Cognitive bias and decision of the judge: an experimental investigation

Issue 4/2019

Abstract. In 2001, researchers Chris Guthrie, Jeffrey J. Rachlinski and Andrew J. Wistricliff who have been involved for almost twenty years in the study of the mechanisms underlying the decision-making process and of the many forms of distortion of thought likely to spoil judicial reasoning, have carried out a well known experimental study aimed at investigating the influence of some errors (so-called bias) in the reasoning of U.S. federal judges. The researchers in fact a sample of 167 federal magistrate judges in a series of five experiments in total, to verify the existence and effects of as many cognitive biases, among the best known in the literature of the time. The survey covered, in particular, (1) the bias of the anchorage, (2) the framing effect (3) the bias “of hindsight” or hindsight bias (4) the heuristics of the representativity(5) the egocentric bias. The analysis of the results obtained and the answers given to the tests showed that, during the experiment, most of the judges fell victim to one or more of the following cognitive biases , thus leading the researchers to conclude that “these cognitive illusions also affect the legal system’s most important and powerful actors: judges“^[1].

SUMMARY: 1. Introduction. – 2. The anchor. – 3. The framing effect . – 4. 4. Hindsight bias, or hindsight bias. – 5. The heuristics of representativeness. – 6. The egocentric bias. – 7. Conclusions.

To read the Reflection, click on “open file”.

^[1] C. Guthrie, J.J. Rachlinsky, A.J. Wistricliff, Inside the Judicial Mind, in Cornell Law Faculty Publications, Vol. 86, 2001, p. 787.