According to a new study by Ben-Gurion University and Columbia University,
fatigue negatively influences the rulings of judges sitting on parole
Indeed, the study, published in the scientific journal
Proceedings of the National Academy of Sciences, found that judges are
statistically more apt to rule in favor of granting parole when
The researchers, Prof. Shai Danziger from BGU’s Faculty of
Business and Management, Columbia Business School Prof.
and BGU graduate Liora Avnaim-Pesso, studied more than 1,000 parole decisions
made by eight experienced judges in Israel over 50 days, in a 10-month
The researchers found that a judge’s willingness to grant parole
can be influenced by the time between their latest break and their current
“We test the common caricature of realism that justice is ‘what
the judge ate for breakfast’ in sequential parole decisions made by experienced
judges,” stated the researchers in their paper. “Our findings suggest that
judicial rulings can be swayed by extraneous variables that should have no
bearing on legal decisions.”
The researchers found that 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, but would return to 65% after a break.
“The evidence suggests
that when judges make repeated rulings, they show an increased tendency to rule
in favor of the status quo,” said Levav. “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 rest or eating that altered the judges’ decision-making processes. The
mood of the judges was also not measured.
“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,” Danziger said.
added that the reason they chose to examine parole boards is that it offers the
opportunity to witness and record multiple decisions in a short period of
“Had we gone to the district court, we also would have been able to
record decisions – but they come less frequently, and it is more difficult to
measure the parameters,” said Danziger.
“The theory determines that
decision-making capacity is a limited resource, and when many decisions are made
in sequence, the mental capacity diminishes.
“That’s when people start
using shortcuts and rely more on the status quo,” Danziger continued. “For a
judge, ruling to deny parole is the simpler decision. The prisoner is already in
jail, and that becomes the fallback position.
The harder decision – the
one that could end with a released prisoner committing a crime, and all the
fallout that goes with it – becomes less likely as mental fatigue wears
Danziger added that an alternative explanation for the findings –
which would suggest that the schedule for hearings is determined by the severity
of the offenses – was examined, and ruled out. He said the researches found the
hearing schedule was randomly fixed on a first come, first serve
“Moreover the parole-committee members themselves decide when to
take the break, so that rules out a rigged system,” Danziger
He added that similar findings were produced from studies of
consumers, indicating that “fresh” shoppers were more selective in their
choices, than those who had been at it for a while. “We are the first ones to
test the theory on professionals, though,” Danziger said.
interpret our findings through the lens of mental depletion, we do not have a
direct measure of the judges’ mental resources and, thus, cannot assess whether
these change over time,” he added. “Nevertheless, our results do indicate that
extraneous variables can influence judicial decisions – which bolsters the
growing body of evidence that points to the susceptibility of experienced judges
to psychological biases.
“Although our focus has been on expert-legal
decisions, we suspect the presence of other forms of decision- simplification
strategies for experts in other important sequential decisions or judgments,
such as legislative decisions, medical decisions, financial decisions and
university admissions decisions.”