Credibility Contests: The Elephant in the Room

Abstract

The primary duty of a court is to do justice. Implicit in this process is the principle that the court should assess the evidence in accordance with current scientific knowledge. Trials by ordeal and combat have long since been abandoned as it was recognised that they did not produce reliable, just outcomes. The law moved with the times. In criminal cases juries are directed that they can only convict ‘if they are sure’. The jurors might be sure, but are they correct? There now exists a substantial body of scientific evidence, which indicates that humans are very poor lie detectors, in fact performing at around chance. Given this incongruity in the system, is it not time to re-evaluate how cases are put before the courts, and what weight is placed on oral testimony? This is particularly acute in ‘credibility contests' where, it is argued, it is usually unsafe to convict.