By Dr. Ken Broda-Bahm:
The way trial and deposition testimony works is that you hear from one witness at a time. We have individual testimony, we don't have group testimony. Or do we? Is there a chance that when we are hearing from the individual, we are hearing a message that has already been formed and filtered in reference to a group's perceptions and opinions? New research shows that the answer might be, "Yes." Based on a release from the University of Huddersfield carried in ScienceDaily, Dara Mojtahedi, a lecturer in forensic psychology, finds support for a phenomena he calls, "co-witness familiarity on statement similarity." What that means is that we are influenced, sometimes decisively, by our reference groups, and that influence leaks into testimony. "It is human nature to give added credence to the views of family and friends," he writes, "but this could lead to inaccurate eyewitness statements in court cases."
The research focuses on the reliability of eyewitness testimony, something that tends to matter more in criminal than civil cases, but one can easily see how the implications apply to witness testimony in general. Mojtahedi took 420 participants and formed them into groups including people who had known each other for three months or more. The participants then watched a video showing a real-life fight breaking out. Then they either gave individual accounts on who was to blame, or they were allowed to confer before giving accounts. The findings showed that the discussions after the event significantly increased the similarity of the resulting accounts. In other words, after conferring, the witnesses were on the same page, sometimes in inaccurate ways. Reporting research showing that in actual trials, eye witnesses know each other around 85 percent of the time, Mojtahedi reasons that this familiarity leads to less skepticism and greater confidence, which in turn allows incorrect perceptions to be repeated and magnified. In this post, I will take a look at what this effect has to say about witness examination and witness preparation.