CBS's 48 Hours recently covered a high-profile Texas murder case involving the death of Jessie Bardwell. Defense attorneys believed that allowing the defendant to tell his story would lead to an acquittal. To gauge jurors' reaction to the defendant's story, defense attorneys put on a mock jury trial. Having never done one before, the attorneys conducted the mock trial on their own using a single panel of jurors. After brief deliberations, mock jurors found the defendant not guilty.

Defense attorneys used the mock trial results to inform their trial strategy—deciding to put the defendant on the stand at trial to tell his story. This time, however, the jury found the defendant guilty of murder. He was sentenced to 50 years in prison.

How could mock jurors so clearly come out one way and the actual jury the exact opposite way? While there is no guarantee that a mock trial will mirror a jury's findings, what happened in the Bardwell case is a prototype of what NOT to do when conducting a mock trial.

Experimenter Effects

The Bardwell attorneys conducted their own mock trial. This can create demand characteristics. Attorneys go into a mock trial with a certain goal (e.g., a not guilty verdict). During the mock trial, jurors may form an interpretation of this goal and change their behavior to fit with that goal. The very short and uninformative Bardwell deliberations speak to the likelihood of demand characteristics.