Effects of continuous exposure to high gravity on gravity preference in rats.

Abstract

Rats were chronically centrifuged in excess of 2.0 g for 6 or 12 mo. They were then given four 24-hr, gravity-preference tests in a spiral centrifuge in which they could adjust the gravity level imposed by locomoting inward or outward radially along a track. Chronically centrifuged rats (Group CC) spent as much time at 2,0 g as at 1.0 g while normally raised controls (Group NO selected only 1.0 g. Group CC initially selected 2.0 g and a preference for 1.0 g developed over the four test sessions. These results suggest that hypergravity is not necessarily an aversive stimulus and that gravity preference may depend initially upon the "reference level" involved. The ultimate selection of 1.0 g by chronically centrifuged animals suggests that a preference for a familiar gravity environment is replaced by a preference for low-gravity stimuli.

Effects of mere exposure on preferences in nonhuman mammals.

“…Some other stimuli have been studied, however. Among the more extreme operations that have been tried was that by McCoy and Jankovich (1972), who used a centrifuge to maintain rats at double the normal gravity for periods of either 6 or 12 months. The rats were subsequently tested in a centrifuge where they could choose their own gravity level, through the range from 1.0 to 2.0 g (g = gravity) by moving closer to the middle (1.0 g) or the outside edge (2.0 g).…”