Confirmation Bias in Criminal Investigations

Abstract

Confirmation bias is the tendency to bolster a hypothesis by seeking consistent evidence while disregarding inconsistent evidence. In criminal investigations, preference for hypothesis-consistent information could contribute to false convictions by leading investigators to disregard evidence that challenges their theory of a case. Two studies examine factors that influence confirmation bias in criminal investigations. In study 1, participants (N = 108) who stated hypotheses early in their review of a mock police file showed bias in seeking and interpreting evidence. In study 2 (N = 109), asking participants to consider why a hypothesis might be wrong remedied bias, but asking them to generate additional hypotheses did not. Implications for improving accuracy of investigations and suggestions for future research are discussed.

Keywords: confirmation bias, false convictions