Summary: Decision processes in simultaneous lineups (an array of faces in which a ‘suspect’ face is displayed along with foil faces) were examined using eye tracking to capture the length and number of times that individual faces were visually analysed. The similarity of the lineup target face relative to the study face was manipulated, and face dwell times on the first visit and on return visits to the individual lineup faces were measured. On first visits, positively identified faces were examined for a longer duration compared to faces that were not identified. When no face was identified from the lineup, the suspect was visited for a longer duration compared to a foil face. On return visits, incorrectly identified faces were examined for a longer duration and visited more often compared to correctly identified faces. The results indicate that lineup decisions can be predicted by face dwell time and the number of visits made to faces. Copyright # 2010 John Wiley & Sons, Ltd. Cognitive psychologists have long been interested in finding measures that can index the quality of a memory report. In the eyewitness memory field, several markers have been employed to assess the accuracy of lineup identification, including decision confidence (e.g. Brewer & Wells, 2006), description accuracy (e.g. Pigott & Brigham, 1985) and response speed (e.g. Sporer, 1994). These markers might one day enable the estimation of eyewitness identification accuracy in actual criminal cases. The cognitive processes at work during an eyewitness identification test might also be established by using such measures. In a simultaneous lineup, the person suspected by the police, who may or may not be the actual culprit, is presented alongside a number offoils (i.e. distractors that are known by the police to be innocent), and the eyewitness has to determine which one, if any, is the culprit. Currently, little is known about how participants allot their time in examining individual faces in a simultaneous lineup. Can the length of time that a face is examined at test index memory for the face, even when the eyewitness does not explicitly remember the face? Does the length and number of visits made to the faces in a lineup relate to differences in accuracy? The present study addressed these questions by testing participants with simultaneous lineups while their eye movements were recorded. Recently, researchers have begun to investigate decision processes in lineups using eye movements (Caspers, Betts, Chowdhry, Peterson, & MacLin, 2009; Flowe, 2010; Mansour, Lindsay, Brewer, & Munhall, 2009). We sought to replicate and extend these studies to further our understanding of cognitive processes in lineups. Lineup decision processes