Although boredom very rarely escapes the notice of those suffering from it, constructing a purely technical instrument for reliably recognising boredom in humans is currently rated as a non-trivial task.
But recently, a team from George Mason University, the University of North Carolina, the Georgia Institute of Technology and the Naval Research Lab, Washington, DC have between them devised a provisional system for doing just that.
Of the twenty-three undergraduates from George Mason University who were recruited as test subjects for the study, one was found to be an ideal candidate for boredom investigation. Researchers employed a 3-D optical flow tracking system to log head-drooping events of the subject as s/he watched a total of nine boring videos for a total of 22.5 minutes.
It was postulated that head-droop events (see graph above) would indicate boredom episodes in the test subject, and subsequent ratings of the videos by two judges (on a 7-point Likert scale) broadly confirmed this.
The paper ‘A preliminary system for recognizing boredom‘ was published as part of the Proceedings of the 4th ACM/IEEE international conference on Human robot interaction (2009)
 The work was supported by the US Office of Naval Research under funding document N0001409WX20173
 “The views and conclusions contained in this document should not be interpreted as necessarily representing the official policies of the U. S. Navy.”
 These results remain preliminary because of the single participant examined.