Visual Salience

http://www.scholarpedia.org/article/Visual_salience
coupled with biological motion.

In terms of the objects – what are the movements that trigger us to note a change – i.e. an asymetrical motion in an object that usually performs symmetrically.

In body language is it the abrupt gestures that turn our attention or is it a fluctuation of a familiar motion, regardless of the size or suddenness?