The United States judicial system is ostensibly built on laws and hard facts. But new research lends weight to the trope that "justice is what the judge ate for breakfast."
A judge's willingness to grant a prisoner parole wanes with time after a lunch or snack break, according to an observational study.
Researchers from Columbia University in New York City and Ben Gurion University of the Negev in Beer Sheva, Israel, analyzed more than 1,000 parole decisions made during 50 days by eight experienced judges in Israel. The proportion of favorable rulings fell from about 65 percent to nearly zero during each session separated by the two food breaks, leaping back to 65 percent immediately after the breaks.
The findings, published today in the Proceedings of the National Academy of Science, suggest that prisoners whose cases were heard at the start of the day or soon after a break have an advantage over other prisoners, and that the rule- and fact-based judicial system is biased.
"It shows that experts are subject to psychological factors in their decisions just like anyone else," said study author Jonathan Levav, associate professor of business at Columbia Business School. "Judicial decision making is no different than human decision making. Judges are people."
Levav, an academic who studies sequential decision making, said he wasn't surprised by the findings. As a citizen, however, he hoped for different results.
"Of course, the disappointment I have as a citizen is greater than the enjoyment I have as an academic in this," Levav said. "You go looking for it because you think I might be there but, still, a part of you says, 'Wow.'"
Levav said the next step is to uncover the impact of the bias.
"If you appear after the break, you're much more likely to be released than someone later," Levav said. "So was the person seen after the break released too soon, or was the person seen before the break in prison too long?"
Both scenarios come at a cost, Levav said. A prisoner released too early might be more likely to recommit a crime. While a prisoner kept behind bars too long contributes to prison overcrowding and costs tax dollars.
"The next step would be to follow these prisoners over 10 years and see which ones are more likely to return to prison," Levav said.
The effects of hunger on mood and cognition have been studied before. People tend to rate their mood better after a breakfast high in carbohydrates. And low blood sugar is linked to poorer self control and can impact the ability to control attention, regulate emotions, cope with stress and resist impulsivity.
"That feeling of hunger is distracting. It can certainly affect your energy level and your ability to focus," said Lisa Cimperman, a registered dietician with University Hospitals Case Medical Center in Cleveland. "It's one more reason not to think on an empty stomach; one more reason to have frequent small meals."
But because the study by Levav and colleagues was observational, meaning not all variables could be controlled, the researchers can't directly link hunger to trends in judgment.
"When you don't run an experiment, it's hard to make a causal association," Levav said. "Ideally, we'd have an experiment where one judge takes a break and eats, and another doesn't eat."
Levav said it would be interesting to measure blood glucose levels.