There’s an old trope that says justice is “what the judge ate for breakfast.  It was coined by Jerome Frank, himself a judge, and it’s a powerful symbol of the legal realism movement. This school of thought holds that the law, being a human concoction, is subject to the same biases and imperfections that affect everything humans do.

We, humans, would suppose that judges are rational and deliberative, making decisions on hard evidence and under written laws. In reality, they can be influenced by irrelevant things like their moods and, as Frank suggested, their breakfasts.

Shai Danziger – a neuroscientist from Ben Gurion University of the Negev – had been spending a period of ten months observing the results of 1,112 parole board hearings in Israeli prisons. Each of the eight observed judges had an average of twenty-two years of experience.

Every day, each judge considered between 14 and 35 cases, spending around 6 minutes on each decision. They took two food breaks that divide their day into three sessions. All of these details, from the decision to the times of the breaks, are duly recorded.

Danziger found something quite puzzling: if the case was assessed by a judge just after he had eaten breakfast, the prisoner had a 65% chance of getting parole. But as time passed through the morning, and the judges got hungry, the chances of parole gradually diminished to 0%. Only After the judges have returned from their breaks, the odds abruptly climb back up to 65% to decrease back to 0% over the course of the afternoon.


A prisoner’s fate could hinge upon the point in the day when their case is heard.

The judges were oblivious to this astonishing bias in their deliberations. Criminologists and social workers were also unaware of it. Why? Because it had never been analyzed. As one of the co-authors of the study put it: “There are no checks about the judges’ decisions because no one has ever documented this tendency before. Needless to say, I would expect there to be something put into place after this.”



  • Danziger S, Levav J, Avnaim-Pesso L. Extraneous factors in judicial decisions. Proceedings of the National Academy of Sciences of the United States of America. 2011;108(17):6889-6892. doi:10.1073/pnas.1018033108.
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