Previous studies have shown that people are truth-biased in that they tend to believe the information they receive, even if it is clearly flagged as false. The truth bias has been recently proposed to be an instance of meta-cognitive myopia, that is, of a generalized human insensitivity towards the quality and correctness of the information available in the environment. In two studies we tested whether meta-cognitive myopia and the ensuing truth bias may operate in a courtroom setting. Based on a well-established paradigm in the truth-bias literature, we asked mock jurors (Study 1) and professional judges (Study 2) to read two crime reports containing aggravating or mitigating information that was explicitly flagged as false. Our findings suggest that jurors and judges are truth-biased, as their decisions and memory about the cases were affected by the false information. We discuss the implications of the potential operation of the truth bias in the courtroom, in the light of the literature on inadmissible and discredible evidence, and make some policy suggestions.
