On Wed, Aug 6, 2014 at 9:00 PM, Charles Z Henry <czhenry@email-addr-hidden> wrote:
> On Tue, Aug 5, 2014 at 8:54 PM, Ralf Mardorf
> <ralf.mardorf@email-addr-hidden> wrote:
>> With my left ear I'm able to hear some frequencies or at least one
>> frequency at very low volumes I'm unable to hear with my right ear, so
>> technically it's my better ear, but with my right ear understanding the
>> content of speech and music is easier to do. Perhaps "content of music"
>> isn't a good phrasing, but similar to the content of speech, there's a
>> difference for the perception of music by comparing my left with my
>> right ear/hearing that seems to be independent of the technical ability
>> of hearing. Wit/reason is interacting different with perception from the
>> left and right ear.
>>
>> JFTR my hearing with both ears is ok, there isn't a difference regarding
>> physical health of the ears. Regarding the brain, I'm right-hander, but
>> dyslexic. Being a left-hander or dyslexic seems to have impact to
>> artistically mind.
>>
>> When mixing music I not only switch between stereo and mono, but I also
>> change the left and right channel.
>>
>> I wonder how clearly the difference between left and right ear
>> perception/understanding is for others?!
>>
>> Regards,
>> Ralf
>
> What you're describing is the right-ear advantage for perception of
> speech. This occurs among people with strongly left-hemisphere speech
> function lateralization. I think it's a relatively small effect size
> (the variance is large by comparison and experiments require a large
> number of subjects to get enough experimental power).
>
> Not all people have left-hemisphere speech lateralization, although it
> is the most common (and strongly wired from birth). A fewer number of
> people have right-hemisphere language dominance and some people have
> no dominant hemisphere for language. The well known Wernicke's area
> is typically found in the left hemisphere planum temporale (secondary
> auditory cortex adjacent to heschl's gyrus).
>
> Language lateralization is strongly correlated with handedness. There
> are many studies of auditory attention in which the results of
> left-handed people do not match with right-handed people.
>
> There are ways to measure lateralization: my favorite is probably
> trans-cranial doppler ultrasound sonography. There is also the
> amobarbitol test which is used prior to brain surgery to avoid
> removing parts of the brain which are necessary for language.
>
> I had written a paper about this subject back in 2006 (my final paper
> in cognitive psychology). My hypothesis in the paper was that
> lateralization facilitates auditory attention. Lesser degrees of
> lateralization translate into less effective inhibition of
> task-unrelated stimuli, according to the Triesman attention model, and
> the corresponding ways in which auditory attention is allocated: by
> spatial location, by spectrum, by content, and by temporal
> characteristics.
>
> I'd be happy to provide anyone with the studies and papers I have read
> (or a copy of the paper I had written which includes the sources).
> Disclaimer: I am not a current expert in the field, only a student,
> and my knowledge may be a little dated.
P.S. There is also the matter of the auditory chiasm which provides
some sub-cortical processing in the auditory mid-brain. Information
from each ear is in fact transmitted to both hemispheres, but it is
unclear how much information is sent ipsi-laterally and
contra-laterally and whether some lateralized processing occurs before
the hemispheres receive the information. The main structures involved
in spatial localization are the olivary complex located in the pons
and the superior colliculus which analyzes differences in time of
arrival between the two ears.
The premise of the right-ear advantage for speech is that information
is strongly transmitted contra-laterally by the auditory mid-brain and
weakly ipsi-laterally.
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Received on Thu Aug 7 08:15:01 2014
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