The combination of eye and head movements plays a major part in our visual process. The neck provides mobility for the head motion and also limits the range of visual motion in space. In this paper, a robotic neck augmentation system is designed to surmount the physical limitations of the neck. It applies in essential a visuomotor modification to the vision-neck relationship. We conducted two experiments to measure and verify the performance of the neck alternation. The multiple test results indicate the system has a positive effect to augment the motions of vision. Specifically, the robotic neck can enlarge the range of neck motion to 200%, and influence the response motion, by overall 22% less in time and 28% faster in speed.