ABSTRACT
When a large visual display is observed rotating about the line of sight, it induces the sensation that the body is tilted, accompanied by an induced torsional rotation of the eyes in the opposite direction. We present three sources of experimental evidence showing that the magnitude of apparent bodily tilt can vary independently of the magnitude of the induced ocular torsion. Whereas visually induced tilt increases when observers perceive themselves to be rotating, increases when the head is tilted off the vertical, and is just as large when the rotating field stimulates central regions of the retina as when it stimulates peripheral regions, visually induced torsion increases when observers perceive themselves to be stationary, does not change when the head is tilted off the vertical, and is larger when the rotating field stimulates central regions of the retina than when it stimulates peripheral regions. These findings suggest that mechanisms underlying visually induced changes in perceived bodily orientation may be dissociated from mechanisms underlying visually induced changes in eye position.
