if you're exposed to a scene depicting two people different slightly in level of attractiveness or don't even if they differ not at all 00:13:32 and we measure eye movements then the more eye movements people that that we can find on a certain object it's not only true for faces also other objects but in phases particularly 00:13:44 and here you see the more red the more eye movements landed in the face of in this case a white person and this is a clear indicator that this person here found more beauty in the right than in the left face and that's very reliable

Eye tracking and head movement detection are widely investigated as alternative interface methods

It also provides the ability to control many devices by mapping the position of the head into control signals.