Can You Hear Me Now?
Research Shows Each Ear Process Different Types of Sound
Thursday, September 09, 2004
By Kelli Miller, WebMD Medical News
Does it seem like your kids or spouse turn a deaf ear every time you talk to them? You may be choosing the wrong ear to shout in.
New research suggests that the right and left ears are not created equal; each one processes different types of sounds. The right ear is better for processing speech sounds, according to a report in the Sept. 10 issue of Science.
"Behaviorally, reaction time is faster and stimulus identification is more accurate when a subject's right ear is presented with speech-type stimuli," write co-authors Yvonne S. Sininger of the University of California, Los Angeles, and Barbara Cone-Wesson of the University of Arizona.
When we hear a sound, tiny hair cells in our ears amplify the noise, causing vibrations that are converted into signals the brain can understand. For the study, Sininger and Cone-Wesson examined how hair cells in babies' left and right ears responded to certain noises. Clicks represented speech; tones resembled music.
The researchers conclude that the right and left ears of infants have unique hearing capabilities. Specifically, the left ear responded more strongly to tones, and the right provided more amplification for speech-like stimuli.
Scientists have long known that the two sides, or hemispheres, of the brain process sound differently. The left side of the brain -- which controls the right ear -- dominates in deciphering speech, while the right side of the brain -- which controls the left ear -- leads in processing music-like sounds. Previous research has assumed that cellular discrepancies in each brain hemisphere were responsible for the differences in sound processing.
The findings suggest that the differences begin in the ears and serve to help the brain hemispheres specialize in sound processing.
"We always assumed that our left and right ears worked exactly the same way," Sininger says in a news release. "As a result, we tended to think it didn't matter which ear was impaired in a person. Now we see that it may have profound implications for the individual's speech and language development."
Source: Sininger, Y. and Cone-Wesson, B. Science, September 2004; vol 301.