Symmetry breaking in the class room

In a dialog between Profs. Patrick Henry Winston and Gerry Jay Sussman on Winston's blog entry on Slice of MIT, Sussman proposes that the first day of classes is determining the mood of the class in the lectures to come. He argues that all students like to be like everyone else and collectively tune in (or not) into the lecture.

"The students don’t realize it, but they all want to be like everyone else, so on the first day of class, they are all sensing the overall mood. Within a few minutes, the symmetry breaks spontaneously, and the class falls into a fixed state."

He therefore suggests to bring graduate students and UROP students to the first lecture to nod approvingly and laugh about jokes to increase the likelihood that the student collective falls into a positive mood.  I know from my own experience that the first few minutes of a speech (both at conferences and private venues) will determine the reception of the audience; the observation that this phenomena can extend over an entire class period is intriguing.

Although the article does not discuss the benefits of a positive atmosphere in class - at first sight there should be no correlation between reaching the learning goals and whether the students think the instructor's jokes are indeed funny - I believe that this positive atmosphere will contribute to lower the threshold of students actually asking questions, being attentive, and consequently improve their learning experience.