Of all the life lessons that Tal D. Ben-Shahar ’96 taught his students in “Positive Psychology” this semester, yesterday’s might have been the most surprising.

When you are the instructor of an 856-student class and you find that the final exam is missing, run as fast as you can.

At 9:15 a.m., the students in Harvard’s largest course this semester packed seven lecture halls across campus, waiting to take their test.

At 10:15 a.m., they were still waiting.

Ben-Shahar attributed the lack of exams to his misunderstanding that the registrar—rather than course administrators—would photo-copy the final.

The mistake was discovered when Ben-Shahar and teaching fellows Jessica Glazer and Shawn J. Achor ’00 arrived at the Science Center to wish the students good luck—only to find the proctors empty-handed.

Harvard’s Xerox machines were already being used to copy today’s exams, so Ben-Shahar, Glazer, and Achor raced to Gnoman Copy to quickly print the 10-page final 1,100 times. When the exams finally reached students’ hands, the multiple choice questions were still warm.

“It was obviously a really stressful situation,” said Glazer, the head teaching fellow, last night. “I don’t think I’ve ever run that fast in my life, and I used to run cross-country. My face was beet red.”

The lessons of the course were put to the test during the mishap, and students performed swimmingly, Ben-Shahar said.

“I think the students were amazing. They were making jokes—they told me to give myself the permission to be human,” he said, referring to one of the main principles of the course.

Faculty of Arts and Sciences Registrar Barry S. Kane said that the University’s policy about Xeroxing exams “has always been clear and unambiguous.”

A handbook distributed to faculty and available online says “all courses are expected to handle the printing and photocopying of their own examinations.”

To make up for the delay, students were given a choice on the short-answer portion of the exam; they only had to answer 50 of the 65 points. Exam time was reduced from the traditional three hours to two.

“Really our main objective was to get all of the students out and finished in the time allotted. We understand that everyone is really busy,” said Glazer.

In an e-mail to the class after the exam, Shahar told students to contact him if they were worried that the delay had affected their performance on the exam.

“I have received some concerns and will take these into consideration so that the students will not be hurt by my mistake,” he said last night.

But though some students said they had been pressed for time, most took it in stride.

“I’m going to be honest. Any time you get the opportunity to take an exam that’s shorter than it was originally going to be, that’s nothing but positive,” said Raquel O. Alvarenga ’07, who used the extra hour to study after pulling an all-nighter.

“Some people studied, some people went to the Greenhouse. We live-blogged,” said Neeraj “Richie” Banerji ’06, who wrote on the Team Zebra blog that the class had “been a mad social experiment to the end.”

Banerji said he initially hoped that no exam existed and that the students, in fact, were the subjects of an experiment.

—Staff writer Natalie I. Sherman can be reached at nsherman@fas.harvard.edu.