Visualizing the pulse of a classroom

Effective classroom teaching often requires an instructor to be acutely aware of every student. The instructor must rapidly look from student to student to catch fleeting gestures or facial expressions. To facilitate the tracking of communicative actions in a remote classroom, we built a multiparty videoconferencing system that automatically determine whether students are speaking, making gestures, or moving in their seats. These activity indicators are displayed over the video such that the instructor can see into the recent past. The activity indicators are also grouped into a visualization of the classroom interaction dynamics, thereby providing a measure of the pulse of the classroom.We conducted a user study where teachers used our system in a simulated class. The teachers found that the activity indicators to be a useful teaching aid during class; however, the indicators are most useful as a record of the class. In a student survey, we found that if audio, video, or activity indicators must be recorded, students overwhelmingly prefer activity indicators since the indicators mask the content of the communication and thus are less intrusive to the students' privacy.