  We performed simultaneous recordings of electroencephalography (EEG) from
multiple students in a classroom, and measured the inter-subject correlation
(ISC) of activity evoked by a common video stimulus. The neural reliability, as
quantified by ISC, has been linked to engagement and attentional modulation in
earlier studies that used high-grade equipment in laboratory settings. Here we
reproduce many of the results from these studies using portable low-cost
equipment, focusing on the robustness of using ISC for subjects experiencing
naturalistic stimuli. The present data shows that stimulus-evoked neural
responses, known to be modulated by attention, can be tracked in for groups of
students with synchronized EEG acquisition. This is a step towards real-time
inference of engagement in the classroom.
