Much psychological research has been done on variables affecting the reliability of eyewitness identification. There are both estimator variables, problems with memory itself, and system variables, problems within the legal system’s process (Walker, 2013).
Estimator variables are completely out of control of the legal system. Common estimator variables include lighting, distance from suspect, and race (Walker, 2013). These factors can affect any part of the memory process (initial perception, decoding, storage, or retrieval) (Walker, 2013). Lighting and proximity will affect accurate perception and storage, for example. Race may affect accurate retrieval. It is more difficult, and less likely, for an eyewitness of a different race than the perpetrator to make an accurate identification (Walker, 2013). Typically, in an event where an eyewitness encounters a perpetrator the eyewitness is under a lot of stress. Studies show that this high stress results in lower accuracy in identifying a suspect. If a weapon is present the eyewitness may experience “weapon focus,” or when the ability of the eyewitness to recall details is reduced because his/her’s attention is on the weapon (Walker, 2013). It is also possible that an eyewitness, during the time between the crime and the retrieval of the memory may experience “unconscious transference,” or mistakenly believe that an innocent person they saw during the time of the crime is actually the perpetrator (Walker, 2013).
In contrast, system variables are in control of the legal system. Most commonly known to affect eyewitness identification is lineups. Instructions given to the eyewitness may affect accuracy in identification; such as instruction failing to include that the culprit may or may not be in the lineup (Walker, 2013). Studies show that eyewitnesses are less likely to identify an innocent person in a lineup without the culprit when they are told the suspect may or may not be in the lineup (Walker, 2013). Studies also show that the way the lineup is presented affects accuracy in eyewitness identification. Eyewitnesses are more likely to make an accurate identification if members of the lineup are presented one-by-one rather than all at once. This way, they are able to focus on one at a time rather than comparing and making a relative judgment (Walker,2013). Another system variable that affects the accuracy of eyewitness identification in lineups is whether the administrator is blind or not. When the administrator knows who the target suspect is, they may lead the eyewitness to choose who the administrator thinks is guilty (Walker, 2013). If an administrator gives positive feedback after an eyewitness makes an identification in a lineup, the eyewitness will likely report higher confidence in their choice (Walker, 2013). Finally, the participants in a lineup should match the general description given by the eyewitness. If only one person in the lineup matches their description, then the eyewitness will choose that person (Walker, 2013).
It is clear that there are limitations to eyewitness identification. It is important that this is known in the court system, particularly by judges and juries. Judges proved to be consistent with expert opinion 67% of the time (Houston, 2013). Specifically, judges were most consistent with expert opinion in regards to the effects of alcohol on the witness at the time of the crime. They also expressed knowledge that an eyewitness statement may have information from after the event (Houston, 2013). Judges expressed less knowledge regarding exposure duration, weapon focus, using police officers as witnesses, the effect of race, mug shot bias, and the relationship between confidence in memory and accurate testimony (Houston, 2013). A judge must provide a jury with instructions involving many things, sometimes including instructions on the evidence presented. 73% of judges believed that the limitations of eyewitness identification and therefore the reliability of eyewitness testimony, is common sense. 75% of these also said that expert witnesses are not required to explain common sense to the court (Houston, 2013). 61% of people (potential jurors) were consistent with expert opinion regarding the reliability of eyewitness testimony (Houston, 2013). Regarding the effects of alcohol consumption by the eyewitness and its affect on identification, 92% were consistent with expert opinion when asked in a multiple choice format, but only 62% when asked in response generation format (Houston, 2013). 49% of responses in multiple-choice format were consistent with expert opinion on weapon focus, but only 26% in response generation (Houston, 2013). This was consistent throughout the study; people were more consistent with expert opinion in the multiple-choice format than in the response generation format (Houston, 2013). This shows that judges and the public have comparable knowledge rates in regards to potential factors that can limit eyewitness identification and testimony. It is also evident that judges overestimate jurors in their knowledge of these factors of “common sense.”
