The Israeli parole judges study is a disturbing demonstration that decisions about liberty can be shaped by the judge’s physical state rather than by the merits of the case alone. Observing eight parole judges in Israel, the study found that approval rates rose to about 65 percent after meals and fell steadily during the following hours, approaching zero immediately before the next food break. The pattern connected hunger and fatigue with a retreat to the default position of denying parole.

Setting and Design

The participants were eight judges who spent entire days reviewing applications for parole. Cases arrived in random order, reducing the likelihood that the sequence itself explained the changing decisions. The judges devoted little time to each application—an average of six minutes—and the researchers recorded the exact time of every decision alongside the timing of the judges’ morning, lunch, and afternoon food breaks.

The institutional default was denial: only about 35 percent of parole requests were approved overall. Against that background, the timing pattern was especially striking. Approval did not remain roughly stable across the day. Instead, the proportion of favorable decisions spiked after each meal, when approximately 65 percent of requests were granted, and then declined during the roughly two hours before the next break.

The Decision Pattern

The study’s central finding was a steady fall in approvals as time since the last meal increased. Shortly after eating, judges were substantially more likely to grant parole; near the next meal, approvals fell to about zero. The same daily rhythm appeared around each of the judges’ food breaks, making the result more than an isolated fluctuation at one point in the schedule.

The researchers carefully examined alternative explanations because the implication was unwelcome. The most plausible account was that tired and hungry judges increasingly fell back on the easier default response—denying parole. Hunger and fatigue probably worked together: the judges’ legal authority and professional role remained unchanged, but the effort available for sustained evaluation did not.

Cognitive Mechanism

The study illustrates the vulnerability of System 2, the effortful mental process responsible for monitoring and controlling intuitive responses. When mental resources are strained, people are more likely to accept an immediately available answer instead of investing the effort required to examine a difficult case. In parole decisions, denial was not merely one option among many; it was the institutional default, so reduced effort could translate directly into fewer approvals.

This mechanism connects the study to broader evidence about cognitive depletion. In another experiment, participants first had to control their attention while watching a silent film and ignoring words moving across the screen. After this effortful task, those who drank a Splenda-sweetened beverage showed the expected increase in intuitive errors, whereas participants who drank glucose-sweetened lemonade did not show the same deterioration. The parole study extends the concern from laboratory performance to consequential decisions affecting whether people are released from prison.

Consequences and Significance

The study does not show that individual judges were careless or that particular parole applications lacked merit. Its force comes from the regularity with which an extraneous condition tracked the outcomes. A decision that appears to reflect a stable assessment of risk can vary with the interval since the decision maker last ate, while the decision maker remains unaware that hunger or fatigue is influencing judgment.

The result also exposes a tension between legal ideals and psychological reality. Rational decision procedures aspire to consistency: equivalent cases should receive equivalent treatment, and outcomes should depend on relevant evidence rather than on the clock or the judge’s last meal. Yet the study suggests that maintaining careful judgment requires resources that fluctuate during the day. The institutional default therefore becomes most powerful precisely when the judges are least able or willing to resist it.

Its broader lesson is methodological as well as ethical. High-stakes institutions cannot assume that professional expertise alone eliminates ordinary human limits. The timing of breaks, the structure of defaults, and the cognitive demands of reviewing many cases may all affect outcomes. By making the daily rhythm of parole decisions visible, the study turns an invisible source of inconsistency into an object of empirical scrutiny.