Eyewitness Testimony

When one is victim of or witness to a crime, it is expected that said person is brought into the police department to be questioned by the police. During this line of questioning it is possible that the victim or witness take part in suspect identification procedures. Such procedures include the use of lineups, showups, photo arrays and others. These procedures are referred to as system variables. These system variables are factors under the control of the investigators that have a demonstrated effect on the accuracy and reliability of eyewitness testimony. Examples of system variables that can influence eyewitness testimony include but are not limited to: statements made to eyewitnesses prior to and after lineups, instructions given to witnesses

Margaret Kovera, a leading authority in the research of lineup administrations, there are several verbal cues and non-verbal cues that can influence a witness’s decision making with regards to a suspect identification. As Dr. Margaret Kovera has a social psychology background, her research focuses more on the social interactions in lineups as opposed to the usual cognitive approach to studying eyewitness identification. In Dr. Kovera’s interview she discusses what is referred to as the experimenter expectancy effect whereby experimenters may behave in such a manner that influences the behaviours of the participants in a study to fit the hypothesis of the experimenter. This premise correlates with Dr. Garry Wells view of lineups being experiments and when conducting a lineup, we should aim to protect suspects against mistaken identifications by trying to minimize or eliminate the types of biases that we try to remove when we are conducting scientific experiments. As Dr. Margaret Kovera exemplifies in her interview, one of the biggest issues in lineup procedures that result in false identifications is the various sources of contamination introduced to the witness by the lineup administrator, which ultimately parallels with the experimenter expectancy effect. Sources of contamination can include steering behaviours conducted by the administrator such as tapping photos, asking questions such as “Are you sure?” or “look again”; really

Wells and C.A. Elizabeth Luus to maintain impartiality and the witness’s autonomy in his identification. First, it is recommended that witnesses should be separated as soon as possible to prevent the misinformation effect where information obtained post event, such as the perspectives of others, distorts and is falsely incorporated into memories. Secondly, it is imperative that the suspect is made aware that the witness is explicitly told that the suspect may or may not be present in the lineup. This is to ensure the witness does not feel compelled to select someone, or falsely believe that a suspect is guaranteed to be present. Third, the officer conducting the lineup should be independent of the investigation to prevent any personal or information induced biases towards any particular individual in the lineup. Fourth, if there is more than one witness, the position of the suspect in the lineup should be changed in each lineup so as to prevent communication of the suspects position between witnesses influencing identifications. Finally, it is recommended that no cues of any kind should be given to the witness concerning whether or not the identified person is the suspect in the case as doing so can