Abstract
Changes in the physical flutter rate of a clicking sound induce simultaneous changes in the apparent flicker rate of a flashing light. For example, for one observer a flicker with a frequency of 10 cycles per second was driven downward to as low as 7 cycles per second and upward to as high as 22 cycles per second by changing the rate of initially synchronous auditory clicks. The reverse does not occur—changes in the flicker rate do not induce changes in apparent flutter rates.