There are many steps and factors in a criminal case that all come together to ultimately produce a verdict of guilt of innocence for the accused. There are several stakeholders in a criminal trial, though the defendant probably has the most at stake, as a verdict can mean the difference between freedom and prison time, which can have lasting negative effects for a lifetime. Social psychology principles and research findings can be effectively applied to the criminal justice system, specifically to help improve how law enforcement officers conduct criminal investigations. A crucial part of the investigation that police strive to achieve is an eyewitness identification of a suspect; however, eyewitness bias and poor procedural steps can taint this process, resulting in false eyewitness identifications of suspects. By studying what procedures influence witness error and bias, eyewitness accuracy can be improved, which can lead to less false positive identifications.
In a criminal case, the prosecutor works closely with law enforcement to build their case; they try to prove the defendant’s guilt beyond a reasonable doubt, and the defense does all that it can to plant reasonable doubt into the minds of the jury. The case begins after a crime has been committed, and the steps that take place from there can all impact the final verdict of the accused. One of the most important pieces of evidence for the prosecution’s case against the defendant is a positive eyewitness identification, often done in police lineups. Unfortunately, false positive identifications do happen, and the repercussions of these errors can be devastating to those who are wrongfully identified. In 2016, the Innocence Project reported that of the 325 cases in which convicts have been exonerated by DNA evidence, 72% of those cases involved false positive eyewitness identifications; it is plain to see how much rests on the accurate identification of suspects by witnesses (Gruman, Schneider, & Coutts, 2017).
Many factors can affect the accuracy of a eyewitness’s identification, such as stress of witness at the time of witnessing the crime, the involvement of weapons in the crime, the timing of the identification of a suspect after the crime occurred, and the ability to see the suspect’s entire face at the time of the crime. Another factor that affect eyewitness accuracy is the “cross–race effect”, which describes the ability to recognize faces of people of one’s own race better than the faces of other races (Gruman et al., p. 304).
In addition to these factors, lineup procedures can have an enormous impact on eyewitness identification. The book of lineup guidelines which is widely used by law enforcement agencies in America, Eyewitness Evidence: A Guide for Law Enforcement, outlines specific procedures that, if followed, would greatly reduce witness identification errors. The guidebook recommends that all lineups should be sequential lineups, where individuals are shown to the eyewitness one a time, versus a simultaneous lineup, which is what we commonly see in movies—where the suspects are lined up all together in a row in one room. Of confronted with all suspects at once, the eyewitness may feel pressure to choose one, even in the face of uncertainty. Foils, or people whom the police know are innocent, should also be used—this reduces the risk of a false identification by the eyewitness. Eyewitnesses may be swayed by the input of others after they identify someone in a lineup, so their confidence level in their decision should be recorded immediately by law enforcement. Police officers sometimes knowingly bias eyewitnesses so that they may have a positively identified suspect; by putting a suspect in the room who is the only individual that matches the eyewitness’s physical description of the suspect, the chances of a positive identification are greatly increased.
Knowledge gained through social psychology research can be applied to the investigative processes in the criminal justice system in many ways. False eyewitness identifications of suspects can result in devastating outcomes, and also leaves the real criminals at large. Errors in lineups can be greatly reduced by following guidelines and procedures that minimize bias and maximize eyewitness accuracy.
References
Gruman, J. A., Schneider, F. W., & Coutts, L. M. (2017). Applied Social Psychology:
Understanding and Addressing Social and Practical Problems (3rd ed.). Thousand Oaks, CA:Sage. ISBN 9781483369730
Tags: criminal justice system