When it comes to passing high-stakes oral exams, timing may be more important than students or professors realize.
A large-scale study of over 100,000 assessments at the University of Messina in Italy found that students were significantly more likely to pass exams scheduled around noon than those held in the early morning or late afternoon. The results, published July 24 in Frontiers in Psychology, suggest that internal biological rhythms—not just academic ability—may influence who succeeds and who fails.
Performance Peaks at Midday
Researchers analyzed 104,552 oral exam outcomes conducted between 2018 and 2020 and found a clear pattern: the likelihood of passing followed a bell curve, peaking around 12:00 p.m. The data showed that about 73% of students passed exams held at noon, compared to just over 50% for those scheduled at 8:00 a.m. or 4:00 p.m.
- Overall pass rate: 57%
- Highest pass rate: Noon (around 73%)
- Lowest pass rates: 8:00 a.m. and 4:00 p.m. (around 51%)
- No significant difference between 11:00 a.m., 12:00 p.m., and 1:00 p.m.
- Early morning and late afternoon pass rates were equivalent
“We show that academic assessment outcomes vary systematically across the day, with a clear peak in passing rates around midday,” said Prof. Carmelo Mario Vicario, lead author and director of the Social-Cognitive Neuroscience Lab at the University of Messina.
Could Job Interviews Be Affected Too?
While the study focused on academic settings, Vicario believes its implications may extend far beyond campus.
“We believe this pattern could extend to job interviews or any evaluative process scheduled throughout the day,” he said. “We would be very interested in investigating whether hiring decisions, too, fluctuate in fairness or outcome depending on time of day.”
Stress, Sleep, and Circadian Clashes
Oral exams at Italian universities are typically unscripted and intense, lasting between 10 and 30 minutes. Unlike standardized tests, they rely heavily on the professor’s real-time judgment. That subjectivity may open the door to unconscious biases influenced by circadian rhythms, mental fatigue, and even hunger.
“Oral exams… can be highly stressful due to their unpredictable nature and the strong weight they carry in academic progression,” Vicario explained.
The study also highlights an intriguing mismatch between student and examiner body clocks. While many university students in their 20s are natural night owls, faculty tend to be morning types. This misalignment may mean students are forced to perform during their cognitive low points while professors are at their most alert—possibly resulting in harsher assessments early in the day.
The Decision Fatigue Factor
Co-author Prof. Alessio Avenanti of the University of Bologna commented on the broader psychological implications of the findings.
“These findings have wide-ranging implications,” he said. “They highlight how biological rhythms—often overlooked in decision-making contexts—can subtly but significantly shape the outcome of high-stakes evaluations.”
Researchers also suspect that decision fatigue plays a role. Just as judges are more lenient after breaks, assessors may become stricter or less focused as the day drags on. A growing body of literature suggests that depleted mental energy can lead to harsher judgments or less flexibility in thinking.
What Can Be Done?
While the study couldn’t account for factors like individual sleep habits or stress levels, the implications are clear enough for institutions and individuals to consider changes.
Vicario suggested that students “might benefit from strategies like ensuring quality sleep, avoiding scheduling important exams during personal ‘low’ periods, and taking mental breaks before performance tasks.” He added that “for institutions, delaying morning sessions or clustering key assessments in the late morning may improve outcomes.”
More Questions Than Answers
Despite the robust data set, the researchers caution that more work is needed to uncover the exact physiological and psychological mechanisms behind the observed pattern. The team plans to investigate how factors such as mood, emotion, stress, and chronotype interact with cognitive performance over the course of the day.
“While we controlled for exam difficulty, we can’t entirely exclude other unmeasured factors,” said Prof. Massimo Mucciardi, the study’s senior author. “We encourage follow-up studies using physiological or behavioral measures to uncover the underlying mechanisms.”
Takeaway: Timing Isn’t Just Logistics
Whether you’re scheduling a university exam, a job interview, or a high-stakes meeting, this research underscores a simple but often overlooked truth: when something happens can be just as important as what happens.
And if you’re a student facing an oral exam, it might be worth aiming for that late-morning slot.
Journal: Frontiers in Psychology
DOI: 10.3389/fpsyg.2025.1605041
Publication Date: July 24, 2025
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