more confident in their inaccurate memories as well as their accurate ones."

Creating a Margin for Error

Regardless of the possibility for error, eyewitness testimony can be extremely helpful in determining innocence or guilt in criminal cases. Despite assertions that traumatic events can destroy memory, psychologists Ofshe and Watters from the University of California point to a study done of children who witnessed the murder of a parent. "Many distorted the memory," they say, "but not one [child] lost it entirely." Sometimes, a victim's eyewitness testimony is the only evidence available.

G.H. Wells, suggests that "[a]lthough...people have faulty beliefs on how memory works and...tend to over-believe eyewitness identifications, this does not mean that they assume that all such identifications are valid."

Wells quotes the U.S. Supreme Court, who, in the 1972 case of Nell v. Biggers, ruled that not all testimony is created equally valid or invalid. In contemporary justice settings, most instructions to the jury include a warning that eyewitness testimony can be subject to error.

Wells goes on to suggest several methods that police and prosecutors, judges, and lawyers can use to "greatly reduce the justice system's role in contributing to false identifications." Wells' methods attempt to limit the influence that the investigator has over the eyewitness. They include:

1. informing the eyewitness that the culprit may not be in a photo spread or suspect lineup; 

2. ensuring that all individuals participating in the lineup or photo spread resemble one another, so that the eyewitness does not choose someone who merely stands out; 

3. having photo spreads and lineups conducted by someone who does not know who is the suspect; and 

4. stopping reinforcing witnesses' choices by prompting (e.g.,  "How about number four?"), challenges (e.g., "Are you sure that's him?"), or congratulations, (e.g., "You're right. That's our suspect.").

Another technique for reducing error in eyewitness testimony has been developed by two professionals operating within the Israeli police system. This new technique, still in its experimental stages, uses computer technology to present a large collection of photos to an eyewitness.

Instead of viewing a limited number of faces chosen by criminal investigators, the eyewitness chooses his or her own "rogue's gallery" of suspects from a computerized photo collection. The eyewitness is not forced to choose a single suspect. Instead, the court is notified as to how many faces were viewed by the eyewitness, whether the suspect appeared among the witness's choices, and how many faces were chosen (the fewer the faces, the stronger the evidence). This technique avoids an "all or nothing" attitude on the part of both investigators and eyewitnesses.

Police lineups and other methods of suspect identification are an essential tool of justice. Most inaccuracies in eyewitness testimony are unintentional and many are detected in the courtroom, but the consequences of mistaken identity can be disastrous for the accused. Our justice system is not, and cannot be, perfect. But there is always room for improvement. Advances in technology and in our understanding of how the human mind functions can only help to serve justice in the future.

For Discussion and Writing

1. Why do you think eyewitness testimony is so powerful?

2. What factors might cause eyewitnesses to make mistakes?

3. What kinds of interactions between criminal investigators and eyewitnesses might create a margin for error in the identification  of a suspect?

4. Describe some methods that criminologists have developed to help eyewitnesses accurately choose or eliminate suspects. Do you think they are effective? Why or why not?


In this activity, students conduct their own experiments on the accuracy of eyewitness accounts.

1. Form small groups of 3-4 students each. Each group should make up a brief skit that the class will witness and describe.

2. When all groups have created and practiced, each group should present its skit to the class as a whole. Each student should write a  brief description of the skit and its participants.

3. Students read their descriptions aloud and compare the results.  



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