“There’s an old trope that says justice is ‘what the judge ate for breakfast,’” writes Ed Yong on Discover Magazine’s “Not Exactly Rocket Science” blog — which is to say that “the law, being a human concoction, is subject to the same foibles, biases and imperfections that affect everything humans do,” biases like a bad mood or even breakfast.
Or make that lunch, writes Yong, reporting on a new study by Shai Danziger, an associate professor and chair of the department of management at Ben-Gurion University of the Negev. Danziger tracked the rulings of eight Israeli judges in 1,112 parole-board hearings over 10 months, and found that the chances of a prisoner being granted parole depended on the time of day that the judge heard the case.
Prisoners’ odds started out high in the morning, at about 65%, before reliably plummeting to almost nothing over the next few hours — a cycle of peaks and valleys that repeated itself throughout the day. Prisoners’ chances of parole leapt back up to 65% at two distinct times: right after the judges’ mid-morning snack and again after lunch.
The rulings Danziger analyzed accounted for 40% of Israel’s total parole requests, and the presiding judges weren’t newbies: they had an average 22 years of experience.
[T]he judges didn’t predict this effect when Danziger asked them, even though they are well aware of their own actions. The criminologists or social workers who sit on the parole boards hadn’t realized either. Jonathan Levav, who co-led the study, says, “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 thinks that the judges’ behavior can be easily explained. All repetitive decision-making tasks drain our mental resources. We start suffering from “choice overload” and we start opting for the easiest choice. For example, shoppers who have already made several decisions are more likely to go for the default offer, whether they’re buying a suit or a car. And when it comes to parole hearings, the default choice is to deny the prisoner’s request. The more decisions a judge has made, the more drained they are, and the more likely they are to make the default choice. Taking a break replenishes them.
In Israel, judges can’t pick the order of the cases they see, so it isn’t possible that they scheduled easy cases after breaks; and since they’re in charge of their own break schedule, prison staff can’t game their schedules either. (In U.S. Civil Court, by contrast, judges do schedule cases as they see fit, and often consider a case’s complexity in planning their day.)
It’s not entirely clear whether the food itself — and the bump in blood sugar and energy level that comes after eating — was the key factor in judges’ decision-making, or whether it had more to do with the simple act of taking a break, walking around and taking a mental rest. Danziger’s “choice overload” theory suggests the latter — and the phenomenon probably applies to lots of other circumstances including financial decisions, college admissions and job interviews.
Yong concludes by quoting Nita Farahany, a professor of law at Vanderbilt University:
“Such studies have helped inform policy changes designed to minimize human errors that arise from lack of sleep, and mental and physical exhaustion,” Farahany says. “That legal decision-makers might also be impacted by mental or physical exhaustion should be unsurprising. Improvements in medicine, military combat, and other critical decision-making contexts have required that attention be paid to the effects of exhaustion.”
The study was published online on April 11 by PNAS.