When Hearing Is Believing

Discusses how our senses influence each other according to Brandeis University psychologist Robert Sekuler. Views regarding the ways on how our senses influence each other; Sekuler and colleagues' test on the effect of sound on sight; Results of the test; Relationships of brain and our senses.

By Jill Neimark, published May 1, 1997 - last reviewed on June 9, 2016

Don't trust your eyes unless you've got earplugs in. Sounds can actuallychange what you "see," research reveals, and that news may impact everything from driving to philosophy.

Brandeis University psychologist Robert Sekuler, Ph.D., had long pondered the way our senses influence each other. "Taste is profoundly affected by smell," he notes. "And the eye can easily trick the ear, as ventriloquists know." But nobody had ever tested the effect of sound on sight. So Sekuler and colleagues designed an optical illusion on computer: Two disks approach each other, merge--overlapping perfectly for an instant--and move on. How does the eye interpret this dance--as two ships passing in the night, or two balls colliding and bouncing backward?

The answer It depends on the presence of sound. Sekuler found that "if there is a tone or click at the moment of collision, people see the disks bouncing off each other twice as often as when there is no sound at all." Are we actually seeing with our ears? No. We see the world with our brain, and at best that organ is merely a very good guesser, says Sekuler. "The retina takes a three-dimensional world and collapses it into signals. It sends those signals to the brain, which makes the best guess it can about what could have given rise to that information." Add a sound, and the brain instantly factors that into the mix.

Armed with this knowledge, Sekuler says driving safety could be improved if we stop blasting the radio and talking on the cellphone, and open the window a crack to hear other cars. As for more important matters--such as baseball--it might be fun to skew the odds by giving one team a set of earplugs and watching scores plummet as they try to play in a world gone silent.

CARTOON: 20/20 hearing? Deciphering the visual world may be a team effort between eyes, ears, and brain.