News Release

How extraneous factors impact judicial decision-making

Study co-authored by Columbia Business School and Ben-Gurion University of the Negev faculty finds that the likelihood of being granted parole can be connected to judges' lunch and snack breaks

Peer-Reviewed Publication

Columbia Business School

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. "


About Columbia Business School

Led by Dean Glenn Hubbard, the Russell L. Carson Professor of Finance and Economics, Columbia Business School is at the forefront of management education for a rapidly changing world. The school's cutting-edge curriculum bridges academic theory and practice, equipping students with an entrepreneurial mindset to recognize and capture opportunity in a competitive business environment. Beyond academic rigor and teaching excellence, the school offers programs that are designed to give students practical experience making decisions in real-world environments. The school offers MBA and Executive MBA (EMBA) degrees, as well as non-degree Executive Education programs. For more information, visit

About Ben-Gurion University of the Negev

Created in 1969 with the mandate to bring development to the region, BGU is internationally-recognized for its unique pioneering spirit that combines outstanding academics and research with a commitment to the community. With more than 19,000 students, five Faculties and a number of internationally-acclaimed research institutes, the University has become a world leader in interdisciplinary research in cutting-edge fields that range from desert studies to nano- and biotechnology, Hebrew literature to international medicine.

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