The personal learning network for educators
That got me thinking about a system where students thought could be translated into signals, allowing the Teacher to see visually how engaged the students were.
It could replace the simple traffic light system for telling the teacher whether the work has been understood (Traffic Lights - Instant Feedback).
However, I would be worried by information overload and interpreting the wrong signals. Instant feedback from thought waves alone could lead to you adjusting your lesson unnecessarily as you react to one students arousal level. After all just because someone yawns in your lesson it does not mean that they are bored.
photo from flickr by Swiss Pavilion