Science Image (IMAGE) Salk Institute Caption During a traditional lineup, eyewitnesses are either shown six photographs of individuals at the same time (simultaneous lineup) or presented one picture at a time (sequential lineup). The paired comparison (PAR) method asks the eyewitness to choose the picture that is more similar to the culprit when shown two photographs at the same time. A technique called signal detection analysis is then used to reveal the structure of the witness's recognition memory and eliminate unconscious bias. Credit Gepshtein et al., <i>Nature Communications</i>. <a href="https://creativecommons.org/licenses/by/4.0/" <a target="_blank" href=>CC by 4.0</a> Usage Restrictions with credit and related coverage. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.