Working in Movement

I loved ventriloquist acts when I was a kid. Edgar Bergen and Charlie McCarthy; and Paul Winchell and Jerry Mahoney were favorites. But with later acts, it almost seemed to me that the dummy was the real brains of the operation and actually supplied the voice of the ventriloquist. New research into vision and hearing suggest that the illusion can work both ways.

The brain gets information from the senses--vision, hearing, touch, smell, taste and my favorite, proprioception or kinesthesia. These senses work pretty well, for the most part, with some notable exceptions for nervous system disorders and that sort of thing. But then there are everyday illusions that trick our sensory system. One of the most delightful of these illusions is ventriloquism where the voice seems to come from a wooden dummy instead of the performer actually supplying it.

Ventriloquism relies on using the eyes to fool the ears, at least as far as where the dummy's voice is coming from. It turns out that the retina is attuned to the direction of light that enters it, but the auditory mechanism is not similarly as sensitive to direction of sound. By focusing your eyes on the dummy, it appears that the sound is coming from those wooden lips. It also works this way in movie theaters where the sound of the actors voices comes from speakers that aren't placed on the screen image of the actor's mouth moving. So vision tends to be primary when figuring out the direction of the source of sound.

Some researchers in Italy have turned this on its head. Reverse ventriloquism on Nature Science Update has the details of the the University of Florence study that pulled off the illusion of reversing the role of the eyes and ears.

You know, come to think of it, there was that Twilight Zone episode where the dummy took over the act. Maybe it's not so far fetched after all.