A colleague, Jeff Rachlinski, alerted me to this news report of a study that detected a positive correlation between chocolate and more favorable professor ratings and course evaluations. The study's money-shot goes as follows: "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." More specifically, "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." (emphasis added) A few interesting particulars about the research design follow.
"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."
In addition to the finding that professor ratings from students receiving chocolate increased on every question, also notable was that a rating's boost was observed without attributing the chocolate to the professor. Just imagine the results if the professor bought and personally served students pizza.