How to measure if participants are keeping their head straight: Mantra?
For an experiment in Open Sesame, I need to ensure that participants keep their head straight (that is, not tilt it to the left or right, forward or backward is okay), because a tilted head could influence the visual bias I'm trying to measure. What would be the easiest way to do this in Open Sesame? AFAIK, standard eye-trackers don't output the location of the eyes themselves (they output the location of what a subject is looking at), but I might be wrong. I was told that Mantra is a tool that could do this, but I don't know how to integrate it within Open Sesame.
Thanks very much in advance,
Jasper de Waard