Percy is injected with a drug that paralyzes his eye muscles. When he is instructed to try to move his eye when looking a stationary scene, he perceives
A) no movement, because his eye muscles can't move.
B) no movement, because the scene is stationary.
C) movement, because there is a CDS and an IDS.
D) movement, because there is a CDS, but not an IDS.

Question

Quizplus · Accepted Answer

Percy perceives movement because there is a corollary discharge signal (CDS) indicating an intention to move the eyes, but no image displacement signal (IDS) since the scene is stationary and the eye muscles are paralyzed. This mismatch leads to the perception of movement.

Percy Is Injected with a Drug That Paralyzes His Eye