@rbassett @phonner See https://micromath.wordpress.com/2008/09/24/psychophysiology-of-blackboard-teaching/ (reposted at https://micromath.wordpress.com/2010/09/24/psychophysiology-of-blackboard-teaching-2/) whose first part is about why boards are better than Powerpoint presentations, but has some speculation at the end on why blackboard seem to work better than whiteboards:

> The following observation belongs to Israel Gelfand. Using chalk on a blackboard, we write by moving the entire arm. With felt markers on a whiteboard, we use smaller scale movements of fingers and the wrist. At a purely instinctive, physiological level, people tend to hold breath when they do small movements with their fingers. On the contrary, wider movements of arms fit naturally in the cycle of breathing and speaking. In mathematics teaching, we have to write on the blackboard and speak more or less simultaneously (although I take care to never speak “to the blackboard” and turn to face the audience every time I utter a word – but I do keep chalk pressed against the board, thus ensuring that I continue writing exactly from the spot where I stopped).

My feeling is that some matters may not be amenable to easy explanation, so things like this (whether students and teachers get better outcomes or more satisfaction) is best determined empirically (conduct experiments to actually measure somehow) rather than guess that “it cannot possible matter”.