Law enforcement may ask people they suspect of committing a crime to participate in an eyewitness lineup. This process allows witnesses to identify the suspect from a line of individuals. Once the witness selects a person from the lineup, the prosecution presents that information in court.

However, there can be flaws in the identification process. Eyewitness testimony and identification can influence the verdict in a trial, which may result in sending an innocent person to jail.

Potential errors in lineup procedures

Several factors can alter the choices made during the eyewitness lineup process, according to the Innocence Project. Lineup administrators’ verbal and nonverbal cues may prompt witnesses to choose a specific person from the lineup. To resolve this, administrators should ideally have no prior knowledge of the details surrounding the case to prevent any undue bias.

Law enforcement departments should organize the lineup in such a way that several people match the perpetrator’s descriptions. For instance, if the perpetrator has a beard and tattoo, the lineup should have more than one person with those characteristics.

Finally, administrators should tell witnesses that the suspect may or may not be present in the lineup. Officers should also tape the entire procedure in case the judge or jury would like further review.

Environmental influences and memory

Environmental influences can affect a witness’s ability to select someone from a lineup. The journal Psychological and Cognitive Sciences lists the following issues as having a role in eyewitness misidentification:

  • The amount of time that has passed since the crime occurred
  • The amount of light at the crime scene
  • Whether the perpetrator wore a mask or face covering
  • Whether the perpetrator used a weapon
  • The distance between the witness and the actual crime

The limitations of human memory may also cause a witness to choose an innocent person from a lineup.