Looks can be deceptive... who should have the vacant sign on their head?

If such a thing happened, you can be sure that this kind of direct biofeedback for your colleagues about your state of concentration would do a lot for making sure that you remained engaged in the proceedings of the meeting! You’d also be very focused on making sure that all of the knowledge and experience you had was focused in on the conversation that you were engaged in. Equally, you’d probably be listening intently, hearing what the other meeting attendees had to say, rather than simply waiting to speak! 

Now, in order to be engaged in the meeting, you probably need to be engaged by the meeting, so there’s a whole lot of stuff that needs to be done in order to set the meeting up properly and allow the talent present to be focused and constantly adding value. The recommendations for effective meetings, from a high performance point of view is probably for a later post. In the mean time, why not do some detective work and see how engaged you can be and how effectively you can help engage others in the meetings you attend. You might not hit 100% engagement in every meeting, but at least you can start monitoring and controlling the performance you deliver in relation to this very simple meeting performance marker!