Recent advances in DNA testing have uncovered an alarming observation: innocent people are in prison and the guilty people that committed those crimes are at large. In the majority of the false conviction cases, faulty eyewitness identification is to blame. One standard police practice, showing witnesses mugshots of potential offenders (or people who may resemble them), accounts for some of these errors. This research identifies cases where the ability of an eyewitness to identify a perpetrator might be harmed or enhanced by the process of searching though a series of mugshots following the crime. Research has shown that witnesses who view mugshots may be less able to correctly identify the perpetrator of the crime. Moreover, witnesses can mistake individuals they view in a mugshot search for the perpetrator, even when subsequently presented with the actual perpetrator. From a memory and decision-making perspective, techniques are needed that avoid biasing a witness? memory, while at the same time aiding the police search for the culprit of the crime. This research includes an empirical exploration of the factors that produce lineup identification errors due to a prior exposure to a mugshot search and develops a formally-specified theoretical explanation for how these effects operate. In addition, new techniques designed to avoid these errors will be tested. This will allow us to develop better police practices for aiding a culprit search without harming the ability of the eyewitness to make an identification.