The American Psychological Association has submitted two “friend of the court briefs” that support the need of the judicial system to scrutinize the weight of eyewitness testimony held in courts (Azar, 2011). The APA submitted the first brief in the case Commonwealth of PA v Walker, which was a Supreme Court case. Pennsylvania is one of the only states that does not allow an expert witness to testify on the limitations of eyewitness testimony (Azar, 2011). In this brief the American Psychological Association explains that juries do not understand the factors that can limit eyewitness identification such as stress, weapon presence, lighting, time exposure, and the length of time between the crime and when they are asked to make an identification (Azar, 2011).
The American Psychological Association submitted the second brief in Perry v New Hampshire. This case addresses whether in order to give due process, the courts must review the validity of eyewitness testimony that was given after improper, suggestive tactics (Azar, 2011). In New Hampshire, this review is only required if law enforcement uses improper tactics, but not if they use suggestive tactics. In this case, the eyewitness identified the perpetrator while the police were handcuffing him, but was unable to identify him from a photo lineup (Azar, 2011). The APA states that any suggestive tactics should be allowed to be questioned by using the extensive eyewitness research (Azar, 2011).
Those who are striving to reform eyewitness identification procedures are working under the assumption that these procedures will reduce the number of false identifications without the number of correct identifications being affected at all (Clark, 2012). According to data this is not true. While there are more false identifications of the innocent avoided, there are less correct identifications of the guilty. This reality makes changing policy more complicated (Clark, 2012). However, there is one procedure that is an exception to this: the showup vs lineup. In a showup, the witness is presented with one person to either say yes or no to. In a lineup, as discussed earlier, the witness is presented with multiple people to either identify one as the perpetrator or to not identify one at all (Clark, 2012). Research shows that lineups show higher correct identification rates and lower false identification rates than showups (Clark, 2012). This brings about the question, why would showups even be an option? Showups have a convenience when police identify a suspect shortly after the crime is committed (Clark, 2012).
In the past, eyewitness testimony has held a lot of weight in court. Research has shown that this should not be the case for a number of reasons. Finally, this research is being looked at in the court system to determine the reliability of eyewitness testimony. According to an article posted by ABC News, eyewitness testimony is losing its importance (Duara, 2013). Eyewitnesses aren’t automatically deemed unreliable, according to Gary Wells of Iowa State University, but cleaning up the procedures involving eyewitness identification can make it more reliable (Daura, 2013). In 2012 the US Supreme Court could have changed the national standard on eyewitness testimony in a case from New Hampshire, but instead delegated that to the states. Each state can choose to change laws on eyewitness testimony or to leave them the way they are (Daura, 2013).
A few states have made the choice to change eyewitness identification procedures. In Maryland, an eyewitness is required to state how confident they are in their identification, officers administering a lineup procedure must inform eyewitnesses that the criminal may not be in the lineup, and use “blind” lineup administrators who doesn’t know who the subject is. In Texas, agencies either have to adopt the Law Enforcement Management of Texas’ lineup guidelines, or submit a plan to adapt it to fit their budget or needs. Oregon and New Jersey have also begun to address changes in eyewitness identification procedures.
There is an overwhelming amount of research and opinion on the limitations of eyewitness identification as well as reform of eyewitness identification procedures. However, there is very little reliable argument about the positives of how much weight eyewitness testimony currently holds in the judicial system. Therefore, it is clear that eyewitness testimony both needs procedure reform to be more reliable as well as reduction of it’s importance in the court room. Juries and judges need to be informed on the limitations of eyewitness identification and therefore be made aware to take caution when considering eyewitness testimony. The evidence presented makes it clear that some limitations may be avoided through change of procedure, but it is important to take caution with these changes, as with most procedure changes, when false identifications are avoided correct identifications decrease as well. There is the other side of the limitation of eyewitness identification, which is memory. As discussed above, memory under certain circumstances does not have a high reliability. This means false identification is more likely due to memory. Clearly the evidence points to eyewitness testimony not holding so much weight in court.
Azar, Beth. "The limits of eyewitness testimony." American Psychological Association 42.11 (2011): 26. Print.
Clark, S. E.. "Costs and Benefits of Eyewitness Identification Reform: Psychological Science and Public Policy." Perspectives on Psychological Science 7.3 (2012): 238-259. Print.