Sound Localization

One trick our brains use to figure out the location of a sound is to compare the time it takes to reach each ear. For example, sound waves emanating from a wind chime located to your right will reach your right ear a few milliseconds earlier than they reach your left ear, and the brain uses this small timing difference to compute exactly how far to your right the chime is located. Researchers have capitalized on this timing difference to test sound localization, using a special experimental trick known as the precedence effect: by playing the same sound, slightly separated in time, out of two loudspeakers located on either side of a subject, they produce the illusion that it is located to the left or the right. When older children or adults hear such a sound sequence—with, say, the right speaker preceding the left by several milliseconds—they perceive the sound as coming from the right. Newborns, however, fail miserably at the precedence effect. They are unable to use timing differences to calculate the location of a sound until about three or four months of age, when the cerebral cortex becomes fully engaged in the process. (But newborns can detect differences in loudness between the two ears, which is the cue they use to localize sounds in the horizontal plane.)


How the brain localizes the origin of a sound by calculating the difference in time between the soundwaves hitting one ear versus the other.

Folksonomies: senses sound localization hearing

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Sound (0.980341): dbpedia | freebase | opencyc
Brain (0.618367): dbpedia | freebase | opencyc
Ear (0.570244): dbpedia | freebase | opencyc
Cerebral cortex (0.528258): dbpedia | freebase
Human brain (0.516524): dbpedia | freebase
Hearing (0.458917): dbpedia | freebase
Sound localization (0.410007): dbpedia | freebase
Left-wing politics (0.367213): dbpedia | freebase | opencyc

 What's Going on in There? : How the Brain and Mind Develop in the First Five Years of Life
Books, Brochures, and Chapters>Book:  Eliot , Lise (2000-10-03), What's Going on in There? : How the Brain and Mind Develop in the First Five Years of Life, Bantam, Retrieved on 2011-07-18
Folksonomies: parenting babies development infants physiology