Eyewitness Misidentification
and Vision Limits
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There is an old saying, "Seeing is believing." I'll reply with an old song title: "It ain't necessarily so."
There is a growing list of psychologists and vision experts that strongly maintain that the vision, memory and testimony of eyewitnesses in both civil and criminal cases may be fallible. This is substantiated by hundreds of peer reviewed social-scientific publications that have commented on the recent rise of exonerations based on DNA evidence. False identification of an innocent suspect as the perpetrator of a crime is the single greatest cause of wrongful conviction in the U.S. Recently the media has headlined a number of misidentification cases into stunning accounts of local and national interest.
Experts agree that it is easier to identify suspects when viewing them at a close distance. The greater the distance from a suspect, the more details that are lost. Even at a distance of ten feet, details concerning a person’s eyelashes are lost. At 200 feet, details of a person's eyes cannot be distinguished. At 500 feet, a person's head is a big blur. The smaller the object or the further the distance that the details are observed, the greater the chance of blurring and misidentification. When witnesses say they viewed something at 120 feet, for example, experts can take a picture of the scene and will know just how much to blur it to match it at that distance. Identifying a person from 450 feet is the equivalent of sitting in the center field bleachers at New York's Yankee Stadium and being able to recognize someone in the box seats behind home plate.
A stumbling block lies in misleading or lack of pre identification instructions. In traditional procedures, eyewitnesses are presented with one or more live or photograph line ups that include a suspect and non suspect "fillers." If not provided with instructions to the contrary, the witness may assume that the perpetrator is in the lineup and that the witness must identify one of the lineup members as the perpetrator or that the lineup depends on their immediately making a successful identification. Therefore witnesses often make "relative judgments" choosing the individual who looks most like the perpetrator when compared to the other lineup members rather then the person who actually committed the crime. The problem is exacerbated when the witness strives to make an identification at all costs. Differences may occur when the administrator of an identification procedure knows the identity of the suspect and may innocently cue the witness through facial expressions and gestures as to the correct answer and undermine the ability of the witness to make an independent identification from memory.
If fillers in a lineup are not chosen who look somewhat like the suspect, that suspect tends to stand out. For instance, if the suspect is bald, has an unusual hairstyle, has tattoos, is of a different race, or has other distinguishing features that cause the suspect to look significantly unlike the fillers, the witness may be unconsciously led to pick the suspect under suspicion. After an identification procedure, law enforcement officials sometimes make statements that inflate the witness' confidence in his/her identification. An administrator may compliment a witness as having done a good job because they identified the same suspect as another witness. This may lead a witness to depend on an overconfident memory rather then to reinforcing comments or clues. Members of a line up or photo array are traditionally presented to a witness simultaneously rather than once at a time.
Recent media revelations and investigations have shown that far too many suspects identified in simultaneous presentations have been proven to be not guilty of the respective crime. Modern methods of video I.D., DNA and other scientific supportive knowledge have pointed to the sequential (individual) line up or photo as the method of choice for obtaining accurate witness identification. This is a checkpoint for witnesses who tend to identify the individual who looks most like the perpetrator by comparing each line up member with their independent memories of the perpetrator's appearance. Other factors that influence the observation of the witness include memory gaps, stress or trauma and the degree of attention that the witness paid to the event.
Eyewitness memory is not a transcript or video record. Memory is an imprecise interpretive reconstruction of events subject to contamination in both its initial encoding and subsequent retrieval. Accurate memory of an event decreases over time. During memory recall, individuals often unconsciously fill in memory gaps with information from other memories, knowledge or assumptions. Examiners call this "unconscious transference." Individuals tend to recall information best under conditions of low to moderate stress. Experiments reveal that under those ideal conditions witnesses correctly identified the perpetrator 62-76 percent of the time. But those exposed to a high stress scenario could only do so 30-34 percent of the time. Another contributing factor is the presence of a weapon because it tends to draw attention away from the perpetrator's appearance to the weapon itself.
Eyewitness identifications of individuals of different races other than the witness are, on average, less accurate than identification of individuals of the same race. This observation may contribute to the disproportionate number of the wrongfully convicted who are minorities compared to the prison population as a whole. In his book, "Judging Innocence," Brandon Garrett writes that 73% of individuals wrongfully convicted of rape and exonerated between 1989 and 2007 were black or Hispanic. A study by Wells (et al) in 1998 examined 40 cases where DNA exonerated wrongfully convicted people. In 90% of the cases, mistaken eyewitness identification played a major role. Huff, in 1987, studied 500 wrongful convictions and concluded that mistaken eyewitness identification occurred in 60% of the cases. This is an amazingly high number since eyewitness identification is important in only 5% of all trials.
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There are other estimator variables as identified by the Texas Innocence Network. They include:
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Age of the witness counts. The identifications by children and the elderly tend to be less accurate than those of adults.
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If a large number of people were present at the scene of the crime, the difficulty of identifying the perpetrator increases.
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With all things being equal, the longer the witness is exposed to the perpetrator, the more accurate the information will be.
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Identification of males by females or females by males tend to be less accurate than identifications by same sexes.
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When a witness views an individual in a different location away from the scene of the crime, it will be more difficult to identify him/her.
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The illumination or lay out of the crime scene can affect the witness ability to perceive, and therefore recall the identity of the perpetrator.
Dr. Paul Michel is an eyewitness expert specializing in eyewitness identification and eyewitness testimony regarding false identification and threat assessment. He is experienced as a doctor of optometry and a specialist police investigator who is qualified to give expert testimony and opinions on eyewitness identification. He feels that when false eyewitness identification is given, the results can be devastating. False identification may occur if the eyewitness is either confused or is deliberately dishonest. Honest confusion can occur when the vision is imperfect and reveals the fallibility of a human sense organ. Some eyewitnesses have been known to report that which is impossible for the human eye to visualize because there are finite limitations to human visual acuity. Yet, unbelievably, they are convinced that they have seen things beyond their capability.
However, under the right conditions vision eyewitness identification can be very accurate. Conditions that limit vision skills, in addition to those already mentioned by Dr. Michel include: movement, time constraints, distance and eye disease. Police investigators, generally, don't understand the significance of the visual environment under which witnesses made their identification. After all, they are police investigators and not vision experts. Insofar as lighting differences are concerned, Dr. Michel recommends that when videos or photos of the crime scene or suspects are provided the precise lighting level and patterns of lighting may be a major factor in determining the validity of the eye witness identification and therefore, should be documented. There are some situations where identification is likely to be more accurate. For instance, if the suspect is someone previously known to the victim or eye witness, then a high level of accuracy is more probable.
As more research is completed in the field of eye witness identification, no doubt more standards will be available to guide police officers during the questioning procedures of potential eye witnesses.
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