The vestibulo-ocular reflex (VOR) is a reflex eye movement that stabilizes images on the retina during head movement. It produces an eye movement in the direction opposite to head movement, thus preserving the image on the center of the visual field. Studies in fish and amphibians revealed a sensitivity in their VOR. They launched into space flight for 9-10, some with developing VOR's and others with already developed reflexes. The fish with developing reflexes developed an upward bend in their tails. The altered gravity resulted in a shift of orientation. Those who were already matured with the reflex were insensitive to the microgravity exposure.