Expert evidence in Mr. Big cases: Does it inform mock jurors' decision making

The Mr. Big technique is a type of undercover operation during which police officers pose as members of a criminal organization in order to infiltrate suspects' lives and gain their trust, over several weeks or months. The objective of the tactic is to elicit confessions from suspects, but the amount of deceit involved increases the risk of false confessions. To date, expert opinion testimony on the psychology of confessions in Mr. Big trials has been deemed unnecessary and has not been admitted. The present study was developed to determine whether the nature and source of commentary on the psychology of confessions could influence the decision making of mock jurors. Undergraduate students acting as mock jurors in a simulated Mr. Big trial read a trial transcript based on an actual case and completed questionnaires. The data indicated that expert witnesses can provide jurors with information that can assist their decision making.