The sweeter side of academics

Professors hoping for positive student evaluations at the end of the semester should look no further than leftovers from Halloween or the candy aisle of their local supermarket.

A recent study to be published in an upcoming issue of Teaching of Psychology Journal, found that students who eat chocolate before filling out a course evaluation may give their professor a higher rating than they otherwise would.

The study, entitled "Fudging the Numbers: Distributing Chocolate Influences Student Evaluations of an Undergraduate Course," was conducted by Cal State-Northridge psychology professor Robert Youmans and Benjamin Jee, a researcher at Northwestern.Their subjects were students in a lecture class that was also separated into two lab sections taught by the same teaching assistant.

To conduct the experiment, Youmans pretended to be administering course evaluations on behalf of the student government. For one section, he passed around a bag of mini Hershey bars and told students that they were leftover from a previous event. The other section, where students were given the course evaluation without any chocolate, served as the control group.

For each of the nine questions on the evaluation form, students who were offered chocolate rated their professor more favorably than students who were not offered chocolate.

"I was actually a little surprised," Jee said. "I was skeptical that we would get this result."

Youmans and Jee repeated the experiment with two other undergraduate classes and found similar results, with students who were offered chocolate averaging a rating of four while students in the control group averaged a rating of three. In total, the survey included 98 students.

Youmans noted that, logically, the sweets should not have swayed students' views. "The administrator of the evaluation was passing out chocolate, which of course should have nothing to do with the evaluation because it is in no way indicative of that professor," he said. "But it did, which is crazy."

The data from Youmans and Jee's study supports recent research that has questioned the reliability of student evaluations as indicators of teacher quality. It also lays new ground in showing how, exactly, that unreliability can manifest itself. Most previous research, Youmans said, has examined uncontrollable factors like the effect of race or gender on student perceptions of a professor.

Both researchers said they hope their study will spark heightened awareness of how student evaluations can be manipulated by outside factors. "We are not advocating that professors give out chocolate on the day they give an evaluation," Youmans said. But, he said, universities should examine student evaluations holistically and try to standardize the way they are conducted.

At Princeton, psychology professors weighed in with a range of possible explanations of Youmans and Jee's results.

"Giving people a small gift, including candy, makes them more cheerful," psychology professor Susan Fiske said in an email. "They then rate everything better right afterwards. There's a large research literature attesting to the ease of putting people in a good mood and mood's effects on ratings."

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On a chemical level, psychology professor Bart Hoebel noted, the ingredients in chocolate increase the brain's levels of dopamine and opioids — neurotransmitters that trigger feelings like enjoyment and motivation. "It's a combination of a food and a drug," he said.

Youmans and Jee's study has implications for Princeton, where student evaluations are taken into account when junior faculty members come up for tenure.

The evaluations, conducted anonymously at the end of a course, are tabulated through the Office of the Registrar. Any professor can see his or her own scores and comments.

Nino Zchomelidse, a tenure-track art history professor, said she would never use the method suggested in the study to sway pupils' assessments of her pedagogical skills. "I have never been afraid of [student evaluations] so that's why I would never give chocolate," she said. "It's like cheating on an exam, in a way."

Zchomelidse, who said she learned of the study through a colleague at another school, added that despite what it suggests about the arbitrary nature of professor assessments, she trusts the feedback she receives from Princeton students.

"Here, students are pretty responsible," she said. "They are very mature students, so it's not like ratemyprofessor.com or something."