Fixation behavior in observation and imitation of human movement.

This paper describes experiments performed with 40 subjects wearing an eye-tracker and watching and imitating videos of finger, hand, and arm movements. For all types of stimuli, the subjects tended to fixate on the hand, regardless of whether they were imitating or just watching. The results lend insight into the connection between visual perception and motor control, suggesting that: (1) people analyze human arm movements largely by tracking the hand or the end-point, even if the movement is performed with the entire arm, and (2) when imitating, people use internal innate and learned models of movement, possibly in the form of motor primitives, to recreate the details of whole-arm posture and movement from end-point trajectories.