False Identification and Biased vs. Unbiased Lineup Instructions

Introduction: Eyewitness Misidentification and Wrongful Convictions

There are many instances where people have been wrongly accused because they were falsely identified, or because there was not enough evidence to prove them guilty. George Allen Jr. was convicted in 1983 on charges of capital murder, rape, sodomy, and first-degree burglary. The reason for his false conviction has been attributed to a false confession, invalid or improper forensic evidence, and government misconduct (Innocenceproject.org, 2013). Another case is that of Barry Gibbs, who was charged with second-degree murder in 1988. He was wrongly charged due to eyewitness misidentification and government misconduct. Barry Gibbs served 17.5 years in prison before he was exonerated in 2005 (Innocenceproject.org, 2013).

These cases illustrate that eyewitness misidentification is a significant cause of wrongful convictions across the country and around the world. It has been argued that eyewitness identification is often unreliable because the human mind does not function like a tape recorder — it cannot remember or recall events exactly as they occurred. Even though eyewitness accounts may seem like reliable evidence, several factors can render them inaccurate.

Given that crime is increasing worldwide, eyewitness identification plays an important role in identifying the guilty. Yet even when eyewitness testimony has led to conviction, that conviction may have been false. With the advent of improved forensic techniques such as fingerprinting and DNA testing, many people have since been exonerated. Research has shown that the confidence and retrospective reports of eyewitnesses vary depending on how jurors and investigators handle them (Wells, Olson, and Charman, 2002). Many factors have been found to affect eyewitnesses' responses, and these identification responses appear to vary according to the ease and bias of the questioning they encounter.

Although eyewitness testimony has helped solve crimes in some cases, the phenomenon has also contributed to considerable injustice worldwide. It is widely considered an unreliable and easily biased form of evidence (Brandon and Davies, 1973). Sobel, Vogelman, Ruoff, and Pridgen (2011) argued that identification is one of the major determining factors in jury verdicts, viewing eyewitness statements as the most persuasive kind of evidence. It should be noted that two kinds of errors can occur in this process. Malpass and Devine (1981) observed that a witness can either wrongly accuse another person or fail to identify the correct person. When presented with a lineup of possible offenders, witnesses may choose the wrong person or state that they do not recognize anyone. In either case, the outcome is that either the guilty party goes uncharged or an innocent person is accused of a crime they did not commit.

Fallible eyewitness testimony thus puts the entire concept of criminal justice at risk. Two categories of variables have been identified as reducing the accuracy of eyewitnesses: estimator variables and system variables.

Estimator Variables in Eyewitness Accuracy

Estimator variables are tied to the actual crime that took place. They are linked to the crime itself, the perpetrator, and the witness, and they cannot be changed after the fact (Wells, 1978). The amount of time a witness was exposed to the relevant stimuli is particularly important. Loftus (1972) stated that picture recognition is a monotonically increasing function of exposure time. Lack of familiarity with the size or distance of surrounding objects can also greatly distort a witness's estimate of the perpetrator's size, distance, and speed (Grether and Baker, 1972).

It should also be noted that a witness observing a crime as it unfolds may be in a highly traumatized and panicked state. Research has shown that witness accuracy decreases as the severity of the crime increases (Leippe, Wells, and Ostrom, 1978). Conversely, when a crime is more complex, the recognizability of details — and ultimately accuracy — may also increase (Loftus, 1972). Johnson (1984) argued that there are greater chances of false identification when the offender involved in the crime is of a different race than the witness; in other words, accuracy tends to be higher in same-race identifications. Furthermore, the degree of stress experienced by the witness may also alter identification accuracy (Christianson, 1992).

Eyewitness confidence is another important concern, since false identifications would be far less consequential if witnesses did not express such high confidence in them. The relationship between identification accuracy and the confidence expressed by a witness has long been a subject of research interest. It has been suggested that overall confidence expressed immediately after a positive identification can serve as a useful guide for investigators regarding how accurate the identification might be. However, Smith, Kassin, and Ellsworth (1989) found that confidence is not a reliable predictor of identification accuracy, and that an investigator cannot guarantee the accuracy of any statement solely on the basis of a witness's expressed confidence.

System Variables and Lineup Instructions

System variables are factors under the control of the criminal justice system (Wells, 1978). The retention interval is particularly important because memory tends to decay over time; research has shown that with longer time delays, witness accuracy diminishes (Lipton, 1977). System variables also include the manner in which law enforcement agencies retrieve and record information from witnesses (Loftus and Palmer, 1974).

A critical system variable is the nature of the instructions given to witnesses before they make their selection from a lineup. The framing of these instructions has been shown to be a major factor in influencing a witness's choice. Buckhout et al. (1975) compared eyewitness lineup performance following biased and unbiased instructions. Biased instructions tended to convince witnesses that the offender was present in the lineup, whereas unbiased instructions gave witnesses a clearer sense that the offender might not be present. Malpass and Devine (1981) conducted a study in which eyewitnesses to staged vandalism received different lineup instructions under conditions in which the offender was either present or absent. Under biased instructions, witnesses were implicitly required to choose someone. Under unbiased instructions, a "no choice" option was explicitly provided. The results revealed that identification errors increased under biased instructions whether the offender was present or absent. Under unbiased instructions, eyewitnesses sometimes produced false results by rejecting the entire lineup even when the offender was actually present (Malpass and Devine, 1981).

Research Hypotheses

The following four hypotheses regarding witness identification were tested in this study:

H1: Identification confidence will be higher following an easy event memory test than following a more difficult one.

H2: False identifications will be more likely following an easy memory test than following a more difficult one.

H3: Identification confidence will be higher when lineup instructions are biased compared to when they are unbiased.

H4: False identifications from a thief-absent lineup will be higher when instructions are biased than when instructions are unbiased.