In my research, I make use of the so called "eye tracking" method. That's a fairly new approach in education which makes use of the fact that the visual attention of a human is to a large extend guided by the "point of gaze". That means that we can draw conclusions about learning processes and learning material development by recording eye movements. This research is conducted in cooperation with the physics education research group at University of Göttingen, Germany.
We have made a video to show how this method looks like in practice:
If you are interested in knowing more about this method, share experiences or even in taking part in one of my studies, reach out to me.