Order effects and the evaluation bias in legal decision making.

Abstract

There has been intense interest in biases in legal decision making, such as order effects and evaluation biases (biases arising from making judgments, as opposed to just observing some information). We extend previous work in three ways. First, we employ a population sample including judges, prosecutors, and attorneys, as well as naïve participants, to investigate the extent of biases for legal professionals. Second, we use realistic materials, summaries of real legal cases. Finally, we study two biases, order effects and the Evaluation Bias, the latter being a bias corresponding to more extreme evaluations if a previous, oppositely valenced piece of information had been evaluated vs. just observed. Both biases were reliably observed across all groups of legal professionals and a group of lay participants; there was no evidence that different groups of participants displayed either of the two biases to a lesser extent. The presence of two, basic decision biases in a study involving realistic legal stimuli and with legal professionals raises questions about the robustness of decision processes in the legal system.