How extraneous factors impact judicial decision-making

BOSTON/NEW YORK – April 12, 2011 –A study by Columbia Business School Professor Jonathan Levav, Class of 1967 Associate Professor of Business, Marketing and Professor Shai Danziger, Chairperson, Department of Management, Guilford Glazer Faculty of Business and Management, Ben-Gurion University of the Negev and Liora Avnaim-Pesso , a graduate student of Ben-Gurion University of the Negev, recently featured online in the Proceedings of the National Academy of Sciences (PNAS), finds that a judge's willingness to grant parole can be influenced by the time between their latest break and their current hearing.

The team studied more than 1,000 parole decisions made by eight experienced judges in Israel over 50 days in a ten-month period. After a snack or lunch break, 65 percent of cases were granted parole. The rate of favorable rulings then fell gradually, sometimes as low as zero, within each decision session and would return to 65 percent after a break.

Professor Levav commented on the meaning of the study, "The evidence suggests that when judges make repeated rulings, they show an increased tendency to rule in favor of the status quo. This tendency can be overcome by taking a break to eat a meal, which is consistent with previous research that demonstrated the positive impact of a short rest and glucose on mental resource replenishment. However, food might not be the only factor; sometimes a mental break can yield a similar result."

The current study does not determine if it was the rest or the eating that altered the judges' decision-making processes. The mood of the judges was also not measured. Professor Danziger remarked, "However, the results do indicate that extraneous variables can influence judicial decisions, which bolsters the growing body of research that points to the susceptibility of experienced judges to psychological biases. "

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