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sequential lineup is one of the two methods used for eyewitnesses to identify criminals in police station. In a standard sequential lineup, the suspects or their photos are presented one at a time to the witnesses only once. Witnesses make decisions about each individual suspect before the next one is shown and they do not know the total number of suspects.
History Although it is hard to pinpoint exactly when sequential lineups were first studied, the knowledge that simultaneous lineups often failed and convicted an innocent person has been common knowledge for many years. The advance of the popularity of sequential lineups can be traced to the Innocence Project and
Gary Wells. Wells has many studies that show that sequential lineups lead to fewer wrongful convictions. The early studies of sequential lineups found that there was a significant difference in the wrongful conviction of innocent persons. Since these early studies there has been a push to increase the accuracy of eyewitness memory even more. One way this is accomplished is by having not just sequential lineups, but also double-blind sequential lineups. A double-blind sequential lineup is conducted by making sure that neither the witness nor the person conducting the lineup has any idea who the suspect is. This eliminates any bias the person conducting the lineup may have. The research for double-blind studies has shown that "now we have proof from the field that witnesses who view double-blind sequential lineups are just as likely to pick the suspect, and perhaps more importantly, less likely to make a misidentification by picking a filler in the lineup." The study of sequential lineups is far from being finished and there is still much left to prove.
The New York Times reported that Wells will continue to "examine the data gathered to gauge the level of certainty of witnesses and the effect of factors like cross-racial identification on accuracy."
Sequential lineup laps A sequential lineup lap is showing the suspects repeatedly after the first round while in a standard sequential lineup eyewitnesses can only view them once. The thinking is that viewing the suspects again can increase the accuracy of identification since the eyewitnesses will be more certain about their answer. Research found that viewing the suspects once more has a large influence on witnesses' performance. Many witnesses moved from no-choice to choice, some changed answers and their confidence went up. Both correct identification rate and mistaken rate increased in a sequential lineup lap when the suspect was present; the error rate increased only when the suspect was absent.
US law While many states agree that sequential lineups can reduce wrongful convictions, they also notice that sequential lineups lead to more of a chance that the guilty would be overlooked and not convicted of their crime. Because of this many states do not want to implement a law that mandates sequential lineups. These states accept their benefits but do not want to rule out other types of lineup. There are different feelings about the advantages and disadvantages of sequential lineups. Gronlund, Carlson, Dailey, and Goodsell state one of the disadvantages: "Sequential lineups do not enhance accuracy but rather make eyewitnesses more conservative in their willingness to choose. Although this is desirable when the police have an innocent suspect, it is problematic if the police have a guilty one." But Lindsay, Mansour, Beaudry, Leach, and Bertrand show one of the advantages of sequential lineups estimating that with them between 570 and 1425 innocent people would not be wrongfully convicted that would be with simultaneous lineups. According to the Innocence Project website, many states and law enforcement agencies have started to implement the tools that would be necessary to run double-blind sequential lineups but have yet to fully embrace them. Brain L. Cutler and Steven D. Penrod conducted this study in 1988 to examine multiple variables' influence on eyewitnesses' accuracy during a lineup. The participants were first given a videotaped store robbery and a questionnaire, then asked to identify the robber in a photo lineup. They were given different videotapes, different lineups, and different instructions. There were 175 participants, all undergraduate college students. The results were: • Correct identification rate: 80% for sequential lineups and 76% for simultaneous lineups (total). • 78% for sequential lineups and 80% for simultaneous lineups when cues were strong. • 84% for sequential lineups and 58% for simultaneous lineups when cues were weak. Mistaken rate in target-absent condition: 19% for sequential lineups and 39% for sequential lineups. In this study, the correct identification rates were very much higher across all situations than normal. They also did not find a significant enough difference in correct identification rate between simultaneous and sequential lineups when the target was present. Most studies found that the correct identification rate is higher for simultaneous lineups. ;
Steblay, Dysart, and Wells (2011) They also replicated the findings that there is about a 22% difference between sequential and simultaneous lineups regarding errors in suspect identification; meaning that sequential lineups are less likely to identify the wrong suspect. == Interactive lineups ==