[Smt-talk] Perfect pitch and aging.

[reinifrosch at bluewin.ch]

Dear colleagues,

In the paper "Dichotomy and perceptual distortions in absolute pitch ability", by E. Alexandra Athos et al., PNAS 104 (2007) 14795-14800, the authors have written: "[...] Indeed, we reason that an increase (not a decrease, as suggested by Vernon) in the elasticity [i.e., in the compliance] of the basilar membrane [BM] would be predicted to cause a displacement in the cochlear frequency map in the sharp direction. In this model, hair cells that formerly resonated for a given tone (e.g., E) and relayed that stimulus to the auditory cortex now respond at a lower frequency (e.g., D#). Because the hair cells that are triggered by this lower frequency remain hard-wired to relay a signal to a higher frequency recognition site in the auditory cortex, one perceives the tone at a higher frequency."

In other words: The BM stiffness is conjectured to decrease with age. I doubt, however, that the change of BM stiffness with age really explains the mentioned frequency-map shift. At frequencies above 1 kHz, the place of maximal excitation shifts apically by about 0.5 octave-distance (i.e., by about 2 mm) if the sound-pressure level is reduced from 100 dB to 30 dB. According, e.g., to Chapter 6 of the fifth edition of "An Introduction to the Psychology of Hearing" by B.C.J. Moore, the analysis of nerve-spike time intervals plays an important part in pitch perception.

Reinhart Frosch,
CH-5200 Brugg.
reinifrosch at bluewin.ch .


----Ursprüngliche Nachricht----
Von: bmarvin at esm.rochester.edu
Datum: 08.02.2012 21:24
An: "smt-talk at lists.societymusictheory.org"<smt-talk at lists.societymusictheory.org>
Betreff: [Smt-talk] Perfect pitch and aging

Dear all,

My understanding is that the creeping sharp of absolute pitch is, as Fred intuits below, a physical change in the ear with age (thus it has nothing to do with listening to early music, etc.).  I am not sure now where I learned this, but I was told that the basilar membrane (in the auditory system’s cochlea) stiffens with age.   In normal hearing the basilar membrane is activated tonotopically, with high frequencies activated at the base of the membrane and low frequencies at the apex; this leads to our perception of pitch.  Somehow the stiffening of the membrane must lead to different activations, here or further up the auditory system.  Does David, or anyone else, know whether this explanation has been studied?

Betsy Marvin
Eastman School of Music.
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