Why Do People Make Errors in Eyewitness Testimony? • 227others by inaccurate memory for what was perceived. We will fi rst look at the evidence
for errors of eyewitness identifi cation and then consider why these errors have occurred.ERRORS OF EYEWITNESS IDENTIFICATION
In the United States, 200 people per day become criminal defendants based on eye-
witness testimony (Goldstein et al., 1989). Unfortunately, there are many instances
in which errors of eyewitness testimony have resulted in the conviction of innocent
people. As of December 2009, the use of DNA evidence has exonerated 248 people in
the United States who were wrongly convicted of crimes after serving an average of
12 years in prison (Innocence Project, 2009). Seventy-fi ve percent of these convictions
were based on eyewitness testimony (Quinlivan et al., 2009; Scheck et al., 2000).
To put a human face on the problem of wrongful convictions due to faulty eyewit-
ness testimony, consider the case of David Webb, who was sentenced to up to 50 years in
prison for rape, attempted rape, and attempted robbery based on eyewitness testimony.
After serving 10 months, he was released after another man confessed to the crimes.
Charles Clark went to prison for murder in 1938, based on eyewitness testimony that,
30 years later, was found to be inaccurate. He was released in 1968 (Loftus, 1979).
Ronald Cotton was convicted of raping Jennifer Thompson in 1984, based on
her testimony that she was extremely positive that he was the man who raped her.
Even after Cotton was exonerated by DNA evidence that implicated another man,
Thompson still “remembered” Cotton as being her attacker. Cotton was released after
serving 10 years (Wells & Quinlivan, 2009).
The disturbing thing about these examples is not only that they occurred, but that
they suggest that many other innocent people are currently serving time for crimes they
didn’t commit. These miscarriages of justice and many others, some of which have
undoubtedly never been discovered, are based on the assumption, made by judges and
jurors, that people see and report things accurately. In essence, many people in the crim-
inal justice system have subscribed to the erroneous idea that memory is like a camera.
We have seen from laboratory research that memory is defi nitely not like a camera,
and research using crime scene scenarios supports this idea. A number of experiments have
presented participants with fi lms of actual crimes or staged crimes and then asked them to
pick the perpetrator from a photospread (photographs of a number of faces, one of which
could be the perpetrator). In one study, participants viewed a security videotape in which
a gunman was in view for 8 seconds and then were asked to pick the gunman from photo-
graphs. Every participant picked someone they thought was the gunman, even though his
picture was not included in the photospread (Wells & Bradfi eld, 1998). In another study,
using a similar experimental design, 61 percent of the participants picked someone from a
photospread, even though the perpetrator’s picture wasn’t included (Kneller et al., 2001).
These studies show how diffi cult it is to accurately identify someone after viewing
a videotape of a crime. But things become even more complicated when we consider
some of the things that happen during actual crimes.THE CRIME SCENE AND AFTERWARD
Even under ideal conditions, identifying faces is a diffi cult task and errors occur (Henderson
et al., 2001). But other factors can intervene to make the task even more diffi cult.Errors Associated with Attention Emotions often run high during commission of a crime,
and this can affect what a person pays attention to and what the person remembers later.
One important example of how attention can affect a witness’s access to relevant informa-
tion is weapons focus. The tendency to focus attention on a weapon results in a narrowing of
attention, so witnesses might miss seeing relevant information such as the perpetrator’s face.
Claudia Stanny and Thomas Johnson (2000) studied weapons focus by mea-
suring how well participants remembered details of a fi lmed simulated crime. They
found that participants were more likely to recall details of the perpetrator, the victim,
and the weapon in the “no-shoot” condition (a gun was present but not fi red) thanCopyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part.