At noon, when students took oral exams, the study found

When it comes to high-risk oral exams, timing may be more important than what students or professors realize.

A large-scale study of more than 100,000 evaluations by the University of Messina, Italy found that compared with the exams held in the early morning or in the afternoon, the possibility of planning to pass the exam around noon is much higher. Results were held on July 24 Field of Psychologysuggesting that internal biological rhythms (not just academic competence) may affect who succeed and fail.

Performance peak at noon

The researchers analyzed the results of 104,552 oral tests conducted between 2018 and 2020 and found a clear pattern: the likelihood of passing through the bell curve peaked around 12:00 pm, and the data showed that about 73% of students passed the exam held at noon, compared to more than 50% of the planned 8:00 AM or 4:00 PM at 4:00 PM

• Overall pass rate: 57%
• Maximum pass rate: noon (approximately 73%)
• Minimum pass rate: 8:00 AM and 4:00 PM (approximately 51%)
• There is no significant difference between 11:00 am, 12:00 pm and 1:00 pm
• Morning and afternoon pass rates are equivalent

“We show that academic evaluation results throughout the day vary systematically, with a significant peak in passing around noon,” said Professor Carmelo Mario Vicario, chief author and director of the University of Messina’s Social Cognitive Neuroscience Laboratory.

Will the interview be affected?

Although the focus of this study is on the academic setting, Vicario believes that its implications may go far beyond campus.

“We think this model can be extended to any assessment process that is scheduled for a job interview or scheduled throughout the day,” he said. “We will be very interested in investigating whether the hiring decision also depends on the time of day or outcome.”

Stress, sleep and circadian rhythm conflict

Oral exams at Italian universities are usually scriptless and intense, lasting 10 to 30 minutes. Unlike standardized tests, they rely heavily on professors’ real-time judgments. This subjectivity may open the door to unconscious biases affected by circadian rhythms, mental fatigue and even hunger.

“The oral examination … can be highly stressed due to its unpredictable nature and the strong weight of academic progress,” explains Vicario.

The study also highlights a fascinating mismatch between the body clocks of students and inspectors. Although many college students in their 20s are natural night cats, faculty and staff tend to be in the morning type. This misalignment may mean that students are forced to perform during cognitive lows, while professors are on the most alert, which may be more rigorously evaluated early in the day.

Decision fatigue factors

Co-author Professor Alessio Avenanti of the University of Bologna commented on the broader psychological implications of these findings.

“These findings have broad implications,” he said. “They highlight how biological rhythms, often overlooked in decision-making settings, can significantly impact the outcomes of high-risk assessments.”

Researchers also suspect that decision fatigue plays a role. Just as the judge is more lenient after a break, the assessor may become more stringent or more focused as the day is delayed. A growing body of literature suggests that exhausted psychological energy can lead to stricter judgments or less flexibility in thinking.

What can be done?

While the study cannot explain factors such as individual sleep habits or stress levels, its implications are sufficient to allow institutions and individuals to consider changes.

Vicario advises that students “may benefit from strategies to ensure high-quality sleep, avoid scheduling important exams during individuals’ “low” periods, and take mental breaks before performance tasks.” He added: “For institutions, delaying morning meetings or performing cluster critical assessments in the early morning may improve outcomes.”

More questions than answers

Although the dataset has a strong dataset, the researchers warn that more work is needed to uncover the exact physiological and psychological mechanisms behind the observed patterns. The team plans to investigate how factors such as emotional, emotional, stress, and time-type interact with cognitive performance over the day.

“Although we control for exam difficulties, we cannot completely rule out other unmeasured factors,” said Professor Massimo Mucciardi, senior author of the study. “We encourage follow-up studies that use physiological or behavioral measures to uncover potential mechanisms.”

Key points: Time is not just logistics

Whether you are scheduling a college exam, a job interview or a high-risk meeting, this study highlights a simple but often overlooked fact: When something happens, what happens is as important as what happens.

And, if you’re a student facing a dental exam, it might be worth targeting that morning slot machine.

Magazine: Field of Psychology

doi: 10.3389/fpsyg.2025.1605041

Publication date: July 24, 2025

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