More Problems with Criminal Trials: The Limited Effectiveness of Legal Mechanisms

This article follows in the heels of an article entitled The Limited Diagnosticity of Criminal Trials. That article applied a body of experimental psychological research to examine how well juries and judges perform the diagnostic function of distinguishing between factual guilt and innocence. It concluded that fact finders encounter numerous difficulties in drawing correct inferences from the evidence presented at trial. This article examines a number of mechanisms that are said to promote the accuracy of the fact finding task: cross-examination, jury instructions, jurors’ assurances of impartiality, the prosecution’s heightened burdens of proof, jury deliberation, and judicial review by appellate or post-conviction courts. This examination concludes that to a limited extent, these mechanisms do indeed enhance diagnosticity, but they often turn out to be ineffective, and even detrimental to the process. It follows that the truth evincing potential of criminal trials is not as strong as generally believed.